| Summary: | 碩士 === 弘光科技大學 === 環境工程研究所 === 105 === Recently, the development of science and technology leads to the fast growth of industrial production. Nitrogen-contained chemical wastewater is one of the important environmental threaten pollutions. Among those nitrogen-contained chemicals, monoethanolamine (MEA) used in thin-film transistor liquid crystal display (TFT-LCD) industries for cleaning and etching process as a stripper is a toxic chemical and should be used and treated with care. Firstly, the MEA wastewater was investigated by UV/H2O2 and UV/Na2S2O8 process for degradation and mineralization. The operating parameters such as MEA initial concentration, oxidant dosage, pH and UV dosage were studied to optimize the process for thoroughly degrade and mineralize MEA. The results showed that with 120W/L UV dosage, 11.6mM H2O2 and 10 min reaction time totally degrades 100 mg/L MEA. And 95% total organic carbons (TOC) can be achieved in 30 min. Moreover, anions exist in UV/H2O2 process show no adverse effect on MEA degradation. On the other hand, with 120W/L UV dosage, 6.3mM Na2S2O8 and 6 min reaction time can totally degrade 100 mg/L MEA. And 80% TOC mineralization can be achieved in 60 min. Anions such as sulfate, nitrate and chloride present inhibition effect on MEA degradation for UV/Na2S2O8 process. Secondly, an Amberlite IR-120 cation exchange resin column was utilized to recover the MEA from wastewater. The ion exchange isotherm and kinetics were studied. The breakthrough study was performed with various MEA concentration, flow rate, and pH as well as MEA acid elution and recovery. The results showed that Amberlite IR-120 cation resin is able to treat MEA wastewater effectively. From kinetic study, 1.5 g/L IR-120 resin reaches 45% removal of MEA. From breakthrough study, the breakthrough volume is 6150 mL for 500 mg/L MEA with 5 mL/min flow rate in a 20g packed resin column. In the column test, the higher flow rate is charged, the larger the breakthrough volume can be reached. On the other hand, the lower MEA concentration is charged, the larger the breakthrough volume can be insured. The effect of pH presents breakthrough volume in consequence of alkaline, neutral and acidic conditions.
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