Kinetics of chemical decolorization of the azo dye C.I. Reactive Orange 96 by sulfide

The mechanism of decolorization of azo dyes based on the extracellular chemical reduction with sulfide (H2S, HS-, S2-) was postulated for sulfate reducing environments. To design technical decolorization processes of textile wastewater treatment with sulfide produced by sulfate reducing bacteria (SRB), kinetics is of great significance. Batch experiments were made in order to investigate the kinetics of abiotic decolorization of the reactive mono-azo dye C.I. Reactive Orange 96 (RO 96) with sulfide, with varying pH. The decolorization of RO 96 by sulfide under the exclusion of O2 corresponded to first-order kinetics with respect to both dye and sulfide concentration. The decolorization of RO 96 with sulfide at neutral pH (7.1) was advantageous compared with that at pH for 4.1, 6.3, and 6.5. This is attributed to an increase in the fraction of HS- of total sulfide species at neutral pH. The rate constants k for the decolorization at 37 degrees C were obtained as 0.01 for pH = 4.1, 0.06 for pH = 6.3, 0.08 for pH = 6.5, and 0.09 for pH = 7.1 in mM(-1) min(-1). The high rate constants for sulfide at pH 6.5-7.1 support that the decolorization through SRB (i.e. by bio-sulfide) can be effective in anaerobic bacterial systems with sulfate.     

Shewanellasp．XB缺氧反硝化降解苯酚

苯酚的生物降解一直受到关注。以苯酚为惟一电子供体,研究了Shewanellasp．XB对苯酚的缺氧降解特性。研究结果表明,在反硝化条件下,当C／N为13．3时,苯酚可以完全降解,NO2--N积累量很少。另外,当加入氧化还原介体,如核黄素3μmol／L、AQDS0．01mmol／L、AQS0．05mmol／L和LQ0．01mmol／L时,苯酚降解速率分别为不加介体时的1．45、1．77、1．67和1．63倍。当以氯化铵代替硝酸盐时,苯酚也能进行厌氧发酵降解。另外,菌株XB反硝化降解苯酚可能是厌氧和好氧降解的混合过程。     

Copper-ligand complex for the decolorization of synthetic dyes

The reaction system containing Cu(II), hydrogen peroxide and D-arabinono-1,4-lactone was found to be effective in the decolorization and reduction of toxicity of azo, thiazine-, triphenylmethane- and anthraquinone-based synthetic dyes. More than 85% decolorization was obtained with 100ppm Acridine Orange, Azure B, Chicago Sky Blue 6B, Crystal Violet, Evans Blue, Poly B-411, Reactive Blue 2, Reactive Blue 5, and Remazol Brilliant Blue R incubated for 24h in the presence of 10mM CuSO(4), 20mM D-arabinono-1,4-lactone and 80 mM H(2)O(2). The rate of decolorization was not affected by pH in the range of 3-9. The rapid decolorization was accompanied by a fast decomposition of H(2)O(2) in the reaction mixture and by a fast production of hydroxyl radicals.     

Fe/Ce/沸石负载型类芬顿催化剂制备及其特性

采用柠檬酸盐溶胶-凝胶法制备了Fe/Ce/沸石负载型芬顿催化剂,通过透射电镜(TEM)和X射线衍射(XRD)对其进行表征,并将其作为非均相类芬顿催化剂处理孔雀石绿染料溶液。研究表明,通过掺杂Ce,可提高催化剂颗粒分散度和催化剂表面的氧气含量,进而提高催化活性。在催化剂投加量3.0 g/L,H2O2投加量67 mg/L,pH=8.0的条件下,反应30 min后,浓度为150 mg/L的孔雀石绿溶液脱色率可达97.3%。     

