BiPO_4/g-C_3N_4可见光催化氧化RhB

通过简单的水热和煅烧方法,把BiPO4纳米颗粒植入g-C3N4层间或表面,成功地制备了BiPO4/gC3N4复合光催化剂.通过XRD、SEM、TEM、N2吸附-脱附等温线和UV-VisDRS分析表明,g-C3N4具有明显的层状结构且与BiPO4纳米颗粒形成了复合物,BiPO4/g-C3N4复合光催化剂具有较大的比表面积(172.9m2·g-1),与纯g-C3N4相比扩展了可见光的响应范围.光降解实验结果表明,负载量为2wt%的BiPO4/g-C3N4复合光催化剂具有最高的可见光催化活性,在降解1h后,罗丹明B的降解率可以达到87.5%,催化活性与纯g-C3N4提高了近3倍.     

Hydrothermal Synthesis of Zn_2SnO_4/Few-Layer Boron Nitride Nanosheets Hybrids as a Visible-Light-Driven Photocatalyst

Zn_2SnO_4/few-layer boron nitride nanosheets(FBNNS) hybrids were synthesized via a one-step hydrothermal method. The structures, morphology, optical properties, electron transformation and separation of the as-prepared products were characterized by X-ray diffraction, transmission electrical microscopy, UV-vis diffuse reflectance spectroscopy and electrochemical impedance spectroscopy, respectively. Rhodamine B was used to evaluate the photocatalytic activities of the as-prepared samples under visible light illumination. The photocatalytic mechanism was also explored. Experimental results showed that the degradation efficiency of rhodamine B was firstly increased and then decreased with increasing the usage amount of FBNNS. When it was 9 wt% based on the weight of Zn_2 SnO_4, the degradation efficiency of the as-prepared Zn_2 SnO_4/FBNNS-9 wt% composites reached to the maximum of 97.5 % in 180 min, which was higher than 39.2 % of pure Zn_2 SnO_4. Moreover, the holes played mainly active roles in photocatalytic reaction process. In addition, the as-prepared hybrids could enhance the separation efficiency of photoexcited carriers compared to pure Zn_2 SnO_4.     

可见光下氮掺杂TiO2制备条件的研究

以钛酸正丁酯、硝酸铵为原料,无水乙醇为溶剂,冰醋酸为抑制剂,乙酰丙酮为螯合剂,聚乙二醇为表面活性剂,采用溶胶-凝胶法,在常温条件下研究制备氮掺杂二氧化钛的最优条件.在此基础上制备的氮掺杂二氧化钛在氙灯(模拟太阳光)下的光催化降解甲基橙(MO)实验表明:N-TiO2在可见光下具有较高的光催化活性,光催化反应1 h,对甲基橙的降解率超过63%.对粉体分别进行XRD、FESEM、FT-IR表征,表明N-TiO2具有75%锐钛矿和25%金红石相混晶结构,粉体为球形,直径约为28 nm.     

Two Dimension C_3N_4/MoS_2 Nanocomposites with Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

MoS_2-decorated C_3N_4(C_3N_4/MoS_2) nanosheets hybrid photocatalysts were prepared by a simple sonication-impregnation method. Face-to-face lamellar heterojunctions were well established between two dimension(2D) C_3N_4 and MoS_2 nanosheets. The effects of MoS_2 content on the light absorption, charge transfer and photocatalytic activity of the hybrid samples were investigated. Characterization results show that MoS_2 nanosheets are well anchored on the face of C_3N_4 nanosheets and the composites have well dispersed layered morphology. After loading with MoS_2, the light absorption of composites was much improved, especially in visible-light region. The photocatalytic activities of C_3N_4/MoS_2 samples were evaluated based on the H_2 evolution under visible light irradiation(λ 400 nm). When the loading amount of MoS_2 was increased to 5 wt%, the highest H_2 evolution rate(274 μmol·g~(-1)·h~(-1)) was obtained. Compared with samples obtained from direct impregnation method, sonication pretreatment is favorable for the formation of 2D layered heterojuctions and thus improve the photocatalytic activity. Slightly deactivation of C_3N_4/MoS_2 composites could be observed when recycled due to the mild photocorrosion of MoS_2. Based on the band alignments of C_3N_4 and MoS_2, a possible photocatalytic mechanism was discussed, where MoS_2 could efficiently promote the separation of the photogenerated carriers of C_3N_4.     

