Materials for Sustainable Environment

Materials for sustainable environment is one of our research themes, which focuses on developing functional materials for environmental remediation.

Structure–Property Relationship of Geopolymers for Aqueous Pb Removal

The geopolymer—an inorganic polymeric material synthesized from the reaction of aluminosilicate precursors and alkaline activating solutions—has gained wide research attention in recent decades as a promising adsorbent for the removal of aqueous heavy metals. However, the high variability of the material and several unanswered questions have limited its development and general adoption in the industry. This study evaluates the impacts of composition and microstructure on the performance of geopolymers for aqueous lead (Pb) removal to elucidate the composition–structure–property relationship…

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Calcium–Alumino Layered-Double-Hydroxide (LDH) Nanocomposites

Calcium–alumino layered-double-hydroxide (LDH) nanocomposites of the alumino–ferrite monosubstituent subgroup hosting alkyl sulfates and poly(ethylene glycol) were synthesized by coprecipitation over the temperature range 5–75 °C. The stability of these nanocomposites was examined following exposure to aqueous solutions conditioned to a range of concentrations of intercalant anions including sulfate, carbonate, chloride, and phosphate. Careful analysis of these “organic–inorganic” nanocomposites reveals that their gallery (interlayer) spacing can vary, and the gallery height is controlled by the chain length (size) and orientation of the surfactant substituents, where, expectedly, anionic surfactants intercalate more robustly than nonionic surfactants…

A thermodynamics-based approach for examining the suitability of cementitious formulations for solidifying and stabilizing coal-combustion wastes

Cementitious binders are often used to immobilize industrial wastes such as residues of coal combustion. Such immobilization stabilizes wastes that contain contaminants by chemical containment, i.e., by uptake of contaminants into the cementitious reaction products. Expectedly, the release (“leachability”) of contaminants is linked to: (i) the stability of the matrix (i.e., its resistance to decomposition on exposure to water), and, (ii) its porosity, which offers a pathway for the intrusion of water and egress of contaminant species. To examine the effects of the matrix chemistry on its suitability for immobilization, an equilibrium thermodynamics-based approach is demonstrated for cementitious formulations based on: ordinary portland cement (OPC), calcium aluminate cement (CAC) and alkali activated fly ash (AFA) binding agents…

Ongoing project includes:

Nanocomposites and functional materials for wastewater treatment and water purification
Waste immobilization in cementitious matrices