Topical Collection "Polymer Materials for Adsorption Applications"

A topical collection in Polymers (ISSN 2073-4360). This collection belongs to the section "Polymer Applications".

Editor

Prof. Dr. George Z. Kyzas
E-Mail Website
Collection Editor
Department of Chemistry, International Hellenic University, 65404 Kavala, Greece
Interests: nanobubbles; wastewater treatment; polymers; decontamination; materials; sorption; transportation phenomena
Special Issues and Collections in MDPI journals

Topical Collection Information

Dear Colleagues,

Adsorption is considered to be one of the most promising techniques for decontamination cleaning. This technique can be applied either in liquid phase for the decontamination of wastewaters (effluents) from various pollutants (dyes, heavy metals, pharmaceuticals/drugs, and organic molecules (phenols, pesticides, herbicides, etc.)) or in gas phase for the binding/capture of environmental gases (COx, NOx, SOx, etc.). Numerous adsorbent materials have been synthesized and characterized to date, but one of the types with a lot of potential is polymeric-based adsorbents. Polymers can easily be modified before use in adsorption. The major advantage of polymers is the existence of modifiable functional groups in their chemical structure. Their modification can be achieved in many ways, such as (i) grafting (insertion of functional groups) and (ii) cross-linking reactions (uniting the macromolecular chains with each other), and leads to the formation of polymeric derivatives with superior properties (an enhancement of adsorption capacity and resistance under extreme media conditions, respectively). In the case of grafting reactions, the addition of extra functional groups to polymers increases the number of adsorption sites and consequently the adsorption capacity. On the other hand, the cross-linking reactions slightly decrease the adsorption capacity because some functional polymeric groups are bound with the cross-linker and cannot interact with the pollutant.

This Topical Collection on “Polymer Materials for Adsorption Applications” seeks high-quality works focusing on (but not restricted to) the latest approaches to the synthesis of polymeric adsorbents, their characterization, and their application to cleaning either in gas or liquid phase.

Dr. George Z. Kyzas
Collection Editor

Manuscript Submission Information

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Keywords

  • polymers
  • adsorption
  • wastewaters
  • gas adsorption
  • synthesis
  • modification
  • characterization
  • filters
  • applications

Related Special Issue

Published Papers (18 papers)

