Optimization of C.I. Acid black 1 biosorption by Cystoseira indica and Gracilaria persica biomasses from aqueous solutions

The aim of this study is to optimize the removal conditions of C.I. Acid black 1 (AB1) by a brown alga biomass, Cystoseira indica, and a red alga biomass, Gracilaria persica, using Box-Behnken design. The variables examined were the biomass dosage (0.5–1.5 g L−1), initial AB1 concentration (10–50 mg L−1), initial pH (2–6) and time (20–80 min). The determination coefficients (R2) of predicted models were 0.9903 and 0.9955 for C. indica and G. persica biomass, respectively. These findings indicated models high validity in predicting the AB1 removal by both of biomasses. At the optimum conditions, the maximum removal efficiencies of AB1 achieved for C. indica and G. persica were 90.76 and 98.18%, respectively. These results also imply that the used brown and red algal biomasses are favorable biosorbents for the removal of AB1 from aqueous solutions.

► Biological removal of textile dye by using the brown and red algae biomasses.
► Optimization of the biological treatment process by Box–Behnken design.
► Comparison of biosorption efficiency of C. indica and G. persica species.