本研究利用含浸硫酸銅、硝酸銅、氯化亞鈷金屬塩類於農業廢棄物-椰殼中，經固定式熱裂解製備成活性碳觸媒應用於甲烷催化氧化降解，本研究探討以不同含浸液濃度所製成之活性碳觸媒對於觸媒孔隙及催化氧化特性之影響，研究中以BET分析觸媒孔隙特性，以SEM-EDS分析觸媒表面形態及活性金屬表面分布之情形，及以TPD-CH4分析碳觸媒對於甲烷氣體吸附能力大小，並以氧氣作為氧化劑進行催化氧化試驗，研究中探討活性碳觸媒中金屬含量、氧化劑/甲烷比例變化及操作溫度條件下，對於甲烷催化氧化降解效率之影響程度。
研究結果顯示，含浸硫酸銅金屬所製成之活性碳觸媒具最高之比表面積 993 m2/g，而其孔隙主要以微孔為主，平均孔徑約為10Å，當含浸氯化亞鈷時，比表面積隨著鈷的含量增加而增加，而其孔隙亦以微孔為主。根據甲烷催化氧化研究結果發現，活性碳觸媒催化氧化活性大小依序為以硝酸銅 >硫酸銅 >氯化亞鈷含浸所製備，且所呈現之催化氧化能力與表面活化金屬分散性成正相關，但高濃度之含浸液並無法提供高吸附面積與較多活性金屬，以適中含浸液所製備之活性碳觸媒材兼具高吸附面積與較多活性金屬分布。由甲烷催化氧化及氧化劑濃度變化研究結果顯示，於300℃、氧氣濃度為1000 ppmv時以0.05M含浸濃度所製備之活性碳觸媒(硝酸銅、硫酸銅、氯化亞鈷)為最佳條件，甲烷轉化率分別為100%、67.7% 和65.9%，研究中亦顯示氧化劑濃度顯著影響活性碳觸媒之甲烷轉化率，過量之氧化劑濃度不利於碳觸媒之催化氧化能力，由催化氧化反應結果得知，當過量氧氣(O2)供應時，由於表面吸附降低之緣故而無法獲得最佳氧化效果。且由氣體熱程控脫附(TPD)分析結果發現硝酸銅於450℃脫附反應溫度具有明顯CH4脫附峰，顯示硝酸銅具有較強之CH4吸附能力，此特性有助於進行催化氧化過程以提高CH4轉化率。 Copper nitrate、copper sulfate、and cobalt chloride were used as the impregnating agent with agriculture waste - coconut shell for preparing activated carbon catalyst. The impregnated coconut shells were activated to form activated carbon catalyst and applied for catalytic oxidation of methane with air. The oxidation activities of catalyst were investigated by considered the porosity and dispersion of active metal on activated carbon. The influence of impregnating agent on the pore characteristics of catalyst were investigated by BET analysis. The morphology and dispersion of active metal were observed by SEM-EDS. The catalytic oxidations were carried on by considering the ratio of air/methane, operating temperature, and activated carbon properties. It was found that the activated carbons with impregnated copper nitrate own the highest surface area, 993 m2/g. The pore volume of catalyst is mainly contributed by the micro pore volume and the mean pore size of this activated carbon is about 10.2 Å. It was also found that the oxidation activity of carbon catalysts are following in copper nitrate> copper sulfate> cobalt chloride as the impregnating agent in catalyst preparation. The catalytic oxidation activity of carbon catalyst depends on the active metal dispersion and adsorption area of carbon catalyst. The higher impregnating agent did not proportional promote a higher surface area and more active sizes on the catalyst due to the high viscosity metal salt hindered the penetration into the coconut shell structure. The optimum concentration of impregnating agent owns the higher surface area and active sizes on the carbon catalyst. In the case of impregnating agent with 0.05M, the methane conversion achieved 100%, 67.7%, and 65.9% (copper nitrate, copper sulfate, cobalt chloride) at 300℃ in oxidation. It was also found that the excess oxidant did not benefit the conversion of methane in oxidation due to the decline in pollutant adsorption on the catalyst.
