Remediation of heavy metal ions from mining wastewater using Azadirachta indica bark adsorbents

The Azadirachta indica bark was powdered and activated with HCl (AIP-H) and NaOH (AIP-N) before being dosed into 50 ml of MW at proportion of 2, 4, 6, 8, and 10 g. The effects of adsorbent dosage, agitation rate, contact time, pH, and temperature on the removal of selected heavy metals (Cu2+, Zn2+, Cd2+, Pb2+, Cr3+, and Co3+) from the MW were studied using batch adsorption studies. The dosage of adsorbent required to achieve 100% removal efficiency for the selected heavy metals was found to be less than 2 g for both adsorbents. For both adsorbents, the optimal agitation rate, contact time, pH, and temperature values were 150-200 rpm, 60-100 minutes, 6-8 and 30 degrees C, respectively. Pseudo second order kinetic model was followed by all heavy metal models. Thus, using Azadirachta indica bark adsorbent to remove heavy metals from wastewater before it is discharged into water bodies is highly recommended.