Document Type


Date of Award

Spring 5-31-1996

Degree Name

Master of Science in Environmental Engineering - (M.S.)


Civil and Environmental Engineering

First Advisor

Mohamed E. Labib

Second Advisor

William R. Spillers

Third Advisor

Dorairaja Raghu


In this thesis we employed advanced characterization techniques such as XRF, XRD, XPS, SEM, and EDS to provide detailed information about the chromium waste _ specifically chromium valence states (Cr(VI) and Cr(III)), and their chemical association with other phases in the waste matrix.

The removal of Cr(VI) was accomplished by leaching with aqueous solutions containing inorganic anions such as Cl-, SO42-, PO43- and others. Cr(VI) can be released from the waste by a combination of desorption and ion exchange processes. The efficiency and kinetics of displacing CrO42- from the waste by anions was extensively studied.

Cr(Ill) removal was achieved by the oxidative dissolution process - i.e., by using different oxidants at various pH conditions. We defined the mechanisms for Cr(III) transformation to Cr(VI) and the leaching of the latter into the environment under different pH conditions. We assessed the conditions and rate for such conversion and leaching processes.