Chemical Modification and Characterization of Cissus populnae Stem as Low-Cost Adsorbent for Removal of Some Toxic Contaminants in Water

Abstract

Context: Environmental pollution due to heavy metals in water sources poses a significant threat to ecosystems and human health. Cissus populnea a natural and low-cost adsorbents derived from agricultural waste are being explored for sustainable water treatment solutions. Objectives: This study aims to modify Cissus populnea, a natural cellulosic fiber, through acetylation and evaluate its efficiency in removing cadmium and lead ions from aqueous solutions. Methods: Cissus populnea was acetylated using acetic anhydride and N-bromosuccinimide as a catalyst under mild, solvent-free conditions. The extent of acetylation was determined by weight percent gain (WPG), which was varied by changing reaction temperature and duration. Fourier Transform Infrared Spectroscopy (FTIR) was used for structural characterization. Batch adsorption experiments were conducted to assess the effects of contact time, pH, adsorbent dosage, and initial metal concentration on the removal of cadmium and lead. Results: The acetylation process resulted in a WPG ranging from 2.1% to 24.7%. FTIR analysis confirmed successful incorporation of acetyl groups. Adsorption experiments showed that the modified fiber removed up to 90% of cadmium and 85% of lead under optimal conditions, indicating high adsorption efficiency. Conclusion: The findings demonstrate that acetylated Cissus populnea is an effective and sustainable biosorbent for the removal of cadmium and lead from aqueous streams. This highlights the potential application of plant-derived waste materials in environmental remediation. Future work will include additional surface and thermal characterization to provide a deeper mechanistic understanding.