Ongoing Projects
Bioinspired Catalysts
Bioinspired Catalysts with Earth-Abundant Metals for Reductive Treatment of Waterborne Contaminants (Funded by NSF Environmental Engineering Program, 2020-2023)
Oxyanion pollutants are widespread and persistent in both natural and engineered aquatic systems, and they pose health risks at low concentrations (ppt to ppm level). Physical separation such as ion-exchange (IX) and reverse osmosis (RO) can quickly remove oxyanions; however, chemical destruction of the enriched oxyanions in waste streams is still required for safe disposal to prevent secondary contamination. The lack of cost-effective oxyanion reduction technologies limits the widespread and prolonged use of physical separation technologies. For example, the regenerable IX systems in water treatment plants in Southern California had been phased out because resin regeneration produced concentrated brines (6‒12 wt % of NaCl) containing enriched perchlorate and nitrate. These regenerant brines could not be reused, and meanwhile municipal wastewater treatment plants denied accepting the concentrated brine that could disrupt active sludge microbial communities. Unfortunately, most chemical degradation technologies developed to date still have major limitations for application, including (1) high cost of chemicals and catalysts, (2) requirements of harsh conditions to promote reactivity, and (3) lack of feasibility for practical engineering adoption. The proposed research will employ a multi-faceted approach that combines catalyst synthesis, characterization, theoretical calculation, and performance evaluation for highly active, low-cost, and practical reduction of oxyanions in water and wastewater.
We are collaborating with Prof. Jinyong Liu at University of California, Riverside and Prof. Yin Wang at University of Wisconsin-Milwaukee to develop a novel class of bioinspired heterogeneous catalysts based on the earth-abundant molybdenum (Mo) and tungsten (W) with high activity and stability for the reductive degradation of waterborne oxyanion pollutants (e.g., perchlorate, nitrate, chlorate, and bromate). Inspired by biological enzymes for oxyanion degradation, we aim to develop simple, effective, stable, and robust chemical catalysts through rational chemical and material design.
Oxyanion pollutants are widespread and persistent in both natural and engineered aquatic systems, and they pose health risks at low concentrations (ppt to ppm level). Physical separation such as ion-exchange (IX) and reverse osmosis (RO) can quickly remove oxyanions; however, chemical destruction of the enriched oxyanions in waste streams is still required for safe disposal to prevent secondary contamination. The lack of cost-effective oxyanion reduction technologies limits the widespread and prolonged use of physical separation technologies. For example, the regenerable IX systems in water treatment plants in Southern California had been phased out because resin regeneration produced concentrated brines (6‒12 wt % of NaCl) containing enriched perchlorate and nitrate. These regenerant brines could not be reused, and meanwhile municipal wastewater treatment plants denied accepting the concentrated brine that could disrupt active sludge microbial communities. Unfortunately, most chemical degradation technologies developed to date still have major limitations for application, including (1) high cost of chemicals and catalysts, (2) requirements of harsh conditions to promote reactivity, and (3) lack of feasibility for practical engineering adoption. The proposed research will employ a multi-faceted approach that combines catalyst synthesis, characterization, theoretical calculation, and performance evaluation for highly active, low-cost, and practical reduction of oxyanions in water and wastewater.
We are collaborating with Prof. Jinyong Liu at University of California, Riverside and Prof. Yin Wang at University of Wisconsin-Milwaukee to develop a novel class of bioinspired heterogeneous catalysts based on the earth-abundant molybdenum (Mo) and tungsten (W) with high activity and stability for the reductive degradation of waterborne oxyanion pollutants (e.g., perchlorate, nitrate, chlorate, and bromate). Inspired by biological enzymes for oxyanion degradation, we aim to develop simple, effective, stable, and robust chemical catalysts through rational chemical and material design.
Completed Projects
Pd-Based Catalysts
Pd and Pd-Cu nanoparticles supported on graphitic carbon nitride (g-C3N4) were synthesized and evaluated for nitrite and nitrate hydrogenation, respectively. Ultrafine nanoparticles (~2 nm) were observed on the support, and the catalysts showed enhanced reactivity, selectivity for nitrogen gas production, and longevity for contaminant degradation.
Shape- and size-controlled Pd nanoparticles were synthesized, and they were used to explore contaminant reduction kinetics. Catalytic performance of the Pd nanoparticles for contaminant removal (e.g., oxyanions, disinfection byproducts, other halogenated compounds) was dependent on the exposed nanoparticle facets.
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TEM images of shape- and size- controlled Pd nanoparticles.
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