John Patrick Barford

Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals are present in wastewater, the adsorbent uptakes the Pb²⁺ ions selectively. This has been attributed to the higher electronegativity value of Pb²⁺ compared to Cd²⁺ which can be more readily adsorbed on the adsorbent surface, displacing the Cd²⁺ ions. The selectivity can be advantageous when the objective is the separation and reuse of the metals besides wastewater treatment. In non-equimolar solutions, a complete selectivity can be observed up to a threshold Pb²⁺ molar ratio of 30%. Below this threshold value, the Cd²⁺ and Pb²⁺ ions are uptaken simultaneously due to the abundance of Cd²⁺ ions and the availability of adsorption sites at very low Pb²⁺ molar ratios. Moreover, the total adsorption capacities of the adsorbent for the multi-component system have been shown to be in the same range as the single-component system for each metal ion which can be of high value for industrial applications.

The effect of pH on the equilibrium ion exchange capacity of nickel using an imino diacetate ion exchange resin has been studied to determine the pH for optimum metal uptake. A series of fixed bed ion exchange studies have been carried out using the resin to remove nickel from water and the effect of a number of process variables, including initial nickel ion concentration, resin particle size and effluent solution flowrate, have been studied. The Bed Depth Service Time (BDST) model has been applied to the experimental date with only limited predictive success and subsequently a modified “BDST” model has been successfully applied to the data to model the system.

Oil spill on water surface and shorelines has been a major source of water pollution. With the damaging impact to ecology and the long term effects...