Bio-sorption of ammonium ions by dried red marine algae (Gracilaria persica): Application of response surface methodology

The bio-sorption of ammonium ions using red marine macroalga Gracilaria persica were investigated by response surface methodology. The sorbent was characterized by SEM and FTIR analysis. The influence of various operating parameters such as ammonium concentration (mg L-1), initial solution pH and alga biomass dosage (g L-1) was optimized using Box–Behnken design. A second-order polynomial model successfully described the effects of independent variables on the ammonium ions removal. At the optimum conditions, the maximum removal efficiency was achieved at 100.01 %. The kinetic results also demonstrated that the bio-sorption of ammonium ions by the dried microalga followed well pseudo-second-order kinetics. FTIR results showed that amide, aliphatic and carbonyl groups might be responsible for the adsorption of ammonium ions in aqueous solution by dried G. persica biomass.