Functional Polymeric Adsorbents

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Processing and Engineering".

Deadline for manuscript submissions: closed (15 October 2022) | Viewed by 34880

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Division of Nanotechnology and Functional Materials, Department of Materials Science and Engineering, Uppsala University, 752 36 Uppsala, Sweden
Interests: functional materials; biopolymers valorization; biorefinery; surfaces and interfaces; adsorption; water treatment
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Special Issue Information

Dear Colleagues,

Due to chemical contamination, water pollution remains a serious environmental and public problem. Drainage of toxic metals and organic compounds to the surface waters poses a threat to the aquatic environment, with such effects as acute and chronic toxicity in aquatic organisms, accumulation of pollutants in the ecosystem, and loss of habitats and biodiversity. As a matter of priority, causes of pollution should be identified and emissions of pollutants should be dealt with at source, in the most economically and environmentally effective manner (Directive 2013/39/EU as regards priority substances in the field of water policy). Organic compounds such as pharmaceuticals, personal care products, surfactants, pesticides, and synthetic dyes along with heavy metal ions are often found in the industrial and domestic waste waters as a result of their wide uses. They are common contaminants in wastewaters, and many of them are known to be toxic or carcinogenic.

Adsorption is one of the most attractive methods for the extraction of molecules or ions from aqueous solutions, as it can be conducted in mild conditions. In order to create both an efficient and sustainable process, the decisive aspect is the type of sorbent material. In this light, biomacromolecules, biobased and biodegradable polymers, are promising materials for the synthesis of functional adsorbents due to their unique physicochemical properties, specific functionality, abundance, and low cost. Therefore, this Special Issue is focused on the development of functional adsorbents for water purification. Original research papers and short reviews addressing the synthesis, characterization, and investigation of the influence of biomacromolecules’ originality and nature on the properties of functional materials as perspective adsorbents for water treatment are invited for submission.

Dr. Tetyana Budnyak
Guest Editor

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Keywords

  • biomacromolecules
  • biomass valorization
  • biopolymers-based adsorbents
  • hybrid composites
  • adsorption
  • organic pollutants
  • inorganic pollutants
  • water treatment

Published Papers (13 papers)

