污泥活性炭处理亚甲基蓝染料废水的研究

采用污泥活性炭处理亚甲基蓝模拟染料废水,研究了模拟废水初始浓度、污泥活性炭投加量、pH值、水浴吸附时间等因素对染料废水的脱色率和COD去除率的影响,探讨污泥活性炭处理染料废水的适宜工艺条件。实验结果表明:随着染料废水初始浓度的增大,脱色率和COD去除率均表现出下降趋势;随着污泥活性炭投加量的增加,脱色率和COD去除率效果均十分明显;随着模拟废水pH值的增大,其脱色率基本呈现增大趋势,而COD去除率则先增大后减小,当pH在7.6～7.8时,脱色率与COD去除率均出现最大值;在延长水浴时间的同时,脱色率和COD去除率均表现出较好的效果。本实验处理染料废水的适宜条件为:染料废水的初始浓度为2.5mg/L,调节染料废水的pH值7~8,加入0.8g污泥活性炭,30℃条件下2h。     

Kinetics and equilibrium studies of removal of an azo dye from aqueous solution by adsorption onto scallop

In the present work removal of an azo dye (Reactive Black 5) was investigated from aqueous solution by adsorption onto scallop as a low-cost and widely available adsorbent. The effect of various operational parameters, such as contact time, pH, initial dye concentration and adsorbent dosage on the removal efficiency of dye was studied. Removal efficiency declined with the increase in solution pH and initial dye concentration but with the decrease in adsorbent dosage. Experimental equilibrium and kinetics data were fitted by Langmuir and Freundlich isotherms and pseudo-first-order and pseudo-second-order kinetic models, respectively.     

TiO2光催化氧化降解偶氮染料废水的研究

以偶氮染料直接耐酸大红4BS模拟废水为研究对象,以TiO2为光催化剂,紫外灯作光源（80W）,探究了不同TiO2催化剂的用量、光照时间、溶液初始pH值及废水初始质量浓度等因素对偶氮染料废水降解率的影响。实验结果表明,偶氮染料直接耐酸大红4BS废水的最佳处理条件为：TiO2催化剂质量浓度1．2g／L,光照时间120min,初始pH值10,废水初始质量浓度20mg／L。在最佳处理条件下,对某染料厂的实际工业废水样进行了降解率的测定,得出其降解率在90％以上。     

Electrochemical oxidation of textile dye indigo

Electrochemical methods are being used increasingly as an alternative treatment process for the remediation of textile wastewaters. This study focused mainly on the colour removal and chemical oxygen demand (COD) reduction of vat textile dye (CI Vat Blue 1: indigo) from its aqueous solution by electrochemical oxidation. The process was carried out in a batch‐type divided electrolytic cell under constant potential using a Pt cage as anode and Pt foil as cathode. Operating variables such as supporting electrolyte, pH, ultrasonification and treatment time were investigated to probe their effects on the efficiency of the electrochemical treatment. Colour removal was estimated by monitoring the disappearance of the absorbance peak at 681.5 nm. It was found that in acidic conditions the electrolysis was more efficient. At pH 1, an NaCl concentration of 0.24 mol dm^?3, a dyeing solution concentration of 0.1% (w/v) and a period of 90 min of electrolysis, there was almost 100% colour removal and 60% reduction in COD. Voltammetric and IR investigations demonstrated that partial degradation of dye was achieved. The experimental results indicate that this electrochemical method could effectively be used as a pretreatment stage before conventional treatment. Copyright © 2005 Society of Chemical Industry     

Enhanced electrochemical oxidation of dye wastewater with Fe2O3 supported catalyst

Electrochemical oxidation of Acid Red 3R was investigated in the presence of Fe₂O₃/γ-Al₂O₃ as Fenton-like catalyst in the reactor. The results showed that the catalyst had catalytic activity in the electrochemical process. Under the optimal conditions, the decolorization efficiency reached 77.2% in 100 min. UV–vis spectrum and LC–MS analysis revealed that the dye molecule was firstly decomposed to aromatic intermediates, further degraded to ring opening products and finally mineralized. The azo dye degradation might be attributed to strong oxidant OH that produced from the synergetic effect of between Fe₂O₃/γ-Al₂O₃ catalyst and electrochemical system.     

