Abstract

In this research, the biosorbents were prepared based on immobilization technique. The two forms of rice husk, raw rice husk and modified rice husk powder, were entrapped in chitosan-alginate bead. The different amounts of rice husk powder ((0.5%, 1.0%, and 2.0% (w/v)) were mixed with 2% (w/v) alginate solution. The bead was formed by dropwise into chitosan solution containing calcium chloride solution with various ratios (1:4, 1:1, and 4:1). For examining dye removal efficiency, two color groups, basic dye (BB09, BR09) and acid dye (AB25, AR18) were applied. The beads (2.0 g) were incubated in 20 ml dye solution containing 50 mg/L of each dye. The results revealed that the suitable condition for beads preparing was 2.0% (w/v) rice husk in 2% (w/v) alginate solution and dropwise into chitosan solution containing calcium chloride solution with ratio 4:1. The bead containing modified rice husk showed the highest removal efficiency for both basic and acid dye. The basic dyes removal efficiency, BB09 and BR09, were observed at 99.00%±0.11%, and 85.07%±1.03%, respectively. For acid dye, AB25 and AR18, which were, 77.15%±1.30% and 84.69%±3.08%, respectively. As the results implied, application of modified rice husk immobilized in chitosan-alginate bead as a biosorbent for dye removal could be an alternative way for utilization of agricultural waste. These could eventually lead to reduction of chemical requirement for wastewater treatment in textile industry.