2021

Jump to: 2020, 2019

Article
Chelating Fabrics Prepared by an Organic Solvent-Free Process for Boron Removal from Water
Polymers 2021, 13(7), 1163; https://doi.org/10.3390/polym13071163 - 05 Apr 2021
Cited by 2 | Viewed by 537
Abstract
A chelating fabric was prepared by graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven fabric, followed by attachment reaction of N-methyl-D-glucamine (NMDG) using an organic solvent-free process. The graft polymerization was performed by immersing the gamma-ray pre-irradiated fabric into the GMA emulsion, [...] Read more.
A chelating fabric was prepared by graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven fabric, followed by attachment reaction of N-methyl-D-glucamine (NMDG) using an organic solvent-free process. The graft polymerization was performed by immersing the gamma-ray pre-irradiated fabric into the GMA emulsion, while the attachment reaction was carried out by immersing the grafted fabric in the NMDG aqueous solution. The chelating capacity of the chelating fabric prepared by reaction in the NMDG aqueous solution without any additives reached 1.74 mmol/g, which further increased to above 2.0 mmol/g when surfactant and acid catalyst were added in the solution. The boron chelation of the chelating fabric was evaluated in a batch mode. Fourier transform infrared spectrophotometer (FTIR) was used to characterize the fabrics. The chelating fabric can quickly chelate boron from water to form a boron ester, and a high boron chelating ability close to 18.3 mg/g was achieved in the concentrated boron solution. The chelated boron can be eluted completely by HCl solution. The regeneration and stability of the chelating fabric were tested by 10 cycles of the chelation-elution operations. Considering the organic solvent-free preparation process and the high boron chelating performance, the chelating fabric is promising for the boron removal from water. Full article
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Article
Barium/[email protected] Glycol Nanocomposites for Dye Removal from Aqueous Solutions
Polymers 2021, 13(7), 1161; https://doi.org/10.3390/polym13071161 - 05 Apr 2021
Viewed by 487
Abstract
Dyes are known as one of the most dangerous industrial pollutants which can cause skin diseases, allergy, and provoke cancer and mutation in humans. Therefore, one of the important environmental issues is the effective removal of dyes from industrial wastewater. In the current [...] Read more.
Dyes are known as one of the most dangerous industrial pollutants which can cause skin diseases, allergy, and provoke cancer and mutation in humans. Therefore, one of the important environmental issues is the effective removal of dyes from industrial wastewater. In the current work, BaFe12O19/CoFe2O4@polyethylene glycol (abbreviated as BFO/[email protected]) nanocomposite was synthesized and evaluated regarding its capacity for adsorptive removal of a model dye Acid Blue 92 (denoted as AB92) from aqueous solutions. The characteristics of the prepared nanocomposite was determined by tests such as X-ray diffraction (XRD), scanning electron microscope (SEM), vibration sample magnetization (VSM), and Fourier transform infrared spectroscopy (FTIR). The effects of conditional parameters including pH (2–12), initial concentration of dye (20–100 mg/L), adsorbent dosage (0.02–0.1 g/L) and contact time (0-180 min) on the adsorption of dye were investigated and then optimized. The results indicated that with the increase of the adsorbent dosage from 0.02 to 0.1 g/L, the removal efficiency increased from 74.1% to 78.6%, and the adsorbed amount decreased from 148.25 to 31.44 mg/g. The maximum removal efficiency (77.54%) and adsorption capacity (31.02 mg/g) were observed at pH 2. Therefore, the general optimization conditions revealed that the maximum adsorption efficiency of dye was obtained in condition of initial concentration of 20 mg/L, contact time of 1 h and pH of solution equal 2. The adsorption isotherm and kinetic data were evaluated using a series of models. The pseudo-second order kinetic model and Freundlich isotherm model show the best fitting with experimental data with R2∼0.999. Full article
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Article
Adsorption Evaluation for the Removal of Nickel, Mercury, and Barium Ions from Single-Component and Mixtures of Aqueous Solutions by Using an Optimized Biobased Chitosan Derivative
Polymers 2021, 13(2), 232; https://doi.org/10.3390/polym13020232 - 11 Jan 2021
Cited by 2 | Viewed by 554
Abstract
In this experimental study, the use of 5-hydroxymethyl-furfural (HMF) organic compound as a grafting agent to chitosan natural polymer (CS) was examined. One optimized chitosan derivative was synthesized, and then tested (CS-HMF), in order to uptake nickel, mercury, and barium metal ions from [...] Read more.
In this experimental study, the use of 5-hydroxymethyl-furfural (HMF) organic compound as a grafting agent to chitosan natural polymer (CS) was examined. One optimized chitosan derivative was synthesized, and then tested (CS-HMF), in order to uptake nickel, mercury, and barium metal ions from single- and triple-component (multi-component) aqueous solutions. The characterization of the material before and after the metal uptake was achieved by scanning electron microscopy (SEM). The ability of the adsorption of CS-HMF was tested at pH = 6. The adjusting of temperature from 25 to 65 °C caused the increase in the adsorption capacity. The equilibrium data were fitted to the models of Langmuir and Freundlich, while the data from kinetic experiments were fitted to pseudo-1st and pseudo-2nd order models. The best fitting was achieved for the Langmuir model (higher R2). The adsorption capacity for nickel, mercury, and barium removal at 25 °C (single component) was 147, 107, and 64 (mg/g), respectively. However, the total adsorption capacity for the multi-component was 204 mg/g. A thermodynamic study was also done, and the values of ΔG0, ΔH0, and ΔS0 were evaluated. Full article
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Editorial
Polymeric Materials for Water and Wastewater Management
Polymers 2021, 13(1), 168; https://doi.org/10.3390/polym13010168 - 05 Jan 2021
Viewed by 789
Abstract
Water is a crucial point of interest nowadays due to its special management [...] Full article

