Remediation Of Surface Water Polluted By Mining Effluent Discharges: Environmental Impacts And Treatment Methods In South-South Region, Nigeria

Heavy metals, including lead (Pb) and mercury (Hg), are highly toxic to both the environment and human health. Prolonged exposure to these metals can lead to significant health disorders. This study aimed to find an effective adsorbent to reduce Pb and Hg concentrations in water samples from South-South Region, Nigeria. The river was found to be highly turbid (average of 355 NTU), making it unsuitable for domestic use without treatment. The research tested modified rice husk (RH-TAM) and orange peels (OP-TAM) using tartaric acid. Results showed that the modified rice husk (RH-TAM) exhibited superior adsorption efficiency for Pb and Hg. Batch experiments were conducted to evaluate the removal efficiency of Pb and Hg using various ad-sorbents (modified and unmodified rice husk and orange peel). Factors such as pH, contact time, and adsorbent dosage were important in the sorption process. The optimal conditions were found to be pH 5, an adsorbent dosage of 0.5 g/20 ml, and a contact time of 4 hours at 35°C. Under these conditions, the highest Pb adsorption efficiencies were 75.56% for RH- TAM and 69.93% for unmodified rice husk (UM-RH). For Hg, RH-TAM achieved 53.26%, while UM-RH reached 45.11%. The adsorption efficiency of OP-TAM was 62.03% for Pb and 44.57% for Hg, with unmodified orange peel (UM-OP) showing the lowest efficiencies. The Langmuir isotherm better fitted the experimental data for both metals.