Optimization of synthesis condition for carboxymethyl cellulose‐based hydrogel from rice straw by microwave‐assisted method and its application in heavy metal ions removal

Abstract

BACKGROUND An alternative carboxymethyl cellulose‐based biosorbent hydrogel was synthesized by grafting 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) onto the prepared carboxymethyl cellulose backbone via microwave heating. Response surface methodology was employed to optimize the hydrogel synthesis condition for maximum gel content with respect to AMPS dose, N,N′‐methylene‐bis‐acrylamide dose, and microwave exposure time. The prepared gels were then characterized and evaluated in terms of their heavy metal ions adsorption performance and reusability. RESULTS The optimum synthesis condition yielded the maximum gel content and maximum equilibrium swelling of 96.33% and 2819 ± 15%, respectively. The Langmuir model fitted the experimental isotherm data well, with maximum adsorption capacity of 86.21, 102.04 and 33.56 mg g‐1 for Cu2+, Pb2+ and Fe3+, respectively. Microwave heating was clearly noted to result in hydrogel of higher porosity and could shorten the synthesis time by 88.33%; the gel content was 7.46% higher compared with that obtained via conventional heating. CONCLUSION Microwave‐assisted heating is a feasible alternative and an efficient technique for CMC‐g‐AMPS hydrogel synthesis. The optimized CMC‐g‐AMPS hydrogel exhibited good performance for Cu2+, Pb2+ and Fe3+ ions removal and was satisfactorily reused, thus contributing to the alleviation of environmental problems caused by discarded rice straw and water contaminated with heavy metal ions. © 2017 Society of Chemical Industry

High‐strength hydrogels: Microstructure design, characterization and applications

“…Chemical synthesis is the major method for high‐strength hydrogel preparation, including free‐radical polymerization (e.g., thermal‐initiated, photo‐initiated), condensation reaction (e.g., carbodiimide chemistry, Knoevenagel condensation), energy irradiation (γ radiation, electron beam, microwave), enzymatic crosslinking, aldehyde complementation, and click chemistry …”

Ion-Induced Synthesis of Alginate Fibroid Hydrogel for Heavy Metal Ions Removal

“…However, the increasing concentration of OH − as pH increases to 7.0 can causes some of the heavy metal ions to precipitate. Thus, removal of Cu 2+ and Pb 2+ ions is not satisfactory at pH of 7.0 (Panchan et al, 2018). The optimal pH values are 4.0 for Cd 2+ and Pb 2+ ions, and 3.0 for Cu 2+ ions, respectively.…”

Optimization of synthesis conditions for carboxymethyl cellulose from pineapple leaf waste using microwave-assisted heating and its application as a food thickener

“…The synthesis methods of CMC were those of Mandal et al (2015) and Panchan et al (2018) with appropriate modification. The first synthesis step was alkalization in which 4.0 g of isolated cellulose was added into a three-neck round bottom flask, which was subsequently placed in a modified domestic microwave oven (LG, MS2343DAR, Seoul, Korea) equipped with a condenser and glass agitator.…”

“…Microwave heating, which is known for its rapid heating capability, is therefore of interest. Microwave-assisted synthesis methods have indeed been reported to provide a number of advantages over the conventional synthesis means (Kappe 2004); such advantages include shortened reaction time and increased product yield and purity (Santos et al 2015;Panchan et al 2018). Nevertheless, there is so far no information on microwave-assisted synthesis of CMC from pineapple leaf waste.…”