La掺杂Bi2O3的制备及其可见光催化降解4-氯酚的研究

采用醇介导法制备了La离子掺杂改性的氧化铋,并通过SEM、IR、PL、BET、XRD等对其结构和性能进行表征.结果表明:L a离子掺杂导致氧化铋的禁带宽度由2.984 eV降低为2.940 eV,加大了氧化铋的光吸收范围并降低了光生电子-空穴的复合几率.掺杂La提高了Bi2 O3的可见光催化活性,在25℃可见光下4-氯苯酚光照8h的降解率可达92.24％.此外,控制实验表明空穴是La-Bi2 O3可见光催化降解4-氯苯酚的主要活性物种.     

Photocatalytic Activity of Lanthanum and Sulfur Co-doped TiO2 Photocatalyst under Visible Light

A novel lanthanum and sulfur co-doped TiO2,photocatalyst was synthesized by precipitation-dipping method,and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM)and UV-Vis diffuse reflectance spectroscopy.Compared with the S-doped TiO2,La-doped TiO2 and the standard Degussa P25 photocatalysts,the lanthanum and sulfur co-doped TiO2 photocatalyst(the molar percentage of La is 3.O%) calcined at 450℃for 2 h showed the strongest absorption for visible light and highest activities for degradation of reactive blue 19 dye in aqueous solution under visible light(?>400 nm)irradiation.It was also discovered that the co-doping of lanthanum and sulfur hindered the aggregation and growth of TiO2 particles,and the doping of lanthanum reduced slightly the phase transition temperature of TiO2 from anatase to rutile.     

In-situ Synthesis of SnO_2 Quantum Dots/ZnS Nanosheets Heterojunction as a Visible-light-driven Photocatalyst for Degradation of Rhodamine B,Potassium Dichromate and Tetracycline

The SnO_2 quantum dots (SnO_2QDs)/ZnS nanosheets (ZnSNs) heterojunction was fabricated via an in-situ synthetic method at room temperature.Rhodamine B,potassium dichromate,and tetracycline were used to discuss the photocatalytic activities of the as-prepared samples under the visible light illumination.The photocatalytic mechanism of the as-prepared samples was also proposed.The experimental results indicate that the degradation efficiency of the as-prepared SnO_2QDs/ZnSNs heterojunction first increases and then decreases with increasing the usage of ZnSNs.When the mass ratio of SnO_2QDs to ZnSNs is 1:2 in 180 min,the as-prepared samples have the highest degradation efficiency of 89.1% for rhodamine B,97.7% for potassium dichromate,and 83.8% for tetracycline,which are much higher than 51.7%,26.8%,and 0.9% of pure SnO_2QDs as well as 37.9%,87.1%,and 19.1% of pure ZnSNs,respectively.After it is repeatedly degraded for 3 times,it possesses the degradation efficiency of 62.5% for rhodamine B,which increases by 200.5% in comparison with 20.8% of the pure SnO_2QDs.Moreover,the enhanced photocatalytic performances of the as-prepared hybrids are attributed to the formation of heterojunction between the SnO_2QDs and ZnSNs.In addition,hydroxyl radicals and superoxide anion radicals play major roles during the photocatalytic degradation process,while holes play a minor role.     

具有可见光响应的V-TiO2/AC光催化剂的制备

采用水热法在温和条件下制备了V掺杂的TiO2/活性炭(AC)光催化剂.利用XRD、SEM、漫反射、红外及荧光光谱对催化剂的物化性质进行了表征.结果显示,V-TiO2仍保持了锐钛矿相,没有出现V的衍射峰.相比纯TiO2,经过V掺杂的样品,具有较高的表面羟基密度,较低的栽流子复合几率,同时吸收光谱向可见光区移动.将纳米级的V-TiO2沉积在AC上可形成微-纳结构.在可见光照射下,V-TiO2/AC催化降解4-氯苯酚的能力高于纯V-TiO2和P25,这可归因于V的掺杂和AC协同作用的结果.     