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Research

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12 pages, 2793 KiB  
Article
In Situ Ring-Opening Polymerization of L-lactide on the Surface of Pristine and Aminated Silica: Synthesis and Metal Ions Extraction
by Liliia M. Polishchuk, Roman B. Kozakevych, Andrii P. Kusyak, Valentin A. Tertykh, Oleg Tkachenko, Maria Strømme and Tetyana M. Budnyak
Polymers 2022, 14(22), 4995; https://doi.org/10.3390/polym14224995 - 18 Nov 2022
Cited by 1 | Viewed by 1417
Abstract
The development of functional materials from food waste sources and minerals is currently of high importance. In the present work, polylactic acid (PLA)/silica composites were prepared by in situ ring-opening polymerizations of L-lactide onto the surface of pristine (Silochrom) and amine-functionalized (Silochrom-NH [...] Read more.
The development of functional materials from food waste sources and minerals is currently of high importance. In the present work, polylactic acid (PLA)/silica composites were prepared by in situ ring-opening polymerizations of L-lactide onto the surface of pristine (Silochrom) and amine-functionalized (Silochrom-NH2) silica. The characteristics of the ring-opening polymerization onto the surface of modified and unmodified silica were identified and discussed. Fourier transform infrared spectroscopy was used to confirm the polymerization of lactide onto the silica surface, and thermogravimetric analysis determined that PLA constituted 5.9% and 7.5% of the composite mass for Silochrom/PLA and Silochrom-NH2/PLA, respectively. The sorption properties of the composites with respect to Pb(II), Co(II), and Cu(II) ions were investigated, and the effect of contact time, initial metal ion concentration, and initial pH were evaluated. Silochrom-NH2/PLA composites were found to have a higher adsorption capacity than Silochrom/PLA for all chosen ions, with the highest adsorption value occurring for Pb2+ at 1.5 mmol/g (90% removal efficiency). The composites showed the highest performance in the neutral or near-neutral pH (created by distilled water or buffer pH 6.86) during the first 15 min of phase contact. The equilibrium characteristics of adsorption were found to follow the Langmuir isotherm model rather than the Freundlich and Temkin models. Perspective applications for these PLA/silicas include remediation of industrial wastewater or leaching solutions from spent lead-acid and Li-ion batteries. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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21 pages, 6054 KiB  
Article
Application of Water Hyacinth Biomass (Eichhornia crassipes) as an Adsorbent for Methylene Blue Dye from Aqueous Medium: Kinetic and Isothermal Study
by Marcelo T. Carneiro, Ana Z. B. Barros, Alan I. S. Morais, André L. F. Carvalho Melo, Roosevelt D. S. Bezerra, Josy A. Osajima and Edson C. Silva-Filho
Polymers 2022, 14(13), 2732; https://doi.org/10.3390/polym14132732 - 4 Jul 2022
Cited by 20 | Viewed by 3133
Abstract
Water pollution has generated the need to develop technologies to remove industrial pollutants. Adsorption has been recognized as one of the most effective techniques for effluent remediation. In this study, parts (stem and leaves) of a problematic aquatic weed, the water hyacinth ( [...] Read more.
Water pollution has generated the need to develop technologies to remove industrial pollutants. Adsorption has been recognized as one of the most effective techniques for effluent remediation. In this study, parts (stem and leaves) of a problematic aquatic weed, the water hyacinth (Eichhornia crassipes), were separated to produce a bioadsorbent. The objective was to evaluate the adsorption of a cationic dye, methylene blue (MB), in an aqueous solution of the biomass from different parts of the water hyacinth (Eichhornia crassipes) plants. The materials were characterized through techniques of infrared spectroscopy, scanning electron microscopy, X-ray diffractometry, and thermogravimetric analysis, before and after the material adsorption. Water hyacinth biomasses presented adsorption capacity above 89%, and the kinetics was faster for stem biomass. The kinetic study found that the adsorption process is better described by the pseudo-second-order model, and the adjustments of the isotherm experimental data indicated that both materials are favorable for adsorption. Therefore, water hyacinth bioadsorbent represents a renewable resource with potential for effluent treatment. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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16 pages, 2825 KiB  
