Sustainable Synthesis and Characterization of Carboxymethyl Cellulose from Agricultural Byproducts: Corn Leaf and Rice Straw
Abstract
This study explores the sustainable production of carboxymethyl cellulose (CMC) from corn (Zea mays L.) leaf (CL) and rice (Oryza sativa L.) straw (RS), two abundant agricultural byproducts. A novel carboxymethylation method was employed, using sodium hydroxide (NaOH) concentrations of 20–60 g/100 mL. Optimal conditions were determined at 40 g/100 mL NaOH, yielding degrees of substitution (DS) of 0.87 for CL and 0.89 for RS. The DS significantly enhances CMC properties, such as water solubility and viscosity, making it suitable for applications in pharmaceuticals and food industries. Fourier transform infrared spectroscopy confirmed the presence of carboxymethyl groups, while thermogravimetric analysis (TGA), X-ray diffraction, and field emission scanning electron microscopy revealed structural and morphological characteristics. Heavy metal analysis via inductively coupled plasma-mass spectrometer (ICP-MS) showed compliance with World Health Organization (WHO)/Food and Agriculture Organization (FAO) limits, except for lead. The high purity of CMCCL and CMCRS (99.35% and 99.36%) exceeds commercial-grade standards, emphasizing their industrial potential in sectors such as paper, textiles, and ceramics.