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Graphical abstract Highlights • Microwave synthesis of Gum Arabic- cl -poly(acrylamide) nanohydrogel. • Studied adsorptive removal of crystal violet dye onto nanohydrogel. • Good adsorption efficacy of 90.90 mg/g for crystal violet dye. • Adsorption process follows Langmuir isotherm. Abstract Natural biopolymers are better adsorbents due to better functionality, surface area, bio-compatibility and ease of procurement. The gum arabic in natural biopolymer derived from Acacia Arabic species. In the present work a novel nanohydrogel of gum arabic with acrylamide has been fabricated using microwave synthesis for adsorption of noxious crystal violet dye from aqueous medium. The prepared gum arabic-cl-poly(acrylamide) nanohydrogel (GA-cl-poly(AAm)) NHG was characterized by numerous techniques including SEM, XRD, TEM and FTIR. The GA-cl-poly(AAm) NHG showed promising adsorption ability for crystal violet dye. The effect of various adsorption factors such as concentration of GA-cl-poly(AAm) NHG and crystal violet, pH, temperature and time has been studied and reported. For understanding the adsorption mechanism three models Langmuir, Freundlich and Temkin were applied to adsorption data The kinetics and thermodynamics of adsorption were also investigated The adsorption capacity of crystal violet onto GA-cl-poly(AAm) NHG according to Langmuir model is found to be 90.90 mg/g. [ABSTRACT FROM AUTHOR]

In this study, we have synthesized a starch/poly(alginic acid-cl-acrylamide) nanohydrogel (ST/PL(AA-c!-AAm) NHG) by co-polymerization method which was used as an effective adsorbent for the removal of coomassie brilliant (CB) blue R-250 dye from the aqueous solution. The synthesized nanohydrogel was characterized by FTIR, SEM and TEM techniques. The effect of initial dye concentration, temperature, and agitation time on the adsorption ability of the nanohydrogel was studied comprehensively. The experimental outcomes exhibited that the prepared nanohydrogel had high adsorption tendency to remove the CB from the aqueous solution. The regression coefficient values for Langmuir (0.99), Frendluich (0.93) and Tempkin (0.98) recommended that adsorption process fit to langmuir isotherm. The pseudo-second-order equation showed the better adsorption kinetics of the adsorption process. The feasibility of CB adsorption onto ST/PL(AA-cI-AAm) NHG was also studied thermodynamically and the results indicated that the adsorption was spontaneous and chemical in nature. [ABSTRACT FROM AUTHOR]

• Atrazine removal using chitin based nanohydrogel- adsorption & desorption. • Chitin- cl -poly(acrylamide-co-itaconic acid) - microwave synthesis. • Results shows the maximum adsorption capacity of 204.08 mg/g. • Chitin- cl -poly(acrylamide-co-itaconic acid) nanohydrogel - pH responsive nature. Removal of commonly used pesticide, atrazine was examined by employing chitin based nanohydrogel. Chitin- cl -poly (acrylamide-co-itaconic acid) nanohydrogel was synthesized by microwave method. Dissolution of chitin was done by freezing thawing method in NaOH/urea solution. The morphology and functional characteristics were confirmed by FTIR, XRD, SEM, TGA, TEM, and EDX techniques. Maximum swelling capacity, isotherm study, kinetics, adsorption and desorption of atrazine pesticide were evaluated in this study. Maximum adsorption capacity of designed nanohydrogel was found to be 204.08 mg/g. Langmuir and pseudo- second order models were determined to be applicable for explaining the undertaken adsorption process. Neutral pH was found to be favorable for maximum adsorption. In addition, results have specified the pH responsive nature of nanohydrogel for controlled release of atrazine. [ABSTRACT FROM AUTHOR]

In this study, chitosan- crosslinked -poly (alginic acid) nanohydrogel ( CN-cl-PL(AA) NHG) was synthesized by co-polymerization method. It was used an effective adsorbent for the exclusion of Cr(VI) metal ion from aqueous medium. The synthesized nanohydrogel was characterized by FTIR, SEM and TEM. The TEM images clearly indicated the appearance of smooth surface with average size of particles ranging from 30 to 80 nm. The effect of different adsorption parameters like agitation time, temperature, initial metal ion concentration and adsorbent dosage was studied and optimized. The results demonstrated that the prepared chitosan- crosslinked -poly (alginic acid) nanohydrogel had high adsorption tendency for the removal of Cr(VI) from the aqueous solution. The pseudo-second-order equation represented the better adsorption kinetics for the adsorption process. The thermodynamic studies showed the adsorption of Cr(VI) onto CN-cl-PL(AA) NHG was spontaneous and chemical in nature. [ABSTRACT FROM AUTHOR]