缺氧-好氧生物滤池中高效菌对活性红KN-3B的降解特性

为了研究高效脱色菌在缺氧好氧生物滤池（A/O biofilter）中对偶氮染料的降解特性,以活性红KN-3B（C.I. reactive red 180）为降解对象,缺氧生物滤池以火山碎石为填料,接种高效脱色菌CK3柯氏柠檬酸杆菌启动,好氧生物滤池以牡蛎壳为填料,接种污水处理厂活性污泥启动。试验考察了不同工况下缺氧-好氧生物滤池对色度和COD的去除效果,结果表明：生物滤池中微生物对偶氮染料活性红KN-3B的脱色和对COD降解的最适pH条件为弱酸性;缺氧滤池中高效菌对色度的去除需要外加碳源,且增加外加碳源有助于脱色率的提高;该高效菌为耐盐菌,当进水NaCl浓度达30 g/L时,色度去除率仍可达93%以上;当染料负荷达500 mg/L时,脱色率仍可达95%。通过紫外-可见扫描图谱分析初步推断CK-3柯氏柠檬酸杆菌对偶氮染料活性红KN-3B的脱色主要是生物降解作用。     

Anaerobic biodegradation of biphenyl in various paddy soils and river sediment

The anaerobic degradation of biphenyl was investigated in four uncontaminated Japanese paddy soils and one river sediment sample contaminated with benzene and chlorinated aliphatics. Two of the paddy soils and the sediment were capable of degrading biphenyl anaerobically without any additional medium or electron acceptors. The half-lives of biphenyl biodegradation in the three samples were 212 d in the Kuridashi soil, 327 d in the Kamajima soil, and 429 d in the river sediment. The Kuridashi soil metabolized 1+/-0.3% of [U-14C]-biphenyl into CO2 and 5+/-2% into water-soluble metabolites after 45 d of incubation. Submerged conditions, which result in lower nitrate and iron oxide contents, and neutral pH, appeared to be the common properties among the samples that influenced their degradation capacities. The addition of 10mM sulfate and 20mM Fe(III) as electron acceptors did not enhance the biphenyl degradation rate, whereas 10mM nitrate completely inhibited biphenyl degradation. The addition of different electron donors (lactate, acetate, or pyruvate) slightly slowed the degradation. Molybdate (an inhibitor of sulfate-reducing bacteria) had an inhibitory effect on biphenyl biodegradation, but bromoethanesulfonic acid (an inhibitor of methanogens) did not. Most biphenyl degradation was observed when only water was added, with no other electron acceptors or donors. These results suggest that sulfate-reducing bacteria and fermentative microbial populations play important roles in anaerobic biphenyl biodegradation in paddy soil.     

Citrobacter sp. CK3对活性红KN-3B的脱色反应动力学研究

采用脱色菌Citrobacter sp. CK3,以活性红KN-3B染料为处理对象,在厌氧批式反应条件下,系统考察了pH值,温度和染料浓度对脱色反应速度的影响;通过动力学模拟及反应过程中染料的UV-Vis扫描图分析,探讨了脱色反应机理。结果表明：Citrobacter sp. CK3对活性红KN-3B的脱色反应的适宜pH为7～9;脱色反应速度在温度为32℃时达到最大。染料初浓度从57 mg/L逐渐增大到458 mg/L时脱色率逐渐降低。脱色过程中染料的偶氮键发生断裂,脱色反应符合二级反应动力学。     

Quantitation of Hydroxyl Radicals from Photolysis of Fe(III)-Citrate Complexes in Aerobic Water (5 pp)

Background For their high photoreactivity, Fe(III)-carboxylate complexes are important sources of H2O2 for some atmospheric and surface waters. Citrate is one kind of carboxylate, which can form complexes with Fe(III). In our previous study, we have applied Fe(III)-citrate complexes to degrade and decolorize dyes in aqueous solutions both under UV light and sunlight. Results have shown that carboxylic acids can promote the photodegradation efficiency. It is indicated that the photolysis of Fe(III)-citrate complexes may cause the formation of some reactive species (e. g. H2O2 and ·OH). This work is attempted to quantify hydroxyl radicals generated in the aqueous solution containing Fe(III)-citrate complexes and to interpret the photoreactivity of Fe(III)-citrate complexes for degrading organic compounds. Methods By using benzene as the scavenger to produce phenol, the photogeneration of ·OH in the aqueous solution containing Fe (III)-citrate complexes was determined by HPLC. Results and Discussion In the aqueous solution containing 60.0/30.0 mM Fe(III)/citrate and 7.0 mM benzene at pH 3.0, 96.66 mM ·OH was produced after irradiation by a 250W metal halide light (l ≥ 313 nm) for 160 minutes. Effects of initial pH value and concentrations of Fe(III) and citrate on ·OH radical generation were all examined. The results show that the greatest photoproduction of ·OH in the aqueous solution (pH ranged from 3.0 to 7.0) was at pH 3.0. The photoproduction of ·OH increased with increasing Fe(III) or citrate concentrations. Conclusion In the aqueous solutions containing Fe(III)-citrate complexes, ·OH radicals were produced after irradiation by a 250W metal halide light. It can be concluded that Fe(III)-citrate complexes are important sources of ·OH radicals for some atmospheric and surface waters. Recommendations and Outlook It is believed that the photolysis of Fe(III)-citrate complexes in the presence of oxygen play an important role in producing ·OH both in atmospheric waters and surface water where high concentrations of ferric ions and citrate ions exist. The photoproduction of ·OH has a high oxidizing potential for the degradation of a wide variety of natural and anthropogenic organic and inorganic substances. We can use this method for toxic organic pollutants such as organic dyes and pesticides.     

