Current Exploratory Research Projects

Heavy metal contaminated soils and water are widespread in the US resulting from mining and other industrial activities. This project envisions these contaminated waste materials as an economic resource. The project is designed to demonstrate that foams and hydrogels chemically modified with ligand groups will i) bind zinc cations and improve the efficiency of their removal and separation from contaminated soils and water, and ii) support plant growth and increase zinc phytoextraction from metal-contaminated substrate by hyperaccumulating plants. Dr. Loy’s research group is chemically modifying foams and hydrogels to create gel-foam composites with high capacity for metal binding with enhanced structural integrity relative to hydrogels by themselves. These foams and gels will then be tested with plants in green house studies to evaluate their ability to enhance the capacity of plants to extract and concentrate contaminant metals of economic significance.

Number of students trained through this project: 17 (7 undergraduates, 9 graduate students, 1 post-doctoral student)

The goal of this research is to develop biodegradable and effective eco-friendly materials for advanced dust control in mining industries. The materials under development are composed of synthetic polymer surfactants and natural cellulosic binders. When sprayed on dust-generating surfaces such as hard rock mine tailings, these materials stabilize the surface by molecular interactions between polymers and dust particles. In a test against a commercial dust suppressant product, these eco-friendly materials increased dust suppression by 85%. The research is focused on further enhancement of the dust-controlling capacity of these materials by replacing the synthetic polymer surfactants with biosurfactants developed by Dr. Raina Maier’s research group. Results thus far have shown that the biosurfactants demonstrate comparable dust controlling capacity when compared to the synthetic surfactants. The dust-suppressing capacity of these materials is being evaluated for both rock and coal particulates using tests based on an US EPA air quality index of “good” against wind speeds of 30 m/s (i.e., 67 mph) or more.

Number of students trained through this project: 1 postdoc and 2 graduate students

In efforts to reduce the knowledge gap and “unveil” environmental regulations, the goal of this project is to make selected environmental legislation and permitting processes that are applied to resource extraction activities accessible in plain language and in multiple media formats. Dr. Ramírez-Andreotta will work with CESM industry partners and select three major resource extraction policies and their associated state permitting processes and generate translational products in English and Spanish.

We are investigating a plant-based solution for the removal and re-use of metal(loids) from dryland ecosystems. This work has two interlinked aims. First, we will maximize the efficiency of metal phytoextraction through manipulation of the rhizospheric microbiome of (hyper)accumulator plants that are adapted to the arid US Southwest (University of Arizona - UA team). Second, we will utilize the resulting metal-enriched plant biomass in high-value catalytic reactions to create new metal-based eco-catalysts (ChimEco laboratory - CNRS team). The research is conducted using metal-contaminated mine tailings from the US Southwest. This region is a major producer of non-fuel minerals and has extensive metalliferous mine tailings sites of different ages, composition, and metal concentrations. Our pioneering work focuses on Zn, Mn, and Cu, which are important micronutrients for plant growth, but also major industrial pollutants of the terrestrial and aquatic environment. This innovative approach of this project has the potential to remediate metal-contaminated soils sustainably and profitably.

Number of students trained through the project: 6 (4 undergraduate, 2 graduate students)

Dust emissions are a constant problem in arid and semi-arid regions, especially for mines and cement, rock and rock products, and aggregate companies. For such industries, in dust-rich regions, a dust event characterized by significant particulate matter emissions and reduced visibility can lead to a significant fine from regulatory agencies.

Building on previous successes (Gardenroots and peer-reviewed research in the journal Science of the Total Environment), we will analyze archived samples and continue to determine the efficacy of foliar surfaces as a method to sample aerosol pollutants in ambient air as it relates to dust in mining communities. Important knowledge gaps include how effective different plants and their associated leaves are in terms of aerosol collection and what parameters can be optimized for a specific type of plant.

Number of students trained through this project: 1 (graduate student)

Uranium mining in the U.S. Southwest has left thousands of legacy mining sites with uranium-contaminated soils. These soils are polluting adjacent water and land resources that, in turn, pose serious threats to human and environmental health. Uranium is also a challenge for modern mining operations as it is often present as a contaminant in mineral processing activities targeting other metals. In addition to uranium, rare earth elements (REE) are also often found as contaminants in coal and some hard-rock mining operations. There is interest in developing alternative REE sources domestically due to the importance of REE to consumer electronics, renewable energy technologies, and national defense.

Through Phase I Small Business Innovation Research grants, UArizona in collaboration with industry partner, GlycoSurf, has demonstrated two technologies capable of the selective removal of uranium and REE from complex mining solutions using rhamnolipid and other bioinspired surfactants: ion flotation and adsorbent materials. Matching funding from CESM is supporting this Phase II project wherein UArizona’s objective is to demonstrate the commercial potential of these technologies for reclaiming mining-impacted waters by:

1. Up-scaling reactor size,
2. Developing treatment processes for continuous flow operations and testing, and
3. Testing novel glycolipid surfactants.

This project aims to provide CESM mining partners with environmentally-friendly technologies suitable for generating new metal resource streams while concurrently reclaiming waters and reducing the environmental impacts of mining operations.

Number of students trained through this project: 4