Assessment of lead biosorption performance of spent Gelidiella acerosa (marine macro algae): Optimization, isotherm, kinetic, and column studies

In this research, biosorption of Lead using spent Gelidiella acerosa from synthetic aqueous phase was studied in batch and fixed bed modes. Biosorbent was prepared from waste biomass of Gelidiella acerosa after extraction of agar as a model industrial waste recycle. The process efficiency and optimum lead uptake were evaluated by considering initial pH, lead concentration, and biosorbent dosage as process variables and contact time and temperature as fixed parameters. Central composite design of Response Surface Methodology was used to optimize process parameters and ANOVA showed that initial pH of lead solution significantly influences the biosorption. Interaction effects of different process parameters on process efficiency were analyzed with the help of surface response plots. The highest lead biosorption of 90.75% was noticed at optimum conditions of pH 5.15, initial lead concentration 27.35 mg L −1 and biosorbent dosage 0.04 g. Various kinetic equations were used to analyze the biosorption mechanism and found that metal binding is due to chemical reaction with multi stage mass transfer. Langmuir isotherm was found to be well fitted to equilibrium data. Column studies were also conducted to assess the suitability of the process to continuous operations. The most popular Thomas and Yoon nelson models were used to evaluate the fitness of column studies. Biosorbent was characterized using FTIR and SEM to determine surface functional groups and surface texture.