Laura Herder

Abstract

Arsenic contamination of groundwater is a major problem in both developing and developed countries as it is quite dangerous at extremely low concentrations and prevalent in many water supplies. Although there are many removal techniques for arsenic, the most promising for developing countries appears to be adsorption, since it is relatively low in cost, is easy to implement, requires no electricity, and can remove trace amounts of materials from solutions. Current adsorbents that have a high affinity for arsenic, but are costly because they have slow adsorption rates, low capacities, limited pH ranges, are affected adversely by competing ions, and often cannot be regenerated. One of the most successful adsorbent materials for arsenic removal is cerium dioxide, but unfortunately, this compound is quite expensive because of its rare earth component, cerium. Previous studies have utilized pure cerium dioxide adsorbents for adsorption. However, it is possible that some of the cerium dioxide may not be accessible to adsorption as a portion of this valuable chemical resides inside the particle itself. This study examines the efficacy of a new adsorbent synthesized such that cerium dioxide nanoparticles are coated over an alumina substrate in an attempt to reduce cost and improve adsorption efficiency. It is found that the coated alumina has fast adsorption rates (95% removed in 5 minutes), is effective over a large pH range, and also preferentially adsorbs arsenic even when other chemicals commonly found in groundwater, such as phosphates, are present. These results are comparable to those of pure cerium dioxide adsorbents and cerium dioxide coated carbon nanotubes used in previous studies. However, the adsorption capacity of the new adsorbent for arsenic is much lower than that for pure cerium dioxide nanoparticles. These results suggest that the effect of new environmental conditions on the efficacy of pure cerium dioxide as an adsorbent may be studied more cost effectively using the cerium dioxide coated alumina as a model system.

Library of Congress Subject Headings

Groundwater--Pollution--Prevention; Drinking water--Contamination--Prevention; Water--Purification--Adsorption; Arsenic wastes; Cerium oxides; Aluminum oxide

Publication Date

5-1-2011

Document Type

Thesis

Department, Program, or Center

School of Chemistry and Materials Science (COS)

Advisor

Langner, Andreas

Advisor/Committee Member

Weinstein, Steven

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: TD426 .H47 2011

Campus

RIT – Main Campus

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