| Summary: | 碩士 === 弘光科技大學 === 環境工程研究所 === 104 === Tetra-methyl ammonium hydroxide (TMAH) containing wastewater from technical industries processing with strong alkaline and bio-refractory properties and human toxicity may cause impacts on eco-environment without proper treatment. Advanced oxidation processes (AOPs) are emerging wastewater technologies for technical industries for their fast reaction and adaptive to high pollutant concentration. UV/persulfate process is one of the AOPs utilizes sulfate radicals and hydroxyl radicals under catalysis of thermal, alkaline, UV and transition metals etc. And it is capable to degrade and mineralize the organic pollutants by sulfate radicals. On the other hand, ion exchange resins are widely used for removal anions and cations from industrial wastewater. In this work, UV/persulfate process and ion exchange column were proposed to degrade and recover target pollutant, i.e., TMAH, under designated operating conditions. Operating parameters such as TMAH initial concentration, sodium persulfate dosage, initial pH and UV dosage were investigated for their effects on UV/persulfate performance. Experimental designs such as ion exchange isotherms, adsorption kinetics and breakthrough studies of fixed bed column were implemented. The experimental results show that UV/persulfate process is able to degrade and mineralize the TMAH wastewater. Under pH 2 acidic condition, and 6.3 mM sodium persulfate dosage, UV/persulfate process can remove 90% TMAH and 60% of total organic carbons (TOC). However, use UV irradiation alone or sodium persulfate oxidation alone shows no effect on TMAH degradation. Furthermore, both UV/"H" _"2" "O" _"2" and UV/Oxone processes can barely degrade TMAH in wastewater. From ion exchange kinetics studies, 1.75 g/L Dowex HCR-W2 and Amberlite IR-120 resins can remove 80 and 75% TMAH, respectively. For column test of resins, under 500 mg/L TMAH, 5mL/min flow rate, the breakthrough volume are 5000 and 6500 mL for Dowex HCR-W2 and Amberlite IR-120, respectively. The results show that the breakthrough volume increases with increasing flow rate and decreasing of TMAH concentration. The alkaline pH is favorable than acidic pH for increasing breakthrough volume. Furthermore, in all tested TMAH recovery experiments, the recovery rates are all above 90% by HCl elution solution from 1 to 9N.
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