Graft Copolymerization Of Acrylic Acid Research Articles

Oral delivery of Sunitinib malate using carboxymethyl cellulose/poly(acrylic acid-itaconic acid)/Cloisite 30B nanocomposite hydrogel as a pH-responsive carrier.

This work aimed to fabricate a Cloisite 30B-incorporated carboxymethyl cellulose graft copolymer of acrylic acid and itaconic acid hydrogel (Hyd) via a free radical polymerization method for controlled release of Sunitinib malate anticancer drug. The synthesized samples were characterized by FTIR, XRD, TEM, and SEM-dot mapping analyses. The encapsulation efficiency of Hyd and Hyd/Cloisite 30B (6 wt%) was 81 and 93%, respectively, showing the effectiveness of Cloisite 30B in drug loading. An in vitro drug release study showed that drug release from all samples in a buffer solution with pH 7.4 was higher than in a buffer solution with pH 5.5. During 240min, the cumulative drug release from Hyd/Cloisite 30B (94.97% at pH 7.4) is lower than Hyd (53.71% at pH 7.4). Also, drug-loaded Hyd/Cloisite 30B (6 wt%) demonstrated better antibacterial activity towards S. Aureus bacteria and E. Coli. High anticancer activity of Hyd/Cloisite 30B against MCF-7 human breast cancer cells was shown by the MTT assay, with a MCF-7 cell viability of 23.82 ± 1.23% after 72-hour incubation. Our results suggest that Hyd/Cloisite 30B could be used as a pH-controlled carrier to deliver anticancer Sunitinib malate.

Biocompatible Quince Seed Mucilage Hydrogel: A Versatile Platform for Efficient Drug Delivery of Ceftriaxone with Enhanced Adsorption Properties

AbstractThe objective of this study was to explore the applicability of biocompatible quince seed mucilage hydrogel as a promising material for drug delivery systems. In this investigation, the hydrogel was synthesized through the graft copolymerization of acrylic acid and allyl polyvinyl alcohol onto quince seed mucilage in an aqueous solution under an argon atmosphere. Characterization of the synthesized hydrogel was performed using Fourier‐transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FE‐SEM), and thermogravimetric analysis (TGA). Subsequently, the developed hydrogel served as a carrier for ceftriaxone antibiotic release in both distilled water and a buffer solution with a pH of 7.4. The results demonstrated an impressive encapsulation efficiency of 96.1% for ceftriaxone within the hydrogel matrix. Additionally, the adsorption properties of ceftriaxone onto the proposed hydrogel structures (I, II, and III) were theoretically investigated in the aqueous phase using Monte Carlo adsorption locator calculations in Materials Studio2017. Our findings revealed strong adsorption on structure (III) compared to structures (I and II), with respective theoretical energies of −2.836 kcal/mol, −2.840 kcal/mol, and −2.127 kcal/mol. Therefore, the proposed hydrogel structure (III) emerges as a promising candidate for drug delivery applications, emphasizing its potential as an efficient carrier system.

Combination of recycled cellulose with nano-thick flower layered double hydroxides: Biomass water retention slow-release fertilizer for sustainable agriculture

The development of crop nutrient, water utilization and increasing the renewability of waste resources sustainable agriculture is essential for improving sustainable agriculture. In this study, a type of nanothick floral layered double hydroxides (nLDHs) for fast and effective pesticide adsorption was created using cyclodextrin (CD) induction. After that, it was composited with recycled cellulose (PCe) derived from waste biomass (pomelo peel). A novel slow-release hydrogel fertilizer (N@nLDHs/PCe-PAA) was synthesized through the graft copolymerization of acrylic acid (AA), which was then employed as a nutrient (urea) carrier in the nLDHs/PCe composite. The swelling, water retention and slow-release capabilities of slow-release fertilizer was evaluated. Additionally, crop cultivation tests were conducted on the material to ascertain its potential use in sustainable agriculture. The results shown that N@nLDHs/PCe-PAA had a swelling rate of 197.02 g/g at 600 min, the water retention rate reached 21.02 % in soil at 60 d, and a nutrient release of 68.78 % in soil at 60 d, which were in accordance with European Committee for Standardization (CEN) standards. Besides, the experiment of crop cultivation showed that N@nLDHs/ CPE-PAA had obvious promotion effect on plant growth, which could improve the root system, rhizomes, chlorophyll content, and relative water content in the leaves of the plants. Therefore, this novel slow-release hydrogel fertilizer (N@nLDHs/PCe-PAA) not only promotes resource reproducibility, but also has excellent soil water retention, slow-release nutrient properties and a function of promoting plant growth. It has great value in promoting the sustainable development of agriculture.

