This proposal aims to develop an innovative selective desalination technology using membranes specifically designed for the treatment of feed water and wastewater of unconventional oil and gas production. Sustainable development of unconventional oil and gas production relies on efficient use of water resources and safe disposal of effluent from hydraulic fracturing processes. A key to attaining these goals lies in the effective removal of a subset of contaminants amid high levels of background electrolytes in alternative (brackish) water sources and in the waste water produced during unconventional oil and gas production operations.
Species of key interest in this project include barium (II) and strontium (II), which give rise to scaling problems and interfere with the proper function of gelling agents. The project will involve close collaboration among two university PIs from Chemistry and Environmental Engineering at Texas Tech and an industrial co-PI with extensive experience in water management for a major oil and gas production company, this proposal will explore conjugating commercial electrodialysis membranes with optimized supported crown ether moieties to enable selective binding and transport of target contaminants in electrodialysis processes. The objective of this project is to develop a class of electrodialysis membranes with novel ion-gating functionality for selective removal of problematic ions in alternative brackish water sources for energy production uses. The central hypothesis of this research is that intrinsic ion selectivity of electrodialysis processes can be significantly improved by incorporating a thin layer of ion sequestrants of suitable structure and density at the surface of electrodialysis membranes, creating localized concentration gradients driving highly selective transport of the target ions. The PIs ability to prepare crown ethers of diverse conformations and to adapt their molecular structure for optimal metal binding specificity renders the proposed technology a versatile method for selective ion separation. One attractive application is to enable the use of alternative water sources for hydraulic fracturing operations. In this one-year project, the project will focus on the removal of two ions of primary concerns to unconventional oil and gas production, namely, Ba2+ and Sr2+, although the concept can in principle be extended to other problematic ions, such as Ra2+, which is the major source of radio-activity in naturally occurring radioactive material and its disposal is subject to stringent regulatory control. The research being addressed in the project will potentially reduce the environmental impacts of unconventional oil and gas production and enhance water sustainability at the energy-water nexus, particularly in regions where the fast-growing practice of hydraulic fracturing has imposed a considerable stress on the local fresh water resources. This project will provide excellent academic training and industry exposure opportunity for undergraduate students and two graduate students from Environmental Engineering and Chemistry through participation in a multidisciplinary team involving strong industry-university collaboration. The industrial partner will advise the research team on practical constraints and potential complications associated with alternative water treatment technologies, so that the PIs will formulate research strategies to address the unique water treatment needs of the energy industry, which are substantially different from water treatment for domestic use. The PIs will expand their current outreach programs to engage K-12 and community college students from under-represented groups in STEM curricula and research. Research data will be reported in public domain including conferences, industrial seminars, and peer-reviewed journals.
