470025 Perchlorate Destruction from Ion-Exchange Regenerants By Catalytic Reduction Process Increases Brine Recovery
Using a nanofiltration (NF) process, perchlorate is separated from the brine. More than 95% perchlorate was separated and retained in the reject. Permeate primarily containing brine was recycled back to the Ion exchange process to be used in the next stage of regeneration. Low volume of the NF reject containing high concentration of perchlorate ions is mixed with a reducing agent in a reactor where the perchlorate ions and the reducing agents undergo an oxidation-reduction (Redox) reaction. During the Redox reaction, perchlorate ions are reduced to chloride ions and the reducing agent is oxidized. The oxidized reducing agent is separated from the water which is regenerated by means of a second reducing agent, and reused in the Redox process. Redox reaction kinetic was significantly improved in presence of catalyst. Various reducing agents including Titanium (III), Manganese (II), and Iron (II) at different temperatures were investigated. The impacts of pH on the reduction kinetic were examined. All reactions were conducted with and without the catalyst. The efficiency of TiO2 and MnO2as the catalyst was compared.
Using an ion Chromatography (IC), perchlorate was measured. Results reveal that within the first two hours of reaction, more than 98% perchlorate was converted to chloride ion in presence of a catalyst. Increasing temperature increased prechlorate destruction efficiency. The process, and the impacts of various process parameters on the perchlorate destruction efficiency will be presented and discussed.
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