Showing papers on "Acrylic acid published in 2019"
TL;DR: Modified cellulose hydrogels were prepared by blending and cross-linking with acrylamide and acrylic acid and the adsorption mechanisms such as physical, chemical, and electrostatic interactions are discussed.
116 citations
TL;DR: Hydrogels synthesized by grafting copolymerization of acrylic acid and acrylamide onto pineapple peel carboxymethyl cellulose with incorporation of graphene oxide showed a selective adsorption behavior to various dyes and the incorporation of GO enhanced the adsorptive performance.
84 citations
TL;DR: Investigation of the effect of crosslinker content and pectin to acrylic acid ratio on the swelling properties of hydrogels showed that introduction of small amount of pECTin to poly(acrylic acid) hydrogel increase the swelling capacity, while further increasing of pectIn ratio cause decrease of swelling.
Abstract: The aim of the research was to develop new pectin-based hydrogels with excellent swelling properties. Superabsorbent hydrogels composed of high methylated pectin and partially neutralized poly(acrylic acid) was obtained by free radical polymerization in aqueous solution in the presence of crosslinking agent—N,N’-methylenebisacrylamide. The effect of crosslinker content and pectin to acrylic acid ratio on the swelling properties of hydrogels was investigated. In addition, the thermodynamic characteristic of hydrogels was obtained by DSC. Furthermore, the structure of pectin-based hydrogels was characterized by FTIR and GPC. It was also proved that poly(acrylic acid) is grafted on pectin particles. The results showed that introduction of small amount of pectin (up to 6.7 wt %) to poly(acrylic acid) hydrogel increase the swelling capacity, while further increasing of pectin ratio cause decrease of swelling.
76 citations
TL;DR: In this paper, the authors demonstrate the preparation and unique functions of elastomeric polyester vitrimer materials with different cross-link densities based on a post-polymerization cross-linking method.
71 citations
TL;DR: The thermal and flammability properties of the cotton fabric were improved after treated with the nanocomposite and the mechanical property of the treated cotton fabric was improved, but the whiteness decreased slightly.
65 citations
TL;DR: The results showed that the novel superabsorbent polymer exhibits excellent water absorbency, which can absorb distilled water 615 g/g and 0.9% NaCl solution 44 G/g, and the introduction of antibacterial groups also enhances antibacterial properties against Escherichia coli and Staphylococcus aureus.
64 citations
TL;DR: In this article, the influence of Ce amount on catalytic behavior of perovskite catalysts La1-xCexFeO3-δ, prepared by coprecipitation, was examined in catalytic wet air oxidation (CWAO) of high concentrated acrylic acid pollutant.
Abstract: The influence of Ce amount on catalytic behaviour of perovskite catalysts La1-xCexFeO3-δ, prepared by coprecipitation was examined in catalytic wet air oxidation (CWAO) of high concentrated acrylic acid pollutant. The catalysts with the molar ratio of Ce/ (La + Ce) upper than 0.4 exhibit high catalytic activity, and outstanding stability. Because Ce doping into the skeleton of LaFeO3 could cause the change of iron valence state as well as the change of the reactive oxygen species and oxygen vacancies of the catalyst. Three ways of O2 involved in this reaction were considered, a synergistic mechanism of oxygen vacancies, the reversible electronic transition Fe3+↔ Fe2+, and direct oxidization of acrylic acid. First-principles calculations revealed that the oxygen vacancy is more easily to form in the case of Ce content increasing in La1-xCexFeO3-δ, and oxygen would adsorb on oxygen vacancy to form reactive oxygen species. Consequently, the reactive oxygen species (O*) could oxidize acrylic acid. In this process, Fe ions of higher valence sate which would attack organic compounds and itself was reduced to Fe2+ to achieve catalytic cycles. Finally, the reaction was verified as first order, which was well explained by a proposed generalized kinetic model, in good accordance with our experimental data.
61 citations
TL;DR: In this paper, a pH sensitive nanocomposite (NC) hydrogel based on katira gum-cl-poly(acrylic acid-co-N, N-dimethylacrylamide) incorporated bentonite (BT) nano clay was prepared by in-situ crosslinked co-polymerization technique using N, N′-methylene-bis-acryamide (MBA) as crosslinker and potassium peroxodisulphate (KPS) as a free radical initiator.