Degradation of azo dye by three clean advanced oxidation processes: Wet oxidation, electrochemical oxidation and wet electrochemical oxidation—A comparative study

This work compared the degradation behaviors of an azo dye, cationic red X-GRL, by three clean advanced oxidation processes: wet oxidation (WO), electrochemical oxidation (EO) and wet electrochemical oxidation (WEO). It was found that the WO process was readily to remove color while the EO process was prone to decompose pollutants. Integrated with the advantage of two processes, the WEO process posed synergetic effects for both efficient removal of color and COD. Even at the low temperature of 120 °C, the color could be almost completely removed at 60 min, and the COD removal was about 43.2% at 120 min, which was greatly protomted from that by WO at similar conditions (about 7.8%). And it demonstrated a better performance under a reduced temperature and a wider dye concentration range, representing the most promising alternative for environmental application among the three processes. The main degradation products for three processes were detected and a simplified five-stages degradation pathway was suggested, which indicated that the WEO process mineralized much more completely than the other two processes.     

光催化技术处理活性紫染料废水

在光催化处理活性紫废液的实验研究中,首先以新建固相脱色率为指标得出脱色的适宜操作条件,即TiO2含量1 g/L、废液初始浓度60 mg/L、设备进气量0.8 m3/h、灯功率105 W;然后在适宜操作条件下进行有机物降解的实验与分析,试图通过多指标的联合使用对有机物降解过程给出新解释。     

Electro-Fenton degradation of azo dye using polypyrrole/anthraquinonedisulphonate composite film modified graphite cathode in acidic aqueous solutions

Amaranth azo dye has been degraded by electro-Fenton method using an undivided cell containing the polypyrrole (PPy)/anthraquinonedisulphonate (AQDS) composite film modified graphite cathode and Pt anode. In acidic media, the PPy/AQDS composite film exhibits the characteristic of gas diffusion cathode and is highly efficient for hydrogen peroxide electrogeneration with high generation rate and current efficiency. This new electro-Fenton system can degrade amaranth azo dye efficiently in various acidic solutions. The amaranth decay and total organic carbon (TOC) removal were determined as a function of pH, cathode potential, Fe²⁺ and doping AQDS concentrations. Total dye decay and 80.3% mineralization were achieved at the optimum conditions (pH 3.0, E_cath = −0.65 V vs. SCE, 2.0 mM Fe²⁺ concentration). The electrochemical stability and electrocatalytic activity of the composite film after use in electro-Fenton process were also investigated using cyclic voltammetry (CV) and Fourier transfer infrared (FTIR) spectroscopy technologies.     

Radiation absorption and degradation of an azo dye in a hybrid photocatalytic reactor

Results are presented for the photocatalytic degradation of an azo dye, reactive blue 69, in a novel hybrid photocatalytic reactor, illuminated by solar radiation and artificial light, under different experimental conditions. A radiative transfer model, based on the P1 approximation, is proposed to evaluate the distribution of local volumetric rate of photons absorption (LVRPA) in the reaction space of the hybrid photocatalytic reactor. This radiation transfer model, together with a first order kinetic model, is used to fit the experimental results. The model correlates well with the experiments, and values for an apparent first order kinetic constant for the degradation of RB69 are obtained. The proposed radiative transfer model (P1 approximation) is simple enough to allow for an analytical solution, yet complex enough to take into account scattering of radiation in all directions and to all orders. Simulations show a distribution of LVRPA that varies smoothly at small catalyst concentration, and is very quickly attenuated for high concentrations. Around of 70% of photons supplied by both illumination sources to the hybrid photocatalytic reactor are absorbed by the catalyst. The experimental results show the decolorization degree increases as catalyst concentration increase. In relation to mineralization process, the removal of total organic carbon is nearly complete after 5 hours irradiation. This indicates that not only the azo bond breakage is carried out, but also that the intermediate species are mineralized. The apparent kinetic constant has a dependence on catalyst concentration which is described by an adsorption model. Addition of oxygen by means of an air diffuser proves to be beneficial to the process.     

Performance of a ZVI‐UASB reactor for azo dye wastewater treatment

BACKGROUND: Zero valent iron (ZVI) is expected to be helpful for creating an enhanced anaerobic environment that might improve the performance of the anaerobic process. Based on this idea, a ZVI packed upflow anaerobic sludge blanket reactor (ZVI‐UASB) was developed to enhance azo dye wastewater treatment. RESULTS: The ZVI‐UASB reactor was less influenced by a decrease in the operational temperature from 35 °C to 25 °C than a reference UASB reactor that did not contain ZVI. In addition, chemical oxygen demand (COD) and color removal efficiencies of the ZVI‐UASB reactor at an HRT of 12 h exceeded those of the reference reactor at an HRT of 24 h. The hydraulic circulation in the ZVI bed enhanced the function of ZVI so that it improved the COD and color removal efficiencies. Moreover, fluorescence in situ hybridization experiments revealed that the abundance of Archaea in the sludge of the ZVI bed was significantly higher than that at the reactor bottom, which made the reactor capable of greater COD removal under low temperature and short HRT conditions. CONCLUSION: This ZVI‐UASB reactor could adapt well to changes in the operational conditions during wastewater treatment. Copyright © 2010 Society of Chemical Industry     

超临界水氧化处理偶氮染料废水的实验研究

在间歇式反应器中进行偶氮染料C.I.活性橙7的超临界水氧化实验,探索染料分子中的偶氮基团在氧化反应中的转化规律.选取反应温度、氧化系数、初始COD质量浓度、反应时间和pH值为过程参数,总氮去除率和氨氮质量浓度为响应量,通过中心组合设计方法进行实验设计,设计了一个五因素、五水平包含22个实验点的实验矩阵.采用响应面分析法...     

