Decolorization and bio degradation metabolism of azo dyes by Pseudomonas S-42

A bacterial strain was isolated from activated sludge and has been identified as Pseudomonas sp. S-42 capable of decolorizing azo dyes such as Diamira Brilliant Orange RR (DBO-RR), Direct Brown M (DBM), Eriochrome Brown R (EBR) and so on. The growing cells, intact cells, cell-free extract and purified enzyme of strain S-42 could decolorize azo dyes under similar conditions at the optimum pH 7.0 and temperature of 37℃. The efficiencies of decolorization for DBO-RR, DBM, EBR with intact cells stood more than 90%. When the cell concentration was 15mg (wet)/ml and the reaction time was 5 hours, the decolorizing activities of intact cells for above three azo dyes were 1.75, 2.4, 0.95 μg dye/mg cell, respectively. Cell-free extract and purified enzyme belonged to azoreductase with molecular weight about 34000±2000 and Vmax and Km values for DBO-RR of 13μmol/mg protein/nun and 54μmol, respectively. The results from the detection of the biodegradation products of DBO-RR by spectrophotometric and NaNO2 reac     

双频超声辐射协同H_2O_2降解偶氮染料废水的研究

采用双频超声协同H2O2降解酸性绿20染料废水,考察超声功率密度、染料初始浓度和pH、饱和气体及H2O2投加量等因素对酸性绿20降解效果的影响,结果表明,在给定实验条件下,双频降解效果优于单频超声波,且降解率随超声功率密度的增大而增大。酸性条件有利于酸性绿20的降解,当染料废水初始pH=4可取得最佳的降解效果;酸性绿20的降解效率随染料初始浓度的增大而降低,其优化初始浓度为40 mg/L。在反应体系中通入空气并投加H2O2,可取得最佳的降解效果。在优化实验条件下,采用双频超声协同H2O2降解5 h,酸性绿20的色度和TOC去除率分别为94.6%和36.3%;分析降解前后的紫外-可见光谱图可知,酸性绿20并非完全被降解为CO2和H2O,而是生成一些小分子有机中间体。     

醌还原酶 醌类化合物对偶氮染料脱色的作用

外加醌类化合物作介体,利用细菌胞内的醌还原酶考察基因工程菌Escherichia coli YB对偶氮染料的脱色能力,以及甲基氢醌预处理对E. coli JM109和厌氧污泥脱色的影响.结果表明,介体2羟基1,4萘醌（lawsone,LQ）的存在对胞内过量表达醌还原酶AZR的E. coli YB的脱色能力有显著的促进作用,0.2 mmol·L^-1 LQ存在下,苋菜红（1 mmol·L^-1）在2 h内可脱色75%.LQ存在时E. coli YB对高浓度的染料也有脱色效果,8 h可使苋菜红（5 mmol·L^-1）脱色50%左右.与LQ相比,甲萘醌作为介体对脱色的促进效果较差,2.5 mmol·L^-1甲萘醌存在下脱色70%需12 h.LQ存在时E. coli YB对苋菜红的重复脱色能力稳定,12 h内能完成4次重复脱色.LQ的存在对于结构较复杂的2种偶氮染料酸性大红GR和活性艳红K2BP的脱色也有促进作用,在最适LQ浓度下,分别在9 h和30 h脱色70%.甲基氢醌预处理对E. coli JM109和厌氧污泥的脱色能力都有促进作用.预处理后在LQ存在下,E. coli JM109在5 h可脱色苋菜红（1 mmol·L^-1）80%左右,而污泥可在11 h脱色75%以上.     

藻类对偶氮染料的降解及定量结构-生物降解性研究

通过研究普通小球藻（ Chlorella vulgaris） 、蛋白核小球藻（Chlorella pyrenoidosa） 、斜生栅藻（Scenedes nusobliquus） 对偶氮染料的降解作用,筛选出优势藻种并优化降解条件;对单偶氮染料进行了定量结构—生物降解性相关关系（QSBR） 研究．3 种藻均能利用偶氮染料为其生长的唯一 C、 N 源,使染料脱色,蛋白核小球藻具有更强的脱色能力;且藻在无 N 环境中的脱色率明显高于无 C 和正常环境;pH 值对染料脱色影响较大,最佳pH值为中性;不同结构的单偶氮染料生物降解性相差很大,脱色率为9.1 ％ （89.9 ％ , QSBR 研究表明, 偶氮键的最低未占据轨道能量是控制生物降解的主要因素,而脱色率与染料的分子量无关．     

