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One of the main problems with water pollution is dye contamination of rivers, industrial effluents, and water sources. It has endangered the world's sources of drinking water. Several remediation strategies have been carefully developed and tested to minimize this ominous picture. Due to their appealing practical and financial benefits, adsorption methods in particular are often listed as one of the most popular solutions to remediate dye-contaminated water. Biopolymer-based hydrogel nanocomposites are a cutting-edge class of materials with a wide range of applications that are effective in removing organic dyes from the environment. Since the incorporation of various materials into hydrogel matrices generated composite materials with distinct characteristics, these unique materials were often alluded to as ideal adsorbents. The fundamental emphasis of the conceptual and critical review of the literature in this research is the significant potential of hydrogel nanocomposites (HNCs) to remediate dye-contaminated water (especially for articles from the previous five years). The review also provides knowledge for the development of biopolymer-based HNCs, prospects, and opportunities for future research. It is also focused on optimum conditions for dye adsorption processes along with their adsorption kinetics and isotherm models. In summary, the information gained in this review research may contribute to a strengthened scientific rationale for the practical and efficient application of these novel adsorbent materials.

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The primary goal of this study is to prepare and characterize a ghatti gum/poly(acrylic acid)/TiO2 (GG/poly(AA)/TiO2) hydrogel nanocomposite for adsorption of the dye malachite green (MG) from the aqueous phase in a discontinuous system. A variety of approaches were used to investigate the structure, morphology, and thermomechanical characteristics of the synthesized hydrogel nanocomposite. Response surface methodology (RSM) was performed to analyze the impact of three processing parameters, namely adsorbent dosage, dye concentration, contact duration, and their interactions on MG dye adsorption capacity. Analysis of variance was used to assess the experimental findings, which revealed that the quadratic regression model was statistically acceptable. The integration of TiO2 nanoparticles into the hydrogel matrix improved its thermal stability, mechanical strength, and performance in adsorbing MG dye from water. The kinetics and isotherm were evaluated, and the adsorption process was well fitted with pseudo-second order and Temkin isotherm models, respectively. Using the Langmuir equation, the maximum adsorption capacity at 45 °C within 50 min was calculated to be 2145 mg/g. Thermodynamic analysis at 25-45 °C revealed that the MG dye was spontaneously absorbed by the hydrogel nanocomposite. The prepared hydrogel nanocomposite demonstrated excellent reusability without a noticeable loss in MG dye adsorption capability for 6 cycles.

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Globally, cancer is affecting societies and is becoming an important cause of death. Chemotherapy can be highly effective, but it is associated with certain problems, such as undesired targeting and multidrug resistance. The other advanced therapies, such as gene therapy and peptide therapy, do not prove to be effective without a proper delivery medium. Polymer-based hybrid nanoarchitectures have enormous potential in drug delivery. The polymers used in these nanohybrids (NHs)provide them with their distinct properties and also enable the controlled release of the drugs. This review features the recent use of polymers in the preparation of different nanohybrids for cancer therapy published since 2015 in some reputed journals. The polymeric nanohybrids provide an advantage in drug delivery with the controlled and targeted delivery of a payload and the irradiation of cancer by chemotherapeutical and photodynamic therapy.

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Herein, a sodium alginate/poly (acrylic acid)/oxidized-multi-walled carbon nanotubes hydrogel nanocomposite (SA/p(AAc)/o-MWCNTs HNC) was synthesized by in situ free-radical polymerization method. The synthesized SA/p(AAc)/o-MWCNTs HNC was used to remove methylene blue (MB) from aqueous solution. The synthesized HNC was confirmed by employing various characterization techniques. The SA/p(AAc)/o-MWCNTs HNC exhibited a maximum swelling capacity of 2265.4% at pH 8.0. The influence of vital parameters in the sorption process including the initial pH, adsorption dose, contact time and concentration were systematically examined on a batch mode. Subsequently, adsorption kinetics as well as isotherm models were applied to assess the nature and mechanism of the adsorption process. Adsorption kinetics were best described by pseudo-second-order model, while the Langmuir isotherm model governed the adsorption isotherm. The SA/p(AAc)/o-MWCNTs HNC exhibited a maximum adsorption capacity of 1596.0 mg/g at 25°C. This adsorbent showed excellent MB uptake and good regeneration ability.

