Research of ad/desorption behaviors of azo dye on carbon nanotubes

• Main Authors: Shu-hui Kuo, 郭淑慧
• Other Authors: Chao-yin Kuo
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/72816175774679732264

碩士 === 國立雲林科技大學 === 環境與安全工程系碩士班 === 94 === Carbon nanotubes (CNTs) were employed as a good adsorbent to remove the azo dyes Procion Red MX-5B from water. The commercial CNTs have been used in this research in order to prove the superiority of CNTs’ adsorption ability; it also compared the adsorption capacity with other porous active carbon materials: powder active carbon (PAC) and granular active carbon (GAC). The adsorption capacity of CNTs, PAC and GAC on azo dyes Procion Red MX-5B is 3.3×10-1, 5.3×10-2 and 2.5×10-3 mg/m2, respectively. The batch experiments result showed that CNTs’ adsorption capacity was influenced in different pH value, it has higher adsorption capacity in low pH than in high pH, the adsorption amount of CNTs at pH 2 is 0.40 mg/m2 which is larger 2 times than the adsorption amount at pH 10 (0.19 mg/m2). The adsorption behavior on CNTs is suggested to be pseudo second order after the kinetics study. It also can be found that the activated energy (Ea) of the reaction between CNTs and the azo dyes Procion Red MX-5B is 19.70 kJ/mol through the adsorption kinetics. The isotherms are well described by Langmuir model in the study. After the thermodynamics studies, the reaction between CNTs and azo dyes Procion Red MX-5B is suggested to be an endothermic reaction due to the thermodynamics calculation. The positive value of enthalpy and negative value of free energy represent endothermic and spontaneous process in this study. Therefore, it can be proved that CNTs is an excellent adsorption material adsorbed the azo dyes Procion Red MX-5B from water.