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|Title: ||Treatment of methyl methacrylate from semiconductor wastewater by catalytic wet oxidation|
|Issue Date: ||2012-03-27 16:26:14 (UTC+8)|
|Abstract: ||Treatment of methyl methacrylate (MMA) from semiconductor wastewater via catalytic wet oxidation (CWAO) was studied. Effects of major operating parameters on the system performances in terms of the normalized concentrations of MMA and chemical oxygen demand (COD) relative to their initial values, namely C(MMA)/C(MMA0) and C(COD)/C(COD0), were investigated. These parameters include (1) the setting temperature T(ST) of operation, (2) the presence of catalyst Pt/Al(2)O(3), (3) the presence of working gas, (4) the amount of Pt/Al(2)O(3) (m(Pt)) and (5) the partial pressure of O(2) (p(O2)). The change of pH value during the course of CWAO was also examined to elucidate the extents of decomposition of MMA and mineralization of COD. The results indicate that the effects of T(ST) on the C(MMA)/C(MMA0) are very vigorous for the case of sole wet oxidation (WAD) without catalyst. At the reaction time t(FR) = 180 min, the C(MMA)/C(MMA0) decreases from 0.89 at T(ST) = 180 degrees C to 0.62 at 200 degrees C and 0.09 at 220 degrees C with p(O2) = 2 MPa (based on the reference temperature T(rf) of 180 degrees C). The effects of T(ST) on the C(COD)/C(COD0) are not strong for the WAO, reducing the C(COD)/C(COD0) only to about 0.78-0.87 at t(FR) = 180 mill with T(ST) in 160-220 degrees C. As for the CWAO ill the presence of Pt/Al(2)O(3) with m(Pt) = 30.38 g, the C(MMA)/C(MMA0) reduces greatly to 0.15 and 0.01-0.05 at t(FR) = 180 min with T(ST) at 160 degrees C and in 180-220 degrees C, respectively, while the C(COD)/C(COD) decreases to about 0.16-0.34 with T(ST) in 160-220 degrees C. The use of Pt/Al(2)O(3) not only improves the removal of MMA and COD but also reduces the T(ST) required for the efficient removal of MMA and COD, saving the energy needed. The results also reveal that the oxidizing gas such as O(2) is required for effective mineralization of COD via CWAO. However, the enhancement effect of increasing p(O2) is not significant if the supplied p(O2) is high enough, say 1-2 MPa, to proceed the CWAO in liquid phase with sufficient dissolved oxygen. Further, the CWAO is more efficient than the advanced oxidation processes of direct ultra violet irradiation (UV), sole zonation (OZ) and combined process of OZ and UV for the effective removal of COD in the treatment of MMA. The information obtained in this study is useful for the proper operation and rational design of the CWAO system for the effective treatment of MMA-containing wastewater from the semiconductor industry. (C) 2009 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.|
|Relation: ||JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS|
|Appears in Collections:||[化學工程與材料工程學系 ] 期刊論文|
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