Biodecolorization and partial mineralization of Reactive Black 5 by a strain of Rhodopseudomonas palustris

A strain of photosynthetic bacterium, Rhodopseudomonas palustris W1, isolated from a lab-scale anaerobic moving bed biofilm reactor (MBBR) treating textile e?uent was demonstrated to decolorize Reactive Black 5 (RB5) effciently under anaerobic condition. By a series of batch tests, the suitable conditions for RB5 decolorization were obtained, namely, pH < 10, light presence, glutamine or lactate as carbon source with concentration more than 500 mg/L when lactate is selected, NH4Cl as a nitrogen source wi...

Burial Records of Reactive Iron in Cretaceous Black Shales and Oceanic Red Beds from Southern Tibet

One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method was applied to these two types of rocks from southern Tibet to investigate the burial records of reactive iron. Results indicate that carbonate-associated iron and pyrite are relatively enriched in the black shales, but depleted or absent in red beds. The main feature of the reactive iron in the red beds is relative enrichment of iron oxides （largely hematite）, which occurred during syn-depostion or early diagenesis. The ratio between iron oxides and the total iron indicates an oxygen-enriched environment for red bed deposition. A comparison between the reactive iron burial records and proxies of paleo-productivity suggests that paleo-productivity decreases when the ratio between iron oxides and the total iron increases in the red beds. This phenomenon could imply that the relationship between marine redox and productivity might be one of the reasons for the sedimentary transition from Cretaceous black shale to oceanic red bed deposition.

Effects of glucose on the decolorization of Reactive Black 5 by yeast isolates

The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium. Color removal of 200 mg dye/L was increased from 76.4% to 92.7% within 60 h to 100% within 18-24 h with the increase of glucose from 5 to 10 g/L, although the activity of manganese dependent peroxidase （MnP） decreased by 2-8 times in this case. Hydrogen peroxide of 233.3 μg/L was detected in 6 h in D. polymorphus culture. The cometabolic functions of glucose and hydrogen peroxide could be also confirmed by the further color removals of 95.8% or 78,9% in the second cycle of decolorization tests in which 7 g glucose/L or 250 μg H202/L was superadded respectively together with 200 mg dye/L.

Response of Reactive Phosphorus Burial to the Sedimentary Transition from Cretaceous Black Shales to Oceanic Red Beds in Southern Tibet

The mechanism of sedimentary transition from the Cretaceous black shales to the oceanic red beds is a new and important direction of Cretaceous research. Chemical sequential extraction is applied to study the burial records of reactive phosphorus in the black shale of the Gyabula Formation and oceanic red beds of the Chuangde Formation, Southern Tibet. Results indicate that the principal reactive phosphorus species is the authigenic and carbonate-associated phosphorus （CAP） in the Gyabula Formation and iron oxides-associated phosphorus （FeP） in the Chuangde Formation which accounts for more than half of their own total phosphorus content. While the authigenic and carbonate-associated phosphorus （CAP） is almost equal in the two Formations; the iron oxidesassociated phosphorus is about 1.6 times higher in the Chuangde Formation than that in the Gyabula Formation resulting in a higher content of the total phosphorus in the Chuangde Formation. According to the observations on the marine phosphorus cyde in Modern Ocean, it is found that preferential burial and regeneration of reactive phosphorus corresponds to highly oxic and reducing conditions, respectively, leading to the different distribution of phosphorus in these two distinct type of marine sediments. It is the redox-sensitive behavior of phosphorus cycle to the different redox conditions in the ocean and the controlling effects of phosphorus to the marine production that stimulate the local sedimentary transition from the Cretaceous black shale to the oceanic red beds.

EQUILIBRIUM AND KINETIC ADSORPTION OF A REACTIVE BLACK KNB DYE ON POLYDIVINYLBENZENE AND STYRENE-DIVINYLBENZENE COPOLYMER RESINS

In this study, two polymeric resins with different pore sizes were synthesized to study comparative adsorption of reactive black KNB dye. Styrene-divinylbenzene copolymer resin NG-8 has an average pore size of 3.82 nm, about half of that of polydivinylbenzene resin NG-7 （6.90 nm）. NG-8 also has a surface acidity about 4 times that of NG-7, resulting in a much more negative surface of the former resin as compared to the latter at pH 6.05. Equilibrium adsorption of KNB was significantly influenced by the surface functionality of the resins, as evidenced by the observations that NG-8 adsorbed constantly less KNB than NG-7 and that the presence of CaCl2 enhanced the adsorption by both resins. The intra-particle diffusion appears to be the primary rate-limiting process. While the pores of both resins are accessible to KNB, the slower adsorption by NG-8 than by NG-7 suggests that the smaller pores of NG-8 further retard the intra-particle diffusion of KNB.