Removal of Nickel and Boron from Plating Rinse Effluent by Electrochemical and Chemical Techniques

In this work, electrotreatment of nickel and boron containing plating rinse effluents was studied with mild steel and aluminum electrodes. Industrial effluent treatment directly by an electrochemical technique is capable of removing 80–85 % nickel. The residual nickel interfered with boron determination by curcumin method. The pH fall during electrotreatment in industrial effluent is due to electrodeposition of nickel at the cathode surface, evidenced by simulated effluent treatment. Nickel concentration can be reduced below the discharge limit from the industrial plating effluent by chemical precipitation and coagulation at pH above 8. Chemical precipitation showed maximum boron removal of about 50 %. Boron removal was 29.3–41.9 % and 20.6–33.1 % with ferric chloride and aluminum sulfate, respectively. A combination of chemical precipitation at pH 8.7 followed by electrotreatment reduces nickel to the discharge limit and also maximizes boron removal up to 59 %.     

Enhanced electrokinetic remediation of polluted kaolinite with an azo dye

In this work, the feasibility of the combination of electrokinetic remediation and electrochemical oxidation for the remediation of polluted soil with organic compounds had been development and evaluated in kaolinite spiked with Reactive Black 5 (RB5) an azo dye. The process consists in the use of two combined phenomena to achieve a full remediation of RB5 spiked kaolinite and the degradation of the organic pollutant. Those phenomena were soil electrokinetic treatment combined to liquid electrochemical oxidation. Reactive Black 5 (0.39 g dye kg⁻¹) could be effectively removed from the kaolinite matrix by electrokinetics, however the removal results largely depended on the operating conditions. Complete removal of RB5 was achieved using K₂SO₄ as processing fluid (which enhanced the desorption of RB5 from the kaolinite matrix) and operating with pH control at 7 on the anode. This favoured the alkalinization of the system and, at high pH values, RB5 was ionized and migrated towards the anode chamber where it was collected and could be oxidized electrochemically. Also, it must be pointed out that in these optimized conditions the electric power consumption (56 kW/mg of removed dye) was ten times lower compared to the unenhanced electrokinetic process (with no pH-control in the electrode solutions). Separate electrochemical decolourization tests of RB5 showed the effectiveness of K₂SO₄ in the efficiency of the process. A linear relationship between K₂SO₄ concentration and the decolourization rate was found. Thus, nearly complete decolourization was achieved after 2 and 3 h of electrochemical treatment when the electrolyte concentration was 0.1 and 0.01 M of K₂SO₄, respectively.     

基于酸改性的半焦对染料废水的吸附性能研究

为制备高效吸附材料,采用化学活化法对延安子长煤低温热解的半焦进行改性,并进行X射线衍射(XRD)、N2等温吸附、扫描电子显微镜(SEM)表征。以罗丹明B、酸性品红为目标物,采用吸附剂添加量、溶液p H、吸附时间等为考察参数,研究了酸改性半焦对罗丹明B、酸性品红模拟染料废水的吸附性能,探索了酸改性半焦对罗丹明B、酸性品红的吸附动力学行为。结果表明:改性半焦对2种染料有良好的吸附性能,准二级动力学模型的相关系数在0.999以上,模型饱和吸附量与实验值相近,很好地描述了2种染料在酸改性半焦上的吸附行为。     

