In this work, an electrocatalytic membrane was prepared to degrade aqueous tetracycline (TC) using a carbon membrane coated with nano-TiO₂ via a sol-gel process. SEM, XRD, EDS, and XPS were used to characterize the composition and structure of the electrocatalytic membrane. The effect of operating conditions on the removal rate of tetracycline was investigated systematically. The results show that the chemical oxygen demand (COD) removal rate increased with increasing residence time while it decreased with increasing the initial concentration of tetracycline. Moreover, pH had little effect on the removal of tetracycline, and the electrocatalytic membrane could effectively remove tetracycline with initial concentration of 50 mg·L⁻¹ (pH, 3.8–9.6). The 100% tetracycline and 87.8% COD removal rate could be achieved under the following operating conditions: tetracycline concentration of 50 mg·L⁻¹, current density of 1 mA·cm⁻², temperature of 25 °C, and residence time of 4.4 min. This study provides a new and feasible method for removing antibiotics in water with the synergistic effect of electrocatalytic oxidation and membrane separation. It is evident that there will be a broad market for the application of electrocatalytic membrane in the field of antibiotic wastewater treatment.

In this study, the effect of cavitation parameters on bisphenol A (BPA) removal using hydrodynamic cavitation (HC) was investigated. The geometry of orifice plate was examined and operational parameters of the process were selected. The effects of initial concentration, temperature, and pressure on the removal of BPA were investigated. It was found that the degradation efficiency rose first and then decreased with increasing temperature and pressure, as well as decreasing solution concentration. In addition, the optimum conditions were determined on the basis of orthogonal tests as follows: solution concentration 10 mg/L, pressure 0.3 MPa, treatment time 3 h, and temperature 35°C, the removal rate of BPA was 27.58% under the optimum conditions. The geometry of orifice plate (α, β, and arrangement) was found to be an important factor in getting the maximum cavitational effect using HC. The result shows that under the same operating conditions, the influence of β on the removal rate of BPA is caused by the different pore diameter and pore number of the porous plate. The system with orifice intersect layout can produce more uniform cavitation cloud and has better treatment effect than that with radial layout. This study suggests that the removal rate of BPA by HC is influenced by a variety of factors, and high BPA removal rate could be achieved under appropriate conditions.

The purpose of this study is to develop a kind of positively charged microporous ceramic membrane which works on the electrostatic adsorption principle to promote adsorption of organic dyes with negative charge. The nano-Y₂O₃ coating which played the role of charged agent was obtained through colloid reaction and a thermal decomposition process. Firstly, the precursor colloid was synthesized by chemical reaction of urea and YCl₃, and subsequently the precursor colloid was calcined in air to transform into nano-Y₂O₃, which was fixed on the surface of a base membrane. The specific surface area of positively charged ceramic membrane increased 36.72% through the coating process, and the nano-Y₂O₃ was evenly attached to the base membrane surface with an isoelectric point of 8.18. The EDS and XPS results demonstrated that there were new chemical bonds formed with Y element between the base membrane and the Y₂O₃ coating, which meant the Y₂O₃ coating did not easily fall off. The positively charged ceramic membrane prepared in this study removed approximately 99.6% of titan yellow and 98.3% of eriochrome black T, which were both small molecule dyes with negative charges in water, and which indicates a potential manufacturing process to yield effective dye filters superior to those of current dye filtration techniques.