Evaluation of The Adsorptive Capacity of Cassava Peels in The Removal of Some Heavy Metals and Microbes in Contaminated Water

Access to clean and safe water remains a major environmental and public health challenge, particularly in developing regions where contamination by heavy metals and microbial pathogens is prevalent. This study investigated the effectiveness of acid-modified cassava peels (Manihot esculenta) as a low-cost and sustainable adsorbent for the removal of selected heavy metals (Cd, Pb, Cr, and Ni) and microbial contaminants from polluted water. Batch adsorption experiments were conducted under varying experimental conditions of pH, adsorbent dosage and contact time. For the heavy metals and microbial contaminants, removal efficiency increased with increasing contact time and adsorbent dosage with optimum remediation performance occurring at neutral pH (7.0). Equilibrium adsorption data were analyzed using both Langmuir and Freundlich isotherm models. The data exhibited a superior correlation with the Freundlich model across all target metals (R²: Cd = 0.999, Pb = 0.999, Cr = 0.997, Ni = 0.998) compared to the Langmuir model (R²: Cd = 0.982, Pb = 0.962, Cr = 0.996, Ni = 0.992) confirming multilayer adsorption mechanism onto heterogeneous binding sites. Kinetic analysis showed that the pseudo-second-order model provided the best fit for Cd, Pb and Ni (R²: Cd = 0.9932, Pb = 0.9932, Ni = 0.9877), whereas Cr showed comparable fits under the pseudo-first-order (R² = 0.9355) and pseudo-second-order (R² = 0.9318) models. The biosorbent demonstrated significant efficacy against Total Coliform and E. coli. The findings establish that acid-modified cassava peel is an efficient, eco-friendly, and cost-effective biosorbent for simultaneous removal of heavy metals and microbial contaminants from water, with strong potential for application in wastewater treatment, particularly in developing regions.