The Efficiency of Cactus Leaves and Wood Charcoal as a Potential Low-Cost Adsorbent for Removal of Toxic Heavy Metals from Industrial Effluents

Abraha Gebrekidan,Alem Halefom

doi:10.4314/mejs.v10i2.3

Abstract

Presence of toxic heavy metals in the environment is of great concern due to their persistence in nature and chronic adverse effects on human health and the environment. Present paper tries to evaluate the efficiency of cactus leaves ( Opuntia f. indica ) and activated carbon made from acacia etbiaca as an adsorbent for the removal of heavy metal pollutants such as cadmium, lead and chromium from water. Adsorption properties such as size, dose, initial concentration and time of contact for cadmium, lead and chromium were studied through batch method. Before removing the toxic heavy metals (Cd, Pb and Cr), the fresh unpeeled cactus leaves (adsorbent) and activated carbon were washed with distilled water to eliminate the turbidity and smell from fresh unpeeled cactus. To describe the equilibrium isotherms, the experimental data were analyzed by the Langmuir and Freundlich isotherm models. Thus, the Freundlich model gave the best correlation with the experimental data. Therefore, the findings indicated that the cactus and activated carbon made locally from acacia etbiaca were found to be effective and low-cost alternative adsorbents for the removal of toxic heavy metals from industrial effluents. The preparation method allowed the use of these materials by local industries for effective remediation of pollution by removing heavy metals from their effluents. Keywords : Cactus leaves; Acacia etbiaca ; Heavy metals; Adsorption, Industrial effluents; Water purification.

Highlights

The toxic heavy metals are commonly present in many environments and as pollutants in many water bodies
The adsorption of heavy metals with fresh cactus as a function of contact time is shown in figure 1(FC); 120 min contact time is considered as a reference
The present study was carried out to examine the ability of fresh cactus (FC) and activated carbon made from woods of acacia etbiaca to adsorb Cr, Cd and Pb from synthetic aqueous solutions

Summary

Introduction

The toxic heavy metals are commonly present in many environments and as pollutants in many water bodies. The potential harmful effects associated with the accumulation of heavy metals in the environment are well known. Chromium(Cr), cadmium (Cd), lead (Pb) and others are frequently used in industrial processes such as tannery, textile, pharmaceuticals, metallurgy, mining, painting, smelting, batteries, and alloys industries (He et al, 2005; Tchounwou et al, 2012; Ahmed et al, 2017). Most of these heavy metals are often present at high concentration in liquid industrial waste and are often deposited directly in the environment without any pre-treatment. The high toxicity of these metals leads to serious ecological damages, there is an increasing

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