Guowei Wang

Preparation of a novel sonocatalyst, Au/NiGa2O4-Au-Bi2O3 nanocomposite, and application in sonocatalytic degradation of organic pollutants

A novel nanocomposite, Au/NiGa2O4-Au-Bi2O3, as an effective sonocatalyst was prepared through hydrothermal process and high-temperature calcination methods, and then characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The sonocatalytic activity of Au/NiGa2O4-Au-Bi2O3 nanocomposite was detected through the degradation of some organic pollutants under ultrasonic irradiation. Furthermore, the influences of mass ratio of NiGa2O4 and Bi2O3, ultrasonic irradiation time and used times on the sonocatalytic degradation efficiency were investigated by using Total Organic Carbon (TOC) and UV-vis spectroscopy. The experimental results showed that, because of the existence of Au nanoparticles (AuNPs) served as both conductive passageway and co-catalyst, the nanocomposite sonocatalyst (Au/NiGa2O4-Au-Bi2O3) displayed an excellent sonocatalytic activity in degradation of some organic pollutants under ultrasonic irradiation.

Preparation of Er3+:Y3Al5O12/WO3-KNbO3 composite and application in treatment of methamphetamine under ultrasonic irradiation

Er3+:Y3Al5O12/WO3-KNbO3 composite powder as an effective sonocatalyst was prepared via collosol-gelling-hydrothermal and high-temperature calcination methods. The textures of materials were observed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). In order to estimate the sonocatalytic activity of Er3+:Y3Al5O12/WO3-KNbO3 composite powder, the sonocatalytic degradation of methamphetamine (MAPA) was performed. Furthermore, the influences of mass ratio of WO3 and KNbO3, ultrasonic irradiation time, catalyst addition amount, initial methamphetamine (MAPA) concentration and used times on the sonocatalytic degradation of methamphetamine (MAPA) caused by Er3+:Y3Al5O12/WO3-KNbO3 composite powder were investigated by using gas chromatography. Under optimal conditions of 1.00g/L Er3+:Y3Al5O12/WO3-KNbO3 addition amount and 10.00mg/L methamphetamine (MAPA) initial concentration, 68% of methamphetamine (MAPA) could be removed after 150min ultrasonic irradiation. The experimental results showed that the Er3+:Y3Al5O12/WO3-KNbO3 as sonocatalyst displayed an excellent sonocatalytic activity in degradation of methamphetamine (MAPA) under ultrasonic irradiation.

Hydrothermal-precipitation preparation of CdS@(Er3+:Y3Al5O12/ZrO2) coated composite and sonocatalytic degradation of caffeine

Here, we reported a novel method to dispose caffeine by means of ultrasound irradiation combinated with CdS@(Er3+:Y3Al5O12/ZrO2) coated composite as sonocatalyst. The CdS@(Er3+:Y3Al5O12/ZrO2) was synthesized via hydrothermal-precipitation method and then characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and UV-vis diffuse reflectance spectra (DRS). After that, the sonocatalytic degradation of caffeine in aqueous solution was conducted adopting CdS@(Er3+:Y3Al5O12/ZrO2) and CdS@ZrO2 coated composites as sonocatalysts. In addition, some influencing factors such as CdS and ZrO2 molar proportion, caffeine concentration, ultrasonic irradiation time, sonocatalyst dosage and addition of several inorganic oxidants on sonocatalytic degradation of caffeine were investigated by using UV-vis spectra and gas chromatograph. The experimental results showed that the presence of Er3+:Y3Al5O12 could effectively improve the sonocatalytic degradation activity of CdS@ZrO2. To a certain extent some inorganic oxidants can also enhance sonocatalytic degradation of caffeine in the presence of CdS@(Er3+:Y3Al5O12/ZrO2). The best sonocatalytic degradation ratio (94.00%) of caffeine could be obtained when the conditions of 5.00mg/L caffeine, 1.00g/L prepared CdS@(Er3+:Y3Al5O12/ZrO2), 10.00mmol/LK2S2O8, 180min ultrasonic irradiation (40kHz frequency and 50W output power), 100mL total volume and 25-28°C temperature were adopted. It seems that the method of sonocatalytic degradation caused by CdS@(Er3+:Y3Al5O12/ZrO2) displayspotentialadvantages in disposing caffeine.