59 citations
TL;DR: In this article, a super-hydrophilic polyvinylidene fluoride (PVDF) membrane was obtained through plasma-induced poly (acrylic acid) (PAA) polymerization followed by titanium dioxide nano particles (TiO2 NPs) self-assembly for oily produced water treatment.
56 citations
TL;DR: A poly(acrylic acid-co-maleic acid) composite hydrogel with enhanced mechanical properties and remarkable water retention was fabricated under accessible conditions and exhibits self-healing abilities at low temperature.
Abstract: Many living tissues possess excellent mechanical properties and water retention which enable them to self-heal at room temperature even below the freezing temperature of water. To mimic the unique features of living tissue, a poly(acrylic acid-co-maleic acid) composite hydrogel with enhanced mechanical properties and remarkable water retention was fabricated under accessible conditions. The hydrogel is functionalized by amino group modified boron nitride nanosheets (BNNS-NH2)/glycerol and exhibits self-healing abilities at low temperature. The self-healing process occurs through the re-establishing of hydrogen bonds and metal coordination interactions at the damaged surfaces. Its anti-freezing abilities enable the hydrogel to self-heal at -15 °C, and the self-healing efficiency based on tensile strength reaches up to ∼70%. Moreover, glycerol also endows the hydrogel with long-lasting water retention, which remains a water content of ∼99 wt% for more than 30 days. Meanwhile, the simultaneous introduction of BNNS-NH2 and glycerol significantly improved the mechanical properties of the hydrogel, which displays great stretchability (∼474%), tensile strength (∼151.3 kPa), stiffness (Young's modulus of ∼62.75 kPa) and toughness (∼355.13 kJ m-3). It is anticipated that these novel hydrogels will develop many fields and be exploited for new applications in extensive external environments.
55 citations
TL;DR: In this article, a biocompatible Dex-MA/PAA hydrogel was prepared through copolymerization of glycidyl methacrylate substituted dextran (Dex-MA) with acrylic acid (AA), which was applied as the adsorbent to remove cationic dyes from aqueous solutions.
Abstract: A biocompatible Dex-MA/PAA hydrogel was prepared through copolymerization of glycidyl methacrylate substituted dextran (Dex-MA) with acrylic acid (AA), which was applied as the adsorbent to remove cationic dyes from aqueous solutions. Dex-MA/PAA hydrogel presented a fast adsorption rate and the removal efficiency of Methylene Blue (MB) and Crystal Violet (CV) reached 93.9% and 86.4%, respectively within one minute at an initial concentration of 50 mg L−1. The adsorption equilibrium data fitted the Sips isotherm model well with high adsorption capacities of 1994 mg g−1 for MB and 2390 mg g−1 for CV. Besides, dye adsorption occurred efficiently over the pH range 3–10 and the temperature range 20–60 °C. Moreover, the removal efficiencies for MB and CV were still >95% even after five adsorption/desorption cycles which indicates the robust nature of the Dex-MA/PAA hydrogel and its potential as an eco-friendly adsorbent for water treatment.
TL;DR: The dynamic mechanical and rheological behavior of polyelectrolyte coacervates and complex precipitates is of interest for many applications ranging from health to personal care as mentioned in this paper.
Abstract: The dynamic mechanical and rheological behavior of polyelectrolyte coacervates and complex precipitates is of interest for many applications ranging from health to personal care. Hydration is an im...
TL;DR: In this article, the potential of cellulose nanofibers (CNFs) treated starch-poly(acrylic acid) (St-g-PAA) superadsorbent hydrogels in removing Cu2+ ions from water was investigated.
