Affiliation:
1. Department of Civil Engineering, University of Ottawa, 161 Louis Pasteur Pvt., Ottawa, ON K1N 6N5, Canada
2. Dowclear Inc., 627 South Island Park Drive, Manotick, ON K4M 1J2, Canada
Abstract
An earlier study has shown that chlorine solutions were capable of effectively regenerating an ammonium-loaded zeolite column; however, the chlorine concentrations were high (1000 mg Cl2/L), and for two hours of the regeneration cycle, the pH was approximately 3. This led to concerns regarding the long-term durability of the zeolite. The objective of this study is to investigate the durability of a zeolite by conducting long-term batch exposure tests using (a) high concentration chlorine solutions and (b) low pH solutions. Particle size analysis, SEM images, N2 gas adsorption tests, FTIR characterization and batch loading tests showed that 35-day exposure to 1000 mg Cl2/L solutions did not significantly impact the zeolite studied. This chlorine exposure is equivalent to 840,000 ppm-h, which is three orders of magnitude higher than the values recommended by the supplier. The 90-day-long low pH exposure tests showed that pH = 4 solutions only slightly impacted the zeolite’s characteristics and ammonium uptake; however, the pH = 3 exposure led to discernable changes, and the pH = 2 exposure led to an even greater impact. At pH = 2, there was a breakdown of some external part of the zeolite particles, leading to a 7.1-fold increase in the fines and a 56% reduction in the ammonium uptake. The decrease in the ammonium uptake was proportional to the percent of fines.
Funder
VIP Program of the Ontario Centre for Innovation
Discovery Grant Program of the Natural Sciences and Engineering Research Council of Canada
Dowclear Environmental Inc.
Milestone Environmental Inc.
Subject
Geology,Geotechnical Engineering and Engineering Geology