Decontamination of Pb2+, Cd2+ and Ni2+ Polluted Water by Adsorption Unto Butterfly Pea (Centrosema pubescens) Seed Pod

Abstract

Heavy metal contaminations of water bodies by industrial and other wastes have been confirmed to exert a significant role in the environment because of expanding risk factor such contamination can cause. In this study, the batch adsorption method is adopted to removed Pb²⁺, Cd²⁺ and Ni²⁺ from an aqueous solution using a butterfly pea pod. The adsorption data reflected the strong dependency of the adsorption on temperature, adsorbent dosage, initial metal ion concentration, a period of contact, and other factors. The adsorption of the three metal ions proceeded through a similar mechanism (i.e. physical adsorption) and the trend was supported by maximum adsorption capacity values (which were Pb(II), Cd(II) and Ni(II) ions was 10.52, 18.32, and 13.18 mg/g),  free energy change data and sticking probability parameters. The adsorption was spontaneous and best fitted Langmuir, Flory Huggins, Freundlich, and Dubinin-radushkevich adsorption models. Results of the present investigation revealed that butterfly pea pot is an excellent adsorbent for lead, cadmium, and nickel ions.