Next Article in Journal
Arsenic Occurrence and Cycling in the Aquatic Environment: A Comparison between Freshwater and Seawater
Previous Article in Journal
Assessment and Influencing Factors of Water Supply Capacity and Water Resource Utilization Efficiency in Southwest China
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Water
Volume 15
Issue 1
10.3390/w15010145
water-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
Correction published on 24 May 2023, see Water 2023, 15(11), 1988.
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Wastewater Management Using Coagulation and Surface Adsorption through Different Polyferrics in the Presence of TiO2-g-PMAA Particles

by
Heba Saed Kariem Alawamleh
1,
Seyedsahand Mousavi
2,
Danial Ashoori
3,
Hayder Mahmood Salman
4,
Sasan Zahmatkesh
5 and
Mika Sillanpää
6,7,*
1
Department of Basic Scientific Sciences, Al-Huson College, AL-Balqa Applied University, P.O. Box 50, Al-Huson 21510, Jordan
2
Department of Environmental Engineering, Faculty of Civil, Water & Environmental Engineering, Shahid Beheshti University, Tehran 1983969411, Iran
3
Department of Apply Chemistry, Faculty of Chemistry Science, Islamic Azad University Tehran-North Branch, Tehran 1983969411, Iran
4
Department of Computer Science, Al-Turath University College Al Mansour, Baghdad 10070, Iraq
5
Tecnologico de Monterrey, Escuela de Ingenieríay Ciencias, Puebla 72453, Mexico
6
Faculty of Science and Technology, School of Applied Physics, University Kebangsaan Malaysia, Bangi 43600, Malaysia
7
International Research Centre of Nanotechnology for Himalayan Sustainability (IRCNHS), Shoolini University, Solan 173212, India
*
Author to whom correspondence should be addressed.
Water 2023, 15(1), 145; https://doi.org/10.3390/w15010145
Submission received: 27 November 2022 / Revised: 20 December 2022 / Accepted: 23 December 2022 / Published: 30 December 2022 / Corrected: 24 May 2023
(This article belongs to the Section Wastewater Treatment and Reuse)
Browse Figures
Review Reports Versions Notes

Abstract

:
For the surface adsorption process, a wide range of studies have been carried out to describe the adsorption process. However, no extensive study has been carried out to investigate the pre-treatment method effect on the separation process. The purpose of the present study is to improve the performance of the membrane process in the treatment of oily wastewater. For this purpose, the effects of pre-treatment, membrane modification, and operational parameters were investigated on the microfiltration membrane system. Two methods of coagulation and surface adsorption were used as pre-treatment, and then a modified polysulfone (PSf) membrane containing TiO2 nanoparticles was applied in the microfiltration process. In order to reduce the membrane fouling and increase the permeate flux, the surface of the nanoparticle was modified. In order to check the performance of coagulation, pretreatments of polyferric sulfate (PFS) and polyferric chloride (PFC) were applied. The results showed that the Chemical Oxygen Demand (COD) reduction of 98% can be obtained using 1 g/L of PFS coagulant at pH = 6, while only 81% of COD was removed using 1 g/L PFC. It was also found that the best pH for the performance of this type of coagulant was measured as pH = 10 and the removal efficiency for 1 and 2 g/L of PFC coagulant was obtained as 96.1% and 91.7%, respectively. The results show that in the case of using a coagulant of less than 1 g/L, using PFS is more efficient than PFC; meanwhile, in more than 1 g/L of coagulant, this effect is reversed and the use of PFS will be less efficient than PFC. The performance of the PSf-TiO2 membrane fabricated by the Nonsolvent-induced phase separation (NIPS) method was investigated using modified nanoparticles with an initial size of 10 nm at different operating conditions. The results show that the permeate flux and the rejection can be increased to 563 L/h m2 and 99%, respectively, using the modified PSf membrane. The results of this paper showed that the performance of the adsorption process can be improved by using the coagulation process as a pre-treatment method.

1. Introduction

The impressive progress of various industries and the increase in the amount of produced wastewater, as well as the challenging issue of water scarcity, have made the wastewater treatment a vital and inevitable matter [1,2,3].
Oily wastewaters are considered as one of the most important sources of pollution, which are obtained from many industries such as oil [2] and gas, metalworking, as well as food industries [4]. So far, various methods have been studied and investigated in the field of oily wastewater treatment, such as flotation [5], separation based on gravity [6], surface adsorption, coagulation [7] and flocculation [8], and ozonation [9], etc. Nevertheless, most of these methods have not been satisfactorily applied in terms of efficiency in the treatment of oily emulsions with an oil particle size of less than 20 μm [10].
Recently, membranes were reported as an attractive method for oily wastewater treatment [9] due to their low cost and energy consumption [11,12]. However, these methods have disadvantages such as fouling and concentration polarization, which can reduce the life of the membrane [13]. Therefore, in order to increase the membrane efficiency, it is possible to act in two ways: (a) preventing the particles in the effluent from reaching the surface of the membrane and (b) surface washing of the membrane [14].
In order to reduce membrane fouling, many methods were previously investigated, among these methods [10], pre-treatment of the wastewater and modification of the hydrophilic property of the membrane are the most important methods, which leads to an increase in the number of pores on the surface and an increase in the flux [15]. Among the common methods used in pre-treatment, the combination of two physical and chemical methods, surface adsorption [11] and chemical coagulation, was given much attention due to its low cost and high performance [16].
In surface adsorption, common adsorbents such as activated carbon and zeolites have provided a strong attraction to a wide range of dissolved particles [15], including colloids, due to their specific surface area and high surface activity [17,18]. On the other hand, coagulants such as iron sulfate, iron chloride, aluminum sulfate, and Polyferric chloride (PFC) are widely used in pre-treatment by chemical coagulation methods due to their availability and low prices [19].
According to the previously reported studies, the type and amount of coagulant [15] and the properties of coagulated particles [7] such as their surface charge in the removal of organic particles in wastewater are one of the most important parameters affecting the process [20,21]. As a result, reducing the accumulation of solid particles dissolved or suspended on the surface of the membrane or modifying the formed coagulates, which leads to the reduction of the phenomenon of membrane fouling, are methods that can obviously affect the treatment process [19]. Another method that has had a significant effect in improving the membrane performance and reducing the membrane fouling is increasing the hydrophilic property of the membrane surface, which has received a lot of attention in recent years [22,23].
Theoretically, membranes can be produced from all of the polymers, but only a few polymers are practically used in membrane production [24], which depends on its physical and chemical properties. Polysulfone (PSf) is a thermoplastic polymer that is widely used in the manufacture of polymer membranes [12] due to its favorable characteristics such as good chemical and thermal stability, high mechanical strength, and high glass transition temperature [25].
In addition to the advantages mentioned for Polysulfone (PSf), it should be kept in mind that this material is hydrophobic enough [22], and as a result, the water permeability has not been satisfactory for practical applications. Recently, some researchers have presented various methods to modify the PSf membranes and improve their properties, for example, by combining hydrophilic and hydrophobic polymers, and grafting hydrophilic branches on the polymer [26].
In addition to combining organic polymers, substantial research has been carried out on the combination of organic and inorganic materials and using nanoparticles in polymer solutions, which leads to improving membrane performance and controlling its surface properties [27,28].
Various types of nanoparticles such as TiO2, Al2O3, ZrO2, SiO2, and Fe2O3 are used to modify the polymer membranes [29,30,31]. Among the mentioned nanoparticles, TiO2 is one of the most widely used because it has favorable chemical properties and suitable performance in the field of polymer membrane modification [32]. In order to reduce the clumping phenomenon of nanoparticles and increase the scattering properties, the surface of nanoparticles is modified by creating a hydrophilic polymer chain on the surface of the membrane [33]. In 2021, Tomczak and Gryta [34] investigated the microfiltration (MF) process of oily wastewaters using capillary polypropylene (PP) membranes. Furthermore, they studied the applicability of the ultrafiltration ceramic membrane for the separation of oily wastewaters generated during maritime transportation and found that the pre-filtration of oily wastewaters adversely affects the permeate flux [35].
It should be noted that the efficiency of a cross-flow membrane process depends on operational parameters such as cross-flow speed, operating pressure, temperature, membrane pore size, and the concentration of suspended particles in the feed [36].
For the surface adsorption process, a wide range of studies have been carried out to describe the adsorption process. However, no extensive study has been carried out to investigate the pre-treatment method effect on the surface adsorption process. Therefore, the coagulation and surface adsorption methods have not been fully understood. In this paper, in order to study the surface adsorption process, different pre-treatment methods have been performed for the removal of oily pollutants. In this regard, the obtained experimental data have been carefully discussed to suggest the optimum method. The aim of this paper is to use two coagulation and surface adsorption methods using polyferric chloride (PFC) and polyferric sulfate (PFS) coagulants and activated carbon adsorbent as pre-treatment methods. In this way, the modified TiO2-g-PMAA membrane was prepared and the membrane performance was investigated by changing the operational parameters. The performance of the membranes was studied based on the permeate flux measurement and the measurement of the oil content in the permeate.