Ionic conductivity and hydrogen permeability of microporous polysulfone membranes grafted by acrylic acid

Energy losses and purity of product gases in alkaline water electrolysis strongly depend on properties of a separator positioned between the electrodes. This paper reports on heterogeneous separators based on microporous polysulfone membranes modified by graft co-polymerization of acrylic acid. After neutralization with KOH, the pores of the modified membranes were filled with potassium polyacrylate, a superabsorbent material forming hydrogel upon intake of an aqueous electrolyte. Under electrolysis conditions of 50 °C and atmospheric pressure, increasing amount of hydrogel in pores suppresses hydrogen permeability without apparent reduction of ionic conductivity. We have identified the product of ionic resistance and hydrogen flux as a suitable parameter to compare performance of separators of various thickness. In terms of this parameter, present separators surpass the performance of Zirfon™ Perl UTP 500 tested under the identical conditions. Ex-situ aging test in 30 wt% KOH at 60 °C has revealed preservation of high wettability for up to 1340 h.

Preparation of bacterial cellulose/acrylic acid-based pH-responsive smart dressings by graft copolymerization method

Conventional wound dressings used in trauma treatment have a single function and insufficient adaptability to the wound environment, making it difficult to meet the complex demands of the healing process. Stimuli-responsive hydrogels can respond specifically to the particular environment of the wound area and realize on-demand responsive release by loading active substances, which can effectively promote wound healing. In this paper, BC/PAA-pH responsive hydrogels (BPPRHs) were prepared by graft copolymerization of acrylic acid (AA) to the end of the molecular chain of bacterial cellulose (BC) network structure. Antibacterial pH-responsive ‘smart’ dressings were prepared by loading curcumin (Cur) onto the hydrogels. Surface morphology, chemical groups, crystallinity, rheological, and mechanical properties of BPPRHs were analyzed by different characterization methods. The drug release behavior under different physiological conditions and bacteriostatic properties of BPPRH-Cur dressings were also investigated. The results of structural characterization and performance studies show that the hydrogel has a three-dimensional mesh structure and can respond to wound pH in a ‘smart’ drug release capacity. The drug release behavior of the BPPRH-Cur dressings under different environmental conditions conformed to the logistic and Weibull kinetic models. BPPRH-Cur displayed good antimicrobial activity against common pathogens of wound infections such as E. coli, S. aureus, and P. aeruginosa by destroying the cell membrane and lysing the bacterial cells. This study lays the foundation for the development of new pharmaceutical dressings with positive health, economic and social benefits.

Highly efficient remediation of chlorpyrifos and malachite green by an SBA-15 incorporated guar gum-grafted-poly (acrylic acid)/cobalt ferrite matrix for water purification

