Synthesis and Characterization of Bagasse Based Cellulose Hydrogel for Methylene Blue Dye Removal from Textile Industry Wastewater

Abstract

Textile industry wastewater comprises a number of toxic pollutants capable of causing serious health and environmental problems. The inevitable impact of these pollutants necessitates removal/treatment before being released to the environment. Although several wastewater treatment approaches have been devised, removal of cation dyes like methylene blue dye – a highly toxic and harmful component of the effluent – remained challenging. To address this, we synthesized a highly efficient and cost-effective sugarcane bagasse based cellulose hydrogel capable of removing methylene blue dye from textile industry wastewater. The hydrogel was synthesized by cross-linking cellulose with the non-toxic citric acid (CA) through esterification reaction and showed good swelling ratio (75.44 g/g), gel content (86.81%), thermal stability and porosity structures, less crystallinity index (66.46%) than cellulose (77.61%) with (50-150) nm particle size, 101.15 nm z-average particle size and low PDI (0.05)—indicators of good uniformity and uni-modal graph of nanomaterial. A predicted removal efficiency of 98.76% at an optimized condition of the input variables 4.97 g/L adsorbent dosage, 10.32 mg/L initial concentration of the dye and 51.97 minute, contact time). Further adsorption isotherm and kinetics modeling indicated that Langmuir adsorption isotherm and pseudo-first-order fit the experimental data. Performance of the hydrogel was assessed using methylene blue dye bearing synthetic wastewater and real textile wastewater collected from Arbaminch Textile industry, Ethiopia. When using the synthetic wastewater in triplicates, the hydrogel showed an average of 98.65% removal efficiency and small deviation between two result (0.1%) show high concordances with the predicted value. When applied on the real textile wastewater, it reduced the color (dyes) from (2459 to 1044) Pt-Co and achieved the safety standard for water quality parameters. Further, we assessed reusability of the hydrogel for five successive cycles and observed a declining tendency of the removal efficiency down to 70.63% at the last cycle. Generally, these results demonstrate the superior efficiency of the hydrogel and its feasibility of for methylene blue dye removal