2020

Jump to: 2021, 2019

Communication
Preparation of a Cellulose Column for Enhancing the Sensing Efficiency of the Biocide 2-n-Octyl-4-Isothiazolin-3-One
Polymers 2020, 12(11), 2712; https://doi.org/10.3390/polym12112712 - 16 Nov 2020
Viewed by 430
Abstract
In this study, a cellulose acetate (CA) membrane with pores generated by a water pressure treatment was investigated for its ability to serve as a pretreatment filter device for the detection of 2-n-octyl-4-isothiazolin-3-one (OIT). Pores were generated by applying a water pressure of [...] Read more.
In this study, a cellulose acetate (CA) membrane with pores generated by a water pressure treatment was investigated for its ability to serve as a pretreatment filter device for the detection of 2-n-octyl-4-isothiazolin-3-one (OIT). Pores were generated by applying a water pressure of 8 bar to a membrane manufactured using a CA-based polymer solution. The CA used for the manufacturing was an environment-friendly, low-cost and highly energy-efficient material. Furthermore, since the fabricated porous CA polymeric film possessed many hydrophilic functional groups, it could strongly bind hydrophilic substances while avoiding interaction with hydrophobic substances. OIT, which comprises a hydrophobic bond that forms weak bonds over time, can break down more easily than hydrophilic impurities. The different extents of interaction occurring between either the toxic fungicide OIT or the hydrophilic impurities and the CA film were determined by Fourier-transform infrared (FT-IR) spectroscopy. The physicochemical changes in the resulting membrane, which occurred when the pores were generated, were investigated through scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Full article
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Article
Self-Nitrogen-Doped Nanoporous Carbons Derived from Poly(1,5-diaminonaphthalene) for the Removal of Toxic Dye Pollutants from Wastewater: Non-Linear Isotherm and Kinetic Analysis
Polymers 2020, 12(11), 2563; https://doi.org/10.3390/polym12112563 - 31 Oct 2020
Cited by 1 | Viewed by 635
Abstract
The high surface area and porosity of self-nitrogen-doped porous carbons (SNPCs) nominates them for potential application in water treatment due to their high efficiency towards the removal of various pollutants. In this study, SNPCs were fabricated from poly(1,5-diaminonaphthalene) (P(1,5-DANPh) by single and simultaneous [...] Read more.
The high surface area and porosity of self-nitrogen-doped porous carbons (SNPCs) nominates them for potential application in water treatment due to their high efficiency towards the removal of various pollutants. In this study, SNPCs were fabricated from poly(1,5-diaminonaphthalene) (P(1,5-DANPh) by single and simultaneous carbonization at the activation step at different temperatures (600, 700, and 800 °C). The carbonization’s temperature plays a vital role in controlling the nitrogen-doping, surface area, porosity, and morphology of SNPCs. The SNPCs-7 sample prepared at 700 °C showed the highest surface area (1678.8 m2 g−1) with pore volume (0.943 cm3 g−1) with a micro/meso porous structure. The prepared SNPCs were used as an effective adsorbent for removal of crystal violet dye (CV) from contaminated water. SNPCs-7 showed the highest adsorption of 487.53 mg g−1 and the adsorption capacity of the SNPCs samples follows the order SNPCs-7 > SNPCs-8 > SNPCs-6, which is consistent with the results of their surface area and porosity. The adsorption for CV dye followed Freundlich isotherm models and a pseudo second order kinetic model. The negative values of Gipps free energy (ΔG°) and positive value of enthalpy (ΔH°) indicated that the adsorption of CV dye onto the surface of SNPCs was a spontaneous and endothermic process, respectively. Based on the results, the adsorption mechanism of CV dye onto the surface of SNPCs was proposed. Full article
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Erratum
Erratum: Synthesis, Characterization, and Analysis of Hybrid Carbon Nanotubes by Chemical Vapor Deposition: Application for Aluminum Removal. Polymers 2020, 12, 1305
Polymers 2020, 12(8), 1702; https://doi.org/10.3390/polym12081702 - 29 Jul 2020
Viewed by 601
Abstract
The authors wish to make a change to the published paper [...] Full article
Article
Synthesis, Characterization, and Analysis of Hybrid Carbon Nanotubes by Chemical Vapor Deposition: Application for Aluminum Removal
Polymers 2020, 12(6), 1305; https://doi.org/10.3390/polym12061305 - 08 Jun 2020
Cited by 6 | Viewed by 1007
Abstract
