| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 87 === The adsorption of five basic dyes, namely, BV-10, BO-14, BG-4, BG-5 and BB-9, onto activated clay, montmorillonite and activated carbon was investigated in this. The study includes four parts: (1) to determine the surface nature of the adsorbents, (2) to analyze the dynamic adsorption process in terms of pseudo-reaction model as well as intraparticle diffusion mechanism with the effect of agitation and initial dye concentration, (3) to analyze the equilibrium adsorption based on isotherm model, and (4) to investigate the thermodynamics of the system in the temperature range of 298-338 K.
Experimental measurements show that all the adsorbents were porous with the large surface area. Measurement from zeta potential meter indicates that the surface of the adsorbents possesses negative charge which is favorable for the adsorption of basic dyes. Experimental data show that the three adsorbents has best effect on BO-14, especially activated carbon. On the other hand, activated clay and activated carbon got the worst effect on BV-10, while montmorillonite on BG-4. The data also show that the adsorption rate increased slightly with agitation speed, and the adsorption capacity increases with increasing the solution temperature. For the dynamic adsorption, it is found that all the data could be satisfactorily fitted by pseudo-second order model, Intraparticle diffusion mechanism indicates that the adsorption indeed includes pore diffusion during the adsorption concerned, the analysis indicates that the Redlich - peterson isotherm is the most favorable for the adsrption of basic dyes onto activated clay and montmorillonite, while Freundlich isotherm for activated carbon. Thermodynamic analysis shows that the adsorption was endothermic with adsorption enthalpy of 20-26 kJ/mol.
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