光催化降解染料ZnO催化剂的性能

光催化法是20世纪70年代发展起来的新型水处理技术，即以某些半导体材料为催化剂，利用光催化法来降解环境污染物。该方法工艺简单，成本较低，在常温下能使大多数不能或难于生物降解的有毒有机物彻底氧化分解。近年来研究最多的是TiO2，由于其带隙较宽(3．2eV)，只能吸收波长λ≤387nm的紫外光，因此研制新型光催化剂仍是重要课题。     

纳米氧化锌光催化降解有机染料性能的研究

用自制的纳米ZnO在室外阴天、太阳光照射、室内紫外灯照射等条件下对不同有机染料的降解性能作了系统的研究。结果表明纳米ZnO在太阳光照射条件下对弱碱性有机染料溶液的降解效果较好。本文还比较了自制纳米ZnO与纳米TiO2对有机染料的降解性能，结果表明ZnO的降解效果优于TiO2。     

Zinc oxide mediated heterogeneous photocatalytic degradation of organic species under solar radiation

The photocatalytic decomposition of eco-persistent toluene, salicylic acid and 4-chlorophenol with sun light in an oxygenated aqueous suspension has been studied under nanocrystalline hexagonal ZnO photocatalyst. The effect of substrate temperature onto the structural, morphological and photoactive properties has been investigated. The degradation of toluene, salicylic acid and 4-chlorophenol were achieved using a photoelectrochemical reactor module equipped with synthesized ZnO electrodes. Kinetic parameters have been investigated in terms of a first order rate equation. The rate constant (-k) for this heterogeneous photocatalysis was evaluated as a function of the initial concentration of original species. Substantial reduction in concentrations of toluene, salicylic acid and 4-chlorophenol was achieved as analyzed from COD and TOC studies. The mechanism for the degradation of toluene, salicylic acid and 4-chlorophenol could be explained on the basis of Langmuir-Hinshelwood mechanism.     

Chalcogen-doped zinc oxide nanoparticles for photocatalytic degradation of Rhodamine B under the irradiation of ultraviolet light

In the present work, the chalcogen (Se²⁺)-doped ZnO nanoparticles (SeZO-NPs) were synthesized using sol-gel precipitation method and tested for photocatalytic degradation of Rhodamine B (RhB). X-ray diffraction pattern of SeZO-NPs showed the hexagonal wurtzite crystal structure regardless of Se concentration. The band edge and defect-level emissions of SeZO-NPs were determined by using the photoluminescence spectra with the excitation source of 370 nm. The bandgap, E_g, of SeZO-NPs was measured from diffused reflectance spectroscopy, which increased from 3.22 to 3.26 eV as Se concentration increased from 0 to 10 wt.%. The highest specific surface area and lowest pore size of 5-SeZO-NPs were observed to be 36.42 m²/g and 13.48 nm, respectively. The photocatalytic degradation of SeZO-NPs was measured under the illumination of ultraviolet (UV) light. The double donor (Se) played an important role toward photodegradation of RhB via reducing the recombination of charge carriers. The highest photocatalytic degradation (98.23%) and mineralization were achieved for the sample 5-SeZO (Se: 5 wt.%). The improved photocatalytic performance of 5-SeZO was attributed to the optimum Se dopant concentration for the production of more reactive oxygen species because of effective separation of charge carriers in UV light.     

New progress in photocatalytic degradation of bisphenol A as representative endocrine disrupting chemicals

Endocrine disrupting chemicals (EDCs) are a kind of hazardous pollutants in the environment which threaten the health of humans and animals at very low concentrations. EDCs and corresponding processing methods have been the hottest topics of scientific research in recent years. In this article, the classification, risks, occurrence, fate, and treatment methods of EDCs were briefly summarized. Among all of the treatment methods, photocatalytic degradation was one of the most ideal methods with bright prospects for BPA removal in the future. We summarized several problems restricting the efficiency of photocatalytic degradation and the latest progress, and proposed some suggestions on the improvement of photocatalytic degradation. Finally, mechanism of BPA's photocatalytic degradation had been summarized on the basis of free radical theory. New progress and opinions were provided in this review and we wish to provide a helpful guidance of EDCs removal for international readers.     

Photocatalytic degradation of anionic surfactant using zinc oxide nanoparticles

In this paper the photocatalytic degradation of anionic surfactant LABS was studied by a batch process using ZnO nanoparticles with diameter size of 20 nm catalyst on irradiation with UV light and their behavior comparatively examined with respect to ZnO commercial powder. The effect of parameters such as initial surfactant concentration, initial solution pH has been studied. Also degradation at LABS in the presence of an electron acceptor like potassium peroxydisulfate and effect of anion presence on surfactant degradation has been systematically investigated. The obtained result demonstrated a high photocatalytic activity of nanosize semiconducting particles.     

