光催化臭氧法对化工制药废水的解毒和降解研究

采用光催化臭氧法(O_3/UV)对某化工制药高浓度毒性废水进行生化系统前的预处理的实验研究,考察了臭氧气体流量对有机物降解影响、O_3/UV对废水可生化性的影响。实验结果表明:光催化臭氧法(O_3/UV)对含有杀菌剂等的高浓度有毒化工制药废水的解毒效果明显,可明显提高废水的可生化性(BOD_5/COD)。     

A novel Ni doped BaTiO3/h-BN nanocomposite for visible light assisted enhanced photocatalytic degradation of textile effluent and phytotoxicity evaluation

The objective of this research is to synthesize novel Ni–BaTiO₃/h-BN nanocomposites. XRD, UV–Vis, PL, FT-IR, SEM, TEM, Zeta potential, XPS, BET, EIS, Mott- Schottky and LC-MS analyses were used to analyze the nanocomposite phase structure, band gap, electron-hole recombination rate, vibrational modes, morphology, elemental analysis stability, oxidation state, pore size distribution, and electron distribution. The nanocomposites have an average particle size of 32 nm, as measured using HR-TEM microscopy. The band gap of synthesized h-BN was found to be 3.82 eV, whereas the Ni–BaTiO₃/h-BN binary nanocomposite shifts it to 2.43 eV. The nanocomposite photocatalytic efficiency was used to degrade textile effluent, followed by a phytotoxicity assessment of real textile effluent. Furthermore, the photocatalytic treatment analysis revealed that the 40 mg Ni–BaTiO₃/h-BN catalyst degraded up to 81.4% and 86% against textile effluent and crystal violet (CV) dye within 120 min under visible light, respectively, and the concentrations of numerous Physico-chemical parameters of textile effluent have significantly decreased in deteriorated textile effluent. According to a pot study, the toxicity of the degraded textile effluent was reduced following photocatalytic treatment. To examine the mechanism, the photodegradation effectiveness of the catalyst was investigated utilizing various scavengers. From the scavenger study, it is found that the holes (h⁺) contribute more to the degradation process. In real textile dye wastewater, the Ni–BaTiO₃/h-BN nanocatalyst was proved to be an excellent and low-cost degrading technique.     

Photocatalytic degradation of dairy effluent using AgTiO2 nanostructures/polyurethane nanofiber membrane

Dairy effluent (DE) is environmentally toxic and needs special attention. Photocatalytic degradation of DE was studied using novel polyurethane (PU)-based membranes. Typically, silver–titanium dioxide nanofibers (AgTiO₂ NFs) and silver–titanium dioxide nanoparticles (AgTiO₂ NPs) were individually incorporated in PU electrospun nanofibers to overcome the mandatory sophisticated separation of the nanocatalysts, which can create a secondary pollution, after the treatment process. These nanomembranes were characterized in SEM, TEM, XRD and UV studies. The polymeric electrospun nanofibers were smooth and continuous, with an average diameter of about 550 nm, and held their nanofibrous morphology even after more than 2 h of photocatalytic degradation of DE, due to the good stability of PU in the aqueous solutions, which indicates good imprisoning of the functional photocatalysts. The PU–AgTiO₂ NPs and PU–AgTiO₂ NFs were effective materials for degradation of DE, even after two successive cycles. PU–AgTiO₂ NPs and PU–AgTiO₂ NFs showed a maximum degradation of 75% and 95%, respectively after 2 h. The significant enhancement of degradation in the PU–Ag–TiO₂ NPs and PU–Ag–TiO₂ NFs is attributed to the photoactivity of Ag–TiO₂ material under visible light irradiation.     

TiO2催化超声波降解钻井污水中CODCr技术研究

为寻求有效降解钻井污水CODCr的新方法,探讨了超声波及超声波和纳米TiO2联合降解钻井污水CODCr的效果,研究了各种因素对超声波催化降解钻井污水中CODCr的影响.在纳米锐钛型TiO2的作用下,二氧化钛超声波催化降解钻井污水的CODCr效果明显优于单纯使用超声波的降解.在超声波频率20 kHz,输出功率为50 W,TiO2催化剂投加质量浓度为0.5～1.0 g/L,pH为3.0,温度为30 ℃,钻井污水的CODCr初始浓度1 881.04 mg/L的条件下,80 min超声波催化处理后的CODCr降解率＞99.1%.     

