Utilization of Chemically Modified Rice Hull for the Treatment of Industrial Wastewater Siew-Teng Ong 1,2 + and Weng-Nam Lee 3 1 Faculty of Science, 2 Centre for Biodiversity Research, Universiti Tunku Abdul Rahman, Jln Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia 3 Department of Science, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jln Genting Kelang, Setapak, 53300 Kuala Lumpur, Malaysia Abstract. Effectiveness of using chemically modified rice hull (MRH) in the treatment of industrial wastewater was investigated. The optimised chemical modification process was preformed by treating 1.00 g of rice hull with 0.02 mol of ethylenediamine (EDA) in a “well stirred” water bath at 80 o C for two hours. Batch and column studies were performed under various experimental conditions and the parameters studied included pH, contact time and bed depth. The experimental results revealed that the optimum pH for the treatment of wastewater from textile industry was in the range of 2 to 5. Uptake of dye under both batch and continuous flow conditions shows similar behavior as in synthetic solutions. Keywords: Wastewater; Dyes; Sorption; Batch Study; Column Study 1. Introduction Colorants are characterized by their ability to absorb or emit light in the visible range (400-800 nm). The term colorant is frequently used to encompass both dyes and pigments. These two terms are often used indiscriminately; in particular, pigments are sometimes considered to be a group of dyes. Indeed, these two groups of colouring materials are quite similar chemically. However, they are distinctly different in their properties and especially in the way they are used. The major characteristic of pigments is their insolubility in the media in which they are applied, especially water. Pigments have to be attached to a substrate by means of additional compounds, e.g., polymers in paints, plastics, or melts. In contrast to pigments, dyes are coloured substances that can be applied to various substrates (textile materials, leather, paper, hair) from a liquid in which they are completely, or at least partly, soluble. In other words, the substrate has a natural affinity for appropriate dyes and readily absorbs them from solutions or aqueous dispersion. The usage of these dyes has continuously increased in many industries such as textile, paper, plastics and cosmetics [1]. It has been reported that approximately 10,000 different types of dyes and pigments are used in industries and over 7 × 10 5 tons of these dyes are being produced annually [2]. Effluents containing dyes from these industries show low level of biodegradability because of high molecular weight and complex chemical structures. Many dyes are difficult to degrade, as they are generally stable to light and oxidizing agents, and are resistant to aerobic digestion [3]. Hence, the presence of dyes even in trace quantities is very undesirable in aqueous environment. The conventional treatment methods for color removal from industrial effluents are divided into three categories which include physical, biological and chemical [4]. For physical treatment, this normally includes filtration, ion exchange, adsorption and membrane process. As for biological treatment, it involves the usage of bacteria or microorganisms to decompose the waste while chemical treatments are often associated to the addition of oxidizing or reducing agents, coagulants and other chemicals. + Corresponding author. Tel.: +605-4688888; fax: +605-4661676 E-mail address: ongst_utar@yahoo.com, ongst@utar.edu.my 122 2012 3rd International Conference on Chemistry and Chemical Engineering IPCBEE vol.38 (2012) © (2012) IACSIT Press, Singapore