Hybrid carbon nanotubes (CNTs) are grown on biomass powder-activated carbon (bio-PAC) by loading iron nanoparticles (Fe) as catalyst templates using chemical vapor deposition (CVD) and using acetylene as carbon source, under specific conditions as reaction temperature, time, and gas ratio that are 550 [...] Read more.
Hybrid carbon nanotubes (CNTs) are grown on biomass powder-activated carbon (bio-PAC) by loading iron nanoparticles (Fe) as catalyst templates using chemical vapor deposition (CVD) and using acetylene as carbon source, under specific conditions as reaction temperature, time, and gas ratio that are 550 °C, 47 min, and 1, respectively. Specifications of hybrid CNTs were analyzed and characterized using field emission scanning electron microscope (FESEM) with energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopic (TEM), Fourier-transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area Brunauer–Emmett–Teller (BET), and zeta potential. The results revealed the high quality and unique morphologies of hybrid CNTs. Furthermore, removal and capacity of Al3+ were optimized by response surface methodology (RSM). However, the results revealed that the pseudo-second-order model well represented adsorption kinetic data, while the isotherm data were effectively fitted using a Freundlich model. The maximum adsorption capacity was 347.88 mg/g. It could be concluded that synthesized hybrid CNTs are a new cost-effective and promising adsorbent for removing Al3+ ion from wastewater. Full article
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Article
Filler-Modified Castor Oil-Based Polyurethane Foam for the Removal of Aqueous Heavy Metals Detected Using Laser-Induced Breakdown Spectroscopy (LIBS) Technique
Polymers 2020, 12(4), 903; https://doi.org/10.3390/polym12040903 - 13 Apr 2020
Cited by 11 | Viewed by 1673
Abstract
The use of polymeric material in heavy metal removal from wastewater is trending. Heavy metal removal from wastewater of the industrial process is of utmost importance in green/sustainable manufacturing. Production of absorbent materials from a natural source for industrial wastewater has been on [...] Read more.
The use of polymeric material in heavy metal removal from wastewater is trending. Heavy metal removal from wastewater of the industrial process is of utmost importance in green/sustainable manufacturing. Production of absorbent materials from a natural source for industrial wastewater has been on the increase. In this research, polyurethane foam (PUF), an adsorbent used by industries to adsorb heavy metal from wastewater, was prepared from a renewable source. Castor oil-based polyurethane foam (COPUF) was produced and modified for improved adsorption performance using fillers, analyzed with laser-induced breakdown spectroscopy (LIBS). The fillers (zeolite, bentonite, and activated carbon) were added to the COPUF matrix allowing the modification on its surface morphology and charge. The materials were characterized using Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and thermal gravimetry analysis (TGA), while their adsorption performance was studied by comparing the LIBS spectra. The bentonite-modified COPUF (B/COPUF) gave the highest value of the normalized Pb I (405.7 nm) line intensity (2.3), followed by zeolite-modified COPUF (Z/COPUF) (1.9), and activated carbon-modified COPUF (AC/COPUF) (0.2), which indicates the adsorption performance of Pb2+ on the respective materials. The heavy metal ions’ adsorption on the B/COPUF dominantly resulted from the electrostatic attraction. This study demonstrated the potential use of B/COPUF in adsorption and LIBS quantitative analysis of aqueous heavy metal ions. Full article
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Article
Removal of Boron and Manganese Ions from Wet-Flue Gas Desulfurization Wastewater by Hybrid Chitosan-Zirconium Sorbent
Polymers 2020, 12(3), 635; https://doi.org/10.3390/polym12030635 - 10 Mar 2020
Cited by 5 | Viewed by 1112
Abstract
Flue gas desulfurization (FGD) wastewater, after the alkaline precipitation and coagulation processes, often requires additional treatment in order to reduce the concentrations of boron and heavy metals below the required limits. In this study, we present an innovative and environmentally friendly method for [...] Read more.
