G Kavitha and N Chitti Babu
Batch and fixed bed column bio-sorption studies were conducted for the removal of lead from aqueous solution using Gracilaria corticata algae powder as bio-sorbent. The effects of agitation time, size and dosage of adsorbent, pH, initial concentration of lead and temperature of aqueous solution are studied in this work. The maximum bio-sorption of lead is attained at an equilibrium time of 60 min. The optimum dosage and pH are 20 g/L and 6 respectively at an initial concentration of 20 mg/L at 3030 K. The monolayer uptake capacity is 5.291 mg/g. The statistical analysis of bio-sorption using Response Surface Methodology (RSM) was studied. The quadratic model for Central Composite Design (CCD) has fitted well to the experimental data. The optimum bio-sorption conditions (CCD) are initial pH = 6.096, initial lead ion concentration = 19.76 mg/L, bio-sorbent dosage = 19.93 g/L and temperature = 303.86 K. The experimental data are well explained by Langmuir, Freundlich and Redlich-Peterson isotherm models. The bio-sorption data follows second order kinetics and the process is feasible, irreversible and endothermic. An up-flow packed bed column is employed to investigate lead bio-sorption as a function of flow rate of aqueous solution, initial lead concentration and bio-sorbent bed height and the bed is formed with Gracilaria corticata powder. The experimental results and application of various models are studied. The performance of packed bed column is finally analyzed using breakthrough curves.
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