Evaluation of lime peel-based filter materials in a packed bed for the treatment of pharmaceutical effluent

Pharmaceutical wastewater treatment presents a significant environmental challenge due to the complex combination of organic and inorganic contaminants involved. This study explored the effectiveness of lime peel-based materials (unmodified lime peel (LP), lime peel biochar (LB), and clay-impregnated lime peel biochar (CI-LB)) for treating pharmaceutical effluent within a packed bed filtration system. The materials were analyzed using FTIR, SEM, XRF, and TGA/DTA/DSC to assess their surface properties, functional groups, elemental composition, and thermal stability. The treatment trials indicated some reductions in biological oxygen demand (BOD from 12.10 to 10.7 mg/L), chemical oxygen demand (COD from 8.14 to 8.09 mg/g), total suspended solids (TSS from 0.10 to 0.05 mg/g), and heavy metal concentrations. CI-LB proved to be the most effective filter material, achieving optimal pollutant removal with 24-hour contact time, reducing Copper, Cadmium, Nickel, Zinc, and Manganese to below-detectable levels. However, all materials showed limited success in decreasing total dissolved solids (TDS) and electrical conductivity (EC), with increases of 48.4%, 113%, and 190.6% for LB, CI-LB, and LP respectively. The study concludes that lime peel-based materials, particularly CI-LB, show significant potential for pharmaceutical effluent remediation but require further optimization to address TDS and EC challenges. Future research should investigate combined treatment strategies and material enhancements to fully address these challenges.