The Santa Barbara Amorphous-15-guar gum-grafted-poly (acrylic acid)/cobalt ferrite (SBA-15-GG-g-PAA/CoFe2O4) mesoporous adsorbent was prepared by graft copolymerization of acrylic acid (AA) onto guar gum (GG) in the Santa Barbara Amorphous-15 (SBA-15) substrate presence, followed by incorporating CoFe2O4 magnetic nanoparticles (MNPs). Diverse analyses were conducted to identify the prepared mesoporous adsorbent’s chemical and morphological properties, thermal resistance, magnetic characteristics, surface area, and porosity. Based on the magnetic hysteresis loops, the mesoporous adsorbent rendered ferromagnetic behavior. According to TGA, it has char yields of 72 wt% at 800 °C and superparamagnetic behavior (Ms of 3.22 emu.g−1). The crystalline structure and cubic phases of CoFe2O4 MNPs in the GG-g-PAA amorphous matrix were demonstrated by XRD. The CoFe2O4 MNP formation with partial aggregations onto smooth, nonporous, and regular surfaces of the GG was depicted by FESEM images. Also, the precisely-arranged hexagonal structure with cylindrical pores of SBA-15 was authenticated by FESEM images. Additionally, the SBA-15 substrate has increased the BET surface area of the prepared mesoporous adsorbent to 40.55 m2/g, which is higher than the composite without SBA-15 mesoporous silica. Several experimental setups were used to evaluate the effectiveness of adsorption, including pH of the medium (4–9), Adsorbent dosage (0.003–0.02 g), Interaction time (1–25 min), and Initial pollutant concentration (50–400 mg/L). Using 0.003 g of mesoporous adsorbent at 25 °C, chlorpyrifos (CPF) and malachite green (MG) had maximum adsorption capacities (Qmax) of 909.1 mg/g and 1000.0 mg/g, respectively. In this study, the Langmuir isotherm model fitted the adsorption data perfectly withRMG2 = 0.9987 andRCPF2 = 0.9994, and the pseudo-second-order model explained the adsorption kinetics with RMG2 = 0.9644 and RCPF2 = 0.9923. MG and CPF adsorption to the SBA-15-GG-g-PAA/CoFe2O4 mesoporous adsorbent was successful due to hydrogen bonds, exchange interactions, diffusion, and entrapment in the hydrogel network. In addition to the three-dimensional structure, the mesoporous adsorbent has available adsorption sites for reactive molecules. The reusability of the SBA-15-GG-g-PAA/CoFe2O4 was perused and showed that the mesoporous adsorbent can be separated efficiently and retrieved in three sequential cycles without considerable diminution in the adsorption efficiency.

Innovative reactor design for the preparation of polymer electrolyte membranes for vanadium flow batteries from preirradiation induced graft copolymerization of acrylic acid and AMPS on PVDF

Abstract An innovative reactor concept is reported that allows for efficient mass transfer from the liquid phase to the base material and compensates for the growth of the material throughout the synthesis of polymer electrolyte membranes (PEM). The novel reactor allows for the synthesis of PEMs with high reproducibility of their dimensions and properties. PEMs are synthesized via graft copolymerization of the monomers acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid on poly(vinylidene fluoride) films serving as base material, which was activated by electron beam treatment. Both monomers are already containing protogenic groups; thus, follow-up functionalization reactions are avoided. The PEMs were characterized with respect to their electrochemical properties (area specific resistance, recharge current, and ion exchange capacity) relevant for application in vanadium flow batteries and compared to commercially available PEMs.

Synthesis of Hydrogel Based on Poly (Acrylic Acid–Co‐Vinyl Acetate) Grafted on Modified Recycled Cellulose for Use in Fertilizer Slow‐Release System

The aim of this work is a synthesis of suitable hydrogel to produce slow‐release fertilizer using recycled cellulose which is obtained from waste paper. For this purpose, initially, we extracted alpha cellulose from waste paper and modified it to obtain carboxymethyl cellulose (CMC). Then, the CMC was converted to a suitable hydrogel through in situ graft copolymerization of acrylic acid and vinyl acetate in the presence of methylene bisacrylamide as a crosslinker. The various factors that affect hydrogel synthesis, such as the amounts of CMC, monomers, initiator, and crosslinker, were evaluated. In the optimized formulation, the weight ratio of monomers to CMC is 7, the molar ratio of monomers to each other is 1, and the crosslinker is used as 3 molar percent of monomers. The products were characterized using Fourier transform infrared, thermal gravimetric analysis, and scanning electron microscope analyses. The swelling behavior of the synthesized hydrogels was evaluated in different environments, such as distilled water, tap water, salt water, and different pH levels. The swelling ratio increases with an increase in pH level. Between the synthesized hydrogels, the best one was selected for slow‐release fertilizer production and loaded with 20‐20‐20 fertilizer (NPK), and the release behavior was evaluated. In an alkaline pH, there was a long time for NPK release within a slow‐release medium and even after 361 h, the release process was continued. Also, the performance of the fertilizer‐loaded hydrogel in soil using water holding capacity and water retention ratio tests were evaluated.

