本研究探討以硫酸亞鐵為活化劑所製備活性碳之物理與化學特性。研究中以硫酸亞鐵含浸濃度、熱裂解溫度、二氧化碳流量、熱裂解升溫速率等製備條件討論對活性碳之表面結構特性與物理及化學特性的影響，並以物理活化程序所製備之活性碳與之比較。研究結果顯示，經過硫酸亞鐵含浸製備而成的活性碳對氮氣等溫吸脫附曲線呈現出IUPAC的TYPE II及H3的型態，及經由BJH分析其孔洞大小分佈在10∼15Å及30∼40Å之間，而以D-R方程式分析結果發現在含浸於低鐵濃度較有利微孔隙的形成，而含浸於高鐵濃度較有利中孔隙形成。熱裂解溫度的影響於850℃利於微孔隙形成當溫度升至950℃則較有利中孔隙形成。本研究結果顯示低流量二氧化碳對孔隙性影響不大，當流量達到1000mL/min對活性碳孔隙性才有明顯的變化，低升溫速率易形成活性碳較佳的孔洞結構。
XRD、FTIR及Boehm酸鹼滴定結果顯示，硫酸亞鐵含浸劑在經熱裂解程序後氧化形成三氧化二鐵之型態存在於活性碳表面，而經由FTIR圖譜鑑定顯示包括了羰基、羧基、芳香族..等含氧官能基團存在於活性碳表面，且活性碳表面酸性含氧官能基含量的分佈隨硫酸亞鐵濃度增加而提升。本研究顯示污染物「酚」之吸附動力模式接近於擬二階方程式，於吸脫附研究中，硫酸亞鐵活化之活性碳其吸附速率高於脫附速率與孔洞分佈比例有關；等溫吸附模式實驗結果顯示本研究之活性碳適用於Freundlich模式，且發現由於活性碳隨含浸劑濃度的增加而具備較高量之酸性含氧官能基，因此對於酚有抑制吸附之效果。 The influence of chemical activation by FeSO4 on physical and chemical properties of coconut-based activated carbons was investigated. The prepared conditions of activated carbon were considered with the immersing salt concentration, flow rate of CO2, activated temperature, and heating rate for improving the adsorption performance. The relationships between adsorption performances and above properties of those activated carbons were compared with the physical activated carbon. Based on the analysis of N2 isotherm, it was indicated that the Hysteresis loop of activated carbon was a typical Type II and H3 form. The D-R analysis showed that the pore distributions of activated carbon were almost ranged in 10-15 Å and 30-40 Å. Based on the BJH analysis method, it was found that the development of micropore was enhanced at low chemical activation concentration in carbon matrix. Otherwise, the mesopore was developed at high chemical activation concentration. This study also showed that the mesopore development was also dominated by the activation temperature and heating rate in the period of activation. The CO2 flow rate was not a dominated factor on the pore development of activated carbon.
The XRD analysis was made to identify the bonding structure of iron in carbon matrix. It was evidenced that the Fe2O3 was formed in activated carbon. The Boehm titration and FTIR analysis indicated that oxygenic group on activated carbon was strong dependent on the preparation condition. It was showed that carboxyl, carbonyl, aromatic, and phenolic groups were found on the activated carbon surface. The functional group analysis also showed that acidic group on activated carbon was proportional to the iron content in carbon matrix. Based on the kinetic study and isotherm analysis, it was found that the adsorption of phenol onto activated carbon was following in a pseudo second order mechanism. It was showed that the adsorption and desorption rate was showed a strong dependent on the pore structure of activated carbon. The Freundlich isotherm was well described the adsorption behavior in aqueous solution. It was also indicated that the adsorption capacity of activated carbon was influenced by the chemical properties on surface of activated carbon. The acidic functional group on activated carbon decreased the sorption capacity of activated carbon with activation by FeSO4.
