Removal of lead from aqueous solution using chemically modified green algae as biosorbent: optimization and kinetics study

In the present study, biosorption of lead using green algae as biosorbent from aqueous solution was studied with one-factor-at-a-time (OFAT) method. The batch biosorption process is a function of agitation time, biomass loading, initial concentration of lead and solution pH. Further, face-centered central composite design under RSM application was applied to optimize the process parameters to get more percentage biosorption of lead. The percentage removal of lead was found to be 71% in batch experiment by OFAT method, whereas in RSM study the maximum biosorption rate 75% was reached at optimum conditions of agitation time 40 min., dosage 3 g, initial ion concentration 15 mg/L and pH 3.35. The adsorbent was characterized by FTIR, scanning electron microscopy (SEM) and Brunauer–Emmett Teller (BET) analysis. The kinetic models were also analyzed to determine the biosorption mechanism. It was found that the data best followed to pseudo second order mechanism. Biosorption isotherms were successfully fitted by Langmuir isotherm (R2 = 0.974) and d) Freundlich isotherm (R2 = 0.983) models.