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

Authors: Ezekiel A. Adetoro; Samson O. Ojoawo

Addresses: Department of Civil Engineering, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria ' Department of Civil Engineering, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria

Abstract: 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°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.

Keywords: Azadirachta indica bark adsorbent; batch adsorption studies; environmental management; heavy metals' remediation; isotherm model; kinetic model; mining wastewater; removal efficiency; waste management.

DOI: 10.1504/IJEWM.2024.139962

International Journal of Environment and Waste Management, 2024 Vol.34 No.3, pp.340 - 366

Accepted: 12 Apr 2022
Published online: 15 Jul 2024 *

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