Adsorption of selected metals from cassava processing wastewater using cow-bone ash
R. A. Olaoye, O D Afolayan, K.A. Adeyemi, L.O. Ajisope, Olusola Adekunle
Abstract
In this study, the efficiency of cow-bone ash (CBA) as an adsorbent for the removal of metals from real-time cassava wastewater was examined. Wastewater was characterized using atomic absorption spectrophotometry (AAS). The adsorbent was characterized using X-ray Fluorescence (XRF), Scanning electron microscopy (SEM), and Fourier transform infrared FTIR. The effect of adsorbent dose, contact time, and agitation speed was investigated by a batch experiment performed in triplicate, and the removal efficiency of the ions calculated. Characterization of the cassava wastewater revealed that the concentration of Fe2+, Zn2+, Pb2+, and Mn2+were above the USEPA permissible limit. The adsorbent's characterization showed that it possesses crystalline nature, porous and rough surface, and the presence of CH, C = O, and CO functional groups. The optimum adsorbent dose was 0.02 g/100 mL for Fe2+ and Zn2+, and 0.04 g/100 mL for Mn2+ and Pb2 at an optimum contact time of 60 min and agitation speed of 150 rpm. The maximum metal removal efficiency obtained were 99%, 97%, 93% and 98% for Fe2+, Zn2+, Pb2+, and Mn2, respectively. Cow-bone ash offers efficient and cost-effective removal of Fe2+, Zn2+, Pb2+, and Mn2+from cassava wastewater.