We use laboratory experiments, and microscopy and synchrotron X-ray spectroscopy to develop new materials for removing metals and organic contaminants from groundwater, soil, and sediment. We also develop autonomous robotic approaches for sampling and measuring soil contaminants over vast areas in remote environments.
Sufidized nanoscale zerovalent iron (SNZVI)
Incorporation of sulfur into nanoscale zerovalent iron improves its properties as a remediation agent. It increases its reactivity with many groundwater contaminants, and lowers its reactivity with water, increasing its reactive lifetime. Our current research aims to understand precisely how to incorporate sulfur into the NZVI (FCC) structure to produce highly reactive and effective remediation materials.
Xu, et al. Sulfur Dose and Sulfidation Time Affects Reactivity and Selectivity of Post-Sulfidized Nanoscale Zerovalent Iron. Environ. Sci. Technol. 53(22) p.13344. https://pubs.acs.org/doi/10.1021/acs.est.9b04210
Xu, et al. Reactivity, Selectivity, and Long-term Performance of Nanoscale Zerovalent Iron having Different Sulfur content and Distribution. Environ. Sci. Technol. 53 (10) 5936-5945. https://pubs.acs.org/doi/10.1021/acs.est.9b00511
Cao, et al. Removal of antibiotic florfenicol by sulﬁde-modiﬁed nanoscale zero-valent iron. Environ. Sci. Technol. 51 (19), pp 11269–11277. https://pubs.acs.org/doi/10.1021/acs.est.7b02480
Polymeric materials for capturing Hg and other heavy metals from oil and water
Polymers containing large numbers of functional groups with affinity for metals can remove those metals from water selectively and efficiently. We use various radical polymerization techniques to synthesize novel polymer nanogels with high affinity and capacity for contaminants like mercury, and for recovery of selected rare earth elements. We synthesize and characterize these materials, and test their efficacy in a wide range of environmental matrices.
TEM images of ~200nm sized S-rich amphiphilic polymer gel for selective removal of chalcophilic elements from water and oil.
Autonomous vehicles for characterizing soil contamination
Successful soil and sediment remediation requires extensive characterization of affected areas to delineate the contamination. Characterization is expensive, time consuming, and potentially dangerous. We are developing on-board automated sensing modalities that can be used on autonomous robots to characterize large or not easily accessible contaminated areas, and artificial intelligence algorithms to sample wisely.