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The Bi-SnO2/C electrocatalytic membrane was fabricated via a simple electrochemical reduction and hydrothermal method. Under the action of electric field, the Sn2+ and Bi3+ were firstly adsorbed and reduced to metallic Sn and Bi on the carbon membrane surface by cathodic reduction reaction, and the Bi-SnO2/C membrane was obtained subsequently through hydrothermal oxidation process. Confirmed by SEM, TEM, XRD, and XPS characterizations, the nano-Bi-SnO2 is homogeneously distributed on the membrane surface and is firmly attached to the carbon membrane via C–O–Sn chemical bond. Through CV, LSV, and EIS electrochemical analysis, the Bi-SnO2/C membrane possesses the higher electrocatalytic activity and stability than carbon membrane. Therefore, the Bi-SnO2/C membrane could continuously efficiently remove and inactivate Escherichia coli in water through flow-through mode. As a result, the sterilization efficiency can reach more than 99.99% under the conditions of cell voltage 4 V, flow rate 1.4 mL/min, and E. coli initial concentration 1.0 × 104 CFU/mL, owing to the synergistic effect of the membrane separation and electrocatalytic oxidation. Moreover, it was found that the oxidation groups of ⋅OH radicals generated by Bi-SnO2/C membrane play the crucial role for bactericidal performance. This work presents a low-cost, highly active, and stable electrocatalytic membrane towards continuous bacterial inactivation, which exhibits promising potential in water disinfection and is beneficial for practical large-scale applications.

Endocrine disruptors (EDCs) are a group of persistent and toxic organic pollutants which can pose a significant threat to human endocrine system. Developing novel technique for contaminants removal or degradation is urgently needed. In this study, a three-dimensional porous membrane was fabricated based on the self-assembly of carbon nanotubes coated with bismuth-doped tin dioxide (Bi-SnO2) nanoparticles. The prepared Bi-SnO2/CNTM was evaluated for treatment of aqueous EDCs using Bisphenol A (BPA) as a model compound. The effect of Bi-SnO2 coating was proved with respect to enhanced BPA removal performance compared with pure CNTM. Furthermore, through in-depth investigation of generated intermediates during degradation process, the BPA degradation pathways were identified. The electrochemical degradation mechanism was also explored by adding radical scavengers and ·OH was determined to be prominent active radical for electrocatalytic degradation. These results indicate the potential of Bi-SnO2/CNTM to continuously and effectively treat EDCs residue in aquatic environment by a flow-through system.

In this work, a novel electrocatalytic filtration membrane with high degradation efficiency and low cost was fabricated by coating nano antimony-doped tin dioxide (Sb-SnO2) on a porous coal-based carbon membrane (CM) through sol-gel method. The nano Sb-SnO2 is homogeneously distributed on the CM surface and is firmly attached to the CM via C-O-Sn chemical bond. Due to the positive effect of nano Sb-SnO2 coating, the Sb-SnO2/CM possesses excellent electrocatalytic activity and shows a much better tetracycline (TC) degradation performance than CM. The TC removal rate of Sb-SnO2/CM could be achieved 96.5% after 6 h operation while that of CM was only 72.8%. Degradation pathway of TC was also explored using HPLC-MS. Furthermore, the effective TC degradation is attributed to the synergistic effects of direct and indirect electrochemical oxidation. During the indirect oxidation process, OH radicals rather than O2- play the dominant role.

A novel microporous nano-MgO/diatomite ceramic membrane with high positive surface charge was prepared, including synthesis of precursor colloid, dip-coating and thermal decomposition. Combined SEM, EDS, XRD and XPS studies show the nano-MgO is irregularly distributed on the membrane surface or pore walls and forms a positively charged nano coating. And the nano-MgO coating is firmly attached to the diatomite membrane via SiO chemical bond. Thus the nano-MgO/diatomite membrane behaves strong electropositivity with the isoelectric point of 10.8. Preliminary filtration tests indicate that the as-prepared nano-MgO/diatomite membrane could remove approximately 99.7% of tetracycline in water through electrostatic adsorption effect. The desirable electrostatic property enables the nano-MgO/diatomite membrane to be a candidate for removal of organic pollutants from water. And it is convinced that there will be a great application prospect of charged ceramic membrane in water treatment field.