Wide-bandgap HfO2-V2O5 nanowires heterostructure for visible light-driven photocatalytic degradation

A novel HfO₂/V₂O₅ nanocomposite has been fabricated for use as photocatalyst. HfO₂ nanoparticles (NPs) were deposited on V₂O₅ using a precipitation method. Both commercial V₂O₅ particles and microwave-assisted hydrothermal (MAH)-synthesized V₂O₅ nanowires (NWs) were used. We demonstrate that the HfO₂/V₂O₅ nanocomposite exhibits better photodegradation efficiency than the V₂O₅. The photodegradation reaction constant of the HfO₂/V₂O₅ nanocomposite is more than 66% higher than that of the V₂O₅. The wide-bandgap, transparent HfO₂ effectively reduces the electron-hole recombination by proving defect levels to quench the recombination. A plausible band structure is proposed to support the existence of these defect levels.     

Controlled synthesis of Fe3O4@SnO2/RGO nanocomposite for microwave absorption enhancement

A ternary nanocomposite of Fe₃O₄@SnO₂/reduced graphene oxide (RGO) with different contents of SnO₂ nanoparticles was synthesized by a simple and efficient three-step method. The transmission electron microscopy and field emission scanning electron microscopy characterization display that plenty of Fe₃O₄@SnO₂ core–shell structure nanoparticles are well distributed on the surface of RGO sheets. The X-ray diffractograms show that the products consist of highly crystallized cubic Fe₃O₄, tetragonal SnO₂ and disorderedly stacked RGO sheets. The magnetic hysteresis measurement reveals the ferromagnetic behavior of the products at room temperature. The microwave absorption properties of paraffin containing 50 wt% products were investigated at room temperature in the frequency range of 2–18 GHz by a vector network analyzer. The electromagnetic data show that the maximum reflection loss is −45.5 dB and −29.5 dB for Fe₃O₄@SnO₂/RGO-1 and Fe₃O₄@SnO₂/RGO-2 nanocomposite, respectively. Meanwhile, the reflection loss less than −10 dB is up to 14.4 GHz and 13.8 GHz for Fe₃O₄@SnO₂/RGO-1 and Fe₃O₄@SnO₂/RGO-2 nanocomposite, respectively. It is believed that such nanocomposite could be used as promising microwave absorbers.     

钆掺杂二氧化钛纳米管光催化降解制药废水

采用阳极氧化法制备TiO2纳米管阵列,并在制备TiO2纳米管阵列的同时掺杂钆元素,形成钆掺杂TiO2纳米管阵列,研究其光催化降解制药废水的性能。结果表明,经过450℃煅烧的催化剂,在碱性条件下,钆掺杂浓度为0.007 5 mol/L时,催化效果最好,光催化5 h后,制药废水降解率达到97.41%,且该催化剂稳定性好,可重复使用。     

V2O5负载量对V2O5／TiO2催化剂SCR法脱硝的影响

以TiO2载体,采用浸渍法制备了不同V2O5负载量的用于选择性催化还原NOx的V2O5／TiO2催化剂。利用BET,SEM和Ⅺ①,对不同V2O5负载量的催化剂组成、结构、形貌和性能进行了表征,考察不同V2O5负载量对催化剂制备的影响。结果表明制备的催化剂具有较多的中孔和微孔,催化剂中V2O5含量的增加,会降低催化剂的表面积;V2O5含量为2％的V2O5／TiO2催化剂样品比表面积最大,但是其活性非常低;V2O5含量为4％催化剂比表面积较大,NOx脱转化率高;V2O5的负载量小时,V2O5主要以等轴聚合的钒基型式（V3O7和V6O13）存在,这些钒基是催化剂的活性中心;当负载量超过6％,V2O5主要以结晶相存在,占据大量活性位,降低催化效果。     

Influence of V2O5 content on ammoxidation of 3-picoline over V2O5/AlF3 catalysts

V₂O₅/AlF₃ catalysts with V₂O₅ loadings ranging from 2 to 15 wt% were prepared by the conventional wet impregnation method, using nonporous AlF₃·3H₂O sample as the support for impregnating NH₄VO₃. It was found that the catalysts evolve porous structures upon calcination at 723 K. The influence of V₂O₅ content was studied on ammoxidation of 3-picoline on the reduced catalysts. The catalyst with 15 wt% V₂O₅ exhibited the highest selective ammoxidation acitivity towards nicotinonitrile. The XRD and oxygen chemisorption studies revealed that vanadia is in a highly dispersed state in the catalysts.     

