彩色濾光片玻璃基板再生製程強鹼染料廢液之催化濕式氧化處理

reatment of Strong Alkaline Dyeing Wastewater from the Process of the Recovery of Color Filter Plate by Catalytic Wet Oxidation

陳以航(Yi-Hang Chen)

指導教授 ： 王天財

國立中央大學/工學院/化學工程與材料工程學系/碩士(2007年)

摘要

彩色濾光片玻璃基板再生製程強鹼染料廢水氫氧化鉀濃度大約2.7 N，須降至適當的pH[9~12]才能做後續處理。而電透析是為最適降低該廢水氫氧化鉀濃度、並且回收氫氧化鉀的方法。而後續處理就是濕式催化氧化。
而本研究是以催化濕式氧化法(Catalytic Wet Air Oxidation ，CWAO)處理彩色濾光片玻璃基板再生製程強鹼染料廢水，(COD約160000-180000 ppm)，pH值>13，導電度約57 mS/cm，本研究首先進行催化劑的選擇，比較五氧化二釩(V2O5)、Ru/c、及二氧化錳(MnO2)對於此反應的催化氧化能力，其反應至120分鐘後，皆能有效的使pH值下降，而COD去除率分別為V2O5 : 34.2%、MnO2 : 37.7%、Ru/C : 36.7%，其結果顯示MnO2與Ru/C有較佳的氧化力，但價格的比較上Ru/C偏高，考慮到成本的因素，所以選擇MnO2為此催化濕式氧化法處理強鹼染料廢水的催化劑。
對於有無添加催化劑的系統，進行導電度、pH值及COD去除率之比較，並改變操作參數，如反應溫度、氧氣壓力、攪拌速率、催化劑含量等可控因素對催化濕式氧化系統之影響，以尋求最適處理條件。攪拌速率方面，在400 rpm以上有較佳的COD去除率，故選擇500 rpm；而溫度方面200℃以上其pH下降較明顯，而COD去除率也較佳，但溫度220℃下反應至120分鐘後其pH值降為1.77，超出排放標準，所以選擇200℃；壓力方面隨著Po2,0(初始通入氧氣量)的增加，COD去除率也相對增加，所以選擇Po2,0 = 350 psig，而反應總壓為600 psig；催化劑量方面顯示0.032 g (3%)及0.048 g (4%)有較佳的COD除去率，故選擇0.048 g MnO2的催化劑量。
隨著反應時間的增加，二氧化碳的量也隨之增加，而減少氧氣進入反應器參與反應，為確定二氧化碳是否為影響因子，進而改變氫氧化鉀的濃度，是否因氫氧化鉀濃度增高而吸收掉二氧化碳，使氧氣能順利進入參與反應，反應式 : CO2 + KOH K2CO3 。在KOH濃度為0.27 M及0.6 M之間有較佳的COD去除率，所以選擇0.27 M為此反應的KOH濃度。
最後綜合以上結果，決定出最適化的操作參數進行反應(攪拌速率500 rpm、KOH濃度0.27 M、溫度200℃、Po2,0 = 350 psig、催化劑量0.048 g(4%))，但反應時間的增加Pco2的量已佔總壓的大部份，使Po2量下降且氧氣不易進入，所以配合多段操作的方式去除產生的二氧化碳，使氧氣能順利進入並參與反應，而本研究的成果在以上最佳操作條件下，以多段操作洩除Pco2方式，在反應210分鐘後COD去除率已達92.4%，已能使高強度的廢水被氧化分解，期望能更進一步進而達到回收再利用的標準。

關鍵字

催化濕式氧化 ； 彩色濾光片

並列摘要

The KOH concentration in strong alkaline dyeing wastewater from the process of the recovery of color glass filter plate is about 2.7N. The strong alkaline dyeing wastewater should be reduced to a suitable pH range of 9~12, so that it can be treated by other process. Electrodialysis is most suitable to reduce the basicity of the wastewater and simultaneously recover the KOH.
And this research is strong alkaline dyeing wastewater from the process of the recovery of color glass filter plate treatment by catalytic Wet Air Oxidation (COD 160000-180000 ppm), pH > 13, conductivity is 57 mS/cm , this research carries on the choice of the catalyst at first, compare V2O5, Ru/C and MnO2 , after 120 minutes, can all make pH drop effectively , and the COD removal is respectively V2O5: 34.2% , MnO2: 37.7% , Ru/C : 36.7%, the result to show MnO2 and Ru/C have better oxidation ability, but the price relatively has Ru/C on the high side, considering the factor of the cost , so choose MnO2 for this wet type of catalysis.
As to adding the system of the catalyst , carry on the comparison of conductivity , pH and COD removal, and change the parameter as reflecting temperature, oxygen pressure, stirring speed , amount of catalyst, in order to seek the optimum condition. stirring speed, there is better getting COD removal in above 400 rpm , so choose 500 rpm; And temperature drops more obvious in pH, but react and lower to 1.77 to its pH value after 120 minutes under 220℃, so choose 200℃; The pressure is increase with Po2, COD removal is also increase relatively, so choose Po2, 0 =350 psig, and Pt = 600 psig; the amount of Catalyst shows that 0.032 g (3% ) and 0.048 g (4% ) have better COD removal, so choose the amount of catalyst of 0.048 g MnO2.
With reflect the increase of time, the quantity of the carbon dioxide increases too, and reduce the oxygen enter the reactor , in order to confirm the carbon dioxide is the influence factor , and then change the concentration of the potassium hydroxide, whether absorb the carbon dioxide because the increase the concentration of potassium hydroxide, enable oxygen to enter and participate in reacting smoothly, reaction: CO2 + KOH K2CO3 . There is better COD removal for 0.27 M and 0.6 M in KOH concentration, so choose 0.27 M.
Synthesize the above result finally, it is determined that the optimum operation parameters (stirring speed 500 rpm , KOH concentration 0.27 M , temperature 200℃, Po2 , 0 = 350 psig ,the amonut of catalysis is 0.048 g (4% )),but with reflect the increase of time, the quantity of the carbon dioxide increases too, makes Po2 drop and difficult to enter reactor, so cooperate with many steps to operate to reject the carbon dioxide, and with the optimum conditions, the many steps, COD removal up to 92.4% already , can make strong alkaline dyeing wastewater to decompose.

並列關鍵字

catalytic wet air oxidation ； color filter

參考文獻

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