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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #237388
Title: Selenium adsorption to aluminum-based water treatment residuals

Author
item Ippolito, James
item SCHECKEL, KIRK - U.S. EPA
item BARBARICK, KEN - COLORADO STATE UNIVERSITY

Submitted to: Journal of Colloid and Interface Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2009
Publication Date: 8/13/2009
Citation: Ippolito, J.A., Scheckel, K.G., Barbarick, K.A. 2009. Selenium Adsorption to Aluminum-based Water Treatment Residuals. Journal of Colloid and Interface Science. 338:48-55.

Interpretive Summary: Aluminum-based water treatment residuals (WTR) can adsorb water- and soil-borne P, As(V), As(III), and perchlorate, and may be able to adsorb excess environmental selenium. WTR, clay minerals, and amorphous aluminum hydroxide were shaken for 24 hours in selenate or selenite solutions at pH values of 5 to 9, and then analyzed for selenium content. Selenate and selenite adsorption edges were unaffected across the pH range studied. Selenate adsorbed on to WTR, reference mineral phases, and amorphous aluminum hydroxide occurred as outer sphere complexes (relatively loosely bound), while selenite adsorption was identified as inner sphere complexes (relatively tightly bound). Selenite sorption to WTR in an anoxic environment reduced Se(IV) to Se(0), and oxidation of Se(0) or Se(IV) appeared irreversible once sorbed to WTR. Al-based WTR could play a favorable role in sequestering excess Se in affected water sources.

Technical Abstract: Aluminum-based water treatment residuals (WTR) can adsorb water- and soil-borne P, As(V), As(III), and perchlorate, and may be able to adsorb excess environmental selenium. WTR, clay minerals, and amorphous aluminum hydroxide were shaken for 24 hours in selenate or selenite solutions at pH values of 5 to 9, and then analyzed for selenium content. Selenate and selenite adsorption edges were unaffected across the pH range studied. Selenate adsorbed on to WTR, reference mineral phases, and amorphous aluminum hydroxide occurred as outer sphere complexes (relatively loosely bound), while selenite adsorption was identified as inner sphere complexation (relatively tightly bound). Selenite sorption to WTR in an anoxic environment reduced Se(IV) to Se(0), and oxidation of Se(0) or Se(IV) appeared irreversible once sorbed to WTR. Al-based WTR could play a favorable role in sequestering excess Se in affected water sources.