负载型纳米TiO2/AC对偶氮染料的光催化降解研究

以钛酸四丁酯和粒状活性炭(AC)为主要原料,采用溶胶-凝胶-浸渍法制备出负载型纳米TiO2/AC催化剂.在流化床反应器中分别对2种典型的偶氮类染料橙黄G、活性艳红X-3B模拟废水进行了光催化降解研究,探讨了pH值、外加氧化剂对光催化降解率的影响,并对催化剂进行了回收再生利用试验.结果表明,TiO2/AC催化剂具有良好的光催化活性、吸附特性及可再生性,60 min后对2种染料反应的光催化降解率分别可达到99.71%和97 12%,反应180 min后的TOC去除率分别达到81.54%和81.99%;反应后TiO2/AC催化剂回收率大于95%,经焙烧再生后对橙黄G反应60 min的光催化降解率仍高达95.93%.     

三维电极法对印染废水脱色的实验研究

对三维电极方法处理模拟印染废水的脱色进行了实验研究,初步探讨了三维电极处理印染废水的机理,对影响处理效果的各种因素,如曝气、填充物质种类、活性炭与铁屑重量比、槽电压、电极间距、初始废水pH值等进行了条件实验。实验结果表明：不曝气的脱色效果比曝气的脱色效果好;填充物为混合物活性炭与铁屑比活性炭、无填充物的脱色效果好;混合物活性炭和铁屑重量比为2：1时的脱色效果最佳;槽电压越高,脱色效果越好,但当大于某个值16v时,处理效果反而会下降;电极间距越小,脱色效果越好,但间距小于1．5cm时易短路而影响脱色效果;中性条件下的脱色率要优于酸性和碱性条件下的;综合考虑,在不曝气,活性炭和铁屑重量比为2：1,槽电压为16v,电极间距为6cm,溶液浓度为200mg／L,pH=6的条件下,降解时间为90win,脱色率可达98．7％。     

基于感应热固定床的CWPO降解偶氮染料实验研究

感应热固定床(IHFB)作为新型热传递方式下非均相反应器,利用感应加热铁磁材料将热量传递至液相,形成固液界面高温微反应区,促进有机废水降解.实验以海绵铁为感应内核,采用浸渍焙烧法制备了C包覆表层负载NiO的感应热催化剂(mNiO/C),在传统催化湿式过氧化氢法(CWPO)中引入感应热代替传统加热,建立新的基于感应热固定床的CWPO工艺(iCWPO),使其在常温常压下实现对有机底物的高效降解.以直接紫D-BL模拟废水为目标污染物,考察了进水条件对iCWPO降解染料的影响,对感应热微观作用进行了分析,并用UV-Vis对降解产物进行了检测.结果表明,依赖于微界面高温的iCWPO降解效率明显高于常规加热的CWPO,彻底破坏了可见光区染料的显色基团NN键,对紫外光区苯环也具有一定的降解作用.     

Comparison of decolorization of reactive microorganisms isolated from various sources

Azo dyes are among the oldest man-made chemicals and they are still widely used in the textile, printing and the food industries.About 10% - 15% of the total dyes used in the industry is released into the environment during the manufacturing and usage. Some dyes and some of their N-substituted aromatic bio-transformation products are toxic and/or carcinogenic and therefore these dyes are considered to beenvironmental pollutants and health hazards. These azo dyes are degraded by physico-chemical and biological methods. Of these, biological methods are considered to be the most economical and efficient. In this work, attempts were made to degrade these dyes aerobically. Theorganisms which were efficient in degrading the following azo dyes-Red RB, Remazol Red, Remazol Blue, Remazol Violet, Remazol Yellow,Golden Yellow, Remazol Orange, Remazol Black- were isolated from three different sources viz., wastewater treatment plant, paper milleffluent treatment plant and tannery was tewater treatment plant. The efficiency of azo dye degradation by mixed cultures from each source wasanalyzed. It was found that mixed cultures from tannery treatment plant worked efficiently in decolorizing Remazol Red, Remazol Orange,Remazol Blue and Remazol Violet, while mixed cultures from the paper mill effluent worked efficiently in decolorizing Red RB, Golden Yellow and Remazol Yellow. The mixed cultures from wastewater treatment plant efficiently decolorized Remazol Black.     