Article
Encapsulation of Saccharomyces pastorianus Residual Biomass in Calcium Alginate Matrix with Insights in Ethacridine Lactate Biosorption
by Lăcrămioara Rusu, Cristina-Gabriela Grigoraș, Andrei-Ionuț Simion, Elena-Mirela Suceveanu, Alexandra-Cristina Blaga and Maria Harja
Polymers 2022, 14(1), 170; https://doi.org/10.3390/polym14010170 - 1 Jan 2022
Cited by 9 | Viewed by 1923
Abstract
Pharmaceuticals are recognized as emerging water microcontaminants that have been reported in several aquatic environments worldwide; therefore, the elimination of these pollutants is a global challenge. This study aimed to develop a biosorbent based on Saccharomyces pastorianus residual biomass encapsulated in a calcium [...] Read more.
Pharmaceuticals are recognized as emerging water microcontaminants that have been reported in several aquatic environments worldwide; therefore, the elimination of these pollutants is a global challenge. This study aimed to develop a biosorbent based on Saccharomyces pastorianus residual biomass encapsulated in a calcium alginate matrix and to evaluate its biosorption performance to remove Ethacridine Lactate (EL) from aqueous solutions. Firstly, the synthesis and characterization of biosorbent has been carried out. Then, the impact of main parameters on biosorption process were investigated by batch experiments. Finally, the kinetics behavior and equilibrium isotherms were evaluated. The resulted beads have an irregular and elongated shape with about 1.89 mm ± 0.13 mm in size with a homogeneous structure. The best removal efficiency for EL of over 85% was obtained at acidic pH 2 and 25 °C for 50 mg/L initial concentration and 2 g/L biosorbent dose. The pseudo-second-order and intraparticle diffusion kinetics describe the biosorption process. The maximum calculated biosorption capacity was 21.39 mg/g similar to that recorded experimentally. The equilibrium biosorption data were a good fit for Freundlich and Dubinin–Radushkevich isotherms. Our findings reveal that the low cost and eco-friendly obtained biosorbent can be easily synthesized and suitable to remove Ethacridine Lactate from water matrices. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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12 pages, 3937 KiB  
Article
The Influence of Self-Heating Iron on the Thermal, Mechanical, and Swelling Properties of PDMS Composites for Organic Solvents Removal
by Mohamed S. A. Darwish and Laila M. Al-Harbi
Polymers 2021, 13(23), 4231; https://doi.org/10.3390/polym13234231 - 2 Dec 2021
Cited by 2 | Viewed by 1880
Abstract
Volatile organic compounds pollute the environment and pose a serious threat to human health due to their toxicity, mutagenicity, and carcinogenicity. In this context, it is highly desirable to fabricate high-performance poly (dimethylsiloxane) (PDMS) composites to remove organic solvents from the environment using [...] Read more.
Volatile organic compounds pollute the environment and pose a serious threat to human health due to their toxicity, mutagenicity, and carcinogenicity. In this context, it is highly desirable to fabricate high-performance poly (dimethylsiloxane) (PDMS) composites to remove organic solvents from the environment using a simple technique. Therefore, in the present study, Fe-PDMS composites were fabricated using a technique based on magnetic induction heating with iron particles serving as a self-heating agent. Under an alternating magnetic field, the iron particles served as a thermal source that assisted in the progression of PDMS crosslinking. The influence of self-heating iron on the properties of the fabricated Fe-PDMS composites was also investigated. The hydrosilation reaction occurring during the crosslinking process was controlled using FT-IR. The heating efficiency of PDMS 1, PDMS 2, and PDMS 3 was studied as the function of induction time (0–5 min) and the function of iron content (0%, 1%, and 30% wt.%). The results revealed that the mechanical properties of the PDMS 2 composite were enhanced compared to those of the PDMS 1 and PDMS 3 composites. The mechanical properties of PDMS 3 were the least efficient due to cluster formation. PDMS 3 exhibited the highest thermal stability among all composites. Furthermore, the swelling behavior of different materials in various organic solvents was studied. PDMS was observed to swell to the greatest extent in chloroform, while swelling to a large extent was observed in toluene, pentane, and petroleum ether. PDMS swelling was the least in n-butanol. The elastomeric behavior of crosslinked PDMS, together with its magnetic character, produces stimuli-responsive magneto-rheological composites, which are quite efficient and suitable for applications involving the removal of organic solvents. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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14 pages, 3917 KiB  