N-Fe共掺杂BiVO_4的制备及其光催化活性的研究

采用溶胶凝胶法制备了N和Fe共掺杂的Bi VO4可见光光催化剂,并用X射线衍射(XRD)、比表面积测试(BET)和紫外-可见漫反射谱(UV-Vis DRS)对其进行了表征.结果显示,N-Fe共掺杂对Bi VO4晶型没有产生影响,掺杂前后均为单斜晶系,但晶粒粒径有所减小,BET比表面积相对增大.由UV-Vis可知,N-Fe共掺杂的Bi VO4的吸光强度明显增强,禁带宽度变窄.以可见光降解甲基橙(MO)考察催化剂的光催化活性,N-Fe共掺杂的Bi VO4对MO的降解速率明显高于纯Bi VO4,证明N-Fe共掺杂产生的协同效应提高了Bi VO4在可见光照射下的光催化活性.     

g-C_3N_4/LSACF复合材料制备及其可见光催化性能研究

在将生物质海绵-丝瓜络纤维通过高温碳化烧制成丝瓜络基活性炭纤维(LSACF)的基础上,以尿素包裹并煅烧制得g-C_3N_4/LSACF复合材料。通过SEM、XRD、EDS、BET等手段对样品微观结构和组成进行表征,通过UV-Vis分析其可见光响应性。结果表明:复合材料对罗丹明B(RhB)有着良好的吸附和可见光催化降解性能,优良的吸附性能源于LSACF的网状多孔结构及负载后复合材料比表面积的有效提高;g-C_3N_4/LSACF在5次循环降解测试中仍维持较好的催化性能,显示了其良好的循环利用价值。该研究为g-C_3N_4负载材料的选择及高效循环利用提供了思路。     

GNR-TiO_2/g-C_3N_4异质结构的制备及其性能研究

采用二次凝胶-溶胶法和水热法合成了具有光催化效应的GNR-TiO_2/g-C_3N_4异质结构,并对其性能进行了研究.研究结果表明:GNR-TiO_2/g-C_3N_4异质结构表现出强的光催化活性,并在可见光照射下,对有机物亚甲基蓝有良好的催化效果.这主要归因于石墨烯纳米带作为载体,不仅增加了异质结构的比表面积,还使空穴-电子对的再结合率降低.     

高浓度絮状颗粒污泥体系的形成及其降解效果

以AA/O(Anaerobic-Anoxic-Oxic)氧化沟曝气池中的活性污泥为接种污泥,利用二次流高效混凝技术包裹固定微生物培养高浓度絮状颗粒污泥,使整个污泥体系形成悬浮的流化态,最后对其进行生物降解效果验证.实验表明:对比常规活性污泥法,高浓度絮状颗粒污泥质量浓度达到20 g/L,水力停留时间(HRT,hydraulic retention time)仅为45 min,平均COD(Chemical Oxygen Demand)去除率达到96%.     

Cu2O/Cu2S 复合材料制备及可见光催化降解甲基橙的研究

通过水热法制备Cu₂O/Cu₂S 复合材料对甲基橙(MO) 进行光催化降解实验。在Cu₂O 中引入S 元素, 通过 改变Cu/S 投加摩尔比, 从而得到不同Cu/S 的复合材料。利用XRD、SEM、UV-vis、EIS 等手段对材料进行表征, 并 对MO 进行光催化降解实验。XRD 结果表明, 随着S 含量的增多, Cu₂S 的衍射强度逐渐上升, Cu₂O 的f111g 晶面 衍射强度逐渐降低。SEM 结果表明Cu₂S 能较好地包覆在Cu₂O 八面体的表面。通过UV-vis 和EIS 结果计算得知, 复合材料带隙为1.49 eV, 电荷转移电阻大幅降低。降解实验结果表明复合材料最佳Cu/S 投加摩尔比为15 : 1, 其在 100 min 时对MO (100 mL, 10 mg/L) 降解率达到91.4%, 明显高于纯Cu₂O 对于MO 的降解率(60.3%)。猝灭实验表 明了?OH 和 ?O₂ ^-在光催化过程中起到主要作用。     

Ag3PO4/BiPO4复合光催化剂的制备及其降解罗丹明B的研究

采用水热法合成复合Ag₃PO₄/BiPO₄光催化剂,考察不同pH和不同复合比例下合成的光催化剂对溶液中罗丹明B的光催化降解性能,并与BiPO₄进行对比。结果表明:在pH=7,复合比例Ag₃PO₄/BiPO₄摩尔比为4:3条件下水热制备的Ag₃PO₄/BiPO₄对可见光的利用率最高,催化性能最好;降解180 min后,对罗丹明B的降解率达到61%,较纯相BiPO₄提升了27%。本文还利用XRD、SEM和紫外可见漫反射(UV-Vis DRS)等测试手段对合成的样品进行表征,分析得出复合Ag₃PO₄之后,催化剂的禁带宽度变窄,并出现较多的独居石晶型BiPO₄,光生电子与空穴复合效率变低,从而使复合材料的光催化降解罗丹明B的能力得到提升。     