2. Materials and Methods

Polysulfone (PSf) with a molecular weight of 68,000 gr/mol was purchased from BASF. Polyvinyl pyrrolidone (PVP) with a molecular weight of 30,000 gr/mol which is applied as an additive and 1-methyl-2-pyrrolidone (NMP) were obtained from Merck. Double distilled water was used as a non-solvent in the coagulation bath. The TiO2 nanoparticles with particle size of 10 nm have been used to improve membrane properties, and in addition, Tri AminoPropylTriMethoxySilane (APTMS) has been used to activate the nanoparticle surface and prepare it for polymerization. In order to prepare an emulsion with high stability in the feed, Tween 80 has been used as an emulsifier. In order to adjust the samples pH, sodium hydroxide, and 0.1 N hydrochloric acid were used. The polyferric chloride (PFC) powder and Polyferric sulfate (PFS) solution were used as coagulants. Activated carbon with the specifications mentioned in Table 1 was applied as an adsorbent.
In order to check the performance of coagulation and to determine the optimal conditions in the application of the coagulation method, the jar test (FP4, Velp scientifica, Usmate, Italy) is applied, which includes 4 stainless steel containers of 1 L and two types of PFC coagulants due to the scope of operation [37]. The jar test operating conditions in all experiments were kept constant according to the following procedure: 60 s of rapid mixing at 140 rpm, 20 min of slow mixing at 40 rpm, and one-hour of settling time.
In order to obtain the equilibrium time, the samples with a concentration of 3000 ppm were prepared. In each of the samples, a specific amount (4 g/L) of activated carbon granules was poured and placed on a shaker at a speed of 200 rpm. Then, 10 different samples were taken in 5 h in 30-min intervals. After the analysis, the contact time was obtained. It should be noted that in all stages the temperature is adjusted to the ambient temperature [38].
In order to investigate the effect of pH value on oil adsorption, samples were prepared from a solution with an initial concentration of 3000 ppm, and the pH of these samples was adjusted by adding a solution of 0.1 N hydrochloric acid and 0.1 N sodium hydroxide. It should be noted that the pH adjustment was carried out using a sample dropper and the pH of the solutions is controlled by a digital pH meter (Metrohm, model 750, Riverview, FL, USA). After pH adjustment, the samples were transferred into a shaker to reach the equilibrium. In order to achieve the optimal amount of adsorbent in oil removal, different amounts of adsorbent were used in water-oil emulsion samples with an initial concentration of 3000 ppm [39].
In this paper, to measure Chemical Oxygen Demand (COD), the open reflux method (5220A-D) was applied using a spectrophotometer (JASCO, model V-550, Japan), which has less error than the titration method. This analysis has been carried out using the common potassium-dichromate oxidation method and using the EPA 410.4 standard [40]. In this method, by using the adsorbance reading from the spectrophotometer for the samples made according to the standard, the COD value is extracted by the calibration chart and finally, the reduction rate is calculated from Equation (1), which, Cf and Cp are the feed and permeate concentration, respectively.
R ( % ) = c f − c p c f × 100
In order to modify the TiO2 nanoparticles, 2.5 g of completely dried nanoparticles were firstly poured into 100 mL of toluene and ultrasonication was applied for 45 min to disperse the nanoparticles in the solvent. Then, 13 mL of APTMS as an activating agent is added to the solution. The reaction is carried out for 24 h at 97 °C. Finally, the solution is centrifuged, and the obtained product is washed three times with deionized water. The obtained activated TiO2 nanoparticles are completely dried in an oven at 95 °C for 24 h [41].
In order to fabricate the membranes, first of all, the Polysulfone (PSf) is placed under vacuum in the oven for 12 h at 110 °C to completely dry. The process of preparing the solution is that first nanoparticles are added to the solvent and an ultrasonic device is used (for 45 min) to distribute nanoparticles uniformly. In this way, to prevent evaporation of the solvent, the solution container is placed in an ice bath and then sonication is performed. Finally, the PSf polymer and polyvinylpyrrolidone are added to the uniform solution in the desired amount [42].
In order to prevent the polymer from clumping, this substance is added to the solution over a long period of time, about an hour. Then the solution is stirred for 24 h at 1000 rpm using a stirrer. After complete dissolution, the solution is kept still for 12 h to remove the bubbles that were created during stirring as the presence of bubbles in the solution causes problems in the process of membrane fabrication.
To examine the structure and observe the surface and cross-sectional surface of the membrane, a Scanning Electron Microscope (SEM) was used with an accuracy of 5 nm and a magnification of up to 30,000. In this way, the prepared samples are, first broken in liquid nitrogen, because otherwise, breaking the samples will change the structure due to the applied force.

