title: Sequestration of toxic Pb(II) ions by chemically treated rubber (Hevea brasiliensis) leaf powder.
abstract: Rubber leaf powder (an agricultural waste) was treated with potassium permanganate followed by sodium carbonate and its performance in the removal of Pb(II) ions from aqueous solution was evaluated. The interactions between Pb(II) ions and functional groups on the adsorbent surface were confirmed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDX). The effects of several important parameters which can affect adsorption capacity such as pH, adsorbent dosage, initial lead concentration and contact time were studied. The optimum pH range for lead adsorption was 4-5. Even at very low adsorbent dosage of 0.02 g, almost 100% of Pb(II) ions (23 mg/L) could be removed. The adsorption capacity was also dependent on lead concentration and contact time, and relatively a short period of time (60-90 min) was required to reach equilibrium. The equilibrium data were analyzed with Langmuir, Freundlich and Dubinin-Radushkevich isotherms. Based on Langmuir model, the maximum adsorption capacity of lead was 95.3 mg/g. Three kinetic models including pseudo first-order, pseudo second-order and Boyd were used to analyze the lead adsorption process, and the results showed that the pseudo second-order fitted well with correlation coefficients greater than 0.99.
authors.affiliation: Faculty of Applied Sciences, Universiti Teknologi MARA Pahang, 26400 Jengka, Pahang, Malaysia. makmh73@yahoo.com.my
authors.forename: Megat Hanafiah Megat Ahmad
authors.initials: MH
authors.lastname: Kamal
authors.forename: Wan Mat Khalir Wan Khaima
authors.initials: WM
authors.lastname: Azira
authors.forename: Mohamed
authors.initials: M
authors.lastname: Kasmawati
authors.forename: Zakaria
authors.initials: Z
authors.lastname: Haslizaidi
authors.forename: Wan Ngah Wan
authors.initials: WN
authors.lastname: Saime
mesh_terms: D000327:Adsorption; D028482:Hevea / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D007854:Lead