Grant: Discovery Grants Program - Individual

Resins with selective functional groups can have adsorption preference to specific metal species, which makes them efficient for capturing metals selectively from aqueous systems. Chemists analyze the trace metals in seawater by enriching them with selective resins. With the depletion of quality metal ore resources, the exploitation of valuable metals from low grade ores or old tailings brings up new challenges for metallurgists to produce metals from the leaching solutions of raw materials with low metal contents. Heavy metals can be toxic to human beings and the environment even at very low concentrations. Removal of the heavy metals from wastewaters and water ecosystems has been of great challenge to environment researchers. Based on the special properties of resins, novel selective adsorption processes using resins can play important roles in both sustainable metal production and environmental protection/remediation, which are problems of global concern and the focus of this program. The adsorption selectivity of a resin to specific metals originates from its chemical structure. Exploring and understanding the chemical structure-performance relationship of resins, which has not been systematically studied, and developing sustainable processes for metal production and environmental protection/remediation using resin adsorption will be the major objective of this program. Continuing but varying from the work conducted in my current DG Program, we will focus on sustainable metal production from lean resources and heavy metal removal for environmental protection/remediation in this new program. Aqueous systems containing important metals for sustainable metals/materials production (e.g., rare earth elements (REEs), V, Ga, and Mn) and environmental protection (e.g., As, Cr, and Hg) will be studied. To simplify the research process, synthetic solutions will be prepared for preliminary metal adsorption tests, then the operation condition will be optimized with practical leach liquors or wastewaters. The recycling of resins with an efficient elution system is crucial for the efficiency and feasibility of the resin adsorption processes, which will also be investigated. The chemical structure-performance relationship of resins with various functional groups, which is critical for the choosing and designing of selective resins, will be studied with quantum chemistry methods, e.g., density functional theory (DFT) and ab initio methods, using quantum chemistry software such as Gaussian. The bonding between the functional groups of resins and metal ions will be studied using modern equipment analyses such as Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Based on preliminary work conducted, the recovery or removal of heavy metals from aqueous systems using resins with selective functional groups for sustainable metal production and environmental protection/remediation is feasible and of strategic significance.