tailieunhanh - Thermodynamics Interaction Studies Solids, Liquids and Gases Part 3

Tham khảo tài liệu 'thermodynamics interaction studies solids, liquids and gases part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 110 Thermodynamics - Interaction Studies - Solids Liquids and Gases The value for the apparent equilibrium constant Ki of the adsorption process of the Cr III in aqueous solution on studied activated carbons were calculated with respect to temperature using the method of Khan and Singh by plotting In qeif Ceqi vs. qeiỊỊ and extrapolating to zero qegj Fig. 5 6 and presented in Table. 4. In general Ki values increased with temperature in the following range of the studied activated carbons Merck_initial Norit_initial Norit_ treated by IM HNOa Merck_treated by IM HNOa Tabl. 4. . However it should to be noted that in the case of the parent Norit and Merck activated carbons the experimental data did not serve well for the apparent equilibrium constants calculation as pointed by the low correlation values R2 on Fig. 7 . 5 8 5 3 - _c 4 8 4 3 - 0 0 2 0 4 0 6 0 8 1 1 2 1 4 Orlll uptake mmol g Fig. 6. Plots of In Cr III uptake Cr III eqi vs. Cr III uptake for the Cr III adsorption on modified by IM HNOa Norit activated carbon at - 22 o - 30 - 40 and A - 50 C. As-depicted irregular pattern of linearised forms of In fleif Ceqi vs. qeqi Fig. 7 are likely to be caused by less developed porous structure of the parent materials and their poor surface functionality thus low adsorption and consequently by the pseudo-equilibrium conditions in the systems with parent activated Norit and Merck carbons. Thermodynamic parameters for the adsorption were calculated from the variations of the thermodynamic equilibrium constant Ki by plotting of In Ki vs. 1 T. Then the slope and intercept of the lines are used to determine the values of H and the equations 13 and 14 were applied to calculate the standard free energy change IƠ 1 and entropy change IS0 with the temperature Table 5 . Based on the results obtained using the thermodynamic equilibrium constant Ki some tentative conclusions can be given. The free energy of the process at all temperatures was Comparison of the Thermodynamic .