Blending of waste biomass for cost-effective chitosan-based biosorbents for removal of reactive dye from aqueous solution

Abstract

Chitosan (CS) is an attractive natural and biodegradable cationic adsorbent material for treatment of anionic pollutants. For chitosan-based sorbents to be practicable, their price should be low. This study aims at cost reduction of chitosan-based sorbent through making of composite chitosan beads with industrial fermentation waste biomass of Escherichia coli. The maximum biomass content for maintaining stable composite bead structure was approximately 70.4% (w/w). The adsorption properties of the bacterial biomass-chitosan composite beads (BCCB) were evaluated using an anionic dye material, Reactive Yellow 2 (RY 2). At pH 4, the maximum uptake of BCCB was 679.13±23.76 mg/g, whereas those of pristine CS bead (CSB) and raw E. coli biomass were 934.71±50.97 mg/g and 200.77±4.51 mg/g, respectively. However, considering bound amount of RY2 to CS molecules in the CS-based beads, the BCCB showed the 2.1 times higher dye sorption capacity of CS than that of the CS in the CSB. In addition, the cost of RY2 treatment process using BCCB is expected to be shortened by 58% compared to CSB. Therefore, this study suggests that compositing CS with biomass waste can be a practical way to design cost-effective adsorbents.