Title
Chemically crosslinked cellulose-based hydrogel prepared from rice straw for the removal of aqueous hexavalent chromium ion from wastewater
Authors
TRANG THI CAM TRUONG, VO VAN BAM, ANH PHUONG LE THI, NGAN THI THU PHAN, TAKAOMI KOBAYASHI, DUONG THI THUY NGA and KHOA DANG NGUYEN

Received September 29, 2023
Published Volume 58 Issue 1-2 January-February
Keywords rice straw, cellulose, hydrogel, adsorption, chromium

Abstract
In this study, cellulose was chemically extracted from rice straw, which is one of the richest sources of agro-waste. Then, this purified cellulose was co-polymerized by the addition of acrylic acid and ammonium persulfate in the presence of N,N-methylenebisacrylamide as crosslinker to form a cellulose-based hydrogel for the removal of hexavalent chromium (Cr(VI)) from wastewater. Here, the impact of various parameters, such as pH, contact time, material dosage, and initial solution concentration, on the adsorption capacity of the hydrogel for Cr(VI) ions is systematically investigated. The experimental findings revealed that the highest adsorption capacity for the treatment of Cr(VI)-containing water reached 1.1 mg Cr(VI)/g at pH 1, contact time of 120 min, and the initial concentration in the aqueous solution of 10 mg/L for an applied adsorbent dosage of 0.2 g. In addition, the equilibrium adsorption data agreed well with the Langmuir isotherm and the maximum adsorption amount was 4.14 mg Cr(VI)/g. Additionally, this material demonstrated good reusability, supporting the notion that it can be efficiently regenerated for multiple uses, a crucial factor for its practical application towards reducing the environmental impact and increasing its economic value.