Investigation into the Optimization Process of Adsorbent Dosage on Heavy Metal Removal

Heavy metals represent pervasive environmental hazards, posing significant threats to human health and ecological balance owing to their enduring presence and toxic nature. Addressing the removal of heavy metals from Ahmadu Bello University’s wastewater stabilization pond (WSP) which was designed to handle the organic pollutants and heavy metals found in the university's generated wastewater, stands as a critical imperative in curtailing these deleterious impacts. Employing adsorption techniques with appropriate adsorbents emerges as a promising avenue for achieving efficient heavy metal removal. This study delves into the optimization of adsorbent dosage using pH of 7.0 condition to study the efficiency of cadmium removal as the selected response, whose optimum variables were used to investigate the effect of pH variation and time for the removal efficacy of other heavy metals, specifically chromium, lead, and copper from WSP. Leveraging a design of experiments approach, the corn cob adsorbent dosage (ranging from 10 to 20 g) and concentrations of cadmium heavy metal solutions (ranging from 20 to 100 g) were varied, utilizing Design Expert software, aimed at pinpointing the optimal dosage and assessing adsorption capacities. The experimental findings underscore the pivotal role of optimized adsorbent dosage and pH conditions in enhancing the efficiency of heavy metal removal from the WSP. The optimum corn cob adsorbent dosage of 15 g exhibited commendable cadmium heavy metal removal efficiency which was selected for optimization study among the other identified heavy metals present in the WSP used, reaching 94.8 % at the end of 98th days. Furthermore, the investigation revealed that peak adsorption efficiencies at the end of study period of 98th days for chromium, lead, and copper were attained at a neutral pH of 7.0, yielding removal percentages of 94.5 %, 93.6 %, and 93.6 %, respectively. In conclusion, these insights emphasize the critical importance of systematically fine-tuning adsorbent dosage and pH conditions to maximize heavy metal removal efficacy.