用氯水治理亚磷酸三甲酯废水

阐述了利用氯氧化特性，将氯氢处理过程中产生的氯水用于处理亚磷酸三甲酯废水，使废水中的COD值及胺含量大大降低的氧化机理及工艺过程。     

Impact of ozonation on subsequent treatment of azo dye solutions

BACKGROUND: Aqueous solutions of four azo‐dyes, Acid Red 14 (AR14), Congo Red (CR), Reactive Black 5 (RB5), and Reactive Violet 5 (RV5) were treated with ozone, and the impact of ozonation on their subsequent treatability by aerobic biodegradation processes was investigated. RESULTS: In all cases, ozonation at the highest ozone doses investigated could remove more than 96% of the original dye, and the corresponding residual colour of the azo dye solutions declined to less than 20 on the Pt‐Co scale. Ozonation also resulted in reduction of chemical oxygen demand (COD), total organic carbon (TOC) the COD/TOC ratio and pH, while in all cases electrical conductivity of the dye solutions increased. Activity of the microbial colonies present in domestic wastewater was not inhibited when un‐ozonized solutions of these dyes were mixed in a 1:1 volumetric ratio with domestic wastewater, although the dyes themselves were not degraded. Also, no significant inhibition of microbial activity was observed in 1:1 mixtures of ozonized dye solutions and domestic wastewater, especially when the initial dye concentration was low and the applied ozone dose was high. In almost all cases, progressively enhanced BOD exertion was observed in mixtures containing dye solutions ozonized with progressively higher doses. This indicated that some ozonation by‐products of the above dyes could be degraded by microorganisms present in domestic wastewater. CONCLUSIONS: It was concluded that the above dye solutions, after ozonation for partial or complete colour removal, could be mixed with domestic wastewater for subsequent treatment by aerobic biological processes, with no adverse impact on the activity of the microbial colonies present in domestic wastewater. Copyright © 2007 Society of Chemical Industry     

Development of Fe2O3-CeO2-TiO2/γ-Al2O3 as catalyst for catalytic wet air oxidation of methyl orange azo dye under room condition

In order to develop a catalyst with high activity and stability for catalytic wet air oxidation (CWAO) process at room temperature and atmospheric pressure, we prepared Fe₂O₃-CeO₂-TiO₂/γ-Al₂O₃ by consecutive impregnation, and determined its properties using BET, SEM, XRF, XPS and chemical analysis techniques. The degradation of an azo dye, methyl orange, in CWAO process with Fe₂O₃-CeO₂-TiO₂/γ-Al₂O₃ used as catalyst at room temperature and atmospheric pressure was also investigated, and the results show that the catalyst has an excellent catalytic activity in treating synthetic wastewater containing 500 mg/L methyl orange, and 98.09% of color and 96.08% of total organic carbon (TOC) can be removed in 2.5 h. The degradation pathway of methyl orange was analyzed by UV–vis and FT-IR spectra. The result of leaching tests shows the catalyst has an excellent stability with negligible leaching ions, and the leaching of Ce is effectively controlled by adding Ti, because Ce and Ti in the catalyst take the form of compound oxides, and the deactivation of the catalyst in successive runs is caused by the adsorption of intermediates on the surface and coverage of the active sites. The catalytic activity of the deactivated catalyst can be generally restored by rinsing it in hydrochloric acid followed by calcination.     

Pathways of solar light-induced photocatalytic degradation of azo dyes in aqueous TiO2 suspensions

The photocatalytic degradation of aqueous solutions of Acid Orange 7 in TiO₂ suspensions has been investigated with the use of a solar light simulating source. The photoreaction was followed by monitoring the degradation of the dye and the formation of intermediates and final products, as functions of time of irradiation, both in solution and on the photocatalyst surface. It has been found that the dye adsorbs on TiO₂ and undergoes a series of oxidation steps, which lead to decolorization and formation of a number of intermediates, mainly aromatic and aliphatic acids. These molecules are further oxidized toward compounds of progressively lower molecular weight and, eventually, to CO₂ and inorganic ions, such as sulfate, nitrate and ammonium ions. A TiO₂-mediated photodegradation mechanism for Acid Orange 7 is proposed on the basis of quantitative and qualitative detection of intermediate compounds.     

机械加工中含油废水处理工艺的研究

研究了活性炭对机械加工中含油废水处理工艺。探讨了在不同吸附条件下（吸附剂量、时间、pH）的吸附效果。结果表明,活性炭吸附的最佳工艺条件是：含油120 mg/L的10 mL废水中,加入活性炭质量0.3 g,加热搅拌时间60 min,pH值为8。在最佳条件下,含油废水在活性炭吸附后的COD为160 mg/L。     

厌氧光生物转盘-好氧生物膜处理偶氮染料废水

利用厌氧光生物转盘-好氧移动床膜生物反应器处理偶氮染料废水,探讨了染料浓度、光照时间、供氧条件、硫酸盐浓度4个操作条件对组合工艺处理效果的影响。实验结果表明,厌氧光生物转盘对染料废水的脱色和COD去除起主要作用,当光生物转盘连续光照时间为12h／d,废水中染料质量浓度为100mg／L,HRT为5h时,光生物转盘的脱色率达90％左右,COD去除率达70％左右。经过后续好氧移动床处理,厌氧出水中的有毒芳香化合物得到有效降解,系统总COD去除率达90％以上。