Photocatalytic remediation of γ-hexachlorocyclohexane contaminated soils using TiO2 and montmorillonite composite photocatalyst

TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane(γ-HCH)in soils.After being spiked with γ-HCH,soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation.The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10%＜70%＜50%＜30%.Moreover,the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2.The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities.In addition,effect of dosage of composite photocatalysts and soil pH on γ-HCH photodegradation was investigated. Pentachlorocyclohexene,trichlorocyclohexene,and dichlorobenzene were detected as photodegradation intermediates,which were gradually degraded with tlle phOtOdegradation evolution.     

Ag-AgI/CN/MA复合物的制备及其可见光催化性能

采用沉淀法和热聚合法分别将AgI、氮化碳(CN)负载在介孔γ-Al_2O_3(MA)上,并通过光还原银离子成功制备了等离子体诱导可见光催化剂Ag-AgI/CN/MA.利用X射线衍射(XRD)、X射线光电子能谱(XPS)、场发射扫描电子显微镜(FESEM)、紫外可见漫反射光谱(UV-vis DRS)和透射电子显微镜(TEM)对Ag-AgI/CN/MA复合材料进行表征,并对其在可见光照射下(λ420 nm)的光催化性能进行了研究,考察了初始溶液pH值及催化剂投加量等条件对光催化反应的影响.结果表明,表面银以Ag+和Ag0形式共存,并且Ag和AgI均匀地分散在CN的表面.与CN和Ag-AgI/MA相比,Ag-AgI/CN/MA复合物对甲基橙(MO)具有更高的可见光催化降解效率,且反应过程中Ag+的释放量显著减少,显示出良好的稳定性.当溶液pH值为7、催化剂投加量为1 g·L~(-1)时,Ag-AgI/CN/MA-2显示出最优的催化性能.同时,其对罗丹明B(Rh B)、甲基红(MR)和刚果红(CR)等不同电性的染料均体现出良好的催化性能.     

Photocatalytic degradation of ciprofloxacin in aqueous media: a short review

The frequent detection of antibiotics such as ciprofloxacin in surface and drinking waters around the world has attracted concern from various researchers. Such presence is an indication that the decontamination of water polluted by antibiotics is beyond the conventional treatment methods. However, among the different treatment methods that have been developed in the area of water purification, heterogeneous photocatalysis using semiconductor as a mediator has been rated as an efficient and a green wastewater treatment method. This is because, the process is effective in degrading and mineralizing organic pollutants, using UV or visible light. The present review paper covers a brief survey over a range of publications in the last decade, involving photocatalytic materials that have been employed in the purification of water contaminated by ciprofloxacin.     

复合光催化剂(TiO2/多壁碳纳米管)制备工艺条件对甲基橙光催化降解动力学的影响

采用溶胶-凝胶法在不同条件下制备了多壁碳纳米管(MwCNTs)负载纳米TiO2的复合光催化剂(TiO2/MWCNTs).以偶氮类染料甲基橙为模拟污染物,研究不同制备工艺参数的复合光催化剂对甲基橙的光催化降解动力学的影响.对TiO2/MWCNTs的表征结果表明,纳米TiO2较好地分散在多壁碳纳米管表面;随着温度的升高,复...     

MWNTs/TiO2对典型氯苯类化合物的光催化降解研究

研究复合光催化剂MWNTs/TiO2对典型氯苯类有机化合物光催化降解动力学及主要光降解路径.结果表明,同一初始浓度和相同光催化降解实验条件下,60min时典型氯苯类有机化合物的光降解率均达到90%以上.其中六氯苯和五氯苯的光催化降解速率常数分别为0.0664h-1和0.0670h-1,其大小明显高于其它氯苯类化合物.1,二氯苯的光催化降解反应速率常数仅为0.0430h4--1,在典型氯苯类化合物中最小.三氯苯的3种同分异构体——1,3-三氯苯、24-三氯苯和1,5-三氯苯的光催化降解速率常数分别为0.0547h2,1,,3,-1、0445h0.-1和0.0439h-1.六氯苯的主要光催化降解路径为:HCB→PeCB→1,2,3,5-TeCB→1,2,4-TCB→1,4-DCB.     