磁性光催化剂Fe3O4/SiO2/TiO2的制备及光催化降解苯酚

采用撞击流-旋转填料床辅助沉淀法连续制备Fe₃O₄磁性纳米颗粒,然后采用溶胶-凝胶法制备了具有磁性核壳结构Fe₃O₄/SiO₂/TiO₂颗粒,通过傅里叶变换红外光谱（FTIR）、X射线衍射仪（XRD）、透射电子显微镜（TEM）、热重分析仪（TGA）、振动样品磁强计（VSM）和紫外-可见漫反射光谱（UV-vis）等对材料的微观结构、形貌及性能进行了表征。考察了正硅酸乙酯添加量、铁钛比对Fe₃O₄/SiO₂/TiO₂磁性催化剂催化性能的影响。结果表明：制得的Fe₃O₄/SiO₂/TiO₂结晶度好,磁响应性高。当正硅酸乙酯添加量为20mL、铁钛比为1∶8时,制备的Fe₃O₄/SiO₂/TiO₂纳米光催化剂表现出较高的光催化活性和磁性能,紫外光照射2h后,苯酚水溶液降解效率高达86.7%。     

Phase equilibrium studies in V2O5-Fe2O3 and V2O5-TiO2 systems

V₂O₅-Fe₂O₃ and V₂O₅-TiO₂ systems represent two important chemical systems with various applications, including energy, catalysts, and high-performance materials. In the present study, high-temperature phase equilibrium experiments were conducted at the temperature range of 670–1000°C in air. Electron probe X-ray micro-analyzer (EPMA) was used to analyze the microstructure and composition of the phases presented in quenched samples. Systematic experiments demonstrated that V₂O₅-containing systems should not be quenched by water-based quenching media. Phase diagrams in both systems were constructed, and the eutectic and peritectic points of the systems were confirmed and compared with previous studies. The present study improved the previous results and could be used as the base for thermodynamic modelings and further applications of the two systems.     

Highly transparent yttria ceramics with Nb2O5/Ta2O5 as novel sintering additives by pressureless vacuum sintering

Highly transparent yttria ceramics were fabricated by pressureless sintering with Nb₂O₅ or Ta₂O₅ as a novel sintering additive. The optical transmittance, microstructural evolution, and thermo-mechanical properties of the samples were investigated. The optimal doping concentrations of Nb₂O₅ and Ta₂O₅ are 0.3 and 0.2 at.%, respectively, which are much lower compared to those of previously reported counterparts. The transmittance of the sample with 0.3 at.% Nb₂O₅ reaches 81.6% at 1100 nm and 72.4% at 400 nm (2 mm in thickness), similar transmittance was obtained in the sample with 0.2 at.% Ta₂O₅. The microhardness (∼7 GPa), fracture toughness (∼0.85 MPa·m^1/2), and biaxial strength (∼200 MPa) of the present samples were confirmed to be comparable or even better compared to those of previously reported transparent yttria ceramics fabricated by pressureless sintering. Furthermore, the present samples, by virtue of the low doping concentrations, possessed relatively high thermal conductivity values (>10 W/m·K), which substantially guaranteed high thermal shock resistance.     

TiO2光催化剂负载及微波协同催化降解制药废水的研究

以TiO2为原料,利用毛竹活性炭负载,采用微波协同技术,光催化降解制药工业废水,制得回用水.实验结果表明,COD去除率为91.74％,脱色率为94.52％.该方法技术先进,处理效果好.解决了工业废水可生化性差的问题,是一种高效、实用的难降解有机工业废水耦合处理技术.催化剂质量稳定,可反复使用,适于应用.     

Physico-chemical and antimicrobial properties of Ag/Ta2O5 nanocomposite coatings

Surface modification of surgical instruments is carried out in order to improve the antibacterial performance against the surgical site infections. Healthcare acquired infections (HAI) and Nosocomial infections are one of the leading causes of complications/deaths after surgery. There is an increasing trend of antibiotic resistance in bacteria such as, vancomycin-resistant Enterococcus (VRE), carbapenem-resistant Enterobacteriaceae (CRE), multi-drug-resistant Mycobacterium tuberculosis (MDR-TB), methicillin-resistant Staphylococcus aureus (MRSA), and Neisseria gonorrhoeae. Thus, surfaces that counteract the adherence and growth of bacteria are employed to avoid the infections. In present study, stainless steel 316 L (SS 316 L) was coated with Silver/Tantalum oxide (Ag/Ta₂O₅) nanocomposite using reactive magnetron sputtering. The as-sputtered Ag/Ta₂O₅ nanocomposite (a-Ag/Ta₂O₅) film was crystallized via thermal treatment at 400 °C. Due to the annealing, the AgNPs migrated to the surface through the columnar paths of the a-Ag/Ta₂O₅. Thus, the crystallized layer (c-Ag/Ta₂O₅) exhibited 302% improvement in adhesion strength and enhanced hydrophopibicity. The c-Ag/Ta₂O₅ also demonstrated excellent antibacterial performance against Staphylococcus aureus (NCTC 6571) (gram-positive bacteria) and Escherichia coli (ATCC 15597) (gram-negative bacteria) according to the inhibition zone measurements. These results suggest that c-Ag/Ta₂O₅ deposition on SS 316 L substrate has a high potential to serve as an adherent, antibacterial layer on the surgical tools, in order to resist surgical site infections.     

