ICMGP - Conference Presentation

Abstract Information :

Metal sulfides (MSs) were proven to be effective traps for permanent elemental mercury (Hg0) sequestration from anthropogenic sources by mimicking its environmental stabilization process, i.e., forming ultra-stable cinnabars (HgS). However, the fabrication of MSs with application flexibility generally involves complex steps and hazardous precursors that compromise the cost-effectiveness and environmental-friendliness. The adoption of natural mineral sulfides, while has been proposed for several years, nevertheless, suffers the lack of feasibility due to the limited Hg0 adsorption capacity, generally less than 1 mg g-1. In this study, a method holding wide opportunity to modify various natural mineral sulfides via an industrially affordable, even preferred, one-step mechanochemical procedure with the addition of cupric chloride (CuCl2) was developed. The introduction of CuCl2 into the adsorbent system was the key in this procedure, a step that reached far beyond its role the chemistry community may expect, i.e., merely introducing hetero-ligands (Cl) to combine with Hg0, while activating sulfide ligands to make them more reactive with Hg0 was proven to be much more fundamentally important. The adsorption capacity of mineral sulfides increased by two magnitudes (approximately 200 folds) after being treated by CuCl2. The microcosmic insight based on characterizations and DFT calculations revealed that both Cu-terminated sites and sulfide ligands in mineral sulfides were activated due to the electronic redistribution and oxidability enhancement. The cost accounting and operation evaluation revealed that this group of novel adsorbents, i.e., mineral sulfides, is potential to replace activated carbons, a series of materials widely used worldwide for anthropogenic Hg0 mitigation, as the improved cost-effectiveness and universality of this method make it applicable regardless of industrial characteristics or geographical limitations. An integrated technology was hence proposed and evaluated based on the performance-enhanced mineral sulfides to ensure its extensive application flexibility under different industrial scenarios.