PEER-REVIEWED ARTICLE bioresources.com Haron et al. (2009). “Cu(II) removal by modified OPEFB,” BioResources 4(4), 1305-1318. 1305 SORPTION OF Cu(II) BY POLY(HYDROXAMIC ACID) CHELATING EXCHANGER PREPARED FROM POL(YMETHYL ACRYLATE) GRAFTED OIL PALM EMPTY FRUIT BUNCH (OPEFB) Md Jelas Haron,* Mariati Tiansih, Nor Azowa Ibrahim, Anuar Kassim, and W. M. Z. Wan Yunus This paper describes the preparation of chemically modified oil palm empty fruit bunch (OPEFB) with hydroxamic acid functional group and its use for the sorption of Cu(II) from aqueous solution. OPEFB was grafted with poly(methylacrylate) (PMA), using H 2 O 2 /Fe 2+ as initiator. The PMA grafted OPEFB (PMA-OPEFB) was treated with hydroxylammonium chloride in alkaline medium to produce hydroxamic acid grafted fiber (PHA-OPEFB). The FTIR spectrum of OPEFB grafted with PMA showed an intense absorption band at 1734 cm -1 which is attributed to C=O vibration in the grafted ester. After hydroxylamine treatment, the intensity of absorption band at 1734 cm -1 decreased and new bands appeared at the 1640 cm -1 related to C=O vibration in hydroxamic acid and at the 1568 cm -1 related to the N-H amide. Sorption of Cu(II) by PHA-OPEFB was effective over a pH range of 4 to 6. The sorption followed the Langmuir model with maximum capacities of 74.1 mg g -1 at 25 °C. The sorption process was exothermic, as shown by the negative value of enthalpy change, ΔH°. The free energy change (ΔG°) for the sorption was negative, showing that the sorption process was spontaneous. A kinetic study showed that the Cu(II) sorption followed a second order kinetic model. Keywords: Methyl acrylate; Grafted; OPEFB; Hydroxamic acid; Cu(II); Sorption Contact information: Chemistry Department, Universiti Putra Malaysia 43400 Serdang, Selangor, Malaysia; *Corresponding authors: mdjelas@science.upm.edu.my INTRODUCTION Removal and recovery of heavy metal ions from wastewater has become an important research area in terms of environmental issues in recent years. Ion exchange is one of the important techniques that have been developed for this purpose. Synthetic resins having functionalities to form chelate structures with metal ions have been used by many researchers for the removal and recovery of heavy metal ions in wastewater (Dinu and Dragan 2008). However, in many cases the petroleum-based synthetic copolymers such as styrene-divinyl benzene and xylene-aldehyde have been utilized (Lin and Juang 2005; Haron et al. 1994; Trivadi et al. 2002). Most petroleum-based synthetic polymers resin are in beads form and neither renewable nor biodegradable. Biomass is more biodegradable, and it could thus be an alternative and economical material for heavy metal removal from wastewater. Oil palm is one of the important economic plants of Malaysia, and the plantation area has been increased every year. Oil palm empty fruit bunch (OPEFB) is one of the biomass wastes of the oil palm industry (Law et al. 2007).