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Carboxymethyl cellulose/poly(acrylic acid) (CMC-cl-pAA) hydrogel and its magnetic hydrogel nanocomposite (CMC-cl-pAA/Fe3O4-C30B) were prepared via a free radical polymerization method and used as adsorbents for adsorption of methylene blue (MB) dye. The samples were characterized using Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy coupled with energy-dispersive X-ray spectrometer, high-resolution transmission electron microscope, and dynamic mechanical analysis. The adsorption performance of the prepared adsorbents was studied in a batch mode. Adsorption kinetics and isotherm models were applied in the experimental data to evaluate the nature as well as the mechanism of adsorption processes. It was deduced that the adsorption followed the pseudo-second-order rate equation and Langmuir isotherm models. The maximum adsorption capacities were found to be 1109.55 and 1081.60 mg/g for CMC-cl-pAA hydrogel and CMC-cl-pAA/Fe3O4-C30B hydrogel nanocomposite, respectively. The adsorption thermodynamic studies suggested that the adsorption process was spontaneous and endothermic for CMC-cl-pAA/Fe3O4-C30B hydrogel nanocomposite. The homogeneous dispersion of the Fe3O4-C30B nanocomposite in the CMC-cl-pAA hydrogel significantly improved the thermal stability, mechanical strength, and excellent regeneration stability. This study demonstrates the application potential of the fascinating properties of CMC-cl-pAA/Fe3O4-C30B hydrogel nanocomposite as a highly efficient adsorbent in the removal of organic dyes from aqueous solution.

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In this study, a sodium alginate poly(acrylic acid) (SA-poly(AA)) hydrogel and sodium alginate poly(acrylic acid)/zinc oxide (SA-poly(AA)/ZnO) hydrogel nanocomposite (HNC) was synthesized by in situ free-radical polymerization for the sequestration of toxic methylene blue (MB) dye from aqueous solution. The structural properties were analyzed using FTIR, XRD, SEM, TEM, TGA, and DMA The swelling analysis revealed that SA-poly(AA)/ZnO HNC exhibited high water uptake capacity. The kinetics, isotherms, and thermodynamics of adsorption were examined, and results showed that equilibrium data fitted the Langmuir isotherm model, and the adsorption kinetics of MB followed pseudo-second-order model. The maximum adsorption capacity was found to be 1129 mg/g for the SA-poly(AA) hydrogel and 1529.6 mg/g for the SA-poly(AA)/ZnO HNC in 0.25 g/L MB solution at pH 6.0 within 40 min. Thermodynamic parameters for SA-poly(AA) hydrogel and SA-poly(AA)/ZnO HNC substantiated the exothermic and endothermic nature of the adsorption processes, respectively. Moreover, SA-poly(AA)/ZnO HNC presented outstanding reusability with relatively better adsorption efficiencies as compared to SA-poly(AA) hydrogel.

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We report the development of a novel graft copolymer, diethylamino ethyl methacrylate grafted xanthan gum (mwXG-g-DEAEMA), by microwave heating. The synthesized graft copolymer was used for potential application of Cr(VI) adsorption. The structure, thermal stability and morphologies of XG and mwXG-g-DEAEMA were characterized to verify the adsorbent formed under optimized reaction conditions. FTIR, XRD, TGA and SEM techniques were used for characterization of XG and mwXG-g-DEAEMA. Furthermore, 1H NMR spectroscopic analyses predict the probable structure of copolymer. Based on the NMR data, a plausible mechanism for copolymer formation has been proposed. The effects of adsorbent loading, pH, contact time and equilibrium concentration of the Cr(VI) adsorption were investigated batch wise. The Cr(VI) adsorption process followed the pseudo-second-order rate model and equilibrium data were best described by Freundlich isotherm model. This work will encourage researchers to focus on this facile green technique for the synthesis of adsorbent with enhanced adsorption capacity.