Flue gas desulfurization (FGD) wastewater, after the alkaline precipitation and coagulation processes, often requires additional treatment in order to reduce the concentrations of boron and heavy metals below the required limits. In this study, we present an innovative and environmentally friendly method for boron and manganese removal that is based on a hybrid chitosan-zirconium hydrogel sorbent. The results from the batch adsorption experiment indicated that the uptake capacity for boron and manganese was equal to 1.61 mg/g and 0.75 mg/g, respectively, while the column study indicated that the total capacity of boron and manganese was equal to 1.89 mg/g and 0.102 mg/g, respectively. The very good applicability of the Langmuir isotherm at 25 °C suggested the monolayer coverage of the boron species onto the hybrid chitosan-zirconium hydrogel with a maximum adsorptive capacity of 2 mg/g. The amounts of boron and manganese in purified water could be decreased to less than 1 mg/dm3 and 0.05 mg/dm3, respectively, starting from the initial concentration of boron equal to 24.7 mg/dm3 and manganese equal to 3.0 mg/dm3 in FGD wastewater. Selective desorption of boron from the loaded bed was favorable when a NaOH solution was used, while manganese was preferentially eluted with a HCl solution. It is important to note that such an innovative method was investigated for the first time by testing borax recovery from wastewater in terms of an eco-technological perspective. Full article
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Article
Efficient Removal of Pb(II) from Aqueous Solutions by Using Oil Palm Bio-Waste/MWCNTs Reinforced PVA Hydrogel Composites: Kinetic, Isotherm and Thermodynamic Modeling
Polymers 2020, 12(2), 430; https://doi.org/10.3390/polym12020430 - 12 Feb 2020
Cited by 24 | Viewed by 1394
Abstract
Polyvinyl alcohol (PVA) hydrogel are still restricted for some applications because their lower mechanical strength and thermal stability. The PVA-based composites are drawing attention for the removal of heavy metals based on their specific functionality in adsorption process. The main objective of this [...] Read more.
Polyvinyl alcohol (PVA) hydrogel are still restricted for some applications because their lower mechanical strength and thermal stability. The PVA-based composites are drawing attention for the removal of heavy metals based on their specific functionality in adsorption process. The main objective of this work is to synthesize oil palm bio-waste (OPB)/multiwalled carbon nanotubes (MWCNTs) reinforced PVA hydrogels in the presence of N,N′-methylenebisacrylamide (NMBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator via simple in-situ polymerization technique. The as-prepared reinforced nanocomposites were characterized by FESEM, BET surface area, differential scanning calorimetry (DSC), TGA and FTIR analysis. The possible influence of OPB and MWCNTs on the tensile strength, elongation at break and elastic modulus of the samples were investigated. It was found that reinforced nanocomposites exhibited enhanced mechanical properties as compared to non-reinforced material. The evaluation of reinforced nanocomposites was tested by the removal of Pb(II) aqueous solutions in a batch adsorption system. The pseudo-second-order kinetic model was used to illustrate the adsorption kinetic results and Langmuir isotherm was more suitable to fit the equilibrium results providing maximum adsorption capacities. The evaluation of thermodynamic parameters describes the spontaneous, endothermic and chemisorption adsorption process while activation energy reveals the physical adsorption mechanism. Therefore, the coordination effects among OPB, MWCNTs and PVA polymer hydrogels can produce a promising adsorbent material for wastewater treatment applications. Full article
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Article
Enhancement of Flux Performance in PTFE Membranes for Direct Contact Membrane Distillation
Polymers 2020, 12(2), 345; https://doi.org/10.3390/polym12020345 - 05 Feb 2020
Cited by 8 | Viewed by 1247
Abstract
This work focused on enhancing the flux on hydrophobic polymeric membranes aimed for direct contact membrane distillation desalination (DCMD) process without compromising salt rejection efficiency. Successful coating of commercial porous poly-tetrafluoroethylene membranes with poly(vinyl alcohol) (PVA) was achieved by solution dipping followed by [...] Read more.
This work focused on enhancing the flux on hydrophobic polymeric membranes aimed for direct contact membrane distillation desalination (DCMD) process without compromising salt rejection efficiency. Successful coating of commercial porous poly-tetrafluoroethylene membranes with poly(vinyl alcohol) (PVA) was achieved by solution dipping followed by a cross-linking step. The modified membranes were evaluated for their performance in DCMD, in terms of water flux and salt rejection. A series of different PVA concentration dipping solutions were used, and the results indicated that there was an optimum concentration after which the membranes became hydrophilic and unsuitable for use in membrane distillation. Best performing membranes were achieved under the specific experimental conditions, water flux 12.2 L·m-2·h-1 [LMH] with a salt rejection of 99.9%. Compared to the pristine membrane, the flux was enhanced by a factor of 2.7. The results seemed to indicate that introducing hydrophilic characteristics in a certain amount to a hydrophobic membrane could significantly enhance the membrane distillation (MD) performance without compromising salt rejection. Full article
