Comparative Analysis of Biochar produced from Eichhornia crassipes and Rice Husk in Removing Contaminants from Waste Water

Abstract

Heavy metal contamination, particularly chromium Cr (VI)), presents significant threats to the environment and human health because of its toxicity and persistence in aquatic systems. The development of low-cost and sustainable adsorbents is essential for effective wastewater treatment. In this study, biochar was prepared from rice husk and water hyacinth (Eichhornia crassipes) through pyrolysis at 600°C. The prepared biochars were characterized using physicochemical parameters, SEM, XRD, and FTIR analyses. Batch adsorption experiments were directed to assess Cr (VI) removal under controlled conditions of pH 3, 30°C, and varying adsorbent dosages and contact times. The results showed that both biochars exhibited adsorption potential for Cr (VI), with removal efficiency increasing with adsorbent dosage and contact time. Rice husk biochar demonstrated higher adsorption efficiency compared to water hyacinth biochar, achieving maximum removal at lower dosage. SEM analysis revealed a more porous and fibrous structure in rice husk biochar, while XRD and FTIR confirmed the presence of functional groups and structural properties favorable for adsorption. Water hyacinth biochar showed comparatively lower performance due to its structural characteristics. The study concludes that rice husk biochar is a more effective adsorbent for Cr (VI) removal, while water hyacinth biochar shows potential with further modification. The use of such waste-derived biochars offers an economical and environmentally friendly method of treating wastewater.