Optimization and equilibrium studies of Pb(II) removal by Grewia Asiatica seed: a factorial design approach

• Published in: Polish journal of chemical technology 2012-01, Vol.14 (1), p.71-77
• Main Authors: Siyal, Ali, Memon, Saima, Khaskheli, Mazhar
• Format: Article
• Language: English
• Subjects: Biosorption; Equilibrium Studies; Factorial design; Grewia seed waste; Optimization; Pb(II) removal; Response Surface Methodology; seed waste
• ISSN: 1509-8117; 1899-4741
• DOI: 10.2478/v10026-012-0062-9

This study aims to explore the efficiency of an agro waste material for the remediation of Pb(II) contaminated water. A factorial design approach is adopted to optimize removal efficiency and to study the interaction between effective variables. A face-centered Draper-Lin composite design predicted 100% removal efficiency at optimum variables; pH 8, initial concentration of Pb(II) ion 12mg/L, sorbent dose 200mg and agitation time 110 min. Regration coefficient (R2 = 99.9%) of a plot of the predicted versus the observed values and p value (>0.05) confirms the applicability of the predicted model. Langmuir and Dubinin-Radushkevich (D-R) isotherm models were applicable to sorption data with the Langmuir sorption capacity of 21.61±0.78 mg/g. The energy of sorption was found to be 13.62±0.32 kJ/mol expected for ion-exchange or chemisorption nature of sorption process. Characterization of Grewia seed suggested a possible contribution of carboxyl and hydroxyl groups in the process of biosorption. The present study shows that Grewia seeds can be used effectively for the remediation of Pb(II) contaminated water.