Biomolecule-assisted Solvothermal Synthesis and Enhanced Visible Light Photocatalytic Performance of Bi_2S_3/BiOCl Composites

Novel Bi_2S_3/BiOCl photocatalysts were successfully synthesized via a facile biomoleculeassisted solvothermal method and biomolecule L-cysteine was used as the sulfur source.The structures,morphology,and optical properties of the synthesized samples were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,transmission electron microscopy(TEM),and UV-vis diffuse reflectance spectroscopy(DRS).The presence of Bi_2S_3 in the Bi_2S_3/BiOCl composites could not only improve the optical properties but also enhance the photocatalytic activities for the degradation of Rhodamine B(Rh B) under visible-light irradiation(λ420 nm) as compared with single Bi_2S_3 and BiOCl.Especially,the sample displayed the best performance of the photodegradation when the feed molar ratio of BiCl_3 and L-cysteine was 2.4:1,which was about 10 times greater than that of pure Bi OCl.The enhanced photocatalytic activities could be ascribed to the effective separation of photoinduced electrons and holes and the photosensitization of dye.Moreover,the possible photodegradation mechanism was also proposed,and the results revealed that the active holes(h+) and superoxide radicals(·O_2~-) were the main reactive species during photocatalytic degradation.     

TiO2-xNx／硅藻土复合光催化剂的制备及其可见光催化活性

以尿素为氮源,硅藻土为载体,用溶胶-凝胶法合成了硅藻土负载氮掺杂纳米TiO2复合光催化剂。采用XRD,UV-vis对样品进行了表征;以罗丹明B为降解对象,考察了罗丹明B初始浓度、催化剂投加量、溶液初始pH值对降解率的影响,同时考察了样品在太阳光下的光催化活性。结果表明,掺氮Ti02450oc焙烧2h后为锐钛矿型,N掺杂使催化剂的吸收边红移至550nm左右,诱发TiO2可见光催化活性;当催化剂用量为2g／L,溶液初始pH值为6．5时,初始浓度为10mg／L的罗丹明B在氙灯光照45min后降解率为100％,太阳光照160min后降解率为97．4％。     

ZnO／TiO2改性催化剂在阳光照射下对溴氨酸水溶液的催化降解

采用溶胶-凝胶法制备了具有可见光响应的ZnO／TiO2催化剂。考察了煅烧温度、煅烧时间、ZnO掺杂量对ZnO／TiO2催化剂性能的影响及阳光下不同紫外线强度对ZnO／TiO2催化剂降解溴氨酸水溶液的影响。结果表明：当煅烧温度为400℃,煅烧时间为2h,ZnO掺杂比为1％时,催化剂性能较佳;紫外线指数为5,光照5h时,溴氨酸水溶液的褪色率达到100％,在太阳光直射下3h后,溴氨酸水溶液的褪色率为97．73％,TOC去除率为82．88％。     

锰砂/H2O2/O3体系预处理高浓度甲醛废水的中试研究

To solve the problems of high sludge production, easy scaling in pipes and high colour of effluent from treating formaldehyde a wastewater with lime, a pilot study was conducted to treat the wastewater of a pharmaceutical company with a high concentration of formaldehyde using the manganese sand/H2O2/O3 catalytic oxidation system, where the reaction conditions affecting the catalysis were investigated. The results show? that the removal rates of formaldehyde,chemical oxygen demand and chromaticity reach 87.3%, 60.0% and 95.0% respectively when the ozone dosage is 100g/h, reaction time is 2h, the hydrogen peroxide?dosage is 0.30% of the wastewater, reaction temperature is 40℃ and the manganese sand dosage is 60% of the container. The content of organic pollutants is significantly reduced after the formaldehyde wastewater is treated by the manganese sand/H2O2/O3 catalytic oxidation system. This technology has the advantages of high oxidation efficiency and simple operation without secondary pollution, which can provide a reference for the treatment of high concentration formaldehyde wastewater.
     

UV/TiO2 and UV/TiO2-film for Degradation of Textile Dyes

Wastewaters fromtextile and dyeingindustries are highly colored by various non-biodegradable dyes whichcause serious environ-mental problems[1].The effluents of the wastewater introduced not only color but alsotoxicityinto aquatic system.The conventionalt…