Abstract: Removal of pollutants by bio-superadsorbent is currently in the limelight due to their low cost and biocompatibility with the environment This research, we investigated the potential of cellulose nanofibers (CNFs) treated starch-g-poly(acrylic acid) (St-g-PAA) superadsorbent hydrogels in removing Cu2+ ions from water It was found that CNFs-incorporated starch-g-poly(acrylic acid) hydrogel exhibit the highest amount of Cu2+ uptake in a solution containing 01 g/L Cu2+ ions, and that adsorption capacity rises significantly with the increase in Cu2+ concentration from 01 to 06 g/L The influence of CNFs on the adsorption of Cu2+ ions was studied by Langmuir and Freundlich adsorption isotherm models, the graphs verged on linearity in Langmuir model while the maximum monolayer adsorption capacity was found to be 0736 g/g for the untreated St-g-PAA hydrogels and 0957 g/g for the CNFs-treated hydrogels in 06 g/L Cu2+ solution at pH 5 In this study, the adsorption capacity was enhanced by increasing the contact time between the bio-adsorbent and solution up to 5 h while longer contact time resulted in reduced adsorption and desorption phenomenon In addition, desorption results showed that maximum adsorbent recovery for pH near to 1–2 This study confirms that the starch-based hydrogel is promising to be used for removal of pollutants from water efficiently
TL;DR: Aiming to facilitate the application of bio‐carboxylation reactions in preparative‐scale biotransformations, their catalytic mechanism and substrate scope are analyzed in this review.
Abstract: The utilization of carbon dioxide as a C1-building block for the production of valuable chemicals has recently attracted much interest. Whereas chemical CO2 fixation is dominated by C-O and C-N bond forming reactions, the development of novel concepts for the carboxylation of C-nucleophiles, which leads to the formation of carboxylic acids, is highly desired. Beside transition metal catalysis, biocatalysis has emerged as an attractive method for the highly regioselective (de)carboxylation of electron-rich (hetero)aromatics, which has been recently further expanded to include conjugated α,β-unsaturated (acrylic) acid derivatives. Depending on the type of substrate, different classes of enzymes have been explored for (i) the ortho-carboxylation of phenols catalyzed by metal-dependent ortho-benzoic acid decarboxylases and (ii) the side-chain carboxylation of para-hydroxystyrenes mediated by metal-independent phenolic acid decarboxylases. Just recently, the portfolio of bio-carboxylation reactions was complemented by (iii) the para-carboxylation of phenols and the decarboxylation of electron-rich heterocyclic and acrylic acid derivatives mediated by prenylated FMN-dependent decarboxylases, which is the main focus of this review. Bio(de)carboxylation processes proceed under physiological reaction conditions employing bicarbonate or (pressurized) CO2 when running in the energetically uphill carboxylation direction. Aiming to facilitate the application of these enzymes in preparative-scale biotransformations, their catalytic mechanism and substrate scope are analyzed in this review.
TL;DR: The modified PVDF-g-PAA-Ag@Ni membrane presented 100% flux recovery and reduced fouling propensity when filtrating 0.1 g/L sodium alginate (SA) solution and involvement of silver in this strategy provided evident antibacterial activity of the modified membranes.
TL;DR: The prepared adsorbent, PAA-L@PVA-PB, was used as a column filling material and its potential use as a countermeasure for removing radioactive cesium from a contaminated water stream was demonstrated.
TL;DR: In this article, carboxymethyl cellulose (CMC) solution and crosslinked poly(acrylic acid) (cPAA) single IPN hydrogel at mass ratios 100:0, 25:75, 50:50, 75:25 and 0:100 were prepared by mixing CMC chains with citric acid.
Abstract: Interpenetrating polymer network (IPN) hydrogels were prepared by mixing carboxymethyl cellulose (CMC) solution and crosslinked poly(acrylic acid) (cPAA) single IPN hydrogel at mass ratios 100:0, 25:75, 50:50, 75:25 and 0:100 and subsequent crosslinking of CMC chains with citric acid, aimed towards the creation of full IPN hydrogels. The resulting CMC:cPAA hydrogels were freeze-dried for the determination of density, swelling degree, compressive modulus and thermal behavior. Morphological and structural parameters were determined by means of scanning electron microscopy, Fourier transform infrared spectroscopy in the attenuated total reflectance mode (FTIR-ATR) and X-ray microtomography (CT) analyses. The efficiency of CMC:cPAA hydrogels as adsorbents for methylene blue (MB) dye at pH 7 and Cu2+ ions at pH 4.5 was systematically investigated at (24 ± 1) °C and evaluated with Langmuir, Freundlich and Dubinin–Radushkevitch adsorption models and kinetic equations. The CMC:cPAA 50:50 hydrogels were particularly interesting because they presented the highest compression modulus (141 ± 3 kPa), swelling degree of 58 ± 2 gwater/g and maximum adsorption capacity (qmax) for MB dye and Cu2+ ions as 613 mg g−1 and 250 mg g−1, respectively. The adsorption kinetics of MB and Cu2+ ions followed the pseudo-second order equation. Fitting with the intraparticle diffusion model showed that in both cases, the adsorbate molecules first diffuse rapidly from the medium to the adsorbent surface, and then in a second slower stage, they diffuse into the network macropores. The hydrogels could be recycled five times without losing efficiency.