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Technical Note
Synthesis of Modified Starch/Polyvinyl Alcohol Composite for Treating Textile Wastewater
Polymers 2020, 12(2), 289; https://doi.org/10.3390/polym12020289 - 01 Feb 2020
Cited by 7 | Viewed by 1200
Abstract
In this work, we demonstrated a strategy to design a modified starch/polyvinyl alcohol composite (CCSP), which was employed as a highly efficient and economical fixed-bed adsorbent for treating textile wastewater. Characterization revealed that most of the CCSP was shaped with the morphology of [...] Read more.
In this work, we demonstrated a strategy to design a modified starch/polyvinyl alcohol composite (CCSP), which was employed as a highly efficient and economical fixed-bed adsorbent for treating textile wastewater. Characterization revealed that most of the CCSP was shaped with the morphology of sphericity, and had some water swelling properties. The crystallinity of the CCSP was lower than that of native starch and polyvinyl alcohol, and its average particle size gradually increased with the dosage increase of cationic starch in the preparation. Adsorption experiments showed that the adsorption capacities of CCSP were more than 605 and 539 mg/g for Reactive Black 5 and Reactive Orange 131, respectively, which were over 10 times larger than that of commercial activated carbon (AC). The mixture adsorbent composed of CCSP and AC could remove starch, polyvinyl alcohol, and dyes from textile wastewater completely and simultaneously combined with the fixed-bed technique, and its adsorption capacity was conducted as a function of the bed height and flow rate. Most importantly, the disabled mixture adsorbent could be converted into regenerated AC through a chemical activation process, thereby avoiding the production of solid waste. This study will provide a new efficient green sustainable method for treating textile wastewater. Full article
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Article
Magnetic Template Anion Polyacrylamide–Polydopamine-Fe3O4 Combined with Ultraviolet/H2O2 for the Rapid Enrichment and Degradation of Diclofenac Sodium from Aqueous Environment
Polymers 2020, 12(1), 72; https://doi.org/10.3390/polym12010072 - 02 Jan 2020
Cited by 2 | Viewed by 790
Abstract
In this study, a novel system was set up by preparing a magnetic flocculant combining with ultraviolet/H2O2 to realize the rapid enrichment and degradation of diclofenac sodium (DCFS). For the magnetic flocculant, template anion polyacrylamide (TAPAM) with anion micro-block structure [...] Read more.
In this study, a novel system was set up by preparing a magnetic flocculant combining with ultraviolet/H2O2 to realize the rapid enrichment and degradation of diclofenac sodium (DCFS). For the magnetic flocculant, template anion polyacrylamide (TAPAM) with anion micro-block structure was prepared. Thereafter, polydopamine was used to modify TAPAM, Fe3O4 nanoparticles was grafted to the modified TAPAM by chelation, named template anion polyacrylamide-polydopamine-Fe3O4 (TAPAM-PDA-Fe3O4). Furthermore, the TAPAM-PDA-Fe3O4 preparation protocol was optimized by the response surface method (RSM). In the DCFS enrichment section, the rapid separation of flocs from water was realized by an external magnetic field and it indicated that the π–π stacking effect was dominant in neutral/alkaline condition, whereas charge neutralization was favored in acidic conditions. Meanwhile, a DCFS enrichment kinetic curve was much fitted by the pseudo-second-order kinetic model and DCFS enrichment isothermal curve was close to the Freundlich isothermal model, indicating the dependence of DCFS quantity enriched by TAPAM-PDA-Fe3O4 and a multilayer heterogeneous enrichment process. The degradation experiment confirmed that DCFS was effectively degraded by ultraviolet/H2O2/TAPAM-PDA-Fe3O4 and the maximum value of DCFS degradation efficiency reached 98.1%. Furthermore, the regeneration experiment showed that the enrichment and degradation efficiency of DCFS could maintain a relatively high level in the initial three recycles. Full article
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2019

