Removal of Cadmium and Chromium from a Pretreated Wastewater with Reverse Osmosis
Abstract
The purpose of this research project was to investigate the removals of cadmium(II) and chromium(VI) from a simulated wastewater by reverse osmosis (RO). The project was one very focused aspect of a major U.S. Navy multi-year research project aimed at achieving zero-discharge from its Industrial Wastewater Treatment Plants. The effects of varied operating conditions on the performance of a thin-film composite brackish water RO membrane were investigated: feed solutions of 1000, 2000, and 3000 mg/l NaCl; 2000 mg/l NaCl at pH 5, 6 and 7; and background feed composition solutions of NaCl and Na2SO4 at four different mix ratios. The effects of temperature in the range of 20 to 36 C, and operating pressures of 400, 300 and 200 psi were also investigated. In nearly all cases metal concentrations were 10 mg/l; a 100 mg/l test was also performed. Typical RO behaviors were observed with water and solute permeation. Both water permeation and solute passage decreased with time due to membrane compaction. On the other hand, water permeation increased with applied pressure. The best rejections for the metals were obtained in feed solutions of sodium chloride and sodium sulfate. A maximum rejection of 99.9 percent was observed for cadmium(II) at a feed solution mole fraction of approximately 0.95 sodium sulfate and a pH of 6. The highest chromium(VI) rejection observed was 99.1 percent at a 0.5 mole fraction of sodium sulfate and pH of 6.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1992
- Accession Number
- ADA257798
Entities
People
- Karen M. Zapp
Organizations
- Purdue University