TL;DR: In this article, a poly(acrylic acid) is converted into a thermoresponsive polymer possessing an upper critical solution temperature (UCST) by copolymerizing with acrylonitrile.
Abstract: Poly(acrylic acid) is water soluble but can be converted into a thermoresponsive polymer possessing an upper critical solution temperature (UCST) by copolymerizing with acrylonitrile. The copolymer...
TL;DR: XG-PAA semi-IPNs are recommended as an environmentally benign and readily non-toxic material with an excellent adsorption capacity for application in drug delivery systems, wound healing and dye removal.
TL;DR: In this article, free radical copolymerization of acrylic acid (AA), 2-hydroxyethyl acrylate (HEA), and monomethacryloxypropyl terminated poly(dimethyl siloxane) (PDMS-MA) yielded graft (g) copolymers P(AA-HEA)-g-PDMS.
TL;DR: In this article, Nanocrystalline cellulose (NCC) was modified with (3-aminopropyl)triethoxysilane (APTES) and hexadecyltrimethoxylane (HDTMS) to obtain NCC and NCC-HPTMS respectively by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and field emission scanning electron microscopy.
Abstract: Nanocrystalline cellulose (NCC) was modified with (3-aminopropyl)triethoxysilane (APTES) and hexadecyltrimethoxysilane (HDTMS) to obtain NCC-APTES and NCC-HDTMS respectively. The modification was confirmed by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) spectroscopy, thermogravimetric analyses (TGA), dynamic light scattering and zeta potential analyses. A series of poly(acrylic acid) (PAA)/NCC, PAA/NCC-APTES, and PAA/NCC-HDTMS hydrogel nanocomposites with various amounts of nanoparticles were synthesized by in situ radical polymerization method. Nanocomposites were characterized using XRD, TGA and field emission scanning electron microscopy. Also, swelling behavior of hydrogel nanocomposites showed that NCC and NCC-APTES helped swelling of hydrogels whereas CNN-HDTMS decreased swelling ratio. The hydrogel nanocomposites were also used as adsorbents for removal of methylene Blue from aqueous solution at different pH values. Results showed that the adsorption capacity for dye increased with increasing pH and contact time. Introducing NCC into hydrogel nanocomposite network affected adsorption capacity. Finally, adsorption kinetics was studied by three kinetic models including pseudo-first-order, pseudo-second-order and intra-particle diffusion models.
TL;DR: In this paper, the surface modification of titanium dioxide in aqueous dispersions of specially tailor-made periodic acrylic acid/isobutylene copolymers, poly(acrylic acid)/polystyrene graft copolymer, and hydrophobically modified polyethyleneoxide urethane by ultrasonic treatment was studied.
Abstract: The surface modification of titanium dioxide in aqueous dispersions of specially tailor-made periodic acrylic acid/isobutylene copolymers, poly(acrylic acid)/polystyrene graft copolymers, and hydrophobically modified polyethyleneoxide urethane by ultrasonic treatment was studied. The pigment surface modification by the above copolymers was comparatively investigated regarding conventional adsorption as contrasted to an ultrasonic treatment assisted procedure. The course and efficiency of the polymer adsorption onto the pigment surface was quantified by electrokinetic sonic amplitude measurements. The higher efficiency of the pigment surface coating by the copolymers as achieved by ultrasonic treatment varies with the copolymer architecture and is a consequence of ultrasonically induced pigment surface activation.
