Biogeochemical interactions play a key role in controlling the speciation and mobility of metals in the environment, through direct metabolic processes such as metal uptake, biotransformation, and biomineralization, or indirectly by changing ambient redox/pH conditions, producing ligands or new biominerals, or altering mineral surfaces. My research group’s overarching objective is to understand and control the complex mechanisms of contaminant transformations in the environment, in order to engineer remediation and resource recovery technologies mimicking natural sustainable processes.

Current research projects include the recovery of valuable Rare Earth Elements from abandoned mine waste by promoting bioleaching reactions, the design of biomimetic membranes for selective separation of heavy metals, and the understanding biological transformations controlling metal and organic contaminants transformation in the rhizosphere of impacted urban and riparian wetlands.

Fate of emerging contaminants in landfill-leachate impacted wetlands

Wetlands are heavy metal accumulators and organic contaminants degraders in the environment, due to their specific biogeochemical processes enhanced by high organic matter and nutrient content, especially in the rhizosphere of wetland soils. A comprehensive understanding of the mechanisms controlling the retention or degradation of emerging contaminants is critical, in order to prevent or attenuate the effect of a changing environment and predict potential human exposure routes. These mechanisms include chemical and biological transformations within water, sediments, microorganisms, and plants.

Biorecovery of rare earth elements from uranium mine waste                                                                              

The overarching goal of this project is to find a sustainable process to recover uranium (U) and rare earth elements (REE) from AM waste, using microbial processes as the main mechanisms for metal leaching and precipitation. This work is based on the hypothesis that ubiquitous microbial communities are able to cycle REE and U under limiting environmental conditions, and that the selective biorecovery of U and REE from mine wastes can be engineered by modifying operational parameters (electron donor, pH, salinity, and temperature) in order to enhance or inhibit microbial metabolic activity.

Design of biomimetic membranes for industrial wastewater treatment                                            

The scarcity of natural resources and increasing waste production emphasize the need to design more efficient treatment technologies that prioritize recovery over removal. The final aim of this research is to develop an industrial wastewater treatment to selectively remove, recover, and concentrate metals using bio-synthetic membranes can be functionalized with specific proteins (metal transporters) for the selective removal and recovery of metals.

Investigation of metal stability in the sediments from legacy contamination in a river (Animas River, CO) (in collaboration with Jose Cerrato’s research group, University of New Mexico)                                                                                                      

The principal goal of this research is to investigate the unique mechanisms governing the mobilization of metals and metal mixtures in the sediments from the Animas River, integrating the chemical and biological processes that will control the contaminants’ fate. The assessment of these mechanisms will be achieved through the identification and quantification of the magnitude and distribution concentrations of a mixture of metals in environmental media.

Investigation of the impact of microbial processes on arsenic stability in sediments from Cheyenne River (in collaboration with Jose Cerrato’s research group, University of New Mexico)                                                                                            

This project investigates the role of microbial processes on arsenic stability in sediments from the Cheyenne River and its potential for transport and mobilization to water and plants which represents a risk for Sioux Tribal lands. The research specifically focus in understanding the microbially-driven redox transformation of arsenic-bearing minerals under local environmentally-relevant conditions. 

Understanding the mechanisms for uranium accumulation in Salt Cedar roots (in collaboration with Jose Cerrato’s research group, University of New Mexico) 

The main objective of this research is to assess the mechanism controlling uranium uptake and accumulation by plants growing in the vicinity of contaminated sites (Jackpile Mine, NM). Fieldwork and in vitro experiments, together with wet chemistry and microscopy and spectroscopy are used to follow the uranium uptake pathway from the river into the plant, and to elucidate the interaction between the uranium and cell. The results from this study can be applied to enhance or prevent metal phytoaccumulation in plants.

Selective recovery of metals from waste batteries   (in collaboration with Wen Zhang’s research group, NJIT)                                             

This project aims to address the technical challenges in pollution prevention and pollution source reduction in metals recovery from waste lithium-ion batteries. Current mainstream metal leaching processes from waste batteries involve the extensive use of hazardous and corrosive acids and bases (e.g., H2SO4, H2O2 HCl, and NaOH) and result in secondary pollution such as acid gases and waste acids for additional disposal. We will assess the metal leaching efficiencies, governing parameters, and reusability of seven different organic acids as candidate leachants. Meanwhile, we will investigate the reuse of organic acids to reduce secondary pollution. Ultimately, the project will deliver innovative methodologies of green chemistry-based metal recovery for waste batteries and empower industrial practitioners with sustainable engineering practices.