亚铁羟基络合物还原转化水溶性偶氮染料

偶氮染料是印染工艺中应用最广泛的一类染料,目前染料废水脱色是污水处理难题。亚铁混凝处理染料废水过程中可能存在亚铁的还原作用,本实验制备了比溶解态亚铁更具还原反应活性的亚铁羟基络合物(ferrous hydroxycomplex,FHC),以5种不同类型的水溶性偶氮染料为目标污染物,研究FHC还原水溶性偶氮染料的脱色性能。实验结果表明,FHC对活性艳红X-3B、酸性大红GR和阳离子红X-GRL有较好的还原脱色效果,仅投加含铁89.6 mg/L的FHC,染料脱色率达到90%以上,继续增大FHC投加量可以完全脱色;中性枣红GRL的FHC还原脱色效果较差,需加入313.6 mg/L的FHC才能达到90%以上脱色率;134.4 mg/L的FHC能够将直接耐酸大红4BS完全脱色,但其脱色主要以混凝沉淀为主;溶液pH对FHC的还原性能产生重要影响,FHC还原染料脱色的适宜的pH值范围为4～10。该研究为亲水性染料脱色提供了一种新的技术,也为FHC运用于印染废水脱色提供了理论基础。     

Role of quantum dots nanoparticles in the chemical treatment of colored wastewater: Catalysts or additional pollutants

The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters. The special interest is devoted to the investigation of their role in the typical treatment of water or wastewater, studying their influence on the effectiveness of applied treatments methods. The standard chemical processes for water treatment and disinfection (direct UV photolysis and direct ozonation) were applied for the degradation of colored organic pollutant, reactive azo dye, in the presence/absence of CdSe/ZnS core-shells quantum dots. The obtained results indicated that investigated nanoparticles inhibit the overall efficiency of applied processes, especially in the case of direct UV photolysis, although catalytic effect might be expected in part due to the semiconductor nature of quantum dots. Such results lead to a conclusion that CdSe/ZnS nanoparticles behave as additional pollutants in the system. They should be removed from the system prior the treatment, because their presence could decrease the efficiency, i.e., prolong the time of treatment and correspondingly increase the costs of the treatment process.     

偶氮染料对斜生栅藻的毒性作用及结构活性相关性研究

为了揭示不同结构染料对水生生态系统的毒性作用,研究９种偶氮类及２种蒽醌类染料对斜生栅藻的生长抑菌作用,并通过剖析毒性一结构之间的相关关系,探讨了偶氮染料的毒作用机理,１１种染产对斜生栅藻的４８ｈＥＣ５０在１．０９－４１．２２ｍｇ．Ｌ＾－１之间,偶氮染料分子中所包含偶氮键的个数及芳香环上取代基的亲水性和电性均影响染料的毒性,进一步证实偶氮染料的毒同理为Ｎ－Ｎ键不宾为一ＮＨ２后,形成Ｎ＋离子活性民生物     

Identification of Sudan III-(deoxy)-guanosine adducts formed in situ in a reaction with no catalyst

Incubation of guanosine and Sudan III induces the formation of a stable adduct, which may be identified using a spectrophotometric technique and mass spectroscopy. The high nucleophilicity of the C⁸ position and its proximity to N⁷ makes the site susceptible to a nucleophilic attack, which explains the S_N2 reaction detected between guanosine and Sudan III dye. In addition, direct interaction of Sudan III with calf thymus DNA was monitored using a simple spectrophotometric technique. The results presented indicate that a simple modification of the chemical structure of Sudan I (monoazo dye) to Sudan III (diazo dye) markedly alters reactivity towards nitrogenous DNA bases.     

Utilization of powdered waste sludge (PWS) for removal of textile dyestuffs from wastewater by adsorption

Acid pre-treated powdered waste sludge (PWS) was used for removal of textile dyestuffs from aqueous medium by adsorption as an alternative to the use of powdered activated carbon (PAC). The rate and extent of dysetuff removals were determined for four different dyestuffs at different PWS concentrations varying between 1 and 6 gl(-1). Biosorbed dyestuff concentrations at equilibrium decreased with increasing PWS concentration for all dyestuffs tested. PWS was more effective for adsorption of Remazol red RR and Chrisofonia direct yellow 12 as compared to the other dyestuffs tested. More than 80% percent dyestuff removal was obtained for all dyestuffs at PWS concentrations above 4 gl(-1) after 6h of incubation. Similar to percent dyestuff removal, the rate of adsorption was maximum at a PWS concentration of 4 gl(-1). Kinetics of adsorption of dyestuffs was investigated by using the first- and second-order kinetic models and the kinetic constants were determined. Second-order kinetics was found to fit the experimental data better than the first-order model for all dyestuffs tested. Adsorption isotherms were established for all dyestuffs used and the isotherm constants were determined by using the experimental data. Langmuir and the generalized adsorption isotherms were found to be more suitable than the Freundlich isotherm for correlation of equilibrium adsorption data. Acid pre-treated PWS was proven to be an effective adsorbent for dyestuff removal as compared to the other adsorbents reported in literature studies.     

咪唑银配位聚合物吸附偶氮染料研究

以咪唑银配位聚合物{Ag（im）}n作吸附剂,对偶氮染料刚果红和甲基橙的吸附进行了研究,结果表明：刚果红的最佳吸附条件是吸附剂加入量为31．5mg,温度为30℃,pH值为3,吸附时间为70min,最高染料脱除率为90。7％;甲基橙的最佳吸附条件是吸附剂加入量为36．7mg,温度为30℃,pH值为2,吸附时间为50min,最高染料脱除率为58．3％。