Assessment of the Potentials of Theobroma Cacao Pod-Feldspar Composite Adsorbent for Heavy Metal Removal in Waste Water

Abstract

Purpose: Most conventional wastewater treatment techniques for the removal heavy metals are highly expensive and may, create sludge disposal problems. Adsorption techniques are relatively cheaper particularly when the process is carried out using low-cost materials and biomass. This paper is on the assessment of the potentials of a modified feldspar composite absorbent developed from waste agricultural biomass (Theobroma cocoa pod) and feldspar mineral in the removal of heavy metals from wastewater. Methodology: The physicochemical analysis were carried out on the wastewater samples before and after treatment with modified feldspar composite using standard methods. Portions of the samples were directly digested and analysed for Pb, Cd, Cr and As, while the second portions were treated with the modified Theobroma cocoa pod-Felspar (TCPF) adsorbent under optimum conditions before analysing for the heavy metals. The desorption (cleaning) of the TCPF adsorbent after the adsorption of the heavy metals (Pb, Cd, As and Cr) from the wastewater was carried out with 0.1 M HCl. Findings: The AAS analysis revealed that, the concentrations of the heavy metals in the wastewater before treatment with TCPF were higher and followed Pb>Cr>Cd>As trend and were above WHO and NESREA standards. The values for the samples treated with TCPF were lower and followed Cr>As>Pb>Cd trend and were within the standards. The differences between the values for the individual metals in the wastewater before and after treatment with the TCPF adsorbent were significant at p< 0.05. The adsorption efficiency of the TCPF was high for Pb (98.92%), Cd (96.88%) and Cr (97.18). Similarly, the TCPF showed high desorption efficiency with 76.8% for Pb, 90.6% for Cd, 94.4% for As and 80.3% for Cr. Unique contribution to theory policy and practice: The modified composite (TCPF) has shown some significant potentials for use in the removal of the selected heavy metals from wastewater and industrial effluent.