Research

 

Integrating Oxidation and Membrane Technologies for High Performance Seawater Desalination

Seawater desalination using reverse osmosis (RO) is one of the most important technologies to address water scarcity worldwide. Recently, marine algal blooms have emerged as a major challenge for RO-based desalination by inducing severe fouling. Current technologies (e.g., disinfection and pretreatment) are insufficient to control fouling during algal blooms, and can generate harmful byproducts in the process. We aim to develop innovative desalination systems that harvest the synergy of oxidation and membrane processes for effective fouling control while minimizing byproduct formation.

 

Efficacy of Peracetic Acid as a Wastewater Disinfectant and Oxidant

Alternative disinfectants featuring efficient pathogen inactivation and low disinfection byproduct (DBP) formation are critical for developing wastewater recycling systems. Peracetic acid (PAA) is a strong disinfectant and forms much less halogenated DBPs that are commonly associated with chlorine, but its performance has not been systematically evaluated for wastewater application. We are collaborating with wastewater utilities and industrial partners to evaluate the efficacy of PAA and PAA/UV systems.

 

Mitigating Nitrosamine Formation in Amine-based CO2 Capture Systems

Amine-based CO2 absorption is currently the most mature technology for post-combustion CO2 capture and has been implemented at industrial scale. However, concerns have arisen regarding the carcinogenic byproducts nitrosamines from these systems. A typical amine system is comprised of an absorber and a desorber. CO2 in the flue gas is absorbed into a countercurrent stream of concentrated amine solution (“solvent”) in the absorber. The CO2-loaded solvent is then routed to a desorber where high temperatures release high purity CO2 for compression and storage. Byproduct nitrosamines and nitramines form from the reactions between flue gas NOx and amines in the absorber, and between nitrite, a NOx hydrolysis product, and amines in the desorber. We are exploring novel solvents to simultaneously minimize byproduct formation and improve CO2 capture performance.

 

Pesticide Transformation on Plant Surfaces Induced by Sunlight and Airborne Oxidants

Foliar application is one of the most common application modes for pesticides, but the transformation of these compounds on leaf surfaces has not been thoroughly investigated. Leaf surfaces feature reaction environments distinct from water and soil. Leaf cuticle is a film composed of lipids and hydrocarbon polymers, resembling non-polar organic solvents. The pesticide molecules on leaves are exposed to sunlight and airborne oxidants such as nitrogen oxides (NOx). My research group is investigating the photochemical and airborne oxidant-induced transformation of both conventional and new pesticides.