| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系碩士在職專班 === 107 === In this work, wastewater from Polarizer washing process containing high concentration of boron was studied. First chemical oxo-precipitation were used on different conditions to confirm the effects of boron-removing and optimal parameters by using Taguchi's Orthogonal Arrays methods. By ap-plying IIA group cations, including Mg, Ca and Ba, as mineralization agents, solution pH value, oxidant ( H2O2 , H3PO4), reaction time, stirring speed, and molar ratio of IIA group cations and boron, the precipitation tended to higher level of 97 % boron removal under the optimal conditions were as follow: BaCl2/B molar ratio of 3, solution pH value of 9, H2O2/B molar ratio of 3, reaction time of 1 hr and stirring speed of 500 rpm.
The precipitations of oxidized boron compound were analyzed by Scanning Electron Microscope (SEM) and X-ray Diffraction Spectrome-ter(XRD).The morphology showed that boron compounds were flake-shaped and have proven to produce the crystallized powder of Ba[B(OH)4].
After COP process as mentioned above, low concentration of boron wastewater was utilized absorption method and the experiment results showed chitosan has a best absorption capacity. In order to improve the ca-pacity, pretreatments of acid and alkaline were proceeded and the results revealed that the hydrolysis reaction of chitosan occurred in acetic acid so-lution when pH value of 4. Furthermore, the greatest absorption capacity was 7.04 mg/g when hydrolyzed chitosan solution mixed with bo-ron-contained wastewater, which the pH value of the mixed solution was 9.
Keywords: boron removal, chemical oxo-precipitation, boron absorption, chitosan
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