Pesticide residues in the aquatic environment pose a threat to ecological environment and human health. The considerable concerns make it necessary to develop efficient strategies for the detection and degradation of pollutants. In this work, a multifunctional membrane was fabricated on the self-assembly of graphene oxide nanosheets with g-C3N4 and Ag NPs intercalated. The prepared GO/g-C3N4/Ag membrane exhibits high enrichment ability for small molecules, which is beneficial to the detection of organic pollutants at low concentrations. It also exhibits excellent SERS sensitivity and photocatalytic activity. Paraoxon-ethyl at nM-level concentrations can be detectable and then degraded almost completely under visible-light irradiation. The high SERS activity can be ascribed to the integration of enrichment ability of GO and surface plasmonresonance (SPR) of Ag NPs. And the photocatalytic mechanism was proposed as the improved separation efficiency of photogenerated electron-hole and the production of active radicals. Through a facile method, this work presents a highly active multifunctional membrane towards simultaneous detection and degradation of low-concentration organic pollutants.

Hydrodynamic cavitation can effectively remove organic pollutants and microorganisms from water. Organic compound degradation and water disinfection removal rate is related to reaction time and operating temperature. Removal rate can be improved by increasing the reaction time or raising the operating temperature. Under our experimental conditions, the removal rate of colority, COD and petroleum pollutants was 80.0%, 72.13% and 70.00%, respectively. In addition, Escherichia coli removal rate was higher than 99.99%. As a new water treatment process, hydrodynamic cavitation can be utilized alone or in combination with other water treatment processes, showing broad application prospects.

It is a challenge to synthesize highly efficient nonprecious metal electrocatalysts with a well-defined nanostructure and rich active species. Herein, through electron engineering and structure manipulation simultaneously, we constructed Fe-embedded pyridinic-N-dominated carbon nanotubes (CNTs) on ordered mesoporous carbon, showing excellent oxygen reduction reaction activity (half-wave potential, 0.85 V) and an overpotential of 420 mV to achieve 10 mA cm–2 for oxygen evolution reaction in alkaline media (potential difference, 0.80 V). Density functional theory calculation indicates those Fe@N4 clusters improve charge transfer and further promote the electrocatalytic reactivity of the functionalized region in CNTs. Rechargeable Zn–air batteries were assembled, displaying robust charging–discharging cycling performance (over 90 h) with voltage gap of only 0.08 V, much lower than that of the Pt/C + Ir/C electrode (0.29 V). This work presents a highly active nonprecious metal-based bifunctional catalyst towa...

Silver nanoparticles (AgNPs) with size distribution 7.1 ± 1.2 nm are continuously biosynthesized with Cacumen platycladi (CP) leaf extract (0.3 g/L) at room temperature (30 °C) in the hydrodynamic cavitation device. The products are characterized by UV-Vis absorption spectra, XRD, TEM, and HRTEM, confirming that AgNPs with uniform distribution are successfully synthesized. CFD and population balance equation (PBE) coupled models are built to simulate the AgNP formation process and calculate the corresponding particle size distribution numerically. The coupled model is validated accurately and effectively with experiment in simulating of AgNP formation and predicting the particle size distribution (PSD) in the hydrodynamic cavitation device.

The Bi-SnO

In this study, positively charged porous ceramic membrane was prepared through mechanical milling, isostatic pressing and subsequent high-temperature sintering. Combined with isostatic pressing technology and solid-state particle sintering, the positively charged porous composite ceramic membrane was prepared and the uniformly dispersed nano-yttria (Y2O3) was used as the inorganic charged agent in the ceramic membrane. The length, outer diameter and inner diameter of tubular ceramic membrane were 7, 2 and 1·1 cm, respectively. The ceramic membrane possessed a large number of irregular pores with pore size of about 0·5 μm and uniformly dispersed spherical Y2O3 nano-particles in the ceramic membrane surface, expecting to get a good surface electrical performance.

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.

Hydrodynamic cavitation (HC) and electrocatalytic membrane (ECM) can be used in the oxidative degradation of oil pollutants, and a combined method with both techniques can improve the overall degradation efficiency. The results of this study show that HC could promote the dispersion and dissolution of oil in water at 35°C with an inlet pressure of 0.30 MPa and cavitation time of 2 h. Under these conditions, the oil concentration increased from initial 90 mg/L to 215 mg/L, at which point the effect of the degradation by HC could be clearly detected. Then, when the cavitation time was 5 h, the oil concentration decreased from maximal 215 mg/L to 139 mg/L. Subsequently, at a current density of 2 mA/cm2, pH 6, residence time of 3.8 min, electrode spacing of 40 mm and solution temperature of 30°C, the removal rate of oil pollutants reached up to 98.81%. Gas chromatography mass spectrometry (GC-MS) analysis shows that ECM could degrade oil pollutants more effectively. Therefore the combination of HC and ECM was demonstrated to be an efficient method for the removal of oil pollutants in water.

