Abstract

Mitiku Abdisa Chimdessa^*
and Birhanu Aseffa Ejeta

DOI : http://dx.doi.org/10.13005/ojc/380107

Toxic heavy metal ions are extremely harmful to living things and the environment due to their toxicity, carcinogenicity, ability to collect in nature, and capacity to contaminate surface and ground water. The focus of this research was to develop an appropriate and low cost adsorbent for the removal heavy metal ions from aqueous solutions. The activated carbon was prepared from avocado kernels and characterized by using XRD, FTIR, and pHPZC. From the XRD spectra the crystal size of AC-1 and AC-2 were calculated. The sample with the smallest crystallite size (40.05 nm) was found to be AC-1 and chosen for the further characterization and sorption experiments. Batch studies on synthetic samples were performed at room temperature. pH effect, initial concentration, adsorbent dosage, initial concentration, and contact time were investigated and also heavy metal ion adsorption isotherms were calculated. At pH 7, the highest removal effectiveness of metals (copper, cadmium, and lead) by activated carbon adsorbent made from avocado kernel was achieved. The best adsorbent dose for cadmium and lead was 500 mg, 700 mg for copper, and the optimum contact times for lead, cadmium and copper ions were 120, 60 minutes, respectively. In these optimum conditions the removal efficiencies were 87%, 89.4%, and 99.5% for copper, Lead, and Cadmium ions respectively. The removal efficiencies for copper, lead, and cadmium ions were 87 %, 89.4 %, and 99.5 %, respectively, under these optimal conditions. The Langmuir isotherm model has the strongest correlation with the obtained results. According to the findings, activated carbon made from avocado kernels has high adsorption capacity for removing heavy metal ions from aqueous solutions.

Activated Carbon; Adsorption; Avocado Kernel; Heavy Metal

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