| Summary: | 博士 === 國立中山大學 === 環境工程研究所 === 104 === This study is focused to compare the adsorption of perchlorate by using granular activated carbon (GAC) and carbon nanotubes (CNT) in synthetically solutions, and to investigate their adsorption capacities and the effects of operation conditions on these adsorptions. In this study GAC and CNT as adsorbents were be carried to isothermal equilibrium and to obtain adsorption models for understanding the adsorption mechanisms of perchlorate by GAC and CNT. Finally thermodynamics and related constants of perchlorate adsorbed by GAC and CNT were discussed with the experimental results of kinetic adsorption.
Experimental results showed the adsorption capacities of perchlorate by GAC and CNT were at 28.2–33.9 mg/g and 10.0 – 13.6 mg/g respectively under a thermostat range 5-45 ℃ of isothermal tests. The all tests results of GAC and CNT were all suitable Langmuir and Freundlich models. In experiments on adsorption of perchlorate by two kinds of adsorbents, results show that dynamics approximately 8 hours to reach equilibrium of adsorption. The adsorption increased and decreased with the increased ionic strengths and concentrations of perchlorate.
The results of kinetic study showed the adsorption of perchlorate by GAC and CNT could all described by Modified Freundlich equation、Pseudo-1st-order equation、Pseudo-2nd-order equation. The constants of thermodynamic on CNT are : ΔGo were in range of - 0.77 ~ - 0.80 kcal/mol , △Ho were in range of - 0.6 kcal/mol, and △So were in range of 0.53 ~ 0.72 cal/mol-K. The constants of thermodynamic on GAC are : ΔGo were in range of - 0.99 ~ - 1.11 kcal/mol, △Ho were in range of - 0.6 kcal/mol, and △So were in range of 1.21 ~ 1.84 cal/mol-K. The reactions of perchlorate adsorbed on GAC and CNT were all belonging to spontaneously exothermic reactions.
|
|---|
