Yuanhua Xie

Synthesis of hollow lantern-like Eu(III)-doped g-C 3 N 4 with enhanced visible light photocatalytic perfomance for organic degradation

A series of hollow structure lantern-like Eu(III)-doped g-C3N4 (xEu-CN, x = 1, 2, 3) was firstly synthesized by heating a mixture of melamine, HNO3 and Eu2O3 at 500 °C for 2 h. The phase, morphology and optical properties of the serial xEu-CN samples were characterized by different techniques, including TEM, XRD, FT-IR, SEM, XPS, BET, UV-vis, PL, photocurrent, and EIS. The results indicated that Eu doping extraordinarily enhanced the photocatalytic activity of pure g-C3N4, and the 2Eu-CN exhibited the highest photocatalytic performance with a 98% (82%) degradation rate for RhB (TC), 6.03 (1.71)-fold of pure g-C3N4(CN). The higher photocatalytic efficiency is ascribed to the synergy effect of Eu(III) and the hollow structures, which led to a larger surface specific area, bandgap narrowing, enhanced light harvesting ability and efficient charge separation.

Effects of Ni doping contents on photocatalytic activity of B-BiVO 4 synthesized through sol-gel and impregnation two-step method

Abstract To enhance the photocatalytic activity of B-BiVO 4 , Ni-doped B-BiVO 4 photocatalyst (Ni-B-BiVO 4 ) was synthesized through sol-gel and impregnation method. The photocatalysts were characterized by XPS, XRD, SEM, EDS, BET and UV-Vis DRS techniques. The results showed that single or double doping did not change the crystalline structure and morphology, but the particle size decreased with Ni doping. The band gap energy absorption edge of Ni-B-BiVO 4 shifted to a longer wavelength compared with undoped, B or Ni single doped BiVO 4 . More V 4+ and surface hydroxyl oxygen were observed in BiVO 4 after Ni-B co-doping. When the optimal mass fraction of Ni is 0.30%, the degradation rate of MO in 50 min is 95% for 0.3Ni-B-BiVO 4 sample which also can effectively degrade methyl blue (MB), acid orange (AOII) II and rhodamine B (RhB). The enhanced photocatalytic activity is attributed to the synergistic effects of B and Ni doping.

Filtration performance comparison of a metal membrane and an organic membrane in bioreactor

AbstractA metal membrane and a polyethersulfone (PES) membrane were compared in this study. The surface morphology, inherent resistance, and critical flux of the membranes were first investigated. The two membranes were then placed in an activated sludge reactor to treat municipal sewage. The two membranes showed similar removal efficiencies of chemical oxygen demand (COD), ammonia, and total nitrogen (TN). The average effluent COD removal efficiencies, effluent ammonia, and effluent TN removal efficiencies were approximately 94.00%, 0.19 mg/L, and 28.22%, respectively. The metal membrane showed lower inherent membrane resistance of 0.27 × 1011 m−1, higher critical flux of 0.7 m3/(m2 d), higher anti-fouling ability, and slower transmembrane pressure increasing rate compared with the PES membrane. The main fouling mechanism of the metal membrane was cake formation, whereas that of the PES membrane was pore blocking. The metal membrane was easy to recover after fouling. The results of the study suggest that...

Dynamic Model and Numerical Simulation of Particle Motion in Rotation Flow Field of Centrifuge

In this study, in order to determine the size, configuration, rotating speed and other parameters of centrifuge separator, particle motion was simulated by the method of numerical integration of Runge-Kutta. For setting up of dynamic model, besides of forces of gravity, buoyancy, drag force and centrifugal force, the forces of imagination mass force, Basset force, Saffman lift force and pressure gradient force were considered. As the results, it was found that there were some relations among the length of drum, the particle diameter and the revolution of drum. There exist much differences of particle motion between different particles in various sizes. The visualization experiments were carried out to verify the calculated results. The experiment and calculation results were suited well.

Treatment of Short-chain Nonylphenol Polyethoxylates by the Technique of Combing Biological Contact Oxidation with an Anoxic/oxic Membrane Bioreacto

The technique of combing biological contact oxidation with an anoxic/oxic membrane bioreactor was designed for the treatment of short-chain nonylphenol polyethoxylates (SC-NPnEO, n<3). The temperature (T), dissolved oxygen (DO) and hydraulic retention time (HRT) were selected as influence factors by an orthogonal experiment of three factors and three levels. Degradation effect of NPEO 0~5 and other components were selected as the evaluation index for the orthogonal experiment, evaluating the influence degree of each parameter to the degradation of the target pollutant, and determining the optimum condition of the system operation. The results showed that the removal rate of COD and NH4-N was stable at more than 85%, and the average removal rate of NPEO0~5 was remained above 98%. The optimum operation parameters of the system were achieved as temperature of 33°C, DO of 5mg/L, HRT of 24h. The largest influence factor to the degradation of total NPEO0~5 was DO, followed by temperature and HRT. These results showed the technique of combing biological contact oxidation with an anoxic/oxic membrane bioreactor had good sludge retention capacity and shock load resistance capacity and efficient degradation of SC-NPnEO and water pollutants, has broad application prospects.