Activated Carbon from Various Agricultural Wastes and their Efficacy for the Removal of Dyes and Metal Ions from Aqueous Solutions

Allan  M. Lizardo,

Activated Carbon from Various Agricultural Wastes and their Efficacy for the Removal of Dyes and Metal Ions from Aqueous Solutions

Abstract:

Industrial effluents are among the major causes of environmental pollution. Among the different pollutants of the aquatic ecosystem, dyes and heavy metals are a large and important group of chemicals. Activated carbon adsorption is one such method which has great potential for removal of dyes, as well as heavy metals from wastewater. In this study, various agricultural wastes such as maize cob, coconut sawdust, and dalandan peels were used to prepare activated carbon. Experiment was conducted to test activated carbon’s efficacy in the removal of dyes and metal ion in aqueous solution.

Maize cob, coconut sawdust, and dalandan peels were carbonized and treated with H3PO4 (85%w) as activating agent. The activating carbon was used in batch mode studies using aqueous solutions of methylene blue, Rhodamine–B, Congo red, methyl violet and Mercury (Hg2+) as adsorbates. Fifty – milliliter dyes or metal ion solution (25 mg/L) and 250 mg adsorbent (particle size < 250 ïm) were taken in a 100mL Erlenmeyer flask and agitated at 160 rpm. The flasks were withdrawn at 1, 3, 24 h interval, centrifuged and subjected to spectrophotometric analysis.

Experimental results showed that carbon was effective in the removal of pollutants from water. Activated carbon prepared from coconut sawdust exhibited 94.4% removal of methyl violet, 93.4% removal of methylene blue, 91.54% removal of Hg solute, 78.76% removal of Congo red and 63.48% removal of Rhodamine-B. .

Activated carbon prepared from corncob exhibited 94.77% removal of Hg solute, 89.25% removal of methyl violet, 75.25% removal of Rhodamine–B, 72.285% removal of methylene blue and 51.71% removal.