Simon W. Freese Award & Lecture (Development and Global Application of Hybrid Ion Exchange Processes in Sustainable Water Treatment: From Decontamination to Desalination)

LECTURE: Development and Global Application of Hybrid Ion Exchange Processes in Sustainable Water Treatment: From Decontamination to Desalination

Increased population and a gradual decrease in fresh water supply are propelling societies globally to rethink strategies to sustain potable, industrial and agricultural water supply to meet the current and future demands. Climate variability has aggravated the crisis further by adversely impacting the reliability of existing fresh water resources. Treated municipal wastewater in cities and metropolis is a water resource that is large, near to the consumption centers and quite insulated from climate change effects. Transforming this huge ‘wastewater’ body into ‘usable’ water offers new opportunities to mitigate water shortages globally. We present an alternate approach, referred to as hybrid ion exchange desalination or HIX-Desal, that uses CO2 as an energy source for desalination and seizes unique properties of HIX for simultaneous phosphate removal and recovery. Also, a recently developed novel pre-treatment process helps remove hardness without needing brine as a regenerant (1).

Zirconium, the 21st most abundant element in the world, is stable, chemically innocuous and non-hazardous. Nanoparticles of zirconium oxide (ZrO2) have unique sorption properties to bind a variety of trace contaminants including arsenic, fluoride, phosphate and lead. We have developed a process to disperse ZrO2 nanoparticles within the gel phase of an anion exchanger with quaternary ammonium functional group. The resulting hybrid ion exchanger, referred to as HIX-NanoZr, is a robust sorbent material that is also amenable to regeneration and reuse.

Although unknown nearly twentyfive years ago, natural arsenic contamination of groundwater has emerged as a major global crisis affecting over fifty countries including the USA, India and China. Nearly 200 million people in Asia and Africa drink groundwater that contains toxic levels of fluoride and arsenic. Both HIX-NanoZr and HIX-NanoFe are now commercial materials and over two million people around the world drink arsenic- and fluoride-safe water through use of these HIX-nanosorbents (2, 3).