Cong-Liang Zhang

Thermodynamic and kinetic parameters of ofloxacin adsorption from aqueous solution onto modified coal fly ash

Batch adsorption experiments were carried out for the removal of ofloxacin from aqueous solution using modified coal fly ash as adsorbent. The effects of various parameters such as contact time, initial solution concentration and temperature on the adsorption system were investigated. The optimum contact time was found to be 150 min. The adsorption isotherm data fit well with the Langmuir model, and the kinetic data fit well with the pseudo-second order and the intra-particle diffusion model. Intra-particle diffusion analysis demonstrates that ofloxacin diffuses quickly among the particles at the beginning of the adsorption process, and then the diffusion slows down and stabilizes. Thermodynamic parameters such as ΔG, ΔH, and ΔS were also calculated. The negative Gibbs free energy change and the positive enthalpy change indicated the spontaneous and endothermic nature of the adsorption, and the positive entropy change indicated that the adsorption process was aided by increased randomness.

Solubility of 3-Caffeoylquinic Acid in Different Solvents at 291–340 K

Using a laser monitoring observation technique the solubilities of 3-caffeoylquinic acid in pure solvents, water, methanol, ethanol, 1-propanol, 1-butanol, and two mixed solvents, methanol + water, ethanol + water have been determined at temperature range from 291–340 K. The experimental data were correlated by the modified Apelblat equation, λh equation, and ideal model. The calculated solubilities were turned out very consistent with the experimental results, and the modified Apelblat equation shows the best agreement.

Optimized photocatalytic degradation of pefloxacin by TiO2/UV process

The photocatalytic degradation of pefloxacin was studied using modified TiO2 as a photocatalyst. The effect of various parameters such as the amount of the photocatalyst, the initial concentration of pefloxacin, initial pH value on the process were investigated, and the optimal conditions were determined. The optimal amount of the photocatalyst is 0.3 g/L. The photodegradation rate of pefloxacin decreases with the increase of initial concentration. Alkaline medium is favorable for the photocatalytic degradation process. The primary photo-degradation products were analyzed by HPLC-ESI-MS/MS and thus the process mechanism was discussed.

Thermodynamics of sulfamethoxazole dissolution in organic solvents at 293.15–323.15 K

The solubilities of the sulfonamide—sulfamethoxazole in methanol, ethanol, 1-propanol, 2-propanol, and chloroform have been determined at 293.15–323.15 K by a static equilibrium method. The experimental results can be approximated with Apelblat equation. The positive enthalpy ΔsolH and entropy ΔsolS for each system revealed that sulfamethoxazole dissolution in each solvent is an entropy-driven process.

Thermodynamics of the solubility of sulfamethoxydiazine in organic solvents in the range 293.15–323.15 K

The solubilities of sulfamethoxydiazine in methanol, ethanol, 1-propanol, 2-propanol, acetone, and chloroform have been determined in the range 293.15–323.15 K by a static equilibrium method. The calculated results show that the correlation of the Apelblat equation for measured systems has less deviation than that of the λh equation. The positive ΔsolH and ΔsolS for each system revealed that sulfamethoxydiazine being dissolved in each solvent was an entropy-driven process.