ABSTRACT
The Automobile workshop runoff sample collected from Nigerian correctional Service Headquarters Office, Mechanical Section, Off Golf Course Road, G.R.A resulting from activities such as vehicle washing, metal working and fluid leak taken to the laboratory for a Physiochemical and Heavy Metal analysis is said to contains toxic metals that can harm the environment and human health. This research project investigates the treatment of automobile workshop runoff, focusing on the removal of Zinc metals present in the sample while looking at the objective of characterizing the pollutant in The initial automobile workshop runoff sample had high concentrations of pollutants, including: pH: 6.9, Total Suspended Solids (TSS): 11370 mg/L, Chemical Oxygen Demand (COD): 1824 mg/L, Lead (Pb): 2.052 mg/L, Cadmium (Cd): 0.632 mg/L, Zinc (Zn): 11.509 mg/L. After treatment with an adsorbent dosage of 3.0 g/L for 2 hours, the concentrations of pollutants were significantly reduced in pH: 4.9, TSS: <1.00 mg/L, COD: 32 mg/L, Lead (Pb): 0.052 mg/L, Cadmium (Cd): 0.032 mg/L, Zinc (Zn): 1.194 mg/L. The activated sawdust was prepared from sawdust having Bulk Density: 0.860 g/cm³ and pH: 3.50. Analyzing the impact of adsorbent dosage and contact time it is seen that increasing the adsorbent dosage from 0.1 g/L to 3.0 g/L led to an increase in the amount of zinc ions adsorbed (qe) from 0.0306 mg/g to 0.1719 mg/g. The removal efficiency of zinc ions also increased from 0.6% to 89.6% as the adsorbent dosage increased. The amount of zinc ions adsorbed (qt) increased from 0.0264 mg/g at 5 minutes to 0.1853 mg/g at 120 minutes, indicating that longer contact times facilitated better v adsorption. The removal efficiency of zinc ions also increased from 9.2% to 64.4% as the contact time increased. The experimental data was fitted to the Langmuir and Freundlich isotherm models, as well as the pseudo-first-order and pseudo-second-order kinetic models. The Langmuir isotherm provided a better fit, suggesting monolayer adsorption and homogeneous surface energies.