铜铈复合氧化物催化降解甲基橙

采用水热法制备的铜铈复合氧化物能够直接催化降解甲基橙,探究了铜铈摩尔比、pH、投加量对催化降解效果的影响。研究发现,pH=3.5、Cu/Ce=1、投加量1.0 g·L-1时,甲基橙的降解效果最佳。在0.5~1.0 g·L-1之间时,随着投加量的增加,甲基橙的脱色速率加快,脱色率也有所增加。随着溶液中的pH逐渐下降,甲基橙脱色率有所增加,pH=3.5时,甲基橙脱色率最高;而进一步降低pH至3.0时,脱色率反而下降,可能是强酸腐蚀了金属氧化物表层,降低了甲基橙的降解效果。甲基橙主要因其被降解而脱色,促使甲基橙脱色的活性物质为·OH,且与体系中的分子氧有关,反应过程消耗一定的H+。     

Fe-AC微电解活化过硫酸盐降解直接耐酸大红4BS

为快速脱色降解偶氮类染料,同时解决零价铁活化效率低、易被氧化的问题,以直接耐酸大红4BS（大红4BS）为模拟废水污染物,通过Fe-AC/PDS（铁碳微电解活化过硫酸钠）反应体系对大红4BS进行脱色降解。对影响大红4BS降解的几种因素如Fe：AC（铁碳质量比）、PDS浓度、初始pH等进行探究。结果表明,大红4BS脱色率在Fe：AC=3：1时高达94.7%。增大PDS浓度能明显促进反应进行,但超过5 mmol·L-1时,对体系影响不大。初始溶液pH对Fe-AC/PDS体系降解大红4BS作用显著,在酸性和中性（pH=3.02、4.67、7.32）时,大红4BS的脱色率分别高达98.8%、96.2%、94.7%,但在碱性（pH=9.38、10.78）条件下,其脱色率只有24.5%、18.7%。无机盐阴离子对Fe-AC/PDS体系降解大红4BS有抑制作用,而阳离子对其产生促进作用。自由基俘获实验表明Fe-AC/PDS体系降解大红4BS并不仅仅只是自由基的氧化反应,还存在其他复杂反应,继而对Fe-AC/PDS体系降解大红4BS的机理进行探讨。     

Degradation of azo dyes using low iron concentration of Fenton and Fenton-like system

This study investigated Fenton and Fenton-like reactions at low iron concentration (相似文献   

响应曲面法优化电化学氧化技术处理染料废水

采用IR和XRD等手段对自制磷钼酸铁(FePMo12)杂多酸进行表征,表明杂多阴离子具有Keggin结构。将FePMo12负载于修饰后的分子筛上制备FePMo12/APTES-4A催化剂填充于电化学反应器中,考察电化学氧化体系对酸性大红3R染料废水的脱色效果,其脱色率高于二维电化学反应器。利用Box-Behnken中心组合实验设计及响应面(RSM)分析,以pH值,板间距,槽电压,曝气量为实验因素,建立了以酸性大红3R的脱色率为响应值的二次多项式回归模型。研究表明,当电解时间为60 min时,曝气量0.05 m3/h、pH为2、板间距3.0 cm、槽电压11.0 V,在此条件下色度去除率可达69.4%,模型预测值与实验值能很好地吻合。方差分析结果表明,槽电压和pH、pH和曝气量的交互作用对响应值具有显著性影响。     