Article
Synthesis, Characterization and Sorption Ability of Epoxy Resin-Based Sorbents with Amine Groups
by Beata Podkościelna, Monika Wawrzkiewicz and Łukasz Klapiszewski
Polymers 2021, 13(23), 4139; https://doi.org/10.3390/polym13234139 - 27 Nov 2021
Cited by 10 | Viewed by 1954
Abstract
Water pollution by toxic substances, such as azo dyes, is a serious environmental problem that needs to be addressed. This study presents the synthesis and characterization of new polymeric sorbents, based on the epoxy resin Epidian® 5 (Ep5), as a potential adsorbent [...] Read more.
Water pollution by toxic substances, such as azo dyes, is a serious environmental problem that needs to be addressed. This study presents the synthesis and characterization of new polymeric sorbents, based on the epoxy resin Epidian® 5 (Ep5), as a potential adsorbent for the removal of the toxic azo dye C.I. Acid Violet 1 (AV1). Triethylenetetramine (TETA) was applied as a cross-linking agent in the amounts of 1 g (6.67 wt %), 1.5 g (10 wt %), and 2 g (13.33 wt %). The use of a compound with amino groups allows for the simultaneous functionalization of the obtained material. The reaction was carried out in an environment of ethylene glycol, with the addition of a porophore solvent (toluene) and bis(2-ethylhexyl)sulfosuccinate sodium salt (S). The attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) revealed the existence of a strong band in the 828–826 cm−1 range corresponding to the second-order amine group, which indicates their incorporation into the epoxy structure. The glass transition and decomposition temperatures of the resins decreased with the increasing amounts of amine in the material. The thermogravimetry (TGA) analysis demonstrated that all products are thermally stable up to 340 °C. The surface morphology and microstructural properties of the obtained sorbents were determined using scanning electron microscopy (SEM) images and showed an irregular star shape, with dimensions ranging from 400 to 1000 µm. The adsorption capacities of Ep5-TETA1, Ep5-TETA1.5, Ep5-TETA2 and Ep5-TETA1.5 + S for AV1 evaluated during batch experiments were found to be 2.92, 3.76, 7.90 and 3.30 mg/g, respectively. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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16 pages, 4969 KiB  
Article
In Situ Stabilisation of Silver Nanoparticles at Chitosan-Functionalised Graphene Oxide for Reduction of 2,4-Dinitrophenol in Water
by Rebaone Makaudi, Hugues Kamdem Paumo, Boniface Kamdem Pone and Lebogang Katata-Seru
Polymers 2021, 13(21), 3800; https://doi.org/10.3390/polym13213800 - 3 Nov 2021
Cited by 8 | Viewed by 2442
Abstract
This investigation reports the in situ growth of silver nanoparticles onto covalently bonded graphene oxide-chitosan, which serve as supported nanocatalysts for the NaBH4 reduction of 2,4-dinitrophenol in aqueous systems. Fumaryl chloride reacted with chitosan in an acidic environment to yield a tailored [...] Read more.
This investigation reports the in situ growth of silver nanoparticles onto covalently bonded graphene oxide-chitosan, which serve as supported nanocatalysts for the NaBH4 reduction of 2,4-dinitrophenol in aqueous systems. Fumaryl chloride reacted with chitosan in an acidic environment to yield a tailored polymeric material. The latter was, in turn, treated with the pre-synthesised graphene oxide sheets under acidic conditions to generate the GO-functionalised membrane (GO-FL-CS). The adsorption of Ag+ from aqueous media by GO-FL-CS yielded a set of membranes that were decorated with silver nanoparticles (Ag NPs@GO-FL-CS) without any reducing agent. Various analytical tools were used to characterise these composites, including Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller surface area analysis, X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray analysis, inductively coupled plasma-mass spectrometry, and transmission electron microscopy. The silver-loaded materials were further used for the remediation of 2,4-dinitrophenol from aqueous