Final Report: A Novel Ion Exchange Process for Selective Removal of As(V) and Enhanced Stability of Process Residuals

EPA Grant Number: R831431
Title: A Novel Ion Exchange Process for Selective Removal of As(V) and Enhanced Stability of Process Residuals
Investigators: Zhao, Dongye , Barnett, Mark
Institution: Auburn University Main Campus
EPA Project Officer: Richards, April
Project Period: November 1, 2003 through October 31, 2005
Project Amount: $99,452
RFA: New Technologies for the Environment (NTE) (2003) RFA Text |  Recipients Lists
Research Category: Nanotechnology , Sustainability , Pollution Prevention/Sustainable Development

Objective:

The overall goal of this research project is to develop an innovative, selective ion exchange (IX) process. The specific research objectives are to: (1) prepare and characterize a new class of IX materials, referred to as polymeric ligand exchangers (PLEs), for highly selective removal of As(V); and (2) develop an engineered approach to reuse the spent regenerant and minimize the volume and As-leachability of process waste residuals.

Summary/Accomplishments (Outputs/Outcomes):

Four new PLEs, designated as XUS 3N-Cu, XAD1180-2N, XAD16-2N, and XAD16-3N, were synthesized for selective arsenate removal. Of the PLEs developed, XUS 3N-Cu is the most promising PLE and displayed several unprecedented novel characteristics for arsenic removal.

Although standard strong base anion (SBA) resins are more selective than arsenate for sulfate, the PLEs offer much greater selectivity for arsenate than sulfate. The binary arsenate/sulfate separation factor for all PLEs is 60-120 times greater than that of standard SBA resins. XUS 3N-Cu can treat more than 9,000 bed volumes of raw water per service run in the presence of high concentrations of competing ions such as phosphate, sulfate, chloride, and bicarbonate. This treatment capacity is more than 15 times greater than that for a standard SBA resin. This substantial arsenic capacity dramatically reduces the regeneration frequency and cuts down the regenerant brine needed by greater than 15 times. The sorption rate of the PLEs also is faster than for standard SBA resins. Based on a conservative treatment capacity of 8,000 bed volumes per service run with XUS 3N-Cu, the alkalinity loss is less than 20 percent per service run, which should not pose water buffering problems for typical source waters. The PLEs can be regenerated efficiently using approximately 20-25 bed volumes of 4-8 percent NaCl at approximately pH 9.0-10, and can be used in multiple cycles of operation without any capacity loss. The spent regenerant can be used repeatedly for regeneration for seven times with only pH adjustment (to pH 9.2-10), and nearly 100 percent of recovery of arsenic capacity was observed consistently.

In addition, we developed and preliminarily optimized an engineered approach for the treatment and reuse of the exhausted brine. The rather straightforward treatment of the spent brine can lead to: (1) nearly complete (> 98%) removal by aluminum chloride of arsenic from the exhausted brine; and (2) greatly enhanced stability (or reduced leachability) of arsenic in the final process solid waste.

Conclusions:

The new IX material (XUS 3N-Cu) showed unprecedented arsenic removal capacity, selectivity, and kinetics, and yet it is highly regenerable. This new material, along with the engineered treatment of the process waste residuals, may lead to a more cost-effective treatment technology to help thousands of water utilities comply with the newly implemented arsenic maximum contaminant level of 10 µg/L.


Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other project views: All 18 publications 5 publications in selected types All 5 journal articles
Type Citation Project Document Sources
Journal Article An B, Steinwinder TR, Zhao D. Selective removal of arsenate from drinking water using a polymeric ligand exchanger. Water Research 2005;39(20):4993-5004. R831431 (Final)
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  • Journal Article An B, Fu Z, Xiong Z, Zhao D, SenGupta AK. Synthesis and characterization of a new class of polymeric ligand exchangers for selective removal of arsenate from drinking water. Reactive and Functional Polymers 2010;70(8):497-507. R831431 (Final)
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  • Journal Article Xiong Z, Dimick P, Zhao D, Kney A, Tavakoli J. Removal of perchlorate from contaminated water using a regenerable polymeric ligand exchanger. Separation Science and Technology 2006;41(11):2555-2574. R831431 (Final)
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  • Supplemental Keywords:

    adsorption, arsenic, arsenate, chemicals, cleanup, co-precipitation, cost benefit analysis, drinking water, engineering, environmental chemistry, groundwater, hazardous waste, heavy metals, ion exchange, innovative technology, leachate, ligand exchange, ligand exchanger, metals, northeast, regenerant reuse, regeneration, remediation, removal, residuals, selective removal, soil, toxics, southwest, TCLP, TTLC, waste minimization, waste reduction, waste residual, water, water treatment, WET,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, TREATMENT/CONTROL, POLLUTANTS/TOXICS, Sustainable Industry/Business, Chemical Engineering, cleaner production/pollution prevention, Environmental Chemistry, Arsenic, Technology, Environmental Monitoring, New/Innovative technologies, Water Pollutants, Drinking Water, inorganics, clean technologies, detoxification, drinking water treatment facilities, green engineering, polymeric ligand exchangers, arsenic removal, drinking water distribution system, analytical methods, drinking water contaminants, pollution prevention, drinking water treatment, drinking water system, green chemistry

    Progress and Final Reports:

    Original Abstract
  • 2004 Progress Report