Exploration of Avocado Seeds as Material for the Elimination of Toxic Metals in Groundwater in Some Communities in the Sefwi Wiawso Municipality, Ghana.

Abstract

The use of activated avocado seeds for adsorption is an environmentally safe, effective and affordable technique for cutting back heavy metal levels in water. In this study, activated carbon was produced from avocado seeds, characterised, and tested for its adsorptive capacity on As, Cd and Pb in selected groundwater resources at Sefwi Wiawso Municipality in the Western North region of Ghana. A physical activation method was used to obtain the activated avocado seeds. Surface properties of the activated avocado seeds produced were assessed by XRF, FTIR and SEM-EDX spectroscopy before and after use in the adsorption process. Surface characterisation analysis showed that the activated avocado seeds were potentially good adsorbents for selected heavy metals. Except for turbidity levels, the physicochemical properties of the water samples used were below WHO permissible limits. As, Cd, and Pb levels in the water samples also exceeded the WHO permissible limit. Over 90% of the ions of the heavy metals were removed from the water samples. The metal ions investigated were removed from the water samples. The Freundlich isotherm and the second-order pseudo-kinetic models best fitted the equilibrium adsorption data of the study. The kinetics studies showed that the adsorption process was chemisorption, whilst the thermodynamics studies found the adsorption to be spontaneous and exothermic. This study recommended a study into the production of activated carbon from other agricultural waste products and assesses their adsorptive capacities on metal-ion removal in water resources.