TiO2/Ag modified penta-bismuth hepta-oxide nitrate and its adsorption performance for azo dye removal

A modified hydrophilic penta-bismuth hepta-oxide nitrate (Bi₅O₇NO₃) surface was synthesized via a precipitation method using TiO₂ and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono-and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy (XPS) results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure Bi₅O₇NO₃;however, the presence of hydrophilic centres such as TiO₂ and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.     

Adsorption behavior of Azo Dye C. I. Acid Red 14 in aqueous solution on surface soils

Azo dyes have received considerable attention because of their association with various human health problems. The aim of the investigation is to determine the adsorption behavior ofazo dyes in aqueous solution on DG06, GSE17200, and GSE17201 soils using C. I. Acid Red 14 （AR14） as example. The experimental results indicate that the Freundlich model expresses the adsorption isotherm better than the Langmuir model and the pseudo-second-order model achieves adsorption of AR14 on the three soils well. Based on the pseudo-second-order model, the adsorption thermodynamic of AR14 on DG06 soil have been studied and the thermodynamics parameter of AGO is determined and AGO value shows the adsorption process of AR14 on DG06 is mainly physical in nature. Furthermore, the effects of temperature, pH and salinity （NaC1） on adsorption have been investigated. The decrease in pH or the increase in salinity enhances the adsorption of AR14 by DG06, GSE17200, and GSE17201.     

磁性吸附剂MZFS吸附偶氮染料中性红的性能及机理

利用正硅酸乙酯水解制备得到"核-壳"结构的磁性吸附剂MZF@SiO₂（MZFS），采用X射线衍射（XRD）、透射电子显微镜（TEM）、振动样品磁强计（VSM）和傅利叶变换红外光谱（FT-IR）对MZFS的结构和性能进行表征，并研究MZFS对偶氮染料中性红（NR）的吸附性能.结果表明，拟二级动力学和Freundlich模型均能较好地描述该吸附过程，吸附过程的速率控制步骤为化学吸附；吸附自由能E为0.472-0.773kJ/mol，△G为-20~0kJ/mol，△H为37.5kJ/mol，表明该过程是以物理吸附为主的自发吸热过程.FT-IR结果表明吸附的主要作用力为分子间氢键，MZFS可采用15% wt H₂O₂进行原位再生.研究结果能为偶氮染料废水处理方法的革新提供基础理论数据.     

TiO2/beads as a photocatalyst for the degradation of X3B azo dye

The feasibility of photocatalytic degradation of X3B azo dye by TiO2/beads photocatalyst was studied.The effects of parameters such as the amount of TiO2/beads,airflow ,as well as the concentrations of H2O2,Fe^3 ,Mg^2 and Na^ on the photocatalytic degradation of X3B azo dye were also studied.The results showed that 25mg/dm^3 X3B azo dye can be photocatalytically degraded completely by 30 min illumination with a 375W medium pressure mercury lamp.Adding a small amount of H2O2 or Fe^3 ,the efficiencies of photocatalytic degradation of X3B azo dye were increased rapidly.The mechanisms of the reaction and the role of the additives were also investigated.After 120 hours TiO2/beads showed no significant loss of the photocatalytic activity.     

Dye removal from wastewater using the adsorbent developed from sewage sludge

Introduction Adsorptionisrelevantinenvironmentalpollutionandprotectionwithreferencetowaterandwastewatertreatment(Bowen,1992).Toxicmaterials,hazardousionsanddyes fromindustrialeffluentsbythewayofadsorptionareofgreatsignificantinconnectionwithenvironmentala…     

Continuous treatment of azo acid dyes by photo-dependent denitrifying sludge

Simultaneous removals of dye and nitrate by photo-dependent denitrifying sludge(PDDS)have been demonstrated in a continuousflow bench-scale reactor.The best C/N for the degradation of azo dyes by PDDS was 1.5.The specific removal rate of azo dye AB92 decreased with a decrease in hydraulic retention time and increased with a decrease in solids retention time.The degradation rate of TOC decreased with a decrease in hydraulic retention time.AB92,which has nitro and hydroxyl substitutions in non-para positions,was uniquely degraded.During continuous flow treatment experiments using PDDS,complete degradation of azo dyes AB92 and AO20 at influent concentrations of 40mg/L and 30mg/L,respectively,was achieved with an HRT of 16.