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In the present study, facile and efficient method was adopted for the synthesis of graft copolymer hydrogel by graft copolymerization of acrylic acid (AA) onto xanthan gum (XG) biopolymer in the presence of N,N'-Methylenebisacrylamide (MBA), and ammonium persulfate (APS) as a cross-linking agent and initiator, respectively, under microwave irradiation. The optimization of hydrogel were selected based on the maximum swelling degree in water media and an optimum hydrogel was further impregnated with reduced graphene oxide (rGO) to form XG-cl-pAA/rGO hydrogel composite. The Fourier transform infrared (FT-IR), X-ray diffraction analysis (XRD), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) were used to study the structure, thermal stability and morphology of XG-cl-pAA and XG-cl-pAA/rGO. The adsorption of methyl violet (MV) and methylene blue (MB) were study in batch mode and results shows adsorption highly dependent on solution pH, contact time, concentration and adsorbent loading. The XG-cl-pAA/rGO exhibited a very high adsorption potential, and the adsorption process followed the pseudo-second-order rate model and Langmuir adsorption isotherm with a maximum adsorption capacity (Qmax) of 1052.63 mg/g and 793.65 mg/g at 25 °C for MV and MB, respectively. We recommend XG-cl-pAA/rGO as environmentally benign, readily recoverable/recyclable material with excellent adsorption capacity for application in dyes removal.

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In this work, xanthan gum-cl-poly acrylic acid (XG-cl-pAA) hydrogel and xanthan gum-cl-poly acrylic acid/oxidized MWCNTs (XG-cl-pAA/o-MWCNTs) hydrogel nanocomposite was successfully surface modify by microwave assisted copolymerization, in which N, N'-methylenebisacrylamide (MBA) was used as a cross-linking agent. A copolymerization of acrylic acid (AA) onto xanthan gum (XG) initiated by microwave radiation method. Different weight percentages of oxidized MWCNTs were incorporated into the hydrogel matrix during the grafting reaction. An optimum hydrogel based on maximum swelling capacity further incorporated with oxidized MWCNTs to form XG-cl-pAA/o-MWCNTs. The structure, thermal stability, wettability and morphology of XG-cl-PAA and XG-cl-PAA/o-MWCNTs were characterized by fourier transform infrared (FTIR), Raman, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Contact angle, and scanning electron microscope (SEM). The effects of pH, contact time and equilibrium concentration on the MB dye adsorption were investigated batch wise. Optimal conditions were obtained at pH⩾6 due to the generation of negatively charged groups (COO-) in the adsorbent, which can strongly interact with the positive charges from MB and time of adsorption equilibrium was achieved in 30 min. The XG-cl-PAA/o-MWCNTs hydrogel nanocomposite exhibited a very high adsorption potential, and its adsorption capacities calculated based on the Langmuir isotherm for MB was 521.0 mg/g at 30 °C. The dye adsorption data fitted well to the pseudo-first-order model and Langmuir model. The adsorption-desorption cycle of hydrogel nanocomposite was repeated several times without significant loss of adsorption capacity.

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In the present project, graft polymerization was employed to synthesis a novel adsorbent using acrylic acid (AA) and xanthan gum (XG) for cationic methylene dye (MB+) removal from aqueous solution. The XG was rapidly grafted with acrylic acid (CH2=CHCOOH) under microwave heating. Fourier-transform infrared spectroscopy (FTIR), Proton Nuclear magnetic resonance spectroscopy (1H NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Thermal gravimetric analysis (TGA) techniques were used to verify the adsorbent formed under optimized reaction conditions. Optimum reaction conditions [AA (0.4M), APS (0.05M), XG (2gL-1), MW power (100%), MW time (80s)] offer maximum %G and %GE of 484 and 78.3, respectively. The removal ratio of adsorbent to MB+ reached to 92.8% at 100mgL-1. Equilibrium and kinetic adsorptions of dyes were better explained by the Langmuir isotherm and pseudo second-order kinetic model respectively. The results demonstrate xanthan gum grafted polyacrylic acid (mw XG-g-PAA) absorbent had the universality for removal of dyes through the chemical adsorption mechanism.