3. Results and Discussion

The average oil particle size in the synthetic wastewater is reported as 105.6 nm as seen in Figure 1.
As mentioned, the pH value is an effective factor not only on the surface charge of coagulants, but also on emulsion stability, and it is the most important parameter affecting the coagulation process. In this way, a suitable pH value, in addition to neutralizing the colloidal particles with a negative charge and connecting these particles together, also helps in the formation of coagulates and their settling process [43].
For this purpose, the effect of pH value was investigated in fixed amounts of coagulant (1 and 2 g/L) and the results are given in Table 2. It should be noted that the initial COD of synthetic effluent was measured as 7500 ppm. Moreover, the pH value range was selected based on optimum performance of previous studies. For a better comparison, the rejection values in different PFS concentrations are shown in Figure 2.
As can be seen in Table 2, the pH value is an effective parameter that can change the performance of polyferric sulfate coagulant. The highest removal efficiency in both cases (1 and 2 g/L of PFS), is evaluated at pH = 6. The results show that upper pH values decrease the efficiency, that can be caused by the formation of negatively charged ions such as Fe(OH)4− which leads to the creation of electrostatic repulsion between ions and organic particles with a negative charge in the wastewater and prevents the formation of larger coagulates [44].
Therefore, in order to maintain the coagulation function in the alkaline pH range, it is necessary to consume more polyferric sulfate coagulant. It should be noted that the removal rate at optimal pH 6 for 1 and 2 g/L of PFS is 98.3% and 96.5%, respectively.
Table 3 shows the pH effect on COD removal and the rejection using different amounts of PFC as a coagulant. The results show that the highest removal efficiency in both cases (1 and 2 g/L of PFS) can be obtained at pH = 10. In order to have a better comparison, the rejection values in different PFS concentrations are shown in Figure 3.
Regarding Table 3, it can be concluded that the best pH for the performance of this type of coagulant is pH = 10 which the removal efficiency for 1 and 2 g/L of PFC coagulant is 96.1% and 91.7%, respectively.
Based on Figure 3, a decrease in the removal efficiency can be seen, which can be referred to as the nature of PFC in water. As can be found, determining the optimal amount of coagulant is the next important parameter in creating suitable operating conditions in the coagulation process. This is because insufficient or excessive amounts of coagulants lead to poor coagulation performance. Therefore, determining the optimal amount of coagulant in order to reduce the cost and increase the coagulation efficiency is inevitable [45].
As can be seen in Table 4, increasing the coagulant amount to a concentration of 1 g/L increases the percentage of removal, which is 98.3% for PFS coagulant and 81.3% for PFC coagulant. Nevertheless, increasing the amount of coagulant higher than 1 g/L, not only has a non-favorable effect on improving the coagulation performance and efficiency, but also led to an increase in the process price, which can be caused by the reversal of the particle charge and the re-stability of colloids and the prevention of clot formation.
Another interesting result that can be seen in Figure 4 is that using coagulant at less than 1 g/L, using PFS is more efficient than PFC; meanwhile, in more than 1 g/L of coagulant, this effect is reversed and the use of PFS will be less efficient than PFC.
The obtained results from the previous sections can be used to check the performance of coagulants, and it can be concluded that PFS has a better performance than PFC coagulant with a small difference in pH and the appropriate amount obtained for both coagulants [46].
By performing adsorption tests in different contact times up to 300 min and a time interval of 30 min, at a constant temperature of 25 °C, the COD reduction rate of the water-oil emulsion was investigated. The results are shown in Figure 5.
As can be seen from Figure 5, in the constant operating conditions, the time required to reach the equilibrium in the surface adsorption process is about 60 min, and this is affected by the high concentration of oil present in the sample to be removed. Therefore, the activated carbon granule adsorbent is saturated in a short time, and it is not possible to achieve a high removal efficiency with this amount of adsorbent. The adsorption capacity is calculated as Equation (2); where V is the volume of the solution and m is the adsorbent mass; and C0 and Ce are the initial and the final concentrations, respectively.
q = C 0 − C e × V m
Figure 6 shows the effect of adsorbent concentration on the percentage of removal efficiency in surface adsorption at pH = 6 and T = 25 °C. As can be seen in Figure 6, with the increase in the amount of adsorbent, the removal efficiency and reduction of COD increased, but the desired removal rate was achieved in high amounts of activated carbon granules. For example, at a concentration of 20 g/L of the adsorbent, only 48% removal can be achieved, which may not be economical to use this amount of adsorbent due to the problem of its recovery.
According to the results, it can be concluded that, to remove the oil particles in the oil-water emulsion and reduce the COD value, a small amount of coagulant can be used. In other words, it was observed that by using a small amount of coagulant the removal efficiency of more than 90% can be achieved. This observation was made in spite the fact that only 48% of COD could be treated using the activated carbon granules as an adsorbent, which indicates the weaker performance of this method as a pre-treatment in removing the high concentration of pollutant.
As it was stated previously, the polymer grafting method has been used on the surface of nanoparticles in order to reduce their accumulation. In the first step, by adding APTMS, which acts as an activator, amine functional groups (NH2) are formed on the surface of the nanoparticle (TiO2-APTMS). In the continuation of the reaction between TiO2-APTMS particles and ammonium persulfate, a free radical compound is formed, and as a result, methacrylic acid polymer begins to form on the surface of TiO2-APTMS particles. Finally, after polymerization, TiO2-g-PMAA particles are obtained. To check the structure of nanoparticles, the Fourier-transform infrared spectroscopy (FTIR) test was applied to ensure that the reactions are carried out completely. This analysis shows well the groups created on the nanoparticle surface. Figure 7 shows the results of FTIR test for pure TiO2 nanoparticles and TiO2-g-PMAA. As it is obvious according to Figure 7, in the spectrum related to TiO2 nanoparticles and before surface modification, a strong adsorption peak in the range of 2989 cm−1 is observed, which is related to hydroxyl groups. In fact, the strong adsorption observed in this range indicates the presence of countless Si-O-H groups on the surface of nanoparticles.
In the spectrum related to TiO2-g-PMAA, the stretching vibrations of the carbonyl group in COOH appeared in the range of 1170 cm−1. On the other hand, the adsorption observed at 2672 cm−1 indicates the hydrogen bond in the COOH group. In addition, the adsorption in the range of 1206 cm−1 is related to the bending vibrations of the hydroxyl group in COOH. These changes in the adsorption spectrum indicate the grafting of the polymer to the nanoparticle surface and the formation of TiO2-g-PMAA particles.
Figure 8 shows the effect of nanoparticle modification on the surface structure of membranes. As can be seen, the addition of nanoparticles to the PSf membrane in the polymer solution has increased the surface pores and their more regular distribution. On the other hand, by adding modified nanoparticles to the membrane structure, due to the greater compatibility that occurs in the polymer solution, more regular and better surface cavities are formed, and as a result, a membrane with more hydrophilicity and more favorable properties to has been achieved [47].
Figure 9 shows the SEM images of the cross-section of PSf, PSf/TiO2 (1%wt), PSf/TiO2-g-PMAA (1%wt), and PSf/TiO2-g-PMAA (2%wt) membranes. As can be seen, the amount of porosity in the membrane increases with the addition of nanoparticles. All membranes show an asymmetric structure including a dense upper layer and a porous finger-like sub-layer. Since the pure PSf membranes have less surface porosity, they limit the penetration of larger amounts of water to the sub-layer and as a result, large porous structures are formed in the sub-layer. Nevertheless, with the addition of nanoparticles in PSf/TiO2 and PSf/TiO2-g-PMAA membranes, finger-like pores are found, which is caused by more surface porosity and more penetration of water into the substrates.
It should be noted that in the pre-treatment section, PFC coagulant with different concentrations is used, which leads to the reduction of COD of the feed. According to the pilot tests which are carried out by changing the operating parameters, the flux diagram is obtained and compared in Figure 10. As can be seen, initially, the permeate flux decreases with a relatively large slope, and then this flux drop gradually decreases. Then, after about 40 min, it reaches a constant value and becomes stable. The reason for this decrease in flux is the accumulation and settling of oil particles on the surface of the membrane [48]. Furthermore, due to changes in applied pressure and the ability to change the shape of oil droplets, there is a possibility of oil droplets penetrating into the membrane pores, which can also lead to a decrease in flux.
As can be seen from Figure 10, increasing the amount of pollutant reduces the amount of permeate flux, and also the slope of flux reduction is much higher at the beginning of the experiment. Furthermore, the results show that increasing the pressure can increase the amount of permeate flux. Therefore, decreasing the inlet pressure and increasing the amount of pollutant have a negative effect on the process. Pressure, as a driving force in the microfiltration process, is one of the most influential operating parameters that can have an undeniable role on the performance of the process due to the process mechanism in this separation operation.
Figure 11 shows the effect of operating pressure on the permeate flux of water-oil emulsion. As seen in Figure 11, with the increase in pressure, the permeate flux has increased up to 50%. In other words, the increase in driving force overcomes the existing resistances and creates a significant increase in the flux. These observations show that generally higher pressures lead to higher fluxes, and due to the increase in applied pressure, issues such as the compression of the cake on the membrane surface, which causes a decrease in the flux at high pressures, have not occurred significantly.
Based on the pressure effects on the flux at a constant flow rate and feed concentration, it can be concluded that the effect of the cake layer accumulation on the membrane surface is only in the steeper slope of the flux decrease at the pressure of 2 bar compared to 1 bar. It also can be understood that by increasing the driving force, the emulsion particles were pushed towards the membrane with more force, and this caused an increase in the membrane fouling but, as can be seen, the increase in the driving force ultimately led to an increase in the flux [49].
It should be noted that above a pressure of 3 bar, increasing the pressure did not have a significant effect on increasing the flux, and the changes in the flux reached a constant level, which was also affected by the entry of oil particles into the membrane pores and the increase in the membrane fouling rate. According to economic issues and reduction of operating costs, applying less pressure to achieve the same flux can be important. Figure 12 shows the effect of increasing pressure on the permeate flux at constant feed concentration and flow rate.
Figure 13 shows the effect of flow rate on the flux of water-oil emulsion at constant pressure and feed concentration. As can be seen from Figure 13, with the increase in flow rate, the permeate flux has increased up to 100%. In other words, the increase in flow rate overcomes the existing resistances and creates a significant increase in the flux. These observations show that generally, higher flow rate led to higher fluxes, and due to the increase in applied pressure, issues such as the compression of the cake on the membrane surface, which causes a decrease in the flux at higher flow rates, have not occurred significantly. It also can be understood that by increasing the driving force, the emulsion particles were pushed towards the membrane with more rates of the feed flow, and this caused an increase in the membrane fouling, but as can be seen, the more increase in the driving force ultimately led to an increase in the flux [50].
As can be seen in Figure 13, the highest amount of permeate flux was obtained at a flow rate of 5 L/min and a pressure of 3 bar. On the other hand, at a constant pressure of 1 bar, the increase in flow rate increased the flow rate by 67%, and at a pressure of 2 bar, by 61% [51,52].
As it can be seen in Figure 14, with an increase in COD concentration of the feed or the oil concentration in the feed emulsion, the flux decreases, which can be referred to the concentration polarization [53,54].
Based on the results, the effect of operational conditions on the oil rejection, the increase in flow rate has led to a decrease in the amount of repulsion, which can be concluded that the increase in flow rate is due to concentration polarization and the creation of a cake layer on the surface. The effect of operating pressure on the oil rejection results indicates that the effect of increasing the pressure of 2 bar on reducing the oil rejection by approximately 2%. However, this amount of reduction in the quality permeate flow is negligible compared to the amount of 98% removal achieved by the membrane at this amount of pressure and flow rate. Furthermore, the effect of increasing the feed concentration on membrane performance shows the improvement of the oil rejection by up to 5%, which can be caused by the effect of increasing the oil concentration on the surface of the membrane and creating a dense, thick layer, which resists against the permeate of oily particles through the membrane [55,56].
Table 5 shows the performance of pure and modified PSf membranes at optimal and constant pressures in the treatment of primary and pre-treated feed. As can be seen in Table 5, it can be stated that the modification of the membrane has greatly contributed to the increase of the permeate flux. Moreover, the pre-treatment process has led to an increase in the permeate flux in all cases [57,58,59,60].