Development of the N-Doped Cu-Carbon Composite as a Novel Catalyst for the Removal Reactive Black 5

In this study, two Cu-based catalysts with and without N doped carbon matrix, named N-Cu/CuO/C and Cu/CuO were synthesized via calcination of melamine-cupper acetate complex and cupper acetate at 500°C under an inert atmosphere. The catalysts were characterized by X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and CHNS elemental analyzer. The catalytic activity of both catalysts was evaluated through the NaBH4 associated reduction of commercial textile dye named reactive black 5 (RB5). The kinetics of the reduction of reactive black 5 was also described by the pseudo-first-order kinetic equation. For the studied reduction, N-Cu/CuO/C exhibited enhanced catalytic activity both in conversion and kinetics (97% conv. in 315 sec) compared to that of by Cu/CuO/C (25% conv. in 1500 sec). Besides, N-Cu/CuO/C also demonstrated good reusability up to four consecutive cycles.

TiO₂PC500 Coated on Non Woven Paper with SiO₂as a Binder-Assisted Photocatalytic Degradation of Reactive Black 5 in Aqueous Solution

Photocatalytic discoloration kinetics of Reactive Black 5 (RB5), a vinylsulfone dye, has been studied spectrophotometrically by following the decrease in dye concentration with time at ambient conditions using a flow loop reactor. UV lump, Black Light Blue (BLB) emitting at maximum wavelength of 365 nm and Ahlstrom Research Service paper consistent of TiO2 P500 coated on non woven paper was used respectively as source of UV light and photocatalyst. At natural pH, the result shows that photolysis of RB5 and its adsorption in the presence of photocatalyst was negligible while the photocatalytic oxidation (PCO) permits 30.8% of RB5 degradation. The degradation of dye was studied under a variety of conditions such as volumetric flow rate, initial pH, photocatalyst reuse, and in the presence of electron acceptor such as sodium persulphate ((Na)2S2O8). The degradation rates were found to be strongly influenced by all the above parameters. The circulation flow rate of 108 L/h was the best. The rate constant calculated when the initial pH was varied shows that pH 3 was more favorable for RB5 removal. Peroxydisulphate ions have the strong effect on RB5 discoloration even in dark without and with photocatalyst. When UV light was used in the presence of photocatalyst, 50 min was enough for quasi-total removal of RB5 with (0.2 M).

Biotransformation of Carmoisine and Reactive Black 5 Dyes Using <i>Saccharomyces cerevisiae</i>

Saccharomyces cerevisiae (baker’s yeast) is the most important industrial microorganisms. This yeast is commonly used as a leavening agent in baking bread and bakery products, where it produces carbon dioxide from converting of the fermentable sugars present in the dough. Nowadays, industrial and chemical activities led to produce new compounds with new kinds of contamination in the environment. Discharge of untreated or partially treated industrial sewage has created the contamination problems of rivers and lakes such as drugs, oil, heavy metals, paints, pesticides and various chemical compounds in them. Hence, it is necessary to control and reduce the levels of these compounds in wastewater and bring them to permissible values. This study aims to study the bioconversion potential of commonly available Saccharomyces cerevisiae for the two textile dyes of Carmoisine and Reactive Black 5. Reaction mixtures for biotransformation of dyes included 50 mg/l Carmoisine or 25 mg/l Reactive Black 5 and 1% dried harvested cells of S. cerevisiae (bread’s yeast) were tested. Harvested dry and wet yeast were studied for this purpose. The results show that harvested cells of Saccharomyces cerevisiae are able to bioconvert Carmoisine and Reactive Black 5. Reactive Black 5, Carmoisine are degraded by biotransformation 85% and 53% within 24 hours in water at the room temperature.

Multiwall Carbon Nanotube Modified Electrochemical Sensor for Reactive Black 5

Cyclic voltammograms of reactive black5 (RB5) at different pHs in the range 1.0 - 13.0 on multiwall carbon nanotube modified glassy carbon electrode revealed the presence of one well-defined irreversible anodic peak around 975 mV in acidic and neutral pHs. Adsorption controlled oxidation observed at acidic pH 1.0 resulted in the maximum peak current response in cyclic voltammograms. A systematic differential pulse stripping voltammetric studies were carried out using the modified electrode at pH 1.0. The accumulation parameters, accumulation potential and time were optimized for maximum adsorption of the dye which was ascertained from the SEM photographs and XRD results. The stripping parameters were optimized and calibration was made under optimum conditions. The range of study was from 0.5 ppm to 100 ppm and the lower limit of determination was 100 ppm. Five identical experiments were carried out and the RSD value obtained was 2.5% suggesting good reproducibility. The proposed method was successfully applied to determine the concentration of dye in the fabric and wastewater after dyeing.