Magnetic Fe3O4-grafted cellulose/graphene oxide nanocomposite for methylene blue removal from aqueous solutions: Synthesis and characterization

This research focuses on the development of efficient and cost-effective methods for the treatment of industrial wastewater. Magnetic Fe3O4 cellulose/graphene oxide nanocomposite was synthesized through free radical graft copolymerization of acrylic acid (AA) and acrylamide (AM) on the cellulose chains. The grafting copolymerization parameters, including molar ratio, temperature, and reaction time, were optimized. Structural characteristics of the prepared samples were analyzed using FT-IR, XRD, and VSM techniques, while morphological characteristics were examined using FE-SEM and HR-TEM. The prepared samples were evaluated for their adsorption capacity towards methylene blue (MB) dye under various conditions. The factors controlling the adsorption process, such as pH, contact time, adsorbent dose, and initial MB concentration, were studied. The experimental data were successfully described by the pseudo-second-order model, and the equilibrium adsorption results fitted the Freundlich and Dubinin-Radushkevich isotherms. Thermodynamic studies revealed that the adsorption process was endothermic and occurred spontaneously, leading to greater disorder. Optimal conditions for MB adsorption onto the magnetic cellulose/graphene oxide nanocomposite were determined to be pH 7, a contact time of 7 h, and an adsorbent dose of 0.0375 g in a 30 mg/L dye solution. The inclusion of magnetite and graphene oxide into cellulose resulted in enhanced removal efficiency of the dye, with the magnetic cellulose/graphene oxide nanocomposite exhibiting a removal percentage of 97%. These findings demonstrate the potential of the magnetic cellulose/graphene oxide nanocomposite as a powerful adsorbent for the removal of methylene blue dye from aqueous solutions, offering promising prospects for the treatment of industrial wastewater.

Sustainable grafted chitosan-dialdehyde cellulose with high adsorption capacity of heavy metal

A novel adsorbent was prepared using a backbone comprising chemically hybridized dialdehyde cellulose (DAC) with chitosan via Schiff base reaction, followed by graft copolymerization of acrylic acid. Fourier transform infrared spectroscopy (FTIR) confirmed the hybridization while scanning electron microscopy (SEM) revealed intensive covering of chitosan onto the surface of DAC. At the same time, energy dispersive X-ray (EDX) proved the emergence of nitrogen derived from chitosan. The X-ray diffraction (XRD) indicated that the crystallinity of the backbone and graft copolymer structures was neither affected post the hybridization nor the grafting polymerization. The adsorbent showed high swelling capacity (872%) and highly efficient removal and selectivity of Ni2+ in the presence of other disturbing ions such as Pb2+ or Cu2+. The kinetic study found that the second-order kinetic model could better describe the adsorption process of (Cu2+, Ni2+) on the graft copolymer. In contrast, the first-order kinetic model prevails for the binary mixture (Pb2+, Ni2+). Moreover, the correlation coefficient values for the adsorption process of these binary elements using Langmuir and Freundlich isotherms confirmed that the developed grafted DAC/chitosan exhibits a good fit with both isotherm models, which indicates its broadened and complicated structure. Furthermore, the grafted DAC/chitosan exhibited high efficient regeneration and high adsorption capacity for Pb2+, Cu2+ and Ni2+.

Preparation of a nano-clay-based super absorbent polymer composite for water absorption applications

Incorporation of naturally occurring fillers like clay and other mineral improves mechanical, chemical, and physical properties. Herein, we report for synthesized nano-clay based superabsorbent polymer by graft copolymerization of acrylic acid and acrylamide This study focusses the effects of filler (nano-clay), crosslinking agent and initiator concentration on the absorption of the copolymer. Six specimens with varying percentages i.e., 30, 32, 34, 36, 38 and 40 wt. % were supplemented with nano-clay in the matrix of the polymer. Time based immersion was carried out in tap, de-ionized and brine for 2 to 24 h the superabsorbent polymer with 36 wt.% of nano-clay absorbed highest percentage i.e., up to 18 folds after submerging in tap water for 2 hours. Detrimental trend of absorption was observed in specimens with 38 and 40 wt. % that could be due to surge in formation of physical and chemical cross-linking networks in the polymer matrix. However, suspension of superabsorbent polymer composite in brine resulted in decreased absorbency. Such course was also observed for specimens containing 36 wt. % of nano-clay after submerging for 4, 6 and 24 hours. Thermal stability analysis also revealed that the polymer composite supplemented with 38 wt. % of nano-clay exhibited ameliorated stability to 350 ℃.

