PREPARATION OF CELLULOSE-BASED HYDROGEL DERIVED FROM TEA RESIDUE FOR THE ADSORPTION OF METHYLENE BLUE

Cellulose was chemically extracted from tea residue and then a cellulose-based hydrogel was fabricated as an adsorbent to remove methylene blue from aqueous solutions. In this study, the cellulose-based hydrogel was prepared based on the copolymerization of acrylic acid (AA) on cellulose materials, with the addition of N,N'-methylene bis-acrylamide (MBA) as crosslinking agent, assisted by ammonium persulfate (APS) as initiator. The adsorption of the methylene blue (MB) solution onto the cross-linked cellulose-based hydrogel was studied by the static adsorption method under different conditions of pH, contact time, adsorbent dosage and initial methylene blue concentration. The results showed that for 50 mg/L of methylene blue solution as the initial concentration, the optimum pH was 10 and the adsorption efficiency was up to 98.89%. The analysis of the adsorption equilibrium isotherm strongly indicated that the adsorption by the hydrogel material was best fitted by the Langmuir model, with the maximum adsorption capacity of 41.67 mg/g. Furthermore, the cellulose-based hydrogel maintained high reusability and efficiency in methylene blue adsorption after desorption.