Fate and transformation of naphthylaminesulfonic azo dye Reactive Black 5 during wastewater treatment process

Certain aromatic amines generated by the decolorization of some azo dyes are not removed substantially by conventional anaerobic–aerobic biotreatment. These aromatic amines are potentially toxic and often released in the wastewater of industrial plants. In this study, the fate and transformation of the naphthylaminesulfonic azo dye Reactive Black 5 (RB5) during different phases of a sequencing batch reactor were investigated. The major products of RB5 decolorization during the anaerobic phase include 2-[(4-aminophenyl)sulfonyl]ethyl hydrogen sulfate (APSEHS) and 1-2-7-triamino-8-hydroxy-3-6-naphthalinedisulfate (TAHNDS). During the aerobic phase, APSEHS was hydrolyzed and produced 4-aminobenzenesulfonic acid, which was further degraded via dearomatization. TAHNDS was transformed rapidly via auto-oxidation into TAHNDS_DP-1 and TAHNDS_DP-2, which were not further removed by the activated sludge during the entire 30-day aerobic phase. In contrast, different behaviors of TAHNDS were observed during the anoxic phase. The transformation of TAHNDS was initiated either by deamination or desulfonation reaction. TAHNDS was then converted into 3,5-diamino-4-hydroxynaphthalene-2-sulfonic acid, which was subsequently removed via ring cleavage reaction under aerobic condition. In conclusion, complete degradation of TAHNDS by activated sludge occurs only during anoxic/aerobic processes instead of the conventional anaerobic/aerobic processes.     

一株嗜热偶氮染料脱色菌的分离鉴定及其脱色特性

从纺织厂的工业废水排污口取样,分离筛选出了一株嗜热的高效偶氮染料脱色菌PDR2。通过形态学、生理生化特征以及16S rDNA基因序列分析等方法对该菌株进行鉴定,发现该菌为厌氧芽孢杆菌,与Anoxybacillus sp（GQ471935）同源性最高。此外,分别考察了菌株PDR2在不同碳源、氮源、pH以及培养温度等条件下对偶氮染料直接黑38脱色性能的影响,在此基础上进一步研究了菌株PDR2对不同浓度直接黑38染料的耐受性。结果表明,菌株PDR2在55℃、pH 6.0且以葡萄糖为碳源,牛肉膏和蛋白胨为混合氮源时其脱色效果最佳,且菌株对偶氮染料直接黑38有着较强的耐受能力,在染料浓度低于0.4 g·L-1时其脱色效果良好。在最佳条件下静置培养24 h时,菌株PDR2对0.1 g·L-1直接黑38染料的脱色率高达92.34%,展出了良好的应用潜力。     

Correlations between toxic Pb effects and production of Pb-induced thiol peptides in the microalga Stichococcus bacillaris

Comparing Pb toxicity to the green alga Stichococcus bacillaris and production of Pb-induced thiol peptides in 24-h exposed cells made it possible to show the level of these peptides to reflect Pb availability to algal cells. LC-ESI/MS analysis of these peptides confirmed that they are phytochelatins PC2-PC4 and their des-Gly derivatives. Studies were carried out at environmentally relevant pH values (5-8.5) and various concentrations of hardness cations (Ca, Mg) and orthophosphate: (0-0.1 mM), chloride (0-100 mM), citrate (0-1 mM), and humic acids (0-10 mg/l). It has been stated, on the basis of the level of Pb-induced thiol peptides, that Pb availability to algae changed significantly within the range of the pH values studied, and was limited in the presence of calcium and of some complexing ligands like orthophosphate, chloride and citrate; it did not decrease in the presence of magnesium or humic acid.     

Degradation of nonylphenol by anaerobic microorganisms from river sediment

We investigated the degradation of nonylphenol monoethoxylate (NP1EO) and nonylphenol (NP) by anaerobic microbes in sediment samples collected at four sites along the Erren River in southern Taiwan. Anaerobic degradation rate constants (k1) and half-lives (t1/2) for NP (2 microg/g) ranged from 0.010 to 0.015 1/day and 46.2 to 69.3 days respectively. For NP1EO (2 microg/g), the ranges were 0.009-0.014 1/day and 49.5-77.0 days respectively. Degradation rates for NP and NP1EO were enhanced by increasing temperature and inhibited by the addition of acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, heavy metals, and phthalic acid esters. Degradation was also measured under three anaerobic conditions. Results show the high-to-low order of degradation rates to be sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. The results show that sulfate-reducing bacteria, methanogen, and eubacteria are involved in the degradation of NP and NP1EO, with sulfate-reducing bacteria being a major component of the river sediment.     