TL;DR: The use of water hyacinth, a notorious weed in Kenyan waters, to produce cellulose-based polymer hydrogels has not been explored and yet, it could form an effective and beneficial way of utilizing this plant.
TL;DR: It is suggested that synthesized TA-poly(AN-co-AA) can be applied successfully to remove cationic dyes from aquatic environments with maximum adsorption capacity after five regeneration cycles.
Abstract: The paper evaluates the adsorptive potential of thiourea-modified poly(acrylonitrile-co-acrylic acid), (TA-poly(AN-co-AA)) for the uptake of cationic methylene blue (MB) from aquatic environments via a batch system. TA-poly(AN-co-AA) polymer was synthesized through redox polymerization and modified with thiourea (TA) where thioamide groups were introduced to the surface. Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), CHNS and Zetasizer were used to characterize the physico-chemical and morphological properties of prepared TA-poly(AN-co-AA). Afterwards, it was confirmed that incorporation of thioamide groups was successful. The adsorption kinetics and equilibrium adsorption data were best described, respectively, by a pseudo-second-order model and Freundlich model. Thermodynamic analysis showed the exothermic and spontaneous nature of MB uptake by TA-poly(AN-co-AA). The developed TA-poly(AN-co-AA) polymer demonstrated efficient separation of MB dye from the aqueous solution and maintained maximum adsorption capacity after five regeneration cycles. The findings of this study suggested that synthesized TA-poly(AN-co-AA) can be applied successfully to remove cationic dyes from aquatic environments.
TL;DR: In this paper, the surface functionalization with thiourea was carried out to provide hydrophilicity on the surface of a polymeric adsorbent, which was a surface modification of poly(acrylonitrile-co-acrylic acid) synthesized by facile redox polymerization.
Abstract: Thiourea-modified poly(acrylonitrile-co-acrylic acid) (TU-poly(AN-co-AA)) adsorbent was a surface modification of poly(acrylonitrile-co-acrylic acid) synthesized by facile redox polymerization. Surface functionalization with thiourea was carried out to provide hydrophilicity on the surface of a polymeric adsorbent. Fourier transform infrared (FTIR) spectrometer, scanning electron microscope (SEM), and Zetasizer characterized the morphology and structures of TU-poly(AN-co-AA). Copolymerization of poly(acrylonitrile-co-acrylic acid) and its successful incorporation of the thioamide group was confirmed by the FTIR spectra. The SEM micrographs depicted uniform and porous surface morphologies of polymeric particles. The average diameter of modified and unmodified poly(acrylonitrile-co-acrylic acid) was 289 nm and 279 nm, respectively. Zeta potentials of TU-poly(AN-co-AA) revealed the negatively charged surface of the prepared polymer. Adsorption capacities of hydrophilic TU-poly(AN-co-AA) were investigated using malachite green (MG) as an adsorbate by varying experimental conditions (pH, initial concentration, and temperature). Results showed that the pseudo-second-order reaction model best described the adsorption process with chemisorption being the rate-limiting step. Furthermore, Elovich and intraparticle diffusions play a significant role in adsorption kinetics. The equilibrium isotherm has its fitness in the following order: Freundlich model > Temkin model > Langmuir model. Thermodynamic analysis indicates that the sorption process is spontaneous and exothermic in nature. The reusability results suggested potential applications of the TU-poly(AN-co-AA) polymer in adsorption and separation of cationic malachite green dye from wastewater.
TL;DR: In this article, the authors reported the greener synthesis and characterization of novel acrylic acid grafted amphoteric chitosan/TiO2 (CAT) bionanocomposites using ultrasonic radiations.