DOE-based synthesis of gellan gum-acrylic acid-based biodegradable hydrogels: screening of significant process variables and in situ field studies.

The current study uses the free radical graft copolymerization of acrylic acid as a monomer, N,N-methylene-bis-(acrylamide) as a crosslinker and ammonium persulfate as an initiator to synthesise GG-cl-poly(AA) hydrogels based on gellan gum utilising response surface methodology (RSM). A full factorial design was used to obtain the greatest percent swelling (Ps), and key process variables were determined using the Pareto chart. To make the procedure cost-effective, a multiple regression model employing ANOVA projected a linear model with a maximum percentage swelling of 556 at the lowest concentration of all three studied factors. As a result, the sequential experimental design was successful in obtaining two-fold increases in the percentage swelling in a systematic way. An RSM-based central composite design was used to optimize the percentage swelling of the three most important synthesis parameters: initiator concentration, monomer concentration, and crosslinker concentration. The best process conditions are 7.3 mM L−1 initiator, 44 μM L−1 monomer, and 21.6 mM L−1 crosslinker. The effective synthesis of GG-cl-poly(AA) was validated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, field emission scanning electron microscopy (FE-SEM), and 1H-nuclear magnetic resonance. The swelling behavior of GG-cl-poly(AA) in water and saline solutions, as well as its water retention capability, was investigated. In comparison to distilled water, the swelling potential of optimized hydrogel was shown to be significantly reduced in saline solutions. The addition of GG-cl-poly(AA) significantly improved the moisture properties of plant growth media (clay, sandy, and clay–soil combination), implying that it has great potential in moisture stress agriculture. GG-cl-poly(AA) biodegradation was studied by soil burial and vermicomposting methods. The composting approach showed 89.95% deterioration after 22 days, while the soil burial method showed 86.71% degradation after 22 days. The synthesized hydrogel may be beneficial for agricultural applications because of its considerable degradation behaviour, strong water retention capacity, low cost, and environmental friendliness.

Preparation of Macroporous High Adsorbent Resin and Its Application for Heavy Metal Ion Removal

AbstractMacroporous high adsorbent resins (MHAR) are important and urgent requirements for qualified adsorbents to remove toxic heavy metals in wastewater since the short adsorption time and large adsorption capacity. Herein, a new type of MHAR was prepared by graft copolymerization of acrylic acid with sodium carboxymethyl cellulose (CMC) and sodium alginate (SA) by using N, N′‐methylenebisacrylamide (MBA) as crosslinking agent, hydrogen peroxide (H2O2) and ascorbic acid as initiator. We characterized the morphology of the MHAR and explored the optimal conditions for MHAR to absorb water. The results showed that pH and temperature had great influences on the amount of heavy metals adsorption. The adsorption process is a linear model of multiphase multilayer molecular adsorption reaction, which belongs to the second‐level kinetic model. The adsorption thermodynamic experiment showed that the adsorption of Cu2+ by MHAR conforms to the Freundlich adsorption isotherm. This work succeeded in preparing a MHAR that may have potential applications in environmental governance.

Hydrogels Based on Starch from Various Natural Sources: Synthesis and Characterization

AbstractHydrogels based on a graft copolymer of acrylic acid (AA) and acrylamide (AAm) on a backbone of starch, obtained from different natural sources, have been prepared and characterized for potential agricultural use, as soil moisture regulators and nutrient sources for plant nutrition. Five types of starch are used: corn, waxy corn, wheat, potato, and rice starch. Hydrogels are prepared by a solution polymerization method, in the presence of ammonium persulphate (PSA) as initiator and N,N'‐methylene‐bis‐acrylamide (MBA) as a cross‐linking agent. Thermal and physico‐chemical properties, such as thermogravimetry analysis and differential scanning calorimetry data and swelling properties of hydrogels, are observed. The influences of the cross‐linking agent on the swelling ratio (SR) and solubility of prepared hydrogels are studied and optimized. The highest SR observed in water corresponded to non‐cross‐linked hydrogels prepared with waxy corn starch (780 g water per g dry matter), and the SR of these hydrogels in ammonium sulfate and calcium nitrate solutions are 9.6 and 1.2 g per g dry matter, respectively. Higher thermal stability is observed with cross‐linked starch‐g‐(AA‐AAm) hydrogels. The non‐cross‐linked hydrogels have a higher SR, but also have significant solubility in water.