溶胶-凝胶法制备复合光催化剂（MWNTs/TiO_2）工艺条件的研究

以多壁碳纳米管（MWNTs）为载体,在煅烧温度200~900℃、煅烧时间1~7 h、溶胶体系pH值为2~10的工艺条件下,采用溶胶-凝胶法制备复合光催化剂（MWNTs/TiO2）。通过其对甲基橙的光催化降解效果对比,评价各种复合光催化剂催化活性之间的差异,结果表明,随着煅烧温度的升高,复合光催化剂中纳米TiO2的晶型由锐钛型逐渐向金红石型转变,500℃时为2种晶型的混合相;pH值为2的强酸性条件有利于形成金红石晶型,pH值为5的中性及弱酸性条件则有利于形成锐钛型,而pH值为3时为2种晶型的混合相;在煅烧温度500℃、煅烧时间3 h、溶胶凝胶体系pH值为3的最佳制备工艺条件下,复合光催化剂催化活性最高,借助扫描电镜发现其TiO2均匀地包覆在多壁碳纳米管管壁上。     

负载型催化剂光催化氧化五氯苯酚钠的效果

研究以TiO₂ 为基本活性组分、空心玻璃珠为载体、硅酸钠为粘合剂的负载型催化剂的制备技术 .选取五氯苯酚钠 (PCP-Na)为处理对象 ,结合对催化剂比表面和晶型结构的表征 ,对制备的催化剂进行筛选评价 .实验结果表明 :在适当的条件下 (二氧化钛、空心玻璃珠、40%硅酸钠溶液重量比为 4∶20∶2,650℃下烧 3h)所制备的C3型催化剂不仅光催化活性高 ,且负载牢固 ,易与水分离 .对初始COD_Cr=400mg·L^-1,PCP-Na=10mg·L^-1的反应液 ,在光照强度为 30kW·m^-2下 2hCOD_Cr去除率大于 65% ,PCP-Na去除率大于 92%.试验进一步探讨C3型催化剂投加量、反应液初始浓度、供氧量对催化反应的影响 .     

微波改性MWNTs/TiO2复合材料对1,2,3-三氯苯的光催化降解研究

在微波辐照干化的条件下用溶胶-凝胶法制备了MWNTs/TiO2复合光催化剂.对该复合材料的表征表明：随着微波功率逐渐增大至400 W,MWNTs/TiO2复合材料管径逐渐变小,且在400 W时制备的MWNTs/TiO2复合材料分散性较好.进一步增大微波功率导致复合材料的管径增大,分散性降低.研究了不同微波辐照条件下制备的MWNTs/TiO2复合光催化剂对1,2,3-三氯苯的光催化降解效果,结果表明,该复合光催化剂对1,2,3-三氯苯的光降解遵循一级反应动力学;在微波功率为400 W、辐照时间为5 min情况下制备的复合光催化剂对1,2,3-三氯苯的降解速率最快,其反应常数为0.023 7 min^-1,该值比非微波加热干化的同样复合材料的反应速率常数值提高了52%.     

Photocatalytic degradation of PCP-Na with TiO2 photocatalysis loaded with platinum

Titanium dioxide(TiO2) samples of different crystal forms were prepared by hydrolysis tetrbutyl titanate in various water to alkoxide ratios and sintering the hydrolysis product at different temperatures.The photocatalysts coated on hollow glass beads and loaded with platinum varying from 0.2% to 2.4% by weight.The photocatalytic degradation rate of sodium pentachlorophenolate (PCP-Na) depends on the preparing conditions such as:sintering temperatures,water to alkoxide ratios(R),platinum content and the size.The proper conditions of preparation photocatalysts are as follows:the ratio of tiO2:sodium silicate:hollow glass beads:platinum is 10:5:20:0.15(w/w),R is 100,sintering temperature is 650℃,and the size of hollow glass is 0.5-1mm.Under these conditions,the ratio between acatase and rutile of the photocatalyst is 2:1,and the photocatalytic activity is high.     

碳纳米管负载TiO2对1,2,4-三氯苯的光降解研究

碳纳米管负载TiO2复合光催化剂与纳米TiO2光催化剂对1,2,4-三氯苯的光催化降解效果,及降解动力学的研究结果表明,复合光催化剂比纳米TiO2有更好的光催化降解效果,经254 nm紫外光辐照60 min后,使用复合光催化剂的1,2,4-三氯苯降解了70%,而使用纳米TiO2为催化剂的1,2,4-三氯苯仅降解了51%...