Sequestering of Ni (II) and Co (II) from Aqueous Solution Using Spines of Bombax buonopozense as Low-Cost Adsorbent

The release of potentially toxic elements either by anthropogenic or industrial activities has deteriorated water quality rendering water bodies unsuitable. It was on this basis that readily available agricultural waste was used to treat simulated wastewater containing the potentially toxic element (Ni and Co). Adsorption studies of Co and Ni from aqueous solution were performed using spines of Bombax buonopozense (raw), carbon prepared from Bombax buonopozense (AC 1) and activated carbon prepared from modification of spines of cotton silk tree (AC 2). Batch adsorption techniques were carried out as a function of contact time, pH, initial concentration, temperature, and dosage. The respective optimum contact times required for adsorption Co and Ni were 90 min. Characterizations of adsorbents were carried out which include: bulk density, hardness, electrical conductivity, ash contents, percentage moisture, and yield. Fourier transform infra-red spectroscopy (FTIR) showed that functional groups in the sorbents were responsible for the adsorption process. The adsorption isotherms data were tested for Langmuir, Temkin and Freundlich equations. The pseudo-first-order, pseudo-second-order, Elovich and diffusion (intra-particle) models were investigated on the adsorption kinetic data. This could be as a result of ion exchange involved in the sequestration of metal ions by the adsorbents. Therefore, sorption using spines of Bombax buonopozense has been adjudged as one of the best tools for replacing conventional methods for the removal of these metals because of its efficiency, cost-effectiveness and the availability of the adsorbents.