Equilibrium and Kinetic Studies of Reactive Black 8 Adsorption onto Crosslinked Chitosan Beads

Environmental pollution problems by the discharge of effluent containing various contaminations from textile, paper and paint industries have become a serious issue in recent years. Dye removal from wastewater has received considerable attention for several adsorbents and several classes of dye. Reactive black 8 is an environmentally hazardous dye and most applicable in textile industries. Chitosan is a non-toxic, biodegradable and biocompatible and acts as an efficient adsorbent because of the amino functional groups. In the present work, the crosslinked chitosan beads were synthesized by using glutaraldehyde as a crosslinker and the adsorptive removal of reactive black 8 by the beads from an aqueous solution was investigated. The effect of contact time and initial dye concentration was evaluated. The adsorbent dosage was retained as 1 g/L and initial dye concentration values were varied from 30 to 150 mg/L. Equilibrium isotherms were analysed by Langmuir, Freundlich, Dubnin–Radushkevich, and Temkin isotherm. Freundlich isotherm model was found fit effectively for the reactive black 8 adsorptions. Kinetic adsorption data were evaluated using the pseudo-first-order kinetic model, the pseudo-second-order kinetic model and the intraparticle diffusion model. The adsorption followed pseudo second order kinetics. Overall, this study indicates chitosan beads as an efficient, eco-friendly and low-cost adsorbent for the removal of reactive black 8 dye from aqueous solutions.

改性凹凸棒土处理活性黑KN-B染料废水的研究

针对许多地区缺水越来越严重的状况,开发了一种高效廉价深度水处理吸附剂PDMDAAC-凹凸棒土,它以凹凸棒土和聚二甲基二烯丙基氯化铵(PDMDAAC)为原料,常温下制备而成。用该改性凹凸棒土对活性黑KN-B染料废水进行处理。结果表明,当活性黑浓度为20mg/L,吸附剂用量为0.03%,pH值为8.0,振荡吸附时间为60min时,活性黑染料废水脱色率达到98.3%,吸附容量为65.5mg/g。

厌氧生物降解活性黑KN-B5

研究了在葡萄糖作为共代谢基质时活性黑KN-B5的降解效果。实验结果表明:当葡萄糖质量浓度为1 500m g/L时,活性黑KN-B5初始质量浓度为30m g/L的染料溶液厌氧生物降解24h和48h后的降解率分别达到77.5%和90.3%;活性黑KN-B5的厌氧降解符合一级动力学方程,其反应速率常数为0.043 6h-1,半衰期为15.9h;葡萄糖质量浓度的增大对提高活性黑KN-B5厌氧生物降解效果有利。紫外-可见光谱扫描结果表明,活性黑KN-B5的降解过程中生成了小分子芳香胺类化合物;扫描电子显微镜照片表明污泥中对活性黑KN-B5起降解作用的菌种主要是杆菌和球菌。

酵母菌Y48对活性黑KN-B的脱色研究

从土壤中分离获得了一株对偶氮染料具有明显脱色效果的酵母菌Pseudozyma rugulosaY48,其对初始浓度为100 m.gL-1的活性黑KN-B的最大脱色率可达99%.采用酵母菌Y48对偶氮染料脱色的优化控制条件是:接种量应不低于3%(体积分数);最适pH值在6—9之间;氮源(NH4)2SO4的浓度不低于0.1%;碳源葡萄糖的浓度为1%.对其脱色机理的研究表明,Y48对活性黑KN-B的脱色是由吸附和降解两个过程完成的,而对活性黑KN-B分子的去除则主要依靠生物降解.此研究表明,酵母菌Y48在染料废水的处理上具有较大的应用潜能.

3种污泥对活性黑KN-B的生物吸附及降解研究

对比研究了好氧污泥、厌氧污泥和厌氧颗粒污泥对染料活性黑KN-B的吸附和降解。结果表明,这3种污泥对活性黑的吸附均符合Freundlich模型(R^2为0.9665～0.9859)和Langmuir模型(R^2为0.9460～0.9906),但3种污泥对活性黑这种染料的吸附量较小;并且厌氧污泥对活性黑的吸附能力优于好氧污泥和厌氧颗粒污泥。实验还发现,3种污泥对活性黑的脱色主要是生物降解作用,而不是吸附作用。

