USE OF RICE STRAW AS A BIOSORBENT FOR REMOVAL OF HEAVY METALS FROM AQUEOUS SOLUTION

Heavy metal contamination in water is a major environmental concern due to the toxicity, persistence, and ability of metals such as copper (Cu), zinc (Zn), iron (Fe), and cobalt (Co) to accumulate in living organisms. Traditional treatment methods, including chemical precipitation and membrane filtration, are often costly and less effective for treating low metal concentrations, especially in developing regions. This has increased interest in biosorption as a low-cost and environmentally friendly alternative. Rice straw, an abundant agricultural residue, contains cellulose, lignin, hemicellulose, and silica, which provide functional groups capable of binding metal ions, making it a promising biosorbent. This study evaluates the capacity of rice straw to remove Cu²⁺, Zn²⁺, Fe²⁺, and Co²⁺ from aqueous solutions under controlled laboratory conditions. Although lignocellulosic materials have been shown to remove heavy metals effectively through mechanisms such as ion exchange and surface complexation, limited research has explored the simultaneous removal of these four metals using rice straw. The results of this study will offer insight into the efficiency of rice straw as a low-cost biosorbent and support its potential for use in sustainable wastewater treatment systems, particularly in regions without advanced treatment technologies