载钛羟基磷灰石光催化降解内分泌干扰物双酚A

对载钛羟基磷灰石（TiHAP）进行了透射电镜、X射线衍射、紫外-可见光谱和Zeta电位表征,并应用液相色谱-质谱技术对比了TiHAP和P25 TiO₂对环境内分泌干扰物双酚A（BPA）的吸附和光催化降解性能,探讨了富里酸和Fe³⁺对TiHAP薄膜光催化性能的影响。结果表明,TiHAP和TiO₂粉体对BPA的吸附符合Langmuir吸附等温方程,且前者吸附性能更大。TiHAP薄膜光催化降解BPA的性能优于TiO₂薄膜;富里酸和Fe³⁺对TiHAP和TiO₂薄膜光催化性能的影响趋势不同,从能带结构、电子转移和吸光性等角度分析了性能不同的原因。本结果可以为应用TiHAP降解环境内分泌干扰物提供依据。     

Parameters affecting carbofuran photocatalytic degradation in water using ZnO nanoparticles

Carbofuran photodegradation in water using zinc oxide nanoparticles as a catalyst was examined as well as some parameters influencing its percentage degradation rate such as zinc oxide load, initial concentration of carbofuran, the temperature of the reaction, the initial pH of the solution, and doping of zinc oxide nanoparticles with 5% (w:w) silver. Zinc oxide and Ag-doped zinc oxide nanoparticles were produced using solvothermal and photoreduction methods, respectively, and silver doping effects on the structural, optical, and photocatalytic properties of zinc oxide nanoparticles were investigated using XRD, UV-VIS spectrophotometer, TEM, SEM, SEM/EDX, and FTIR. The average diameter of the synthesized samples was 26.6, 30.55 nm for undoped zinc oxide and Ag-doped zinc oxide, respectively. Zinc oxide doping with silver did not change the shape of the zinc oxide crystal, but decreased the reflection in the visible region, as well as the energy of the bandgap, and increased the zinc oxide photocatalytic activity.     

Enhancement of oxygen vacancies and solar photocatalytic activity of zinc oxide by incorporation of nonmetal

B-doped ZnO and N-doped ZnO powders have been synthesized by mechanochemical method and characterized by TG-DTA, XRD, SEM-EDX, XPS, UV-visible and photoluminescence (PL) spectra. X-ray diffraction data suggests the hexagonal wurtzite structure for modified ZnO crystallites and the incorporation of nonmetal expands the lattice constants of ZnO. The room temperature PL spectra suggest more number of oxygen vacancies exist in nonmetal-doped ZnO than that of undoped zinc oxide. XPS analysis shows the substitution of some of the O atoms of ZnO by nonmetal atoms. Solar photocatalytic activity of B-doped ZnO, N-doped ZnO and undoped ZnO was compared by means of oxidative photocatalytic degradation (PCD) of Bisphenol A (BPA). B-doped ZnO showed better solar PCD efficiency as compare to N-doped ZnO and undoped ZnO. The PCD of BPA follows first order reaction kinetics. The detail mechanism of PCD of Bisphenol A was proposed with the identification of intermediates such as hydroquinone, benzene-1,2,4-triol and 4-(2-hydroxypropan-2-yl) phenol.     

Ring-fluorinated fluoresceins as an organic photosensitizer for dye-sensitized solar cells using nanocrystalline zinc oxide

Four kinds of ring-fluorinated fluoresceins and sulfofluorescein from tetrafluororesorcinol and/or tetrafluorophthalic anhydride have been synthesized and the photochemical properties of the zinc oxide nanocrystalline electrode sensitized by the ring-fluorinated fluoresceins were investigated.     

Kinetic modelling and proposed mechanistic pathway for photocatalytic degradation of 4-aminopyridine using cuprous oxide nanoparticles

Research on Chemical Intermediates - Cuprous oxide nanoparticles (Cu2O NPs) were synthesized using Tabernaemontana divaricate leaves extract, a reducing and stabilizing agent. Prepared Cu2O NPs...     

Chemical etching of zinc oxide for thin-film silicon solar cells

Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided.     

The photocatalytic degradation of cationic surfactant from wastewater in the presence of nano-zinc oxide using Taguchi method

The photocatalytic degradation of cetyl pyridinium chloride (CPC) has been investigated in aqueous phase using ultraviolet (UV) and ZnO nanopowder. Kinetic analysis showed that the extent of surfactant photocatalytic degradation can be fitted with pseudo-first-order model and photochemical elimination of CPC could be studied by Taguchi method. Our experimental design was based on testing five factors, i.e., dosage of K₂S₂O₈, concentration of CPC, amount of ZnO, irradiation time and initial pH. Each factor was tested at four levels. The optimum parameters were found to be pH 5.0; amount of ZnO 11 mg; K₂S₂O₈ 3 mM; CPC 10 mg/L; irradiation time, 8 h.     

