Model Development on Using Clay Membranes for Arsenic Removal from Drinking Water
EMSL Project ID
5096a
Abstract
Use of clay membranes for arsenic removal from drinking water has been explored at the University of Missouri-Columbia, supported by a CAREER grant from the National Science Foundation. Arsenic is a toxic and carcinogenic metalloid that presents a major human health threat. Many municipalities draw drinking water supplies from groundwater containing elevated levels of arsenic. In recognition of the high risk associated with arsenic in drinking water, US EPA has recently revised arsenic maximum contamination level (MCL) down from 50 mg/L to 10 mg/L. In our preliminary study, clay membranes made of smectite and kaolinite are shown to reject arsenate at over 90% under some conditions. It is hypothesized that the ability of clay membranes to reject arsenate is due to the negative charge associated with the clay particles. The charged surface results in development of an electrical double layer that provides resistance to the passage of arsenate. The exact mechanism of the solute rejection by clay membranes, however, is unknown. There is no model available to describe the solute rejection processes, and there is no modeling tools available to assess how various parameters, such as pH and ionic strength, will affect the membrane efficiency. The objective of this EMSL User Facility Proposal with Dr. Chongxuan Liu is to develop a mathematical model by incorporating the hydraulic and electrical double layer properties of clay membranes, aiming to predict/simulate water permeability and solute rejection. It is expected that model be applied to explain the experimental observations on arsenate treatment. In addition, the model may be modified to model many other geohydraulic, geochemical, and geotechnical processes.
Project Details
Project type
Exploratory Research
Start Date
2006-12-05
End Date
2007-12-09
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members