4. Conclusions

To describe the adsorption process, a variety of studies have been carried out. However, no extensive study has been carried out to investigate the effect of the pre-treatment method on oily wastewater. The purpose of this work was to improve the performance of the membrane process in the treatment of oily wastewater using coagulation and surface adsorption as pre-treatment. In this way, the membrane modification and the operational parameters have been investigated on the microfiltration membrane system. To investigate the coagulation process, two types of coagulants, polyferric sulfate (PFS) and polyferric chloride (PFC), were used in different amounts at different pH values. It was found that upon using coagulant of less than 1 g/L, the in the case of using PFS is more efficient than PFC; meanwhile, in more than 1 g/L of coagulant, this effect is reversed and the use of PFS will be less efficient than PFC. The adsorption studies show that with the increase in the amount of adsorbent, the removal efficiency and reduction of COD increased, but the desired removal rate was achieved in high amounts of activated carbon granules. For example, at a concentration of 20 g/L of the adsorbent, only 48% removal can be achieved, which may not be economical to use this amount of adsorbent due to the problem of its recovery. It was found that the PFS coagulant has shown a better performance as a pre-treatment method than PFC coagulant and activated carbon adsorbent.
It was also explained that due to the high hydrophilicity of the PSf membranes, it is necessary to modify the polymer using TiO2 nanoparticles. For this purpose, the radical polymerization method was used to graft polymethacrylic acid to the surface of the nanoparticle and modify its surface. Finally, the membranes were fabricated using NIPS method to treatment of oily wastewater. The effect of operating conditions on membrane performance was also investigated. The change of operating conditions during the microfiltration process shows the positive effect of increasing the pressure and flow rate up to 3 bar and 5 L/min on the flux passing through the modified membrane and pre-treated effluent compared to the untreated primary effluent. However, this increase in pressure and flow rate does not have a favorable effect on oil rejection. In addition, by comparing the performance of the pure PSf membrane and the modified one by TiO2 nanoparticles, it can be concluded that this also affects the performance of the membrane and the permeate flux. The optimized membrane was applied in the purification of synthetic samples using different feed concentration. In order to increase the efficiency of oil removal, it is suggested to use ion exchange resins or modified activated carbon as a pre-treatment method of high-concentration oil in water emulsion.
This work was the first step in the pre-treatment effect on the adsorption process, which can lead to optimization of the adsorption process. It is suggested that in the future, with the development of more effective coagulants, the simultaneous processes to be performed and the possibility of oily wastewater treatment using the adsorption process to be investigated.

