THERMAL ACTIVATION OF NATURAL ZEOLITE FOR ENHANCING ITS ADSORPTIVITY TO THE SALT IONS IN SEAWATER

• Main Author: WIBOWO (NIM: 30212002), EDY
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/21880
• Institution: Institut Teknologi Bandung

Characterization and thermal activation of natural zeolite from Sukabumi have been conducted. The characterization results show that the type of zeolite is clinoptilolite with high silica content (% of mass Si = 38.32; Si/Al = 4.61) and high crystalline degree (d = 3.98 Å; FWHM = 0.85&#730;; &#948; = 18,94 nm and &#949; = 9x10-3&#730;) therefore owing high mechanical strength and good thermal resistance. The activation was conducted by using furnace. It was obtained that the optimum condition of activation is at temperature of 225 &#730;C for 3 h. The adsorptivity of zeolite was examined for reducing the salinity of seawater. <br /> <br /> <br /> Based on isotherms, thermodynamics and kinetics aspects, we obtained that the adsorption of salt ions onto zeolite surface is considered as physical process (E < 20 kJ/mol). The negative &#916;G&#730; (-27.193 to -29.144 kJ/mol) indicates the spontaneous nature of adsorption. The negative &#916;H&#730; (-30.856 kJ/mol) confirms the exothermic nature of adsorption, while the value of separation factor, RL = 0.588, shows the nature of adsorption process is favorable. In addition, the adsorption kinetic well fits to the pseudo-second-order model shows that the adsorption process could be fast occurred. <br /> <br /> <br /> The inserting of thermal shock on the activation process was able to enhance the adsorptivity of zeolite. The adsorptivity of zeolite increases until three times higher than the standard thermal process. Besides enhance the adsorptivity of zeolite, thermal shock caused the zeolite particles to transform into smaller particles. The average diameter of the particles as a result of thermal shock, which was approximately 1/4 of the initial particle diameter. A mathematics model was proposed to explain the mechanism of fragmentation. A criterion for fragmentation of brittle materials was also introduced. The proposed model and criterion are able to qualitatively explain why the diameters of zeolite particles resulting from thermal shock are approximately 1/4 of the initial particle diameter. This method is expected applicable for enhancing the adsorptivity of others material.