Jump to: 2021, 2020

Article
Ultrasound-Assisted Preparation of Chitosan/Nano-Activated Carbon Composite Beads Aminated with (3-Aminopropyl)Triethoxysilane for Adsorption of Acetaminophen from Aqueous Solutions
Polymers 2019, 11(10), 1701; https://doi.org/10.3390/polym11101701 - 16 Oct 2019
Cited by 5 | Viewed by 1146
Abstract
A composite chitosan/nano-activated carbon (CS-NAC) aminated by (3-aminopropyl)triethoxysilane (APTES) was prepared in the form of beads and applied for the removal of acetaminophen from aqueous solutions. NAC and APTES concentrations were optimized to obtain a suitable adsorbent structure for enhanced removal of the [...] Read more.
A composite chitosan/nano-activated carbon (CS-NAC) aminated by (3-aminopropyl)triethoxysilane (APTES) was prepared in the form of beads and applied for the removal of acetaminophen from aqueous solutions. NAC and APTES concentrations were optimized to obtain a suitable adsorbent structure for enhanced removal of the pharmaceutical. The aminated adsorbent (CS-NAC-APTES beads) prepared with 40% w/w NAC and 2% v/v APTES showed higher adsorption capacity (407.83 mg/g) than CS-NAC beads (278.4 mg/g). Brunauer–Emmett–Teller (BET) analysis demonstrated that the surface area of the CS-NAC-APTES beads was larger than that of CS-NAC beads (1.16 times). The adsorption process was well fitted by the Freundlich model (R2 > 0.95), suggesting a multilayer adsorption. The kinetic study also substantiated that the pseudo-second-order model (R2 > 0.98) was in better agreement with the experimental data. Finally, it was proved that the prepared beads can be recycled (by washing with NaOH solution) at least 5 times before detectable performance loss. Full article
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Article
Assembly of Soft Electrodes and Ion Exchange Membranes for Capacitive Deionization
Polymers 2019, 11(10), 1556; https://doi.org/10.3390/polym11101556 - 25 Sep 2019
Cited by 3 | Viewed by 1224
Abstract
The responsible use of water, as well as its reuse and purification, has been a major problem for decades now. In this work, we study a method for adsorbing ions from aqueous solutions on charged interfaces using highly porous electrodes. This water purification [...] Read more.
The responsible use of water, as well as its reuse and purification, has been a major problem for decades now. In this work, we study a method for adsorbing ions from aqueous solutions on charged interfaces using highly porous electrodes. This water purification process is based on the electric double layer concept, using the method known as capacitive deionization (CDI): If we pump salty solutions through the volume comprised between two porous electrodes while applying a potential difference to them, ions present in the solution are partially removed and trapped on the electrode surfaces. It has been well established that the use of carbon electrodes in combination with ion exchange membranes (membrane-CDI) improves the efficiency of the method above that achieved with bare activated carbon. Another approach that has been tested is based on coating the carbon with polyelectrolyte layers, converting them into “soft electrodes” (SEs). Here we investigate the improvement found when combining SEs with membranes, and it is shown that the amount of ions adsorbed and the ratio between ions removed and electrons transported reach superior values, also associated with a faster kinetics of the process. The method is applied to the partial desalination of up to 100 mM NaCl solutions, something hardly achievable with bare or membrane-covered electrodes. A theoretical model is presented for the ion transport in the presence of both the membrane and the polyelectrolyte coating. Full article
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Review
A Review on Reverse Osmosis and Nanofiltration Membranes for Water Purification