Biosynthesis of zinc oxide nanoparticles using Euphorbia milii leaf constituents: Characterization and improved photocatalytic degradation of methylene blue dye under natural sunlight

A facile biosynthesis route was followed to prepare zinc oxide nanoparticles (ZnO NPs) using Euphorbia milii (E. milii) leaf constituents. The SEM images exhibited presence of spherical ZnO NPs and the corresponding TEM images disclosed monodisperse nature of the ZnO NPs with diameter ranges between 12 and 20 nm. The Brunauer–Emmett–Teller (BET) analysis revealed that the ZnO NPs have specific surface area of 20.46 m²/g with pore diameter of 2 nm–10 nm and pore volume of 0.908 cm³/g. The EDAX spectrum exemplified the existence of Zn and O elements and non-appearance of impurities that confirmed pristine nature of the ZnO NPs. The XRD pattern indicated crystalline peaks corresponding to hexagonal wurtzite structured ZnO with an average crystallite size of 16.11 nm. The FTIR spectrum displayed strong absorption bands at 512 and 534 cm^?1 related to ZnO. The photocatalytic action of ZnO NPs exhibited noteworthy degradation of methylene blue dye under natural sunlight illumination. The maximum degradation efficiency achieved was 98.17% at an illumination period of 50 min. The reusability study proved considerable photostability of the ZnO NPs during photocatalytic experiments. These findings suggest that the E. milii leaf constituents can be utilized as suitable biological source to synthesis ZnO NPs for photocatalytic applications.     

氧化锌纳米棒的水热合成及其光催化性能

以分析纯ZnO作为锌源、NaOH为矿化剂、盐酸为反应溶液pH调节剂,利用水热反应制备了花状ZnO纳米棒;采用扫描电子显微镜和X射线衍射仪分析了产物的形貌和结构,考察了水热温度以及Zn2+和OH-浓度比对产物形貌的影响;以甲基橙为目标降解物,采用紫外-可见分光光度计研究了ZnO纳米棒的光催化性能.结果表明,在水热反应温度80℃、Zn2+/OH-浓度比1∶7.5条件下所得ZnO纳米棒呈花状聚合,直径约为200nm,长度约为2μm,具有六方纤锌矿结构.当甲基橙初始浓度为30 mg.L-1、ZnO纳米棒的投放量为1.5g.L-1时,以300W紫外灯照射150min,甲基橙的降解率可达90%.     

Ag-single atoms modified S1.66-N1.91/TiO2-x for photocatalytic activation of peroxymonosulfate for bisphenol A degradation

In this study,Ag_0.23/(S_1.66-N_1.91/TiO_2-x) single-atom photocatalyst was synthesized by in-situ photoreducing of silver on S,N-TiO_2-x nanocomposite and used to degrade bisphenol A（BPA） through heterogeneous activation of potassium peroxymonosulfate（PMS） under visible-light illumination.The structure,physicochemical property,morphology,and electronic property were evalutated by X-ray diffraction（XRD）,Raman spectrum,X-ray photoelectron spectra（...     

Role of bio-derived zinc oxide nanoparticles in antifungal and photocatalytic activities

Research on Chemical Intermediates - Zinc oxide nanoparticles (ZnO-NPs) are known as a material in the treatment of environmental pollutions. In this study, ZnO-NPs were synthesized using...     

Effect of doped zinc species on the photocatalytic activity of gallium oxide for hydrogen production

Zn-doped Ga(2)O(3) samples were prepared by a homogeneous precipitation (HP) method, and the local structures of Zn ions and their photocatalytic activities for hydrogen production were examined. In the sample with low doping amount, the Zn(2+) ions substituted for the Ga(3+) ions in the Ga(2)O(3) photocatalyst and enhanced the photocatalytic activity, since they would improve the migration of the photoexcited electrons in the conduction band of the Ga(2)O(3) photocatalyst. In the sample with high doping amount, the Zn ions formed a composite ZnGa(2)O(4) phase in the bulk of the Ga(2)O(3) photocatalyst to decrease the photocatalytic activity in the present reaction.     

Electrochemical aptasensor for the determination of bisphenol A in drinking water

We present an electrochemical aptasensor for rapid and ultrasensitive determination of the additive bisphenol A (BPA) and for screening drinking water for the presence of BPA. A specific aptamer against BPA and its complementary DNA probe were immobilized on the surface of a gold electrode via self-assembly and hybridization, respectively. The detection of BPA is mainly based on the competitive recognition of BPA by the immobilized aptamer on the surface of the electrode. The electrochemical aptasensor enables BPA to be detected in drinking water with a limit of detection as low as 0.284 pg?mL^?1 in less than 30 min. This extraordinary sensitivity makes the method a most powerful tool for on-site monitoring of water quality and food safety.