Malaysian Journal of Analytical Sciences, Vol. 7, No. 2 (2001) 453-456 ___________________________________________________________________________________________ Preliminary Study on Application of Sago Starch Based Poly(Hydroxamic Acid) Resin for Extraction of Lanthanide Group Elements from Aqueous Media Mohamad Zaki Ab Rahman, Md Lutfor Rahman, Md Jelas Haron, Sidik Silong, Wan Md Zin Wan Yunus and Mansor B. Ahmad Department of Chemistry, Faculty of Science and Environmental Studies, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Received 6 September 2000) Abstract: Sago starch was used as a backbone polymer for synthesizing poly(hydroxamic acid) chelating resin. The hydroxamic acid functional group was identified by visual color test and infrared spectroscopy. The chelating behaviors of the hydroxamic acid ligand with a series of lanthanide elements were studied by using batch technique. The binding capacity of lanthanum was about 2.30 mmol g -1 at pH 6, higher than other metal ions tested namely dysprosium, praseodymium and cerium which were found to have significant binding capacity at pH 7. The rate of exchange (t ½ ) of copper ion was found to be < 5 min, which was fast. It was also observed that the metal ions binding capacity were pH dependent and its selectivity towards these metal ions is in the following order: La 3+ > Dy 3+ > Pr 3+ > Ce 3+ > Nd 3+ > Gd 3+ > Eu 3+ > Tb 3+ . This chelating ligand has the advantage of significant binding capacity and a fast rate of equilibrium. It could be considered as an efficient resin for extraction of heavier lanthanide elements from the environment or other sources. Abstrak: Kanji sagu telah digunakan sebagai tulang belakang polimer untuk menyedia resin pengkelat poli(asid hidroksamik). Kumpulan berfungsi asid hidroksamik pada resin telah dikenalpasti melalui ujian warna dan spektroskopi infra merah. Keupayaan ligan asid hidroksamik mengkelat unsur-unsur kumpulan lantanida telah dikaji dengan kaedah kelompok. Muatan ion logam lantanum yang terikat pada resin tersebut adalah tinggi iaitu kira-kira 2.30 mmolg -1 pada pH 6 sementara unsur- unsur disprosium, praseodimium dan serium didapati mempunyai muatan yang bermakna pada pH 7. Kadar penukaran (t ½ ) ion kuprum adalah cepat iaitu kurang daripada 5 min. Mautan ion logam juga didapati bergantung kepada pH dan kepilihan resin terhadap ion logam yang dikaji adalah seperti berikut: La 3+ > Dy 3+ > Pr 3+ > Ce 3+ > Nd 3+ > Gd 3+ > Eu 3+ > Tb 3+ . Kelebihan ligan pengkelat ini ialah ia mempunyai muatan ion logam yang agak tinggi dan juga kadar keseimbangan yang cepat. Ia berkemungkinan besar dapat digunakan sebagai resin untuk mengekstrak unsur lantanida berat daripada persekitaran dan punca-punca lain. ___________________________________________________________________________________________ Introduction Ion exchange resins bearing chelating functional groups have long been of interest for removing metals from water. The design of chelating ligands depends on the stability of the basic macromolecular network and its ability to add on the desired chelating functional groups [1, 2]. Because the alkali and alkaline earth metals occur in relatively high concentrations in natural waters, a desirable property of metal chelating ligands having useful environmental or commercial application is their ability to bind heavier elements selectively. They should be able to bind the heavier transition, rare earth, and main group metal ions in the presence of high concentration of calcium, magnesium, sodium and potassium. The chelating resins containing hydroxamic groups can also play a vital role in environmental monitoring of toxic trace metals. Highly promising is the use of this resin for extraction of toxic metals in the environment and sewage water [3]. There is also a possibility of using poly(hydroxamic acid) resin to extract rare earth from seawater. The commercial importance of poly(hydroxamic acid) resin seems to have potential, together with the knowledge that hydroxamic groups can form complexes with a wide range of metals [4- 6]. The chelating polymer materials are mainly used in analytical, industrial and radiochemical laboratories, but only a limited extent in solving environmental problems. Metal pollution of the environment possesses a unique problem, since metals are not subjected to biodegradation. Among the newer chelating ion exchange resin, the preparation of this chelating poly(hydroxamic acid) resin from poly(methyl acrylate) (PMA) grafted sago starch is a new starting polymer to obtain this resin. The starting material for the resin preparation especially sago starches are available and also it is a renewable source. In this report, the poly(hydroxamic acid) chelating resin was prepared using modified method [7] by cheapest starting material and the chelating behavior was investigated.