Kinetics, Equilibrium and Thermodynamics Studies of Fe<sup>3+</sup>Ion Removal from Aqueous Solutions Using Periwinkle Shell Activated Carbon

• 作者: Akpa Jackson Gunorubon Nduka Chukwunonso
• 来源期刊: 化学工程与科学期刊(英文)
• 学科: 化学
• 关键词: Adsorption Iron Ions KINETICS ISOTHERM Thermodynamics
• 年，卷（期）: 2018,（2）
• 页码范围: 49-66
• 页数: 18页
• 分类号: O6

摘要

Iron (III) adsorption from aqueous solutions unto periwinkle shell carbon (PSC) was studied using batch experiments. Activated periwinkle shell carbon was prepared (pyrolysed at 300°C and activated with nitric acid) and characterized to determine its physiochemical properties. Batch adsorption experiments were conducted to investigate the effects of process parameters (contact time, particle size, carbon dosage and pH of stock solution) on adsorption rate. Adsorption kinetics was tested using pseudo first and second order models. Adsorption Isotherms were analyzed using the Langmuir, Freundlich and Temkin isotherms while Thermodynamics parameters such as Enthalpy change (ΔH°), Entropy change (ΔS°) and Gibbs-free energy change (ΔG°) were determined. Results showed that adsorption rate increase with increase in contact time, adsorbent dose and pH and decreased with increase in particle size. Batch adsorption Kinetics experiments revealed that the mechanism of adsorption followed pseudo-second-order kinetic model. Isotherm data showed that the Langmuir isotherm accurately described the adsorption data indicating that adsorption process was mainly monolayer on a homogeneous adsorbent surface. Thermodynamic parameters results showed that adsorption process was endothermic with Enthalpy change (ΔH°): 222.91 kJ/mol;a positive Entropy change (ΔS°) of 19.19 kJ/mol, indicating an increase in the degree of freedom (or disorder) of the adsorbed species and a negative Gibb’s free energy (ΔG°) at all temperature indicating that the adsorption process was spontaneous and favorable at high temperature.