Author Contributions

For Conceptualization, H.S.K.A. and S.M.; methodology, H.S.K.A. and S.M.; software, D.A. and S.Z.; validation, H.S.K.A. and S.Z.; investigation, H.S.K.A.; resources, S.M.; data curation, H.S.K.A.; writing—original draft preparation, S.Z. and M.S.; supervision, validation, and writing—review and editing, D.A. and H.M.S.; project administration, D.A. and H.M.S.; funding acquisition, H.S.K.A. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Ram, S.A.; Irfan, Z.B. Application of System Thinking Causal Loop Modelling in Understanding Water Crisis in India: A Case for Sustainable Integrated Water Resources Management across Sectors. HydroResearch 2021, 4, 1–10. [Google Scholar] [CrossRef]
  2. Liu, W.; Zheng, J.; Ou, X.; Liu, X.; Song, Y.; Tian, C.; Rong, W.; Shi, Z.; Dang, Z.; Lin, Z. Effective Extraction of Cr (VI) from Hazardous Gypsum Sludge via Controlling the Phase Transformation and Chromium Species. Environ. Sci. Technol. 2018, 52, 13336–13342. [Google Scholar] [CrossRef] [PubMed]
  3. Xu, D.; Li, J.; Liu, J.; Qu, X.; Ma, H. Advances in Continuous Flow Aerobic Granular Sludge: A Review. Process Saf. Environ. Prot. 2022, 163, 27–35. [Google Scholar] [CrossRef]
  4. Li, T.; Su, T.; Wang, J.; Zhu, S.; Zhang, Y.; Geng, Z.; Wang, X.; Gao, Y. Simultaneous Removal of Sulfate and Nitrate from Real High-Salt Flue Gas Wastewater Concentrate via a Waste Heat Crystallization Route. J. Clean. Prod. 2022, 382, 135262. [Google Scholar] [CrossRef]
  5. Shen, W.; Mukherjee, D.; Koirala, N.; Hu, G.; Lee, K.; Zhao, M.; Li, J. Microbubble and Nanobubble-Based Gas Flotation for Oily Wastewater Treatment: A Review. Environ. Rev. 2022, 30, 359–379. [Google Scholar] [CrossRef]
  6. Yin, X.; He, Y.; Li, H.; Ma, X.; Zhou, L.; He, T.; Li, S. One-Step in-Situ Fabrication of Carbon Nanotube/Stainless Steel Mesh Membrane with Excellent Anti-Fouling Properties for Effective Gravity-Driven Filtration of Oil-in-Water Emulsions. J. Colloid Interface Sci. 2021, 592, 87–94. [Google Scholar] [CrossRef]
  7. Liu, J.; Qu, X.; Zhang, C.; Dong, W.; Fu, C.; Wang, J.; Zhang, Q. High-Yield Aqueous Synthesis of Partial-Oxidized Black Phosphorus as Layered Nanodot Photocatalysts for Efficient Visible-Light Driven Degradation of Emerging Organic Contaminants. J. Clean. Prod. 2022, 377, 134228. [Google Scholar] [CrossRef]
  8. Zhao, C.; Zhou, J.; Yan, Y.; Yang, L.; Xing, G.; Li, H.; Wu, P.; Wang, M.; Zheng, H. Application of Coagulation/Flocculation in Oily Wastewater Treatment: A Review. Sci. Total Environ. 2021, 765, 142795. [Google Scholar] [CrossRef]
  9. Khalifa, O.; Banat, F.; Srinivasakannan, C.; AlMarzooqi, F.; Hasan, S.W. Ozonation-Assisted Electro-Membrane Hybrid Reactor for Oily Wastewater Treatment: A Methodological Approach and Synergy Effects. J. Clean. Prod. 2021, 289, 125764. [Google Scholar] [CrossRef]
  10. Hamta, A.; Ashtiani, F.Z.; Karimi, M.; Sadeghi, Y.; MoayedFard, S.; Ghorabi, S. Copolymer Membrane Fabrication for Highly Efficient Oil-in-Water Emulsion Separation. Chem. Eng. Technol. 2021, 44, 1321–1326. [Google Scholar] [CrossRef]
  11. Tomczak, W.; Gryta, M. The Impact of Operational Parameters on Polypropylene Membrane Performance during the Separation of Oily Saline Wastewaters by the Membrane Distillation Process. Membranes 2022, 12, 351. [Google Scholar] [CrossRef] [PubMed]
  12. Al-Anzi, B.S.; Siang, O.C. Recent Developments of Carbon Based Nanomaterials and Membranes for Oily Wastewater Treatment. RSC Adv. 2017, 7, 20981–20994. [Google Scholar] [CrossRef]
  13. Ikhsan, S.N.W.; Yusof, N.; Aziz, F.; Ismail, A.F.; Jaafar, J.; Salleh, W.N.W.; Misdan, N. Superwetting Materials for Hydrophilic-Oleophobic Membrane in Oily Wastewater Treatment. J. Environ. Manag. 2021, 290, 112565. [Google Scholar] [CrossRef] [PubMed]
  14. Zhang, W.; Hao, T. Insights into the Role of Concentration Polarization on the Membrane Fouling and Cleaning during the Aerobic Granular Sludge Filtration Process. Sci. Total Environ. 2022, 813, 151871. [Google Scholar] [CrossRef]
  15. Tomczak, W.; Gryta, M. Membrane Distillation of Saline Water Contaminated with Oil and Surfactants. Membranes 2021, 11, 988. [Google Scholar] [CrossRef] [PubMed]
  16. Song, W.; Li, N.; Ding, S.; Wang, X.; Li, H.; Zhang, Y.; Feng, X.; Lu, J.; Ding, J. Nanofiltration Desalination of Reverse Osmosis Concentrate Pretreated by Advanced Oxidation with Ultrafiltration: Response Surface Optimization and Exploration of Membrane Fouling. J. Environ. Chem. Eng. 2021, 9, 106340. [Google Scholar] [CrossRef]
  17. Hamta, A.; Ashtiani, F.Z.; Karimi, M.; Moayedfard, S. Asymmetric Block Copolymer Membrane Fabrication Mechanism through Self-Assembly and Non-Solvent Induced Phase Separation (SNIPS) Process. Sci. Rep. 2022, 12, 771. [Google Scholar] [CrossRef] [PubMed]
  18. Wang, N.; Zhao, R.; Zhang, L.; Guan, X. Molecular Insights into the Adsorption of Chloride Ions in Calcium Silicate Hydrate Gels: The Synergistic Effect of Calcium to Silicon Ratio and Sulfate Ion. Microporous Mesoporous Mater. 2022, 345, 112248. [Google Scholar] [CrossRef]
  19. Wei, Y.; Ding, A.; Chen, Y. Removal of Refractory Dyes by a Novel Chlorine-Free Coagulant of Polyferric-Silicate-Acetate (PFSA): Characterization and Performance Evaluation. J. Environ. Chem. Eng. 2022, 10, 108524. [Google Scholar] [CrossRef]
  20. Hamta, A.; Mohammadi, A.; Dehghani, M.R.; Feyzi, F. Liquid–Liquid Equilibrium and Thermodynamic Modeling of Aqueous Two-Phase System Containing Polypropylene Glycol and NaClO4 at T =(288.15 and 298.15) K. J. Solut. Chem. 2018, 47, 1–25. [Google Scholar] [CrossRef]
  21. Ge, D.; Yuan, H.; Xiao, J.; Zhu, N. Insight into the Enhanced Sludge Dewaterability by Tannic Acid Conditioning and PH Regulation. Sci. Total Environ. 2019, 679, 298–306. [Google Scholar] [CrossRef] [PubMed]