Decolorization and detoxification of two textile industry effluents by the laccase/1-hydroxybenzotriazole system

The aim of this work was to determine the optimal conditions for the decolorization and the detoxification of two effluents from a textile industry—effluent A (the reactive dye bath Bezactive) and effluent B (the direct dye bath Tubantin)—using a laccase mediator system. Response surface methodology (RSM) was applied to optimize textile effluents decolorization. A Box–Behnken design using RSM with the four variables pH, effluent concentration, 1-hydroxybenzotriazole (HBT) concentration, and enzyme (laccase) concentration was used to determine correlations between the effects of these variables on the decolorization of the two effluents. The optimum conditions for pH and concentrations of HBT, effluent and laccase were 5, 1 mM, 50 % and 0.6 U/ml, respectively, for maximum decolorization of effluent A (68 %). For effluent B, optima were 4, 1 mM, 75 %, and 0.6 U/ml, respectively, for maximum decolorization of approximately 88 %. Both effluents were treated at 30 °C for 20 h. A quadratic model was obtained for each decolorization through this design. The experimental and predicted values were in good agreement and both models were highly significant. In addition, the toxicity of the two effluents was determined before and after laccase treatment using Saccharomyces cerevisiae, Bacillus cereus, and germination of tomato seeds.     

外源营养物质对土壤中六氯苯厌氧降解效能的影响

实验以水淹法营造厌氧环境,研究了4种外源营养物质葡萄糖、乙酸、硫酸亚铁、氯化铁及其组合在不同添加浓度下对实际工业污染土壤中六氯苯厌氧降解效能的影响。研究结果表明,在低添加浓度下,无论单独添加还是组合添加营养物质都能明显强化六氯苯的厌氧降解效能,其强化能力大小顺序为：乙酸+硫酸亚铁>乙酸>葡萄糖>乙酸+氯化铁>氯化铁>硫酸亚铁。当乙酸和硫酸亚铁的添加浓度分别为8 g/L和1 g/L时,六氯苯的降解率达到最大,为62.72%,乙酸与硫酸亚铁的组合对六氯苯的降解起到了协同降解的作用。此外,研究还对高添加浓度下,六氯苯降解效能降低的原因进行了初步探索。     

产酸克雷伯氏菌Klebsiella oxytoca对硝基苯及4-氯硝基苯的降解

硝基苯类化合物生物降解菌的筛选及性能研究,是制药、染料等行业废水达标的重要基础。以浓度梯度升高法筛选到一株硝基苯厌氧降解菌Klebsiella oxytoca NBA-1。考察了该菌对氧气的需求,以及在厌氧条件下,温度、pH值、外加葡萄糖及硝基苯初始浓度等环境因子对菌株降解硝基苯能力的影响,并进一步讨论菌株对氯取代硝基苯类化合物的降解情况。结果表明,该菌在厌氧条件下生长比好氧条件下慢,但降解速度更快;厌氧降解硝基苯的最佳pH值和温度和分别为8．3和30～35℃;加入0．3％～0．5％的葡萄糖可促进降解,且对300mg／L以下的硝基苯均有降解能力;该菌能将4-氯硝基苯转化为4-氯苯胺,并进一步脱氯为苯胺。研究结果可为硝基苯及含氯硝基苯的处理工艺选择提供相关的参考依据。     

SDS改性沸石吸附结晶紫简

以表面活性剂十二烷基硫酸钠（SDS）对沸石进行改性,改性后的沸石对结晶紫溶液进行吸附,以紫外可见分光光度计分析最佳吸附条件。实验结果表明,在30℃,SDS改性沸石投入量为0.25 g;吸附平衡时间为1 h;pH为8的条件下,对含50 mg/L结晶紫染料的去除率可达到92.6%,吸附量达到4.63 mg/g。SDS改性沸石吸附结晶紫的等温吸附曲线与Henry型和Freundlich型均拟合较好。热力学参数计算结果表明,吸附符合自发吸热过程。