solutions under batch operation. The BET analysis revealed that the functionalisation of GO with chitosan and Ag NPs (average size 20–60 nm) resulted in a three-fold increased surface area. The optimised catalyst (Ag mass loading 16.95%) displayed remarkable activity with an apparent pseudo-first-order rate constant of 13.5 × 10−3 min−1. The cyclic voltammetry experiment was conducted to determine the nitro-conversion pathway. The reusability/stability test showed no significant reduction efficiency of this metal-laden composite over six cycles. Findings from the study revealed that Ag NPs@GO-FL-CS could be employed as a low-cost and recyclable catalyst to convert toxic nitroaromatics in wastewater. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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16 pages, 2748 KiB  
Article
Synthesis, Characterization and Application of Polypyrrole Functionalized Nanocellulose for the Removal of Cr(VI) from Aqueous Solution
by Norah Salem Alsaiari, Khadijah Mohammedsaleh Katubi, Fatimah Mohammed Alzahrani, Abdelfattah Amari, Haitham Osman, Faouzi Ben Rebah and Mohamed A. Tahoon
Polymers 2021, 13(21), 3691; https://doi.org/10.3390/polym13213691 - 26 Oct 2021
Cited by 24 | Viewed by 2623
Abstract
Heavy metals are toxic substances that pose a real danger to humans and organisms, even at low concentration. Therefore, there is an urgent need to remove heavy metals. Herein, the nanocellulose (NC) was synthesized by the hydrolysis of cellulose using sulfuric acid, and [...] Read more.
Heavy metals are toxic substances that pose a real danger to humans and organisms, even at low concentration. Therefore, there is an urgent need to remove heavy metals. Herein, the nanocellulose (NC) was synthesized by the hydrolysis of cellulose using sulfuric acid, and then functionalized using polypyrrole (ppy) through a polymerization reaction to produce polypyrrole/nanocellulose (ppy/NC) nanocomposite. The synthesized nanocomposite was characterized using familiar techniques including XRD, FT-IR, SEM, TEM, and TGA. The obtained results showed a well-constructed nanocomposite with excellent thermal stability in the nano-sized scale. The adsorption experiments showed that the ppy/NC nanocomposite was able to adsorb hexavalent chromium (Cr(VI)). The optimum pH for the removal of the heavy metal was pH 2. The interfering ions showed minor effect on the adsorption of Cr(VI) resulted from the competition between ions for the adsorption sites. The adsorption kinetics were studied using pseudo 1st order and pseudo 2nd order models indicating that the pseudo second order model showed the best fit to the experimental data, signifying that the adsorption process is controlled by the chemisorption mechanism. Additionally, the nanocomposite showed a maximum adsorption capacity of 560 mg/g according to Langmuir isotherm. The study of the removal mechanism showed that Cr(VI) ions were removed via the reduction of high toxic Cr(VI) to lower toxic Cr(III) and the electrostatic attraction between protonated ppy and Cr(VI). Interestingly, the ppy/NC nanocomposite was reused for Cr(VI) uptake up to six cycles showing excellent regeneration results. Subsequently, Cr(VI) ions can be effectively removed from aqueous solution using the synthesized nanocomposite as reusable and cost-effective adsorbent. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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15 pages, 3421 KiB  
Article
Superabsorbents and Their Application for Heavy Metal Ion Removal in the Presence of EDDS
by Dorota Kołodyńska, Alicja Drozd and Yongming Ju
Polymers 2021, 13(21), 3688; https://doi.org/10.3390/polym13213688 - 26 Oct 2021
Cited by 1 | Viewed by 1427
Abstract
Three acrylic-based superabsorbents—TerraHydrogel®Aqua (THA), Zeba®Hydrogel (ZH) and Agro®Hydrogel (AH) were used to investigate the influence of chemical conditions on kinetic and adsorption behavior towards metal ions in the presence of a chelating agent of a new generation [...] Read more.
Three acrylic-based superabsorbents—TerraHydrogel®Aqua (THA), Zeba®Hydrogel (ZH) and Agro®Hydrogel (AH) were used to investigate the influence of chemical conditions on kinetic and adsorption behavior towards metal ions in the presence of a chelating agent of a new generation called ethylenediamine-N,N′-disuccinic acid (EDDS). The effects of relevant parameters—mainly including those of sorbent dose, pH of the solution and initial concentration of Cu(II), Zn(II), Mn(II) and Fe(III) complexes with EDDS as well as phase contact time and temperature—on the adsorption efficiency were studied in detail by the static method. The experimental data were also characterized by kinetic and adsorption parameters obtained based on the Langmuir and Freundlich models of sorption as well as the Lagergren, Ho and McKay and Weber–Morris models. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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14 pages, 2673 KiB  