Synthesis of cassava starch-g-acrylic acid/dimethylaminopropyl methacrylamide: A new hydrogel for brine solution

A new hydrogel copolymer was synthesized via the graft copolymerization of acrylic acid (AA) and dimethylaminopropyl methacrylamide (DMAPMA) on cassava starch (CSt) in aqueous solution. FTIR, TGA–FTIR, solid-state 13C NMR, SEM analyses were used to characterize the polymer. The swelling behavior of the polymer was investigated in distilled water and in various brine solutions. The effects of CSt and the ratio of the two monomers on the water absorbency of the polymer was evaluated. CSt improved the polymer swelling properties. Both polyelectrolyte and anti-polyelectrolyte effects occurred and the polymer had good salt-resistance properties in brine solutions. Such polymers have potential applications in the absorption of ultra-high concentration brine solutions.

Equilibrium and kinetics study of methyl violet adsorption by pineapple leaf fibers‐cl‐poly(acrylic acid‐co‐2‐dimethyl amino ethyl acrylate) hydrogel

AbstractThe pine apple leaf fiber‐cl‐poly(acrylic acid‐co‐2‐dimethyl amino ethyl acrylate) hydrogel is prepared by crosslinked graft copolymerization of acrylic acid and 2‐(dimethyl amino) ethyl acrylate onto the pine apple leaf fibers to be used as an adsorbent for the remove dye from aqueous solutions. Several characterization techniques like Fourier transform infrared spectroscopy field emission scanning electron microscopy‐Energy‐dispersive X‐ray spectroscopy and X‐ray diffraction analysis. The synthesized hydrogel shows strong water swelling characteristics (780.93%) and also exhibits faster deswelling property. The methyl violet (MV) adsorption data are fitted well with the Freundlich isotherm model with maximum monolayer adsorption capacities 625 mg/g for MV. The equilibrium kinetics follow pseudo second order model together with intra particle diffusion, one step process. Thermodynamic parameters show that the MV adsorption by the hydrogel is spontaneous and endothermic in nature. The overall removal efficiency is found to be 98.23% under optimum condition.

Investigation on Synthesis of Hydrogel Starting from Vietnamese Pineapple Leaf Waste-Derived Carboxymethylcellulose.

Carboxymethyl cellulose (CMC) is obtained from Vietnamese pineapple leaf waste through etherification. By treating pineapple leaf powder with a solution of NaOH then with HNO3 at 90°C for an appropriate time, cellulose can be efficiently extracted. To obtain CMC, carboxymethylation was performed by reaction of the pineapple cellulose with chloroacetic acid at 60°C for 1.5 h. The optimal conditions for this reaction were established. The resulting CMC had a degree of substitution (DS) of 0.91. The hydrogel was prepared by graft copolymerization of acrylic acid and acrylamide to the synthesized CMC. During that reaction, N,N′methylenebisacrylamide (MBA) served as the crosslinking agent and ammonium persulfate (APS) as the initiator. The maximum hydrogel absorbencies for distilled water and 0.9 wt.% NaCl solution were relatively high, namely, 588.2 g/g and 79.3 g/g, respectively. Additionally, the water swelling and water retention behaviors of the hydrogel in soil were also investigated. The results showed that this hydrogel can be employed as a suitable moisture-holding additive in soil for cultivation purposes.

