摘要
本研究利用椰殼含浸氯化銅/硫酸鋅製備成活性碳金屬觸媒，並利用連續流式(Continuous-flow stirred-tank reactor，CSRT)氧化系統對於水中的污染物酚進行氧化降解處理。本觸媒製備完成後以氮氣吸附原理分析其比表面積，並以掃瞄式電子顯微鏡(SEM)觀察觸媒表面的結構，利用能量分散光譜儀(Energy Dispersive X-ray Spectrometer，EDS)分析活性碳表面的金屬含量，所製備之金屬觸媒以X射線繞射儀(X-ray Diffraction， XRD)來分析觸媒金屬之氧化物型態，污染物氧化降解後以高效能液相層析儀(High Performance Liquid Chromatography，HPLC)與化學需氧量(Chemical Oxygen Demand，COD)來分析反應過後酚的轉化率與COD去除率。
活性碳的煅燒過程不同的煅燒容器所燒出的活性碳其比表面積差異顯著，本研究中以石英管所燒結出的活性碳比表面積比起鋼製熱裂解管高，但因鋼製管產量較高而實驗所需觸媒量較多，所以選擇鋼製管微煅燒容器。
含浸氯化銅/硫酸鋅比例為0.03M/0.07M以石英管煅燒過後比表面積為最高(1147m2/g)，並且發現當硫酸鋅的濃度提高時其比表面積增加而以鋼製熱裂解管煅燒比表面積約為(610m2g~700m2/g)左右差異不大，因鋼製管鍛燒時易產生焦油而堵塞孔隙，所以比表面積較低。
本研究之活性碳觸媒配合過氧化氫處理含酚廢水，實驗中發現不同的反應變數影響酚之轉化率與COD的去除效果，在酸性的環境反應下有較快反應與降解速率，pH值3時其酚的轉化率約94%，而COD去除率約84%。此外增加雙氧水濃度也能有效提高酚的轉化率，在實驗中當雙氧水濃度提高至4000ppm時，酚的轉化率與去除率達到最佳，轉化率和去除率分別為90%以及75%，但當提高至5000ppm時反而酚的轉化率與COD去除率分別降至85%及73%，因為當雙氧水濃度達到飽和時再增加雙氧水反而會因過多的氫氧自由基產生抑制氧化效果。不同條件的實驗變數下得知，濕式連續流氧化系統在於酸性(pH=3)的環境下與提高溫(80℃)以及增加適當的雙氧水濃度(4000ppm)將有利於此系統的氧化效果。
關鍵字:銅、鋅、活性碳、酚、氧化、化學需氧量 Abstract
In this study, the coconut shell based carbon catalyst with Copper/Zinc impregnated were prepared and applied for the degradation of phenol in a Continuous-Flow Stirred-tank Reactor (CSRT). The surface area and pore properties of carbon catalysts were analyzed via the nitrogen adsorption experimental at 77 K. The morphology and elementary analysis on the surface were observed by the SEM/EDS. The XRD spectra were used to confirm the crystal form of metal and identified the oxides on the surface of catalyst. The degradation rate of phenol and efficiency were evaluated by the HPLC analysis and COD determination, respectively.
It was found that the chamber space of carbonization reactor strongly affected the pore properties and yield of catalyst. For example, the small volume of glassy rector preferred a good performance than the larger volume stainless steel chamber to prepare a high porosity catalyst. For example, the surface area of catalyst with glass reactor preparation owns an 1147m2/g surface area. But the same pregnant concentration of salt, the surface area of catalyst with stainless steel reactor only owns a 610m2/g surface area. It was found that the increase in Zinc content in catalyst enhanced the surface area of catalyst.
The carbon catalysts present a good oxidation activity on the degradation of phenol and COD removal on the wastewater in CWPO process. The pH is the significant factor to dominate the phenol degradation. The low pH accelerated the oxidation and improved the COD removal and Phenol degradation. The 94% phenol conversion and 84% COD removal can be achieved in CWPO process at initial pH=3. One of the other dominate factors is H2O2 concentration in reactor. It was found that the optimum concentration of H2O2 enhanced the oxidation rate but the over dosage of H2O2 lowed the conversion and COD removal due to the self combination reaction in reactor. It is suggested that the optimum condition to carry out the CWPO process to degrade phenol and remove the COD is under low pH with 2-4 times concentration of H2O2 at 80℃.
Key words:copper、zinc、activated carbon、phenol、COD、CSRT