  22. Huang, Z.; Yang, G.; Zhang, J.; Gray, S.; Xie, Z. Dual-Layer Membranes with a Thin Film Hydrophilic MOF/PVA Nanocomposite for Enhanced Antiwetting Property in Membrane Distillation. Desalination 2021, 518, 115268. [Google Scholar] [CrossRef]
  23. Hu, Z.; Shi, T.; Cen, M.; Wang, J.; Zhao, X.; Zeng, C.; Zhou, Y.; Fan, Y.; Liu, Y.; Zhao, Z. Research Progress on Lunar and Martian Concrete. Constr. Build. Mater. 2022, 343, 128117. [Google Scholar] [CrossRef]
  24. Hamta, A.; Dehghani, M.R. Application of Polyethylene Glycol Based Aqueous Two-Phase Systems for Extraction of Heavy Metals. J. Mol. Liq. 2017, 231, 20–24. [Google Scholar] [CrossRef]
  25. Hamta, A.; Dehghani, M.R.; Gholami, M. Novel Experimental Data on Aqueous Two–Phase System Containing PEG–6000 and Na2CO3 at T =(293.15, 303.15 and 313.15) K. J. Mol. Liq. 2017, 241, 144–149. [Google Scholar] [CrossRef]
  26. Mamah, S.C.; Goh, P.S.; Ismail, A.F.; Suzaimi, N.D.; Yogarathinam, L.T.; Raji, Y.O.; El-badawy, T.H. Recent Development in Modification of Polysulfone Membrane for Water Treatment Application. J. Water Process Eng. 2021, 40, 101835. [Google Scholar] [CrossRef]
  27. Xiao, Y.; Xu, S.; Li, Z.; An, X.; Zhou, L.; Zhang, Y.; Shiang, F.Q. Progress of Applied Research on TiO2 Photocatalysis-Membrane Separation Coupling Technology in Water and Wastewater Treatments. Chin. Sci. Bull. 2010, 55, 1345–1353. [Google Scholar] [CrossRef]
  28. Moghadassi, A.R.; Rajabi, Z.; Hosseini, S.M.; Mohammadi, M. Preparation and Characterization of (PVC-Blend-SBR) Mixed Matrix Gas Separation Membrane Filled with Zeolite. Arab. J. Sci. Eng. 2014, 39, 605–614. [Google Scholar] [CrossRef]
  29. Hamta, A.; Zokaee Ashtiani, F.; Karimi, M.; Safikhani, A. Manipulating of Polyacrylonitrile Membrane Porosity via SiO2 and TiO2 Nanoparticles: Thermodynamic and Experimental Point of View. Polym. Adv. Technol. 2020, 32, 872–885. [Google Scholar] [CrossRef]
  30. Itzhak, T.; Segev-Mark, N.; Simon, A.; Abetz, V.; Ramon, G.Z.; Segal-Peretz, T. Atomic Layer Deposition for Gradient Surface Modification and Controlled Hydrophilization of Ultrafiltration Polymer Membranes. ACS Appl. Mater. Interfaces 2021, 13, 15591–15600. [Google Scholar] [CrossRef]
  31. Ohno, S.; Nakata, I.; Nagumo, R.; Akamatsu, K.; Wang, X.; Nakao, S. Development of Low-Fouling PVDF Membranes Blended with Poly (2-Methoxyethyl Acrylate) via NIPS Process. Sep. Purif. Technol. 2021, 276, 119331. [Google Scholar] [CrossRef]
  32. Dong, P.; Zhang, Y.; Zhu, S.; Nie, Z.; Ma, H.; Liu, Q.; Li, J. First-Principles Study on the Adsorption Characteristics of Corrosive Species on Passive Film TiO2 in a NaCl Solution Containing H2S and CO2. Metals 2022, 12, 1160. [Google Scholar] [CrossRef]
  33. Kusworo, T.D.; Susanto, H.; Aryanti, N.; Rokhati, N.; Widiasa, I.N.; Al-Aziz, H.; Utomo, D.P.; Masithoh, D.; Kumoro, A.C. Preparation and Characterization of Photocatalytic PSf-TiO2/GO Nanohybrid Membrane for the Degradation of Organic Contaminants in Natural Rubber Wastewater. J. Environ. Chem. Eng. 2021, 9, 105066. [Google Scholar] [CrossRef]
  34. Tomczak, W.; Gryta, M. Application of Capillary Polypropylene Membranes for Microfiltration of Oily Wastewaters: Experiments and Modeling. Fibers 2021, 9, 35. [Google Scholar] [CrossRef]
  35. Tomczak, W.; Gryta, M. Application of Ultrafiltration Ceramic Membrane for Separation of Oily Wastewater Generated by Maritime Transportation. Sep. Purif. Technol. 2021, 261, 118259. [Google Scholar] [CrossRef]
  36. Uri-Carreño, N.; Nielsen, P.H.; Gernaey, K.V.; Flores-Alsina, X. Long-Term Operation Assessment of a Full-Scale Membrane-Aerated Biofilm Reactor under Nordic Conditions. Sci. Total Environ. 2021, 779, 146366. [Google Scholar] [CrossRef]
  37. Hussein, T.K.; Jasim, N.A. A Comparison Study between Chemical Coagulation and Electro-Coagulation Processes for the Treatment of Wastewater Containing Reactive Blue Dye. Mater. Today Proc. 2021, 42, 1946–1950. [Google Scholar] [CrossRef]
  38. Inam, M.A.; Khan, R.; Inam, M.W.; Yeom, I.T. Kinetic and Isothermal Sorption of Antimony Oxyanions onto Iron Hydroxide during Water Treatment by Coagulation Process. J. Water Process Eng. 2021, 41, 102050. [Google Scholar] [CrossRef]
  39. Lee, H.W.; Lu, Y.; Zhang, Y.; Fu, C.; Huang, D. Physicochemical and Functional Properties of Red Lentil Protein Isolates from Three Origins at Different PH. Food Chem. 2021, 358, 129749. [Google Scholar] [CrossRef]
  40. Rohyami, Y.; Aprianto, T. Validation Method on Determination of Chemical Oxygen Demand Using Indirect UV-Vis Spectrometry. In Proceedings of the Advanced Materials Research; Trans Tech Publications Ltd.: Bäch, Switzerland, 2021; Volume 1162, pp. 101–108. [Google Scholar]
  41. González-Calderón, J.A.; Peña-Juárez, M.; Zarraga, R.; Contreras-López, D.; Vallejo-Montesinos, J. The Role of Alkoxysilanes Functional Groups for Surface Modification of TiO2 Nanoparticles on Non-Isothermal Crystallization of Isotactic Polypropylene Composites. Rev. Mex. Ing. Quim. 2021, 20, 435–452. [Google Scholar] [CrossRef]
  42. Wang, W.; Shi, Y.P.; Zhang, P.; Zhang, Z.C.; Xu, X. Fabrication of an Antifouling GO-TiO2/PES Ultrafiltration Membrane. J. Appl. Polym. Sci. 2021, 138, 51165. [Google Scholar] [CrossRef]
  43. Shu, Z.; Lü, Y.; Huang, J.; Zhang, W. Treatment of Compost Leachate by the Combination of Coagulation and Membrane Process. Chin. J. Chem. Eng. 2016, 24, 1369–1374. [Google Scholar] [CrossRef]
  44. Chakrabarty, B.; Ghoshal, A.K.; Purkait, M.K. Cross-Flow Ultrafiltration of Stable Oil-in-Water Emulsion Using Polysulfone Membranes. Chem. Eng. J. 2010, 165, 447–456. [Google Scholar] [CrossRef]
  45. Yao, C.W.; Burford, R.P.; Fane, A.G.; Fell, C.J.D. Effect of Coagulation Conditions on Structure and Properties of Membranes from Aliphatic Polyamides. J. Memb. Sci. 1988, 38, 113–125. [Google Scholar] [CrossRef]
  46. Zhao, Y.; Geng, J.; Wang, X.; Gu, X.; Gao, S. Tetracycline Adsorption on Kaolinite: PH, Metal Cations and Humic Acid Effects. Ecotoxicology 2011, 20, 1141–1147. [Google Scholar] [CrossRef] [PubMed]