Abstract: The present investigation reports the greener synthesis and characterization of novel acrylic acid grafted amphoteric chitosan/TiO2 (CAT) bionanocomposites using ultrasonic radiations. This was done by grafting of acrylic acid onto chitosan in the presence of potassium persulfate by free radical polymerization reaction. The uniform distribution of metal oxide in CA/TiO2 nanocomposites was achieved on grafted acrylic acid/chitosan which contains a weak anionic group (-COOH) using ultrasonication technique. Physiochemical techniques such as X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), Fourier Transform Infra-Red spectroscopy (FT-IR), Energy Dispersive X-ray spectroscopy (EDX), and Thermal Gravimetric Analysis (TGA) were employed to characterize synthesized CAT. Nanocomposite CAT was applied for degradation of industrial dye. Malachite green (MG) often presents in the waste waters. The degradation kinetics were studied by monitoring the photocatalytic reaction for degradation of MG under visible light, and the rate constant of the reaction was found to be 7.13x10−3min−1. The current research work opens vistas for the new dimensions in the area of water treatment by solving the issues related to degradation reaction efficiency in visible light and cost effectiveness.
TL;DR: The dyes in effluents are among the most aggressive pollutions as discussed by the authors, and synthetic dyes have been widely used in several industries such as textiles, rubber, paper, plastic, and leather tanning.
Abstract: At present, synthetic dyes have been widely used in several industries such as textiles, rubber, paper, plastic, and leather tanning. The dyes in effluents are among the most aggressive pollutions ...
TL;DR: In this article, the authors investigated the effect of oxides (SiO2, SiO2-Al2O3, Nb2O5, nb2o5-SiO 2O3), heteropolyacids (HPAs), and supported HPAs on the oxides as bifunctional catalysts with varying ratios of Lewis to Bronsted acid sites on cellulose conversion into lactic acid.
TL;DR: In this article, the magnetic Fe3O4-based starch-poly (acrylic acid) nanocomposite hydrogel was designed and synthesized using free radical method to remove toxic dyes and heavy metal ions.
Abstract: Aimed to removal of toxic dyes and heavy metal ions, the magnetic Fe3O4-based starch- poly (acrylic acid) nanocomposite hydrogel (Fe3O4@St-AcANCH) is designed and synthesized using free radical method. The main procedure for the synthesis of superabsorbent nanocomposite hydrogel is chemical crosslinking of starch and poly (acrylic acid). The as-prepared nanocomposite hydrogel present high removal percentage toward Cu(II), Pb (II), MV and CR solution through a spontaneous physic-sorption process that have a good consistence with pseudo-second-order and Langmuir isotherm models. It is indicated that nanocomposite hydrogel is an effective adsorbent for removal of dyes and metal ions which would provide a new platform for water and environmental considerations. Finally, the swelling properties and mechanical parameters of the prepared adsorbents were investigated preliminarily.
TL;DR: In this paper, a commercial polyamide nanofiltration membrane was achieved by UV induced graft polymerization of acrylic acid and incorporation of carboxylated-MWCNTs.
Abstract: Surface modification of a commercial polyamide nanofiltration membrane was achieved by UV induced graft polymerization of acrylic acid and incorporation of carboxylated-MWCNTs (COOH-MWCNTs). The grafting process was done under different monomer concentrations and UV exposure times. The modified membranes were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle and zeta-potential analysis, and cross-flow filtration experiments. Changes in the surface hydrophilicity, negative charge and roughness of the modified membranes improved their permeability and fouling resistance significantly. The membrane grafted with 50 g/L acrylic acid under 5 min UV exposure showed the best filtration performance including pure water flux of 38.8 L/m2 h, salt rejections of 97.43% (Na2SO4) and 93.4% (NaCl), and flux recovery ratio (FRR) of 80.2% during bovine serum albumin (BSA) filtration. After optimizing grafting condition, different amounts of COOH-MWCNTs were dispersed in the monomer solution for embedding in the grafting layer. By adding 0.2 wt% COOH-MWCNTs to the grafting layer, a water flux improvement of around 30% was observed. But, excess loading of the COOH-MWCNTs led to compaction of the grafting layer and made it inflexible and subsequently, reduced the hydrophilicity and permeability of the membrane. Fouling tests with BSA aqueous solution showed that antifouling ability of the modified membranes was remarkably improved at all concentrations of the COOH-MWCNTs. Furthermore, salt rejection results displayed that simultaneous surface modification through grafting and COOH-MWCNTs embedding could effectively improve the nanofiltration performance of the membranes in the term of permeability, desalination and fouling resistance.