Polymers 2019, 11(8), 1252; https://doi.org/10.3390/polym11081252 - 29 Jul 2019
Cited by 81 | Viewed by 5676
Abstract
Sustainable and affordable supply of clean, safe, and adequate water is one of the most challenging issues facing the world. Membrane separation technology is one of the most cost-effective and widely applied technologies for water purification. Polymeric membranes such as cellulose-based (CA) membranes [...] Read more.
Sustainable and affordable supply of clean, safe, and adequate water is one of the most challenging issues facing the world. Membrane separation technology is one of the most cost-effective and widely applied technologies for water purification. Polymeric membranes such as cellulose-based (CA) membranes and thin-film composite (TFC) membranes have dominated the industry since 1980. Although further development of polymeric membranes for better performance is laborious, the research findings and sustained progress in inorganic membrane development have grown fast and solve some remaining problems. In addition to conventional ceramic metal oxide membranes, membranes prepared by graphene oxide (GO), carbon nanotubes (CNTs), and mixed matrix materials (MMMs) have attracted enormous attention due to their desirable properties such as tunable pore structure, excellent chemical, mechanical, and thermal tolerance, good salt rejection and/or high water permeability. This review provides insight into synthesis approaches and structural properties of recent reverse osmosis (RO) and nanofiltration (NF) membranes which are used to retain dissolved species such as heavy metals, electrolytes, and inorganic salts in various aqueous solutions. A specific focus has been placed on introducing and comparing water purification performance of different classes of polymeric and ceramic membranes in related water treatment industries. Furthermore, the development challenges and research opportunities of organic and inorganic membranes are discussed and the further perspectives are analyzed. Full article
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Article
Cost Estimation of Polymeric Adsorbents
Polymers 2019, 11(5), 925; https://doi.org/10.3390/polym11050925 - 27 May 2019
Cited by 14 | Viewed by 1797
Abstract
One of the most promising techniques of recent research is adsorption. This technique attracts great attention in environmental technology, especially in the decontamination of water and wastewaters. A “hidden” point of the above is the cost of adsorbents. As can be easily observed [...] Read more.
One of the most promising techniques of recent research is adsorption. This technique attracts great attention in environmental technology, especially in the decontamination of water and wastewaters. A “hidden” point of the above is the cost of adsorbents. As can be easily observed in the literature, there is not any mention about the synthesis cost of adsorbents. What are the basic criteria with which an industry can select an adsorbent? What is the synthesis (recipe) cost? What is the energy demand to synthesize an efficient material? All of these are questions which have not been answered, until now. The reason for this is that the estimation of adsorbents’ cost is relatively difficult, because too many cost factors are involved (labor cost, raw materials cost, energy cost, tax cost, etc.). In this work, the first estimation cost of adsorbents is presented, taking into consideration all of the major factors which influence the final value. To be more comparable, the adsorbents used are from a list of polymeric materials which are already synthesized and tested in our laboratory. All of them are polymeric materials with chitosan as a substrate, which is efficiently used for the removal of heavy metal ions. Full article
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