  47. Bassyouni, M.; Abdel-Aziz, M.H.; Zoromba, M.S.; Abdel-Hamid, S.M.S.; Drioli, E. A Review of Polymeric Nanocomposite Membranes for Water Purification. J. Ind. Eng. Chem. 2019, 73, 19–46. [Google Scholar] [CrossRef]
  48. Mohammadi, T.; Kazemimoghadam, M.; Saadabadi, M. Modeling of Membrane Fouling and Flux Decline in Reverse Osmosis during Separation of Oil in Water Emulsions. Desalination 2003, 157, 369–375. [Google Scholar] [CrossRef]
  49. Ezzati, A.; Gorouhi, E.; Mohammadi, T. Separation of Water in Oil Emulsions Using Microfiltration. Desalination 2005, 185, 371–382. [Google Scholar] [CrossRef]
  50. Mohammadi, T.; Kohpeyma, A.; Sadrzadeh, M. Mathematical Modeling of Flux Decline in Ultrafiltration. Desalination 2005, 184, 367–375. [Google Scholar] [CrossRef]
  51. Jiang, H.; Zahmatkesh, S.; Yang, J.; Wang, H.; Wang, C. Ultrasound-enhanced catalytic degradation of simulated dye wastewater using waste printed circuit boards: Catalytic performance and artificial neuron network-based simulation. Environ. Monit. Assess. 2023, 195, 1–12. [Google Scholar] [CrossRef]
  52. Sonawane, C.; Alrubaie, A.; Panchal, H.; Chamkha, A.; Jaber, M.; Oza, A.; Zahmatkesh, S.; Burduhos-Nergis, D.; Burduhos-Nergis, D.P. Investigation on the Impact of Different Absorber Materials in Solar Still Using CFD Simulation—Economic and Environmental Analysis. Water 2022, 14, 3031. [Google Scholar] [CrossRef]
  53. Sundaramurthy, S.; Bala, S.; Sharma, A.; Verma, J.; Zahmatkesh, S.; Arisutha, S.; Verma, S.; Sillanpaa, M.; Ravichandran, N.; Panneerselvam, B. Performance Evaluation of Environmentally Sustainable Precast Cement Concrete Paver Blocks Using Fly Ash and Polypropylene Fibre. Sustainability 2022, 14, 15699. [Google Scholar] [CrossRef]
  54. Surani, K.; Patel, S.; Alrubaie, A.; Oza, A.; Panchal, H.; Kumar, S.; Zahmatkesh, S. Performance comparison of powder mixed EDM and traditional EDM on TZM-molybdenum super alloy using response surface methodology. Int. J. Interact. Des. Manuf. 2022, 1–12. [Google Scholar] [CrossRef]
  55. Zahmatkesh, S.; Amiri, M.; Zaferani, S.; Emami, M.; Hajiaghaei-Keshteli, M.; Albaqami, M.; Tighezza, A.; Shafahi, M.; Han, N. Machine learning modeling of polycarbonate ultrafiltration membranes at different temperatures, Al2O3 nanoparticle volumes, and water ratios. Chemosphere 2022, 313, 137424. [Google Scholar] [CrossRef] [PubMed]
  56. Zahmatkesh, S.; Hajiaghaei-Keshteli, M.; Bokhari, A.; Sundaramurthy, S.; Panneerselvam, B.; Rezakhani, Y. Wastewater treatment with nanomaterials for the future: A state-of-the-art review. Environ. Res. 2022, 216, 114652. [Google Scholar] [CrossRef] [PubMed]
  57. Zahmatkesh, S.; Klemeš, J.; Bokhari, A.; Wang, C.; Sillanpaa, M.; Amesho, K.; Vithanage, M. Various advanced wastewater treatment methods to remove microplastics and prevent transmission of SARS-CoV-2 to airborne microplastics. Int. J. Environ. Sci. Technol. 2022, 1–18. [Google Scholar] [CrossRef]
  58. Zahmatkesh, S.; Ni, B.-J.; Klemeš, J.; Bokhari, A.; Hajiaghaei-Keshteli, M. Carbon quantum dots-Ag nanoparticle membrane for preventing emerging contaminants in oil produced water. J. Water Process Eng. 2022, 50, 103309. [Google Scholar] [CrossRef]
  59. Zahmatkesh, S.; Rezakhani, Y.; Arabi, A.; Hasan, M.; Ahmad, Z.; Wang, C.; Sillanpää, M.; Al-Bahrani, M.; Ghodrati, I. An approach to removing COD and BOD based on polycarbonate mixed matrix membranes that contain hydrous manganese oxide and silver nanoparticles: A novel application of artificial neural network based simulation in MATLAB. Chemosphere 2022, 308, 136304. [Google Scholar] [CrossRef]
  60. Zahmatkesh, S.; Rezakhani, Y.; Chofreh, A.; Karimian, M.; Wang, C.; Ghodrati, I.; Hasan, M.; Sillanpaa, M.; Panchal, H.; Khan, R. SARS-CoV-2 removal by mix matrix membrane: A novel application of artificial neural network based simulation in MATLAB for evaluating wastewater reuse risks. Chemosphere 2023, 310, 136837. [Google Scholar] [CrossRef]
Water 15 00145 g001 550
Figure 1. The average size of oil particles in the emulsion.
Figure 1. The average size of oil particles in the emulsion.
Water 15 00145 g001
Water 15 00145 g002 550
Figure 2. The comparison of the rejection values at different pH values using different concentrations of PFS. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Figure 2. The comparison of the rejection values at different pH values using different concentrations of PFS. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Water 15 00145 g002
Water 15 00145 g003 550
Figure 3. The comparison of the rejection values at different pH values using different concentrations of PFC. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Figure 3. The comparison of the rejection values at different pH values using different concentrations of PFC. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Water 15 00145 g003
Water 15 00145 g004 550
Figure 4. The effect of coagulant concentration on the rejection at pH = 6 using different coagulants. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Figure 4. The effect of coagulant concentration on the rejection at pH = 6 using different coagulants. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Water 15 00145 g004
Water 15 00145 g005 550
Figure 5. Equilibrium time in surface adsorption process at pH = 6 and T = 25 °C, pollutant concentration = 6000 ppm. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Figure 5. Equilibrium time in surface adsorption process at pH = 6 and T = 25 °C, pollutant concentration = 6000 ppm. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Water 15 00145 g005
Water 15 00145 g006 550
Figure 6. The effect of adsorbent concentration on the percentage of removal efficiency in surface adsorption at pH = 6 and T = 25 °C, pollutant concentration = 6000 ppm. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Figure 6. The effect of adsorbent concentration on the percentage of removal efficiency in surface adsorption at pH = 6 and T = 25 °C, pollutant concentration = 6000 ppm. The upper and lower 95% confidence intervals are shown as error bars that extend above and below the top of the mean column.