Article
Removal of Toxic Copper Ion from Aqueous Media by Adsorption on Fly Ash-Derived Zeolites: Kinetic and Equilibrium Studies
by Gabriela Buema, Luisa-Maria Trifas and Maria Harja
Polymers 2021, 13(20), 3468; https://doi.org/10.3390/polym13203468 - 9 Oct 2021
Cited by 20 | Viewed by 2690
Abstract
This study investigated the adsorption capacity of one material based on the treatment of fly ash with sodium hydroxide as a novel adsorbent for toxic Cu2+ ion removal from aqueous media. The adsorbent was obtained through direct activation of fly ash with [...] Read more.
This study investigated the adsorption capacity of one material based on the treatment of fly ash with sodium hydroxide as a novel adsorbent for toxic Cu2+ ion removal from aqueous media. The adsorbent was obtained through direct activation of fly ash with 2M NaOH at 90 °C and 6 h of contact time. The adsorbent was characterized by recognized techniques for solid samples. The influence of adsorption parameters such as adsorbent dose, copper initial concentration and contact time was analyzed in order to establish the best adsorption conditions. The results revealed that the Langmuir model fitted with the copper adsorption data. The maximum copper adsorption capacity was 53.5 mg/g. The adsorption process followed the pseudo-second-order kinetic model. The results indicated that the mechanism of adsorption was chemisorption. The results also showed the copper ion removal efficiencies of the synthesized adsorbents. The proposed procedure is an innovative and economical method, which can be used for toxicity reduction by capitalizing on abundant solid waste and treatment wastewater. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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24 pages, 8020 KiB  
Article
Polymer Adsorbents vs. Functionalized Oxides and Carbons: Particulate Morphology and Textural and SurfaceCharacteristics
by Volodymyr M. Gun’ko
Polymers 2021, 13(8), 1249; https://doi.org/10.3390/polym13081249 - 12 Apr 2021
Cited by 9 | Viewed by 2528
Abstract
Various methods for morphological, textural, and structural characterization of polymeric, carbon, and oxide adsorbents have been developed and well described. However, there are ways to improve the quantitative information extraction from experimental data for describing complex sorbents and polymer fillers. This could be [...] Read more.
Various methods for morphological, textural, and structural characterization of polymeric, carbon, and oxide adsorbents have been developed and well described. However, there are ways to improve the quantitative information extraction from experimental data for describing complex sorbents and polymer fillers. This could be based not only on probe adsorption and electron microscopies (TEM, SEM) but also on small-angle X-ray scattering (SAXS), cryoporometry, relaxometry, thermoporometry, quasi-elastic light scattering, Raman and infrared spectroscopies, and other methods. To effectively extract information on complex materials, it is important to use appropriate methods to treat the data with adequate physicomathematical models that accurately describe the dependences of these data on pressure, concentration, temperature, and other parameters, and effective computational programs. It is shown that maximum accurate characterization of complex materials is possible if several complemented methods are used in parallel, e.g., adsorption and SAXS with self-consistent regularization procedures (giving pore size (PSD), pore wall thickness (PWTD) or chord length (CLD), and particle size (PaSD) distribution functions, the specific surface area of open and closed pores, etc.), TEM/SEM images with quantitative treatments (giving the PaSD, PSD, and PWTD functions), as well as cryo- and thermoporometry, relaxometry, X-ray diffraction, infrared and Raman spectroscopies (giving information on the behavior of the materials under different conditions). Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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Review