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.

To study an emergency power based on solar battery charging. Based on the electric-generation principle of solar panel, solar energy is changed into electrical energy. Through voltage conversion circuit and filter circuit, electrical energy is stored in the energy storage battery. The emergency power realizes the conversion from solar energy to electrical energy. The battery control unit has the function of PWM (Pulse-Width Modulation) charging, overcharging protection, over-discharging protection and over-current protection. It also realizes the fast and safe charging of energy storage battery. The emergency power could provide both 12V AC power for emergency equipment such as miniature PSA oxygen concentrator and 5V USB for electronic equipment (mobile phone, GPS device, rechargeable light, etc.).

To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane. The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421L/(m(2)·hr) under the trans-membrane pressure of 0.03bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10mg/L between pH3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater.

A facile method was developed to prepare antimony doped tin oxide (Sb-SnO2)/carbon aerogel (CA) for use as an electrocatalytic filtration membrane. The preparation process included synthesis of a precursor sol, impregnation, and thermal decomposition. The Sb-SnO2, which was tetragonal in phase with an average crystallite size of 10.8 nm, was uniformly distributed on the CA surface and firmly attached via carbon-oxygen-tin chemical bonds. Preliminary filtration tests indicated that the Sb-SnO2/CA membrane had a high rate of total organic carbon removal for aqueous tetracycline owing to its high current efficiency and electrode stability.

The NaA zeolite membrane was synthesized on the surface of TiO 2 /α-Al 2 O 3 composite support with TiO 2 as modifier of α-Al 2 O 3 porous tubular ceramic membrane support by crystallization method. The structure characterization indicated that the TiO 2 of the support surface could effectively improve the surface properties of the support. It didn’t affect the crystallization of NaA synthesis liquid and synthesis process of NaA zeolite membrane. There were no obvious defects between the crystal particles with size of approximate 6μm. The perfect and complete membrane with thickness of approximate 15μm combined closely with support to connection together by TiO 2 modified. The oxygen permeability of the membrane on TiO 2 /α-Al 2 O 3 composite support improves of 47% compared with that of α-Al 2 O 3 support. So the process of TiO 2 modifying the surface of α-Al 2 O 3 support should increase the oxygen permeability of the NaA zeolite membrane.

A design of detection system about dissolved oxygen is proposed based on C8051F020 which is an integrated mixed-signal system-on-chip MCU. It can quickly and accurately detect Dissolved Oxygen (DO) in the water. The software adopts Multi-sensor data fusion and temperature compensation to eLiminate the effects of temperature and the sensor itself, enhance the measurement precision. And serial communication of RS232 is used in this system which can sent data to upper PC. The system is of high practicabiLity.

Glucose oxidase biosensors were fabricated by vacuum-impregnation of a glucose oxidase in a polyvinyl alcohol (PVA) aqueous solution into carbon nanotube non-woven fabrics (CNTFs). The performance of the biosensor was evaluated by an electrochemical method, using the biosensors as working electrode, Pt wire as a counter electrode and Ag/AgCl as a reference electrode. The electrical conductivity of the CNTFs was tested with a four-probe method. Tensile strength was measured by a tensile tester. Results show that the response currents of the biosensors increase linearly with the glucose content in aqueous solutions. The linear range is from 2.5 to 30 mmol/L, the detection limit is 2.5 mmol/L and the response time is about 10 s. An acid treatment of the CNTF with 65% HNO3 can increase the response current.

The removal of petroleum-based pollutants from water by ozone is studied. The results indicate that the oxidation effect of ozone on the petroleum-based pollutants is associated with water temperature, pH, dosage of ozone and reaction time. The removal efficiency of petroleum-based pollutants increases with the rise of temperature, pH, amount of ozone and reaction time, and reaches 83% under the conditions that the ratio of ozone to petroleum-based pollutants is 1:1 and the reaction time is 10 min. GC/MS analysis reveals that the amount of petroleum-based pollutants in water is reduced 39% from the previous 61 organics to 37 organics, the total peak area is reduced 36% after ozone oxidation treatment. Therefore, ozone has an excellent effect on the removal of petroleum-based pollutants and can be applied in the treatment of petroleum wastewaters.