Influence of the V2O5 Loading on the Structure and Activity of V2O5/TiO2 SCR Catalysts for Vehicle Application

In this paper the effect of the vanadium oxide loading on the surface vanadia structure and the activity as well as selectivity in the catalytic reduction of NO with NH₃ was studied for a V₂O₅/TiO₂ model system. A series of TiO₂ (WO _x stabilized anatase) supported vanadia catalysts with varying loadings were characterized by laser Raman spectroscopy, ⁵¹V MAS-NMR, V K XANES. To determine the acidic properties, DRIFTS measurements were done with pyridine adsorbed on the samples. The measurements indicate that with increasing active phase loading square pyramidal coordinated surface vanadia species are replaced by an amorphous highly dispersed vanadium oxide phase with a coordination like V₂O₅. In addition, the ratio of Brønsted to Lewis acid sites is shifted from a comparatively low to an equal level at high loadings. This structural change is accompanied by a clearly improved catalytic activity and selectivity.     

Oxidative Dehydrogenation of Propane on V2O5/ZrO2 Catalyst

The performance of zirconia supported vanadia catalyst has been investigated for the oxidative dehydrogenation of propane. Vanadia loading was varied from 1.6 to 22.7 wt%, both below and well above monolayer coverage. The turnover frequency was highest for the catalyst with a vanadia surface density of 5 VO _x /nm². The effect of vanadia loading on the redox behavior of the catalysts was investigated by temperature-programmed reduction and temperature-programmed oxidation. The specific activity increased with ease of reducibility of the catalyst. The extent of reduction and ease of reoxidizability of the catalysts were also found to depend on the surface vanadia structure and to influence the catalytic activity. The effect of vanadia loading on the basicity of the catalysts was also investigated.     

Promoting Effect of Pt Addition to V2O5/ZrO2 Catalyst on Reduction of NO by C3H6

The effect of Pt addition to a V₂O₅/ZrO₂ catalyst on the reduction of NO by C₃H₆ has been studied by FTIR spectroscopy as well as by analysis of the reaction products. Pt loading promoted the catalytic activity remarkably. FTIR spectra of NO adsorbed on the catalysts doped with Pt show the presence of two different types of Pt sites, Pt oxide and Pt cluster, on the surface. The amount of these sites depends on Pt contents and the catalyst state. Pt atoms highly disperse on the surface as Pt oxide at low Pt content, being aggregated into Pt metal clusters by increasing Pt amount or reducing the catalysts. The spectral behavior of V=O bands on the surface also supports the formation of Pt clusters. It is concluded that Pt promotes the NO–C₃H₆ reaction through a reduction–oxidation cycle between its oxide and cluster form.     

V2O5/Al2O3上异丁烷脱氢反应研究

用浸渍法制备了质量分数为12%V₂O₅/Al₂O₃负载型催化剂，考察了催化剂的活化气氛，反应中异丁烷与氢气的比例和反应温度对异丁烷脱氢活性的影响。结果表明，用N2作活化气，反应中异丁烷与氢气的体积比为1∶1时，在质量分数为12%的V₂O₅/Al₂O₃催化剂上异丁烷脱氢转化率和选择性较好，在625 ℃时，转化率达到52%，选择性为80%。     

V_2O_5-WO_3/TiO_2催化剂的制备

采用工业钛白粉作为烟气脱硝催化剂的载体原料,通过添加助剂M对其改性,研制出了一种V2O5-WO3/Ti O2烟气脱硝催化剂,并确定助剂M的最佳量为质量分数10%;同时考察了焙烧温度对该催化剂比表面积及脱硝性能的影响,确定了最佳焙烧温度为500℃;最佳活性组分钒含量为质量分数1.5%,稳定助剂钨含量为质量分数8%的催化剂性能最好。