Youtao Song

Microwave-induced carbon nanotubes catalytic degradation of organic pollutants in aqueous solution

In this study, a new catalytic degradation technology using microwave induced carbon nanotubes (MW/CNTs) was proposed and applied in the treatment of organic pollutants in aqueous solution. The catalytic activity of three CNTs of 10-20nm, 20-40nm, and 40-60nm diameters were compared. The results showed that organic pollutants such as methyl orange (MO), methyl parathion (MP), sodium dodecyl benzene sulfonate (SDBS), bisphenol A (BPA), and methylene blue (MB) in aqueous solution could be degraded effectively and rapidly in MW/CNTs system. CNTs with diameter of 10-20nm exhibited the highest catalytic activity of the three CNTs under MW irradiation. Further, complete degradation was obtained using 10-20nm CNTs within 7.0min irradiation when 25mL MO solution (25mg/L), 1.2g/L catalyst dose, 450W, 2450MHz, and pH=6.0 were applied. The rate constants (k) for the degradation of SDBS, MB, MP, MO and BPA using 10-20nm CNTs/MW system were 0.726, 0.679, 0.463, 0.334 and 0.168min(-1), respectively. Therefore, this technology may have potential application for the treatment of targeted organic pollutants in wastewaters.

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 (5.0%)Er3+:Y3Al5O12/Pt-(TiO2-Ta2O5) nanocatalysts and application in sonocatalytic decomposition of ametryn in aqueous solution

(5.0%)Er3+:Y3Al5O12/Pt-(TiO2-Ta2O5) powder, as a high effective sonocatalyst, was prepared using sol-gel and calcination method. Then it was characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). In order to evaluate the sonocatalytic activity of the prepared (5.0%)Er3+:Y3Al5O12/Pt-(TiO2-Ta2O5) powder, the sonocatalytic decomposition of ametryn was studied. In addition, some influencing factors such as different Ti/Ta molar ratios on the sonocatalytic activity of the prepared (5.0%)Er3+:Y3Al5O12/Pt-(TiO2-Ta2O5) powder, catalyst added amount with ultrasonic irradiation time and used times on the sonocatalytic decomposition efficiency were examined by using ion chromatogram determination. The experimental results showed that the best sonocatalytic decomposition ratio of ametryn were 77.50% based on the N atom calculation and 95.00% based on the S atom calculation, respectively, when the conditions of 10.00mg/L initial concentration, 1.00g/L prepared (5.0%)Er3+:Y3Al5O12/Pt-(TiO2-Ta2O5) powder (Ti/Ta=1.00:0.25 heat-treated at 550°C for 3.0h) added amount, 150min ultrasonic irradiation (40kHz frequency and 300W output power), 100mL total volume and 25-28°C temperature were adopted. Therefore, the (5.0%)Er3+:Y3Al5O12/Pt-(TiO2-Ta2O5) composite nanoparticles could be considered as an effective sonocatalyst for decomposition of ametryn in aqueous solution.

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.

Preparation of Er(3+):Y3Al5O12/KNbO3 composite and application in innocent treatment of ketamine by using sonocatalytic decomposition method.

A novel sonocatalyst, Er(3+):Y3Al5O12/KNbO3 composite, was synthesized, and then, characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). In order to evaluate the sonocatalytic activity of prepared Er(3+):Y3Al5O12/KNbO3 composite, the sonocatalytic degradation of ketamine, a kind of narcotic drug, was studied. In addition, some influencing factors such as mass ratio, heat-treated temperature and heat-treated time on the sonocatalytic activity of prepared Er(3+):Y3Al5O12/KNbO3 powders and ultrasonic irradiation time on the sonocatalytic degradation of ketamine were examined by using GC-MS machine. The experimental results showed that the Er(3+):Y3Al5O12/KNbO3 composite is a good sonocatalyst in the field of ultrasonic chemistry and the sonocatalytic degradation was an effective method for the innocent treatment of ketamine.

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.

Photodegradation of dissolved organic matter in ice under solar irradiation.

The photodegradation behavior of dissolved organic matter (DOM) with different origins in ice under solar irradiation was investigated. Exposure to sunlight at 2.7 × 10(5) J m(-2) resulted in dissolved organic carbon (DOC) reductions of 22.1-36.5% in ice. The naturally occurring DOM had higher photodegradation potentials than the wastewater-derived DOM in ice. Ultraviolet (UV)-absorbing compounds in DOM, regardless of DOM origin, had much higher photodegradation potentials than gross DOC in ice. The susceptibility of UV-absorbing compounds with natural origin to sunlight exposure in ice was higher than those derived from wastewater. Trihalomethane (THM) precursors were more susceptible to photochemical reactions than gross DOC and haloacetic acid (HAA) precursors in ice. THM precursors in naturally occurring DOM were more photoreactive than those in wastewater-derived DOM in ice, while the photoreactivity of HAA precursors in ice was independent of DOM origin. In ice, the photoreactivity of humic-like fluorescent materials, regardless of DOM origin, was higher than that of gross DOC and protein-like fluorescent materials. DOC reductions caused by sunlight irradiation were found to be negatively correlated to DOC levels, and positively correlated to the aromaticity of DOM. The photodegradation of both wastewater-derived and naturally occurring DOM in ice was significantly facilitated at both acid and alkaline pH, as compared to neutral pH. The photodegradation of DOM in ice, regardless of the origin, was facilitated by nitrate ion [Formula: see text] , nitrite ion [Formula: see text] , ferric ion (Fe(3+)) and ferrous ion (Fe(2+)), and on the other hand, was inhibited by chloridion ion (Cl(-)) and copper ion (Cu(2+)).

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.

Microwave hydrothermal-assisted preparation of novel spinel-NiFe 2 O 4 /natural mineral composites as microwave catalysts for degradation of aquatic organic pollutants

In this study, novel spinel-NiFe2O4/natural mineral (sepiolite, diatomite and kaolinite) composites were developed using microwave (MW) hydrothermal method, and applied in MW-induced catalytic degradation (NiFe2O4/natural mineral/MW) of organic pollutants such as sodium dodecyl benzene sulfonate (SDBS), azo fuchsine (AF), methyl parathion (MP), and crystal violet (CVL) in solution. Catalytic activities of three NiFe2O4/natural mineral composites were compared. The effects of material synthesis process parameters such as molar ratios of NiFe2O4 and natural mineral, and pH of precursor solutions for synthesizing catalysts, and degradation parameters such as MW irradiation time and catalyst reuse cycles were also investigated. The principle on NiFe2O4/natural mineral/MW degradation was provided. The results reveal that organic pollutants in wastewater can be removed completely using NiFe2O4/natural mineral/MW within minutes. NiFe2O4/sepiolite shows higher catalytic activity than the others. The calculated degradation rate constants are 1.865, 0.672, 0.472, and 0.329 min-1 for SDBS, AF, MP, and CVL, respectively, using NiFe2O4/sepiolite/MW system. The performance of NiFe2O4/natural mineral can be maintained for three reuse cycles. Active species OH, O2-, and h+ play main roles in NiFe2O4/sepiolite/MW degradation. Hence, NiFe2O4/sepiolite/MW technology with rapid and cost-effective degradation, magnetic separation, and no secondary pollution, demonstrates to be promising in treating organic contaminants in wastewater.