Green superabsorbent nanocomposite hydrogels for high-efficiency adsorption and photo-degradation/reduction of toxic pollutants from waste water

Developing renewable-based biomaterials is an important and sustainable solution to solve environmental and resource problems. Bio-super adsorbent treatment of contaminants is highly effective due to their minimal costs and environmental biocompatibility. Herein, superabsorbent nanocomposite hydrogels have been formed by grafting copolymerization of acrylic acid and acrylamide onto natural polysaccharide (green starch) with incorporation of NPs such as NiFe2O4 NPs and TiO2 NPs into the hydrogel matrix utilizing (MBA) N·N-methylene-bisacrylamide which acts as a cross linker and (APS) ammonium persulphate as an initiator in aqueous medium. Starch-g-poly(acrylic acid-co-acrylamide)/NiFe2O4 (NiFe2O4/SANCH) and starch-g-poly (acrylic acid-co-acrylamide)/TiO2 (TiO2/SANCH) were identified by (TGA) thermal gravimetric analysis, (SEM) scanning electron microscope, (EDX) energy dispersive X-ray, (TEM) transmission electron microscopy, (XRD) X-ray diffraction, and (FTIR) Fourier transform infrared spectroscopy. The adsorption/photodegradation performance of the NiFe2O4/SANCH and TiO2/SANCH were also studied under visible light using Cr(VI) and Congo red dye as template of dyes for a photodegradation target, then comparing the results to the neat starch-g-poly(acrylic acid-co-acrylamide superabsorbent hydrogel (SAH). The effect of irradiation time, pH, and catalyst dose photocatalytic reduction/degradation of Cr(VI) and CR on the prepared hydrogels was evaluated. The results show that, NiFe2O4/SANCH composite has effective photoefficiency towards Cr(VI) and CR than TiO2/SANCH and SAH polymers. The producibility of the reused NiFe2O4/SANCH and TiO2/SANCH composites were also investigated for five cycles with high efficiency. Therefore, these nanocomposite hydrogels possess high photocatalytic degradation/reduction efficiency and can be removed safely by direct filtration from the reaction. With such characteristics, NiFe2O4/SANCH and TiO2/SANCH hydrogels are mostly named green Polymers for usage in the adsorption/photodegradation technique to reduce many contaminants.

Developing persulfate-activator soft solid (PASS) as slow release oxidant to remediate phenol-contaminated groundwater

The research objective was to develop a persulfate-activator soft solid (PASS) as a biodegradable slow-release oxidant to treat phenol-contaminated groundwater. PASS was prepared by graft copolymerization of acrylic acid (AA) and acrylamide (AM) onto 1% (w/v) sodium alginate mixed with 500 mg L−1 sodium persulfate and 5 mg L−1 ferrous sulfate. The physical and chemical properties of PASS were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, the water content and swelling ratio. Various variables, including the ratio of AA/AM, pH, temperature and the type of groundwater cations affecting PS release, were investigated. The maximum PS release in DI water was 98% in the ratio of PASS 1 (AA/AM, 75/25), 96% at pH 3, 83% at 25 °C, and 80% with Na+. The major factors controlling PS release were the AA/AM ratio and pH. PASS 1 can be stable in size and shape for 6–8 days and completely degraded within 34 days. The degradation rates of 10 mgL−1 phenol using PASS produced the highest kobs values for each variable at a ratio of PASS 1 (k=0.1408 h−1), pH 7 (k=0.1338 h−1), 25 °C (k=0.1939 h−1), and Ca2+ (k=0.1336 h−1). The temperature of the groundwater was key to driving the reaction between PS and phenol. PASS 1 was applied in simulated phenol-contaminated groundwater via horizontal tanks containing Ottawa sand. The results indicated 93.2% phenol removal within 72 h in a narrow horizontal flow tank and 41.7% phenol removal in a wide horizontal flow tank with aeration.

Полиэлектролитный герметик для топливных элементов на основе привитых фторсополимеров

The preparation of grafted copolymers for electrochemical devices by chemical grafting copolymerization of acrylic acid and α-, β-, β-trifluorostyrene to a film fluorinated copolymer of hexafluoropropylene with vinylidene fluoride is described. The grafted copolymers contained carboxyl groups and the sulfonation process was carried out for additional introduction of ionic sulfo- groups. The optimal conditions for the process have been determined, which make possible to obtain grafted copolymers with a wide range of electrochemical and physical-mechanical properties. The resulting products in the form of ion-conducting membranes can be used as part of current sources and other electrochemical devices and have a specific volumetric electrical resistance of 0.46—1.41 Ohm.m, exchange capacity 1.45—1.62 meq / g, moisture content 25—62%, breaking stress 0.82—1.08 MPa.