Preparation of Ce 4+ -doped BaZrO 3 by hydrothermal method and application in dual-frequent sonocatalytic degradation of norfloxacin in aqueous solution

In this paper, the dual-frequent sonocatalytic degradation of norfloxacin (NOR), an antibiotic, caused by Ce4+-doped BaZrO3 is studied. The used Ce4+-doped BaZrO3 as a novel sonocatalyst with highly efficient and stable sonocatalytic activity is prepared via hydrothermal method. The prepared sample is characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Fourier transform infrared spectra (FT-IR) in order to investigate the structure, morphology and chemical composition. The dual-frequent sonocatalytic activity of prepared Ce4+-doped BaZrO3 powder is evaluated through sonocatalytic degradation of norfloxacin (NOR) as a model organic pollutant. Some influencing factors such as single/dual-frequent ultrasonic frequent, cerium and zirconium molar proportions, ultrasonic irradiation time and used times are studied in detail by using UV-vis spectra. The generated reactive oxygen species (ROS) during the dual-frequent sonocatalytic degradation process of norfloxacin (NOR) are confirmed by using two different trapping agents. The holes (h+) and hydroxyl radicals (OH) are identified and the holes plays a major role during the oxidation process. Finally, the possible mechanism for the dual-frequent sonocatalytic degradation of norfloxacin (NOR) caused by Ce4+-doped BaZrO3 is proposed. The experimental results show that the Ce4+-doped BaZrO3 displays a good sonocatalytic activity under dual-frequent ultrasonic irradiation. Under optimal conditions, the most of norfloxacin (NOR) can be removed under dual-frequent ultrasonic irradiation for 150 min.

A novel Z-scheme sonocatalyst system, Er 3+ :Y 3 Al 5 O 12 @Ni(Fe 0.05 Ga 0.95 ) 2 O 4 -Au-BiVO 4 , and application in sonocatalytic degradation of sulfanilamide

A novel Z-scheme coated composite, Er3+:Y3Al5O12@Ni(Fe0.05Ga0.95)2O4-Au-BiVO4, was designed for sonocatalytic degradation of sulfanilamide and fabricated by sol-hydrothermal and calcination methods. The prepared sample was characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), UV-vis diffuse reflectance spectra (DRS), fourier transform infrared (FT-IR) spectra, Raman spectra and photoluminescence (PL) spectra. In Er3+:Y3Al5O12@Ni(Fe0.05Ga0.95)2O4-Au-BiVO4, Ni(Fe0.05Ga0.95)2O4 and BiVO4 form a Z-scheme sonocatalytic system, Er3+:Y3Al5O12 as an up-conversion luminescence agent (from visible-light to ultraviolet-light) provides the ultraviolet-light for satisfying the energy demand of wide band-gap Ni(Fe0.05Ga0.95)2O4 and Au nanoparticles as co-catalyst forms more active sites to enrich electrons. Also, Au nanoparticles as conductive channels promotes the electrons (e-) from conduction band of BiVO4 to transfer to valence band of Ni(Fe0.05Ga0.95)2O4. Due to the characteristics of valence state diversity, the Fe3+ and V5+ constitute a redox reaction recombination system, which can also push electrons (e-) on conduction band of BiVO4 to quickly transfer to valence band of Ni(Fe0.05Ga0.95)2O4. The sonocatalytic activity of Er3+:Y3Al5O12@Ni(Fe0.05Ga0.95)2O4-Au-BiVO4 nanocomposite was detected through degradation of sulfanilamide under ultrasonic irradiation. A high sonocatalytic degradation ratio (95.64%) of sulfanilamide can be obtained when the conditions of 10.00 mg/L sulfanilamide, 1.00 g/L Er3+:Y3Al5O12@Ni(Fe0.05Ga0.95)2O4-Au-BiVO4, 300 min ultrasonic irradiation and 100 mL total volume were adopted. Some factors such as ultrasonic irradiation time and cycle number on the sonocatalytic degradation efficiency are also investigated by using TOC and UV-vis spectroscopy. Subsequently, the effects of hydroxyl radicals (OH) and hole scavengers were investigated to elaborate the mechanism. The researches show that the prepared Z-scheme Er3+:Y3Al5O12@Ni(Fe0.05Ga0.95)2O4-Au-BiVO4 coated composite displayed an excellent sonocatalytic activity in degradation of sulfanilamide under ultrasonic irradiation.