[Utilization of powdered peanut hull as biosorbent for removal of anionic dyes from aqueous solution]

An untried, low cost, locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated. Powder prepared from peanut hull had been used for biosorption of three anionic dyes, amaranth (Am), sunset yellow (SY) and fast green FCF (FG). The effects of various experimental parameters (e.g. initial pH and dye concentration, sorbent dosage, particle size, ion strength, contact time etc.) were examined and optimal experimental conditions were decided. At initial pH 2.0, three dyes studied could be removed effectively. When the dye concentration was 50 mg x L(-1), the percentages of dyes sorbed was 95.5% in Am, 91.3% in SY and 94.98% in FG, respectively. The ratios of dyes sorbed had neared maximum values in all three dyes when sorbent dose of 5.0 g x L(-1) and the sorbent particle size in 80-100 mesh was used. The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes. The equilibrium values arrived at about 36 hour for all three dyes. The isothermal data of biosorption followed the Langmuir and Freundlich models. The biosorption processes conformed the pseudo-first-order rate kinetics. The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater.