ACTIVATED CARBON DERIVED FROM GROUNDNUT SHELL AND RICE HUSK FOR THE ADSORPTION OF HEAVY METALS IN TANNERY WASTEWATER

Abstract

The Effluents from tanneries are considered to be one of the major environmental pollutants from industries. The challenge from leather processing arises from the nature and quality of the chemicals used along with the amount of wastes generated and discharged. Heavy metals present in tannery wastewater pose a significant risk to both the environment and public health. This study investigates the use of activated Carbon produced from Composite of Groundnut shell and Rice husk (GR-AC) to remove heavy metals (Pb, Cr and Cd) from tannery wastewater. The raw material was carbonized at temperature of 400 ͦ C for 1 hour to obtain bio char. The obtained char was impregnated with NaOH and H 3PO 4 for 24 hours thereafter, filtered and washed several times until a neutral pH was obtained. A measured amount of the adsorbent, 0.5g was introduced into 250mL vessel with 50mL wastewater, it was stirred at 250rpm for 60minutes and later subjected to centrifugation and the concentrations of residual Lead, Chromium and Cadmium was determined using Flame Atomic Absorption Spectrometry. The produced adsorbent was characterized using Fourier transform infrared (FTIR) spectroscopy, Energy-dispersive X-ray fluorescence (EDXRF) and scanning electron microscopy (SEM), elemental composition analysis. The effects of adsorbent dosage and contact time on the adsorption process were studied in a batch system. From the research conducted, it shows that pH, adsorbent dosage, contact time, initial Concentration and temperature plays a vital role in the uptake of heavy metals. Optimal conditions for effective adsorption were determined at a pH range of 7 to 8, an adsorbent dosage of 0.5g, contact time of 60 min and a temperature of 40 0C. The maximum adsorption capacities of Pb, Cr and Cd adsorbed onto GR-AC were found to be 98.2, 82.4 and 75.2 mg/g respectively. Therefore, the GR-AC can be effectively utilized as agricultural waste to remove heavy metals in tannery effluents.