活性黑KN-B染料的生物降解研究

通过试验考察了厌氧条件下活性黑KN-B的生物降解历程,同时对染料的降解动力学及降解机理进行了初步探讨与分析。结果表明:厌氧颗粒污泥可以单独降解活性黑KN-B(以活性黑为单一碳源时,活性黑KN-B的24降解率为43.1%),也可以在以葡萄糖为共基质条件下降解活性黑KN-B;以活性黑KN-B为单一碳源时其降解过程符合一级反应动力学方程,而以葡萄糖为共基质时其降解过程符合二级反应动力学方程;对降解前和降解24h后的降解液采用UV一可见、红外光谱分析,用UV-可见光谱发现活性黑KN-B在可见光区600nm处的吸收峰已消失,并且紫外区309nm处的吸收峰减弱,但255nm处的吸收峰增强,说明活性黑KN-B染料中的偶氮键断裂后生成芳香胺类化合物,这些中间产物可进一步降解。用红外光谱分析,结果与UV-可见光谱分析一致。

活性黑KN-B的M^(n+)/H_2O_2型高级氧化脱色研究

开展Mn+(Fe2+、Fe3+、Co2+、Cu2+)/H2O2型高级氧化体系对活性黑染料KN-B的氧化脱色研究。发现实验条件下经典Fenton体系(Fe2+/H2O2)对KN-B脱色效果随酸性增强、反应时间延长、反应温度升高和初始染料浓度降低增加;在pH=7,T=25℃,KN-B、H2O2与催化剂Fe2+初始浓度比例为1∶5∶1.6时,100 min脱色率可达96.60%。分别进行pH=3,7和10条件下Fe3+/H2O2、Co2+/H2O2、Cu2+/H2O2体系对KN-B的脱色研究,结果表明与Fe2+/H2O2高级氧化体系相比,Co2+/H2O2体系脱色效果不明显,而Fe3+/H2O2和Cu2+/H2O2分别在中性和碱性条件下可在短时间内达到更高的脱色率。初始pH=7,50 min后Fe3+/H2O2体系脱色率可达98%以上,该体系更适于KN-B氧化脱色。

橙色活性染料的合成及其与活性黑KN-B拼色的研究

本文以J酸为偶合组分合成了22只橙色活性偶氮染料,研究了其中一些染料的合成工艺。指出了染料中游离的J酸增加,会使染料的色光偏红,偶合反应最终pH升高是由于作为缚酸剂的碳酸钠分解逸出二氧化碳所致。活性橙1,2与活性黑KN—B分别以1:4.95、1:4.73的配比拼色可以使活性黑KN—B的乌黑度大幅提高。

活性黑KN-B的日晒牢度与染色工艺关系的研究

本文对活性黑KN-B(C.I.Reactive Black 5)染纯棉织物的染料浓度,固色率和染色后处理条件与日晒牢度的关系,以及三原色拼色时对日晒牢度的影响做了探讨,同时对涤/棉织物两浴法染色的活性黑KN-B与分散蓝HBGL对其日晒牢度的影响做了研究。结果表明:活性黑KN-B染纯棉织物,其日晒牢度随染料浓度和固色率的增加而提高,且固色率为70％以上时,日晒牢度大幅度提高。染色后处理,碱剂与皂煮对日晒牢度亦有一定的影响。使用活性黑KN-B,活性红M-3BE,活性黄M-3RE拼色对织物染色时,在KN-B的浓度为1％以下,其日晒牢度随浓度的增加而下降,在KN-B的浓度超过1％时其日晒牢度随浓度的增加而升高;日晒牢度随活性红M-3BE与活性黄M-3RE的浓度的增加而增大。采用分散/活性二浴法染涤/棉织物,其日晒牢度随KN-B浓度的增加,先降低后升高,在染料浓度大于1％时,日晒牢度几乎不在变化;但其日晒牢度随分散蓝HBGL的浓度的增加而增大。

活性黑KN-B合成及膜处理工艺

本文对活性黑KN-B合成及膜处理工艺进行了探讨,探索了提高藏青含量的合成方法。通过高效液相色谱分析,得出最佳合成工艺条件。由于反应产物中含有大量的无机盐,染料的纯度低,因此对反应产物进行膜处理,分离反应产物中的无机盐,从而提高活性黑KN-B的纯度。

铝阳极电凝聚处理活性黑KN-B染料模拟废水

对铝阳极电凝聚处理活性黑KN-B模拟废水进行了初步的实验研究。考察了电流密度、初始pH值、电解质浓度及种类、温度、染料浓度等因素的影响。结果表明,在一定实验条件下,活性黑KN-B模拟废水的脱色效率可达到88%;电流强度、染料浓度、电解液初始pH值、氯化钠电解质浓度、温度对染料溶液脱色效率的影响明显,而硫酸钠电解质浓度对脱色效率的影响不显著;在电凝聚处理过程中,主要作用机理是吸附网捕占主导地位;活性黑KN-B在阴极上发生了还原反应。