The removal of cadmium（Cd） from synthetic solutions by batch adsorption process was performed using eggshell powder, which is mainly composed of calcite（CaCO3）. In order to optimize the adsorption process, a re- s...The removal of cadmium（Cd） from synthetic solutions by batch adsorption process was performed using eggshell powder, which is mainly composed of calcite（CaCO3）. In order to optimize the adsorption process, a re- sponse surface methodology（RSM） based on Central Composite Design（CCD） was applied. Developed model for Cd removal yields（R, %） response was statistically validated by variance analysis（ANOVA） which showed a high de- termination coefficient value（R2=0.9889）. According to Minitab software, the optimal conditions were found at tem- perature of 44℃, eggshell adsorbent dose of 2.98 g, initial Cd concentration of 36.74 mg/L and initial pH of 7. Under these conditions, the Cd removal yield was 98.76%. The deviation value of 1.24% confirms the validity of the model for the adsorption process optimization. The adsorption isotherm has been described by a Freundlich model. In addition, the predominant sorption mechanisms are the chemisorptions or precipitation（non-reversible） and ion ex- change（reversible）.展开更多
Chemical preparation, X-ray single crystal diffraction, thermal analysis, electrochemical measurements, IR, Raman and UV spectroscopic investigations of a novel organic-inorganic hybrid material（CaH7N2）CdCl3（H2O）...Chemical preparation, X-ray single crystal diffraction, thermal analysis, electrochemical measurements, IR, Raman and UV spectroscopic investigations of a novel organic-inorganic hybrid material（CaH7N2）CdCl3（H2O）（1） were described. 1-Methylimidazolium aquapentachlorocadmate（II） crystallized in the monoclinic system with P2 1/n space group. Its structure provided a new interesting example of infinite inorganic layers of [CdCl3（H2O）]n n- centered by （-101） planes. The [CdCl5（H2O）]- anions were interconnected by O-H...Cl hydrogen bonds. Acidic protons of the chloride group were transferred to the organic molecule, giving the singly-protonated cations. The ability of ions to form a spontaneous three-dimensional structure through O-H…Cl and N-H…Cl hydrogen bonds was fully utilized. These hydrogen bonds induced notable vibrational effects. IR and Raman spectra were reported and discussed on the basis of group theoretical analysis and on quantum chemical density theory（DFT） calculation. The molecular HOMO-LUMO compositions and their respective energy gaps were also drawn to explain the activity of our compound. The role of the intermolecular interaction in this crystal was analyzed. The optical study was also investigated by UV-Vis absorption spectrum. Thermal analysis reveals the hydrous character of the compound. Cyclic voltammetry was studied to evaluate the spectral and structural changes accompanying electron transfer.展开更多
文摘The removal of cadmium（Cd） from synthetic solutions by batch adsorption process was performed using eggshell powder, which is mainly composed of calcite（CaCO3）. In order to optimize the adsorption process, a re- sponse surface methodology（RSM） based on Central Composite Design（CCD） was applied. Developed model for Cd removal yields（R, %） response was statistically validated by variance analysis（ANOVA） which showed a high de- termination coefficient value（R2=0.9889）. According to Minitab software, the optimal conditions were found at tem- perature of 44℃, eggshell adsorbent dose of 2.98 g, initial Cd concentration of 36.74 mg/L and initial pH of 7. Under these conditions, the Cd removal yield was 98.76%. The deviation value of 1.24% confirms the validity of the model for the adsorption process optimization. The adsorption isotherm has been described by a Freundlich model. In addition, the predominant sorption mechanisms are the chemisorptions or precipitation（non-reversible） and ion ex- change（reversible）.
文摘Chemical preparation, X-ray single crystal diffraction, thermal analysis, electrochemical measurements, IR, Raman and UV spectroscopic investigations of a novel organic-inorganic hybrid material（CaH7N2）CdCl3（H2O）（1） were described. 1-Methylimidazolium aquapentachlorocadmate（II） crystallized in the monoclinic system with P2 1/n space group. Its structure provided a new interesting example of infinite inorganic layers of [CdCl3（H2O）]n n- centered by （-101） planes. The [CdCl5（H2O）]- anions were interconnected by O-H...Cl hydrogen bonds. Acidic protons of the chloride group were transferred to the organic molecule, giving the singly-protonated cations. The ability of ions to form a spontaneous three-dimensional structure through O-H…Cl and N-H…Cl hydrogen bonds was fully utilized. These hydrogen bonds induced notable vibrational effects. IR and Raman spectra were reported and discussed on the basis of group theoretical analysis and on quantum chemical density theory（DFT） calculation. The molecular HOMO-LUMO compositions and their respective energy gaps were also drawn to explain the activity of our compound. The role of the intermolecular interaction in this crystal was analyzed. The optical study was also investigated by UV-Vis absorption spectrum. Thermal analysis reveals the hydrous character of the compound. Cyclic voltammetry was studied to evaluate the spectral and structural changes accompanying electron transfer.
