Articles by Yi Wai Chiang in JoVE
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent Evangelos Georgakopoulos1, Rafael M. Santos2, Yi Wai Chiang3, Vasilije Manovic4 1Department of Offshore, Process and Energy Engineering, Cranfield University, 2School of Applied Chemical and Environmental Sciences, Sheridan College Institute of Technology and Advanced Learning, 3School of Engineering, University of Guelph, 4Carbon Systems Engineering, Centre for Combustion, Carbon Capture and Storage, Cranfield University A protocol for the parallel production of precipitated calcium carbonate and zeolitic material from blast furnace slag via mineral carbonation and alkaline hydrothermal conversion, respectively, is presented. The performance of the zeolitic material towards nickel adsorption is tested.
Other articles by Yi Wai Chiang on PubMed
Atom-efficient Route for Converting Incineration Ashes into Heavy Metal Sorbents ChemSusChem. Jan, 2014 | Pubmed ID: 24339229 Bottom ashes produced from municipal solid-waste incineration are suitable for sorbent synthesis because of their inherent composition, high alkalinity, metastable mineralogy, and residual heat. This work shows that bottom ashes can be atom-efficiently converted into valuable sorbents without the need for costly and hazardous chemicals. The ashes were hydrothermally treated in rotary autoclaves at autogenic pH conditions to promote the conversion of precursor mineral phases into zeolites and layered silicate hydrates. Two main mineral phases were formed: katoite and sodium aluminum phosphate silicate hydrate. These mineral alterations are accompanied by a tenfold increase in specific surface area and a twofold reduction in average particle size. Performance evaluation of the new sorbents for Cd(2+), Zn(2+), and Pb(2+) adsorption at pH5 indicates sorption capacities of 0.06, 0.08, and 0.22 mmol g(-1), respectively, which are similar to those of natural adsorbents and synthetic materials obtained from more demanding synthesis conditions.
Impacts of Nickel Nanoparticles on Mineral Carbonation TheScientificWorldJournal. 2014 | Pubmed ID: 24578669 This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP) as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO₂ and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO₂ mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags), on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO₂ bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting.
Tolerance of Chemoorganotrophic Bioleaching Microorganisms to Heavy Metal and Alkaline Stresses Bioinorganic Chemistry and Applications. 2015 | Pubmed ID: 26236176 The bioleaching potential of the bacterium Bacillus mucilaginosus and the fungus Aspergillus niger towards industrial residues was investigated by assessing their response towards various heavy metals (including arsenic, cadmium, cobalt, chromium, nickel, lead, and zinc) and elevated pH. The plate diffusion method was performed for each metal to determine the toxicity effect. Liquid batch cultures were set up for more quantitative evaluation as well as for studying the influence of basicity. Growth curves were prepared using bacterial/fungal growth counting techniques such as plate counting, optical density measurement, and dry biomass determination. Cadmium, nickel, and arsenite had a negative influence on the growth of B. mucilaginosus, whereas A. niger was sensitive to cadmium and arsenate. However, it was shown that growth recovered when microorganisms cultured in the presence of these metals were inoculated onto metal-free medium. Based on the findings of the bacteriostatic/fungistatic effect of the metals and the adaptability of the microorganisms to fairly elevated pH values, it is concluded that both strains have potential applicability for further research concerning bioleaching of alkaline waste materials.