The Adsorption of Chromium (VI) at the Oxide/Water Interface
Abstract
Because of its toxicity, chromium has a potential environmental impact, and it is imperative that mechanisms which control the movement of this metal through the environment be known. It has been documented that adsorption to suspended and deposited materials is important in controlling the concentration of heavy metals in natural waters. Numerous previous investigations have been concerned with the adsorption of hydrolyzable heavy metals; however, chromium exists in aqueous solution as the anionic oxocomplex. In this report data on adsorption of chromium and phosphate are compared at the water interface of various metal oxides. The conclusions of this investigation are: (1) for Al2O3 both chromium and phosphate adsorb at low pH's; however, upon increasing pH, there is a decrease in the percentage adsorption; (2) chromium adsorption decreases with increasing ionic strength; (3) phosphate exhibits a higher specific adsorption energy than does chromium; (4) adsorption of both chromium and phosphate is low for solids which have isoelectric points at low pH's; (5) with a more valid method of determining the surface potential other than the Nernst equation, the simple electrical double layer model can be used to give reasonable predictions of the pH and surface charge response for adsorption of anions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1975
- Accession Number
- ADA032083
Entities
People
- Michael G. Macnaughton