Jump to: Research

30 pages, 7013 KiB  
Review
Highlighting the Importance of Characterization Techniques Employed in Adsorption Using Metal–Organic Frameworks for Water Treatment
by Thabiso C. Maponya, Katlego Makgopa, Thabang R Somo and Kwena D. Modibane
Polymers 2022, 14(17), 3613; https://doi.org/10.3390/polym14173613 - 1 Sep 2022
Cited by 5 | Viewed by 2499
Abstract
The accumulation of toxic heavy metal ions continues to be a global concern due to their adverse effects on the health of human beings and animals. Adsorption technology has always been a preferred method for the removal of these pollutants from wastewater due [...] Read more.
The accumulation of toxic heavy metal ions continues to be a global concern due to their adverse effects on the health of human beings and animals. Adsorption technology has always been a preferred method for the removal of these pollutants from wastewater due to its cost-effectiveness and simplicity. Hence, the development of highly efficient adsorbents as a result of the advent of novel materials with interesting structural properties remains to be the ultimate objective to improve the adsorption efficiencies of this method. As such, advanced materials such as metal–organic frameworks (MOFs) that are highly porous crystalline materials have been explored as potential adsorbents for capturing metal ions. However, due to their diverse structures and tuneable surface functionalities, there is a need to find efficient characterization techniques to study their atomic arrangements for a better understanding of their adsorption capabilities on heavy metal ions. Moreover, the existence of various species of heavy metal ions and their ability to form complexes have triggered the need to qualitatively and quantitatively determine their concentrations in the environment. Hence, it is crucial to employ techniques that can provide insight into the structural arrangements in MOF composites as well as their possible interactions with heavy metal ions, to achieve high removal efficiency and adsorption capacities. Thus, this work provides an extensive review and discussion of various techniques such as X-ray diffraction, Brunauer–Emmett–Teller theory, scanning electron microscopy and transmission electron microscopy coupled with energy dispersive spectroscopy, and X-ray photoelectron spectroscopy employed for the characterization of MOF composites before and after their interaction with toxic metal ions. The review further looks into the analytical methods (i.e., inductively coupled plasma mass spectroscopy, ultraviolet-visible spectroscopy, and atomic absorption spectroscopy) used for the quantification of heavy metal ions present in wastewater treatment. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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12 pages, 634 KiB  
Review
Waste Materials as a Resource for Production of CMC Superabsorbent Hydrogel for Sustainable Agriculture
by Vojkan Miljković, Ivana Gajić and Ljubiša Nikolić
Polymers 2021, 13(23), 4115; https://doi.org/10.3390/polym13234115 - 26 Nov 2021
Cited by 22 | Viewed by 3694
Abstract
Waste materials are receiving more attention as concerns about the future of our planet increase. Cellulose is the most common substance in agricultural waste. Agricultural wastes containing cellulose are misplaced resources that could be reused in various fields for both environmental and economic [...] Read more.
Waste materials are receiving more attention as concerns about the future of our planet increase. Cellulose is the most common substance in agricultural waste. Agricultural wastes containing cellulose are misplaced resources that could be reused in various fields for both environmental and economic benefits. In this work, 32 different kinds of waste are investigated for chemical modification in order to obtain carboxymethyl cellulose for the production of a superabsorbent hydrogel that can be applied in agriculture. A brief literature review is provided to help researchers wishing to obtain carboxymethyl cellulose by carboxymethylation starting with waste materials. We also provide details about methods to obtain as well as verify carboxymethylation. Carboxymethyl cellulose (CMC), as a constituent of cellulosic water and superabsorbent hydrogels with applications in agriculture, is described. Superabsorbent hydrogels with CMC are able to absorb huge amounts of water and are biodegradable. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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32 pages, 41164 KiB  
Review
Solid-Phase Extraction of Active Compounds from Natural Products by Molecularly Imprinted Polymers: Synthesis and Extraction Parameters
by Sazlinda Kamaruzaman, Najihah Mohammad Nasir, Siti Munirah Mohd Faudzi, Noorfatimah Yahaya, Nor Suhaila Mohamad Hanapi and Wan Nazihah Wan Ibrahim
Polymers 2021, 13(21), 3780; https://doi.org/10.3390/polym13213780 - 31 Oct 2021
Cited by 15 | Viewed by 4182
Abstract
Molecularly imprinted polymers (MIPs) are synthetic polymers with a predetermined selectivity for a particular analyte or group of structurally related compounds, making them ideal materials for separation processes. Hence, in sample preparation, MIPs are chosen as an excellent material to provide selectivity. Moreover, [...] Read more.
Molecularly imprinted polymers (MIPs) are synthetic polymers with a predetermined selectivity for a particular analyte or group of structurally related compounds, making them ideal materials for separation processes. Hence, in sample preparation, MIPs are chosen as an excellent material to provide selectivity. Moreover, its use in solid-phase extraction, also referred to as molecular imprinted solid phase extraction (MISPE), is well regarded. In recent years, many papers have been published addressing the utilization of MIPs or MISPE as sorbents in natural product applications, such as synthesis. This review describes the synthesis and characterization of MIPs as a tool in natural product applications. Full article
(This article belongs to the Special Issue Functional Polymeric Adsorbents)
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