Water 15 00145 g006
Water 15 00145 g007 550
Figure 7. The spectra of TiO2 and TiO2−g−PMAA for nanoparticles with a size of 10 nm.
Figure 7. The spectra of TiO2 and TiO2−g−PMAA for nanoparticles with a size of 10 nm.
Water 15 00145 g007
Water 15 00145 g008 550
Figure 8. The Scanning Electron Microscope (SEM) images of the membrane surface (a) pure PSF; (b) PSF/TiO2 1%wt; (c) PSF/TiO2-g-PMAA 1%wt; (d) PSF/TiO2-g-PMAA 2%wt.
Figure 8. The Scanning Electron Microscope (SEM) images of the membrane surface (a) pure PSF; (b) PSF/TiO2 1%wt; (c) PSF/TiO2-g-PMAA 1%wt; (d) PSF/TiO2-g-PMAA 2%wt.
Water 15 00145 g008
Water 15 00145 g009a 550Water 15 00145 g009b 550
Figure 9. The cross-SEM images of the membrane surface (a) pure PSF; (b) PSF/TiO2 1%wt; (c) PSF/TiO2-g-PMAA 1%wt; (d) PSF/TiO2-g-PMAA 2%wt.
Figure 9. The cross-SEM images of the membrane surface (a) pure PSF; (b) PSF/TiO2 1%wt; (c) PSF/TiO2-g-PMAA 1%wt; (d) PSF/TiO2-g-PMAA 2%wt.
Water 15 00145 g009aWater 15 00145 g009b
Water 15 00145 g010 550
Figure 10. The effect of operational conditions on membrane performance.
Figure 10. The effect of operational conditions on membrane performance.
Water 15 00145 g010
Water 15 00145 g011 550
Figure 11. The effect of operating pressure on the flux of water-oil emulsion at constant flow rate and feed concentration.
Figure 11. The effect of operating pressure on the flux of water-oil emulsion at constant flow rate and feed concentration.
Water 15 00145 g011
Water 15 00145 g012 550
Figure 12. The effect of increasing pressure on the permeate flux at constant feed concentration and flow rate.
Figure 12. The effect of increasing pressure on the permeate flux at constant feed concentration and flow rate.
Water 15 00145 g012
Water 15 00145 g013 550
Figure 13. The effect of flow rate on the flux of water-oil emulsion at constant pressure and feed concentration.
Figure 13. The effect of flow rate on the flux of water-oil emulsion at constant pressure and feed concentration.
Water 15 00145 g013
Water 15 00145 g014 550
Figure 14. The effect of COD value of feed on the flux of water-oil emulsion at constant pressure and flow rate.
Figure 14. The effect of COD value of feed on the flux of water-oil emulsion at constant pressure and flow rate.
Water 15 00145 g014
Table
Table 1. The specifications and characterization of the obtained activated carbon.
Table 1. The specifications and characterization of the obtained activated carbon.
ParameterSpecification
Iodine Number (mg/g)1093 mg/g
Hardness88%
Density (kg/m3)422 kg/m3
Ash (%)2.4%
Humidity (%)<9%
pH7
Specific Surface (m2/g)1110 m2/g
Table
Table 2. The pH effect on COD removal and the rejection using different amount of PFS as a coagulant.
Table 2. The pH effect on COD removal and the rejection using different amount of PFS as a coagulant.
PFSpH = 4pH = 5pH = 6pH = 7pH = 8pH = 9pH = 10
COD%RCOD%RCOD%RCOD%RCOD%RCOD%RCOD%R
1 g/L41297.139498.238198.359191.367380.8152068.3291355.0
2 g/L53393.347595.241196.566988.789273.2173756.8316648.3
Table
Table 3. The pH effect on COD removal and the rejection using different amount of PFC as a coagulant.
Table 3. The pH effect on COD removal and the rejection using different amount of PFC as a coagulant.
PFCpH = 4pH = 5pH = 6pH = 7pH = 8pH = 9pH = 10
COD%RCOD%RCOD%RCOD%RCOD%RCOD%RCOD%R
1 g/L155971.3117475.994881.376684.751288.331993.318896.1
2 g/L194565.2146369.1124873.998879.871683.253388.239791.7
Table
Table 4. The effect of coagulant amounts on the COD removal and the rejection at pH = 6.
Table 4. The effect of coagulant amounts on the COD removal and the rejection at pH = 6.
Coagulant Dose0.05 g/L0.1 g/L0.5 g/L1 g/L1.5 g/L2 g/L3 g/L
COD%RCOD%RCOD%RCOD%RCOD%RCOD%RCOD%R
PFS423035.1381252.9312269.2216698.3154268.3119166.556358.4
PFC361248.3313051.6285559.7188881.3123973.995373.436661.1
Table
Table 5. The performance of pure and modified PSf membrane at optimal and constant pressure in the treatment of primary and pre-treated feed.
Table 5. The performance of pure and modified PSf membrane at optimal and constant pressure in the treatment of primary and pre-treated feed.
MembraneFeed ConcentrationPressureFlow RatePermeate FluxRejection
Pure PSf8000 ppm (pre-treated)3 bar4 L/h453 (L/h m2)95%
8000 ppm (primary feed)3 bar4 L/h412 (L/h m2)96%
Modifed PSf8000 ppm (pre-treated)3 bar4 L/h563 (L/h m2)99%
8000 ppm (primary feed)3 bar4 L/h572 (L/h m2)99%
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Alawamleh, H.S.K.; Mousavi, S.; Ashoori, D.; Salman, H.M.; Zahmatkesh, S.; Sillanpää, M. Wastewater Management Using Coagulation and Surface Adsorption through Different Polyferrics in the Presence of TiO2-g-PMAA Particles. Water 2023, 15, 145. https://doi.org/10.3390/w15010145

AMA Style

Alawamleh HSK, Mousavi S, Ashoori D, Salman HM, Zahmatkesh S, Sillanpää M. Wastewater Management Using Coagulation and Surface Adsorption through Different Polyferrics in the Presence of TiO2-g-PMAA Particles. Water. 2023; 15(1):145. https://doi.org/10.3390/w15010145

Chicago/Turabian Style

Alawamleh, Heba Saed Kariem, Seyedsahand Mousavi, Danial Ashoori, Hayder Mahmood Salman, Sasan Zahmatkesh, and Mika Sillanpää. 2023. "Wastewater Management Using Coagulation and Surface Adsorption through Different Polyferrics in the Presence of TiO2-g-PMAA Particles" Water 15, no. 1: 145. https://doi.org/10.3390/w15010145

APA Style

Alawamleh, H. S. K., Mousavi, S., Ashoori, D., Salman, H. M., Zahmatkesh, S., & Sillanpää, M. (2023). Wastewater Management Using Coagulation and Surface Adsorption through Different Polyferrics in the Presence of TiO2-g-PMAA Particles. Water, 15(1), 145. https://doi.org/10.3390/w15010145

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop