Progress and prospects of Mg-based amorphous alloys in azo dye wastewater treatment

Mg-based amorphous alloys exhibit efficient catalytic performance and excellent biocompatibility with a promising application probability,specifically in the field of azo dye wastewater degradation.However,the problems like difficulty in preparation and poor cycling stability need to be solved.At present,Mg-based amorphous alloys applied in wastewater degradation are available in powder and ribbon.The amorphous alloy powder fabricated by ball milling has a high specific surface area,and its reactivity is thousands of times better than that of gas atomized alloy powder.But the development is limited due to the high energy consumption,difficult and costly process of powder recycling.The single roller melt-spinning method is a new manufacturing process of amorphous alloy ribbon.Compared to amorphous powder,the specific surface area of amorphous ribbon is relatively lower,therefore,it is necessary to carry out surface modification to enhance it.Dealloying is a way that can form a pore structure on the surface of the amorphous alloys,increasing the specific surface area and providing more reactive sites,which all contribute to the catalytic performance.Exploring the optimal conditions for Mg-based amorphous alloys in wastewater degradation by adjusting amorphous alloy composition,choosing suitable method to preparation and surface modification,reducing cost,expanding the pH range will advance the steps to put Mg-based amorphous alloys in industrial environments into practice.

Decolorization of Blue CL-BR dye by AOPs using bleach wastewater as source of H_2O_2

This research was focused on the investigation of the efficacy of advanced oxidation processes （Fenton, ozonation and UV/H2O2） for decolorization of reactive azo dye （Blue CL-BR） using bleach wastewater as possible source of H2O2. All the experiments were performed on the laboratory scale set-up. The results showed that colour removal efficiencies by UV or bleach （H2O2） alone were not so efficient. Fenton process with bleach wastewater was found to be the most effective at process conditions such as pH of 3 and HEO2/Fe^2＋ ratio of 24：1, resulting in 64% colour removal. Almost complete colour removal, i.e., 99% and 95% were achieved by UV//H2O2 and UV/bleach wastewater in 30 and 60 min, respectively. Ozonation proved an efficient method for decolorization of Blue CL-BR dye at alkaline pH. It was possible to achieve 98% colour removal with 30 min of ozonation at pH 9. The colour removal of dye was found to follow first order kinetics.

Bacterial Influence on Textile Wastewater Decolorization

The study aims to isolate and optimize bacterial strains having the ability to degrade and decolorize azo dyes produced in the final effluent of textile dying industries. In this regard, ten bacterial strains were isolated from wastewater treatment plants, and most of them were subjected to the colored effluents resulting from dilapidated houses. The ability of these bacterial isolations to use a wide range of azo dyes to determine the sole carbon source was determined. According to these screening testes, two bacterial isolations were selected as the most potent decolorizer for azo dyes, and they were identified as Comamanas acidovorns-TN1 and Burkholdera cepace-TN5. The optimization process started with the addition of 1 g/l yeast extract, where the decolorization ability of the two strains increased sharply and according to this experiment, the two azo dyes, Acid orange 7 and Direct blue 75, were selected to complete the study. The effect of different conditional and chemical factors on the decolorization process of Acid orange 7 and Direct blue 75 by Comamanas acidovorns-TN1 and Burkholdera cepace-TN5 was studied. Factors that contributed to the difference were different pH, temperature, incubation period, inoculum size, carbon source, nitrogen source and the respective concentrations of yeast extract. This study recommends the application of the two most potent bacterial strains in the decolorization of the azo dyes, along with acid orange 7 and direct blue 75, specifically in the industrial effluents under all nutritional and environmental conditions.

改性TiO_(2)在光电协同下处理偶氮染料废水的研究进展

偶氮染料(AZO)是一类难被生物降解的水溶性高分子有机物,近些年来,由于良好的染色性能被广泛应用于印染等相关行业,但AZO废水一旦排入自然水体将会造成重大的环境污染问题。本文主要介绍了不同类型的改性TiO_(2)对AOZ废水的处理效果并分析了作用原理,对比分析了单一TiO_(2)与改性TiO_(2)的优缺点,积极探索改性TiO_(2)催化剂的催化机理,解析金属和非金属掺杂在其中的具体作用,为今后更加精准地控制掺杂金属或者非金属比例、提高催化剂效率提供科学依据和技术支持。

好氧颗粒污泥处理纺织印染废水研究进展

纺织印染废水成分复杂,含有大量染料、重金属等有毒难降解污染物,是最难处理的工业废水之一。传统的生物处理法因耐毒性差、处理负荷低、受外部环境影响等存在一定的局限性,难以高效处理该类废水。好氧颗粒污泥胞外聚合物含量高,且含有大量氨基、羧基等官能团,此外,其具有不同的氧化还原微环境,能够有效吸附、降解污染物。但好氧颗粒污泥对印染废水中重金属的去除仍存在局限性,对染料的脱色和矿化效率仍有较大提升空间。针对纺织印染废水的污染物特性,总结并论述好氧颗粒污泥技术的优点及其对废水中重金属、偶氮染料的去除机理;综述好氧颗粒污泥处理模拟与实际纺织印染废水的研究进展,并对其运行方式进行总结分析。基于重金属离子去除存在局限性、染料降解不够彻底、实际废水具有复杂性等各种问题,展望其发展方向,以期为今后好氧颗粒污泥高效处理纺织印染废水的研究提供参考。

生物质炭/TiO_(2)复合材料去除偶氮染料的研究进展

偶氮染料被认为是工业生产中使用最广泛的合成染料,其化学惰性较高,产生的废水成分较为复杂,比天然染料更加难以通过物理和化学等方法进行脱色。偶氮染料及其降解产物有较强的生物毒害性,大量排放会对环境造成严重危害。在众多染料废水的处理技术中,吸附和光催化协同是一种先进的废水处理手段,具有高效、节能、环保及成本低廉等优点,是现阶段环境修复领域的研究热点。光催化材料的催化活性主要取决于材料的带隙宽度、比表面积和电子-空穴对的产生。吸附材料生物质炭具有丰富的表面官能团和大的比表面积,可增加TiO_(2)等光催化剂与污染物的接触,提高降解效率。同时基团的掺杂可以降低催化剂带隙宽度,延长光生载流子的寿命,有效提高光催化活性;而光催化可以降解附着的污染物,使生物质炭恢复吸附能力,达到回收再利用的效果。通过利用生物质炭/TiO_(2)复合材料,不仅可以实现“吸附+光催化”同步去除偶氮染料的效果,而且复合材料的协同作用还可以弥补两种处理方法的不足。综述了生物质炭和TiO_(2)分别用来处理偶氮染料的研究现状并分析了不足之处,概括了生物质炭/TiO_(2)复合材料的制备方法及去除偶氮染料的协同作用机理,最后对生物质炭/TiO_(2)复合材料用于偶氮染料废水处理的现状和未来发展进行了总结与展望。

MES-AnMBR耦合工艺处理模拟偶氮染料废水及膜污染特性研究

采用微生物电化学系统(MES)-厌氧膜生物反应器(AnMBR)耦合工艺处理模拟偶氮染料废水,考察了该工艺的产电情况、对偶氮染料刚果红(CR)的脱色率和膜污染特性。结果表明,外阻为50Ω时,反应器阳极的电化学活性最高,平均输出电流、最大功率密度和电流密度分别为(0.43±0.03)mA、78.98 mW/m^(2)和644.63 mA/m^(2);50Ω、400Ω和1000Ω3组反应器的平均COD去除率在81.44%~85.20%,平均脱色率分别为(89.50±3.14)%、(85.00±3.15)%和(82.00±2.87)%;与对照组相比,50Ω、400Ω和1000Ω3组反应器将膜堵塞的时间从16 d分别延长至39 d、35 d和24 d。反应器产生的电流能够促进泥饼层中溶解性微生物产物(SMP)和胞外聚合物中蛋白质和多糖的降解,随着输出电流的增加,SMP和松散型胞外聚合物含量逐渐降低。

Steady performance of a zero valent iron packed anaerobic reactor for azo dye wastewater treatment under variable influent quality

Zero valent iron （ZVI） is expected to help create an enhanced anaerobic environment that might improve the performance of anaerobic treatment. Based on this idea, a novel ZVI packed upflow anaerobic sludge blanket （ZVI-UASB） reactor was developed to treat azo dye wastewater with variable influent quality. The results showed that the reactor was less influenced by increases of Reactive Brilliant Red X-3B concentration from 50 to 1000 mg/L and chemical oxygen demand （COD） from 1000 to 7000 mg/L in the feed than a reference UASB reactor without the ZVI. The ZVI decreased oxidation-reduction potential in the reactor by about 80 mV. Iron ion dissolution from the ZVI could buffer acidity in the reactor, the amount of which was related to the COD concentration. Fluorescence in situ hybridization test showed the abundance of methanogens in the sludge of the ZVI-UASB reactor was significantly greater than that of the reference one. Denaturing gradient gel electrophoresis showed that the ZVI increased the diversity of microbial strains responsible for high efficiency.

Construction of defect-containing UiO-66/MoSe_(2) heterojunctions with superior photocatalytic performance for wastewater treatment and mechanism insight

Metal-organic frameworks are recognized as promising multifunctional materials,especially metal-organic framework-based photocatalysts,which are considered to be ideal photocatalytic materials.Herein,a new type of UiO-66/MoSe_(2) composite was prepared using the solvothermal method.The optimum composite was selected by adjusting the mass ratio of UiO-66 and MoSe_(2).X-ray diffraction analysis showed that the mass ratio influenced the crystal plane exposure rate of the composite,which may have affected its photocatalytic performance.The composite is composed of ultra-thin flower-like MoSe_(2) that wrapped around cubic UiO-66,a structure that increases the abundance of active sites for reactions and is more conducive to the separation of carriers.The photocatalytic properties of the composite were evaluated by measuring the degradation rate of Rhodamine B and the catalyst’s ability to reduce Cr(VI)-containing wastewater under visible light irradiation.Rhodamine B was decolorized completely in 120 min,and most of the Cr(VI)was reduced within 150 min.The photochemical mechanism of the complex was studied in detail.The existence of Mo^(6+)and oxygen vacancies,in addition to the Z-type heterojunction promote the separation of electrons and holes,which enhances the photocatalytic effect.

Efficient treatment of azo dye containing wastewater in a hybrid acidogenic bioreactor stimulated by biocatalyzed electrolysis

In this study, a novel scaled-up hybrid acidogenic bioreactor（HAB） was designed and adopted to evaluate the performance of azo dye（acid red G, ARG） containing wastewater treatment. Principally, HAB is an acidogenic bioreactor coupled with a biocatalyzed electrolysis module. The effects of hydraulic retention time（HRT） and ARG loading rate on the performance of HAB were investigated. In addition, the influent was switched from synthetic wastewater to domestic wastewater to examine the key parameters for the application of HAB. The results showed that the introduction of the biocatalyzed electrolysis module could enhance anoxic decolorization and COD（chemical oxygen demand） removal. The combined process of HAB-CASS presented superior performance compared to a control system without biocatalyzed electrolysis（AB-CASS）. When the influent was switched to domestic wastewater, with an environment having more balanced nutrients and diverse organic matters, the ARG, COD and nitrogen removal efficiencies of HAB-CASS were further improved, reaching 73.3% ± 2.5%, 86.2% ± 3.8% and 93.5% ± 1.6% at HRT of 6 hr, respectively, which were much higher than those of AB-CASS（61.1% ± 4.7%,75.4% ± 5.0% and 82.1% ± 2.1%, respectively）. Moreover, larger TCV/TV（total cathode volume/total volume） for HAB led to higher current and ARG removal. The ARG removal efficiency and current at TCV/TV of 0.15 were 39.2% ± 3.7% and 28.30 ± 1.48 mA,respectively. They were significantly increased to 62.1% ± 2.0% and 34.55 ± 0.83 mA at TCV/TV of 0.25. These results show that HAB system could be used to effectively treat real wastewater.

基于梯级控制的偶氮染料废水电氧化处理研究

以实际偶氮染料废水为研究对象,采用电氧化法对其进行处理,考察了废水中COD和氨氮同步去除的情况,并分析了该过程中的电流效率和能耗。试验结果表明,在流速150 mL/min,初始pH值6,电极间距1 cm,电流密度20 mA/cm^(2)时,COD和氨氮的去除率分别为75.1%和100%,电流效率为21.2%,能耗为31.6 kWh/m^(3)。在此基础上,提出了一种梯级控制方法,在电解过程中逐步调控电流密度,有利于活性氯的产生,且缓解ClO3-的积累,从而提高电解体系的氧化还原电位(ORP),可实现73.7%的COD去除和100%的氨氮去除,电流效率可提升至27.9%,能耗下降至20.3 kWh/m^(3),达到了35.8%的节能。经梯级控制方法处理后的偶氮染料废水满足《纺织染整工业水污染物排放标准》(GB 4287—2012)。

偶氮染料废水处理技术的研究进展

偶氮染料易于合成、着色能力强,使用广泛。其使用过程中产生大量的偶氮染料废水,严重污染环境。探索高效节能、环境友好且成本较低的偶氮染料治理方法已成为环境修复领域的研究重点。综述了物理法、化学法和生物法处理偶氮染料废水的研究进展,对生物法脱色偶氮染料的研究进展,并展望了偶氮染料废水处理技术的研究趋势。

TiO_2光催化/膜分离耦合过程降解偶氮染料废水

以钛酸丁酯为前驱体,采用酸性溶胶法在低温下(<100oC)制备了纳米级TiO2粉末,X射线衍射分析表明,样品为锐钛矿型,晶粒尺寸为3.6nm.以250W紫外灯为光源,在自制悬浮式光催化膜反应器中进行降解活性艳红X-3B有机染料废水实验,采用尼龙6(N6)和混合纤维素(CN-CA)两类微滤膜对TiO2颗粒进行截留分离.综合考察了影响光催化和膜分离效率的因素.结果表明,反应起始pH值和催化剂用量对光催化膜反应器运行性能影响很大,该耦合体系的最佳pH值为4,染料和催化剂最佳浓度比为2:1,0.45和0.22μm的CN-CA膜对TiO2颗粒截留率可达96.5%以上.

用气相沿面放电生成臭氧方式降解偶氮染料废水的影响因素分析

为提高臭氧降解和脱色染料废水的效果,通过沿面放电臭氧生成-废水处理一体化反应器降解偶氮染料废水研究了供电电源类型、放电电压、放电反应器内注入的气体组分及流量、废水电导率、催化剂等因素对染料降解的影响。研究结果表明:同50Hz工频电源相比,在相同的输入功率下,高频电源降解偶氮染料效果更快;沿面放电反应器内注入的气体成分影响染料降解率,注入氧气时,甲基红降解率最高,注入氮气时,甲基红几乎没有降解;注入气体流量影响气相和液相臭氧浓度及染料废水的湍流度,进而影响甲基红的降解率;废水电导率对甲基红降解影响不大;二氧化钛添加量影响甲基红的降解,染料降解初期,适量的二氧化钛有利于甲基红的降解。

电化学催化氧化法降解水中甲基橙的研究

采用电沉积-热解氧化法制备了含有中间层SnO2+Sb2O3的钛基体二氧化铅电极(Ti/SnO2+Sb2O3/PbO2),以甲基橙水溶液为模拟废水,研究了所制备的电极对其所具有的电催化氧化脱色性能。考察了电极制备条件对电极催化性能的影响,同时对甲基橙脱色降解实验条件进行了优化。用该电极对含60mg/L甲基橙的模拟废水处理2h,脱色率可达到82.21%,COD去除率为76.75%。

高铁酸盐/Al(OH)_3对偶氮类染料的降解脱色研究

以电化学循环伏安法研究了FeO42-、甲基橙、酸性铬蓝以及铬黑T等偶氮类染料的氧化还原电位.实验结果表明FeO42-有足够高的氧化电位来氧化偶氮类染料中的生色基团.用紫外-可见光谱法分析了FeO42-对甲基橙、酸性铬蓝、铬黑T等偶氮类染料的降解脱色行为.经高铁酸盐处理后偶氮染料类废水溶液中的有机成分逐渐减少,脱色率高于90%.经FeO42-/Al(OH)3混凝剂处理偶氮染料类废水,CODCr去除率可以达到60%以上,脱色率达100%.

偶氮染料废水的电解处理

用复极性固定床电解槽处理偶氮染料废水，在正交试验确定的原水ＣＯＤ２００ｍｇ／Ｌ、槽电压３０Ｖ、停留时间２ｈ、导电颗粒与绝缘颗粒体积比１４的条件下，色度和ＣＯＤ去除率分别达到９９％以上和７８．４％～９７．２％。

超声强化铋掺杂氧化铟降解偶氮染料废水

本实验利用溶剂热法合成了铋掺杂氧化铟催化剂,利用XRD、EDS和SEM对催化剂的结构和形貌进行了表征.研究表明,铋离子已经掺杂进氧化铟的晶格中.掺杂后的催化剂粒径为纳米级,且具有良好的球形形貌.本文以偶氮染料直接大红废水为目标降解物,分别考察了不同催化剂对该染料废水的降解性能以及铋掺杂氧化铟催化剂的投加量、染料的浓度、溶液的p H、超声频率和超声功率对该染料的降解性能.在本实验条件下,催化剂投加量为7.5 mg、染料浓度为10 mg·L^(-1)、pH值为6、超声频率为45 kHz、功率为100 W时,对染料废水的去除效果最优,总去除率可达83.7%,比空白实验的去除率提高将近5倍.

纳米TiO_2/矿物复合光催化降解染料废水研究

直接热合Fe2O3制备纳米TiO2/高岭石复合光催化材料。用XRD、FTIR、Raman技术对材料的晶体结构和分子结构进行表征分析。偶氮染料废水初始浓度40 mg/L,催化剂添加量2 g/100 mL废水,废水初始pH=4,紫外光和太阳光下6 h后偶氮废水降解脱色率分别为98.4%和62.5%。

响应面法应用于臭氧处理偶氮废水优化研究

针对偶氮废水深度处理,在单因素实验的基础上,利用Design-Expert8.0.6.1软件和Central Composite实验设计原理,以偶氮废水脱色率为响应值,设计了一个4因素5水平的响应面法用于臭氧深度处理偶氮废水的工艺优化。结果表明,对于200 mL初始浓度为100 mg/L的橙黄Ⅱ废水,当臭氧通量为1 602.06 mg/h,MgO投加量为0.32 g,废水初始pH为7.04,反应温度为29.32℃,反应5 min后废水脱色率达到最大值,为95.52%。通过软件对模型的方差分析、残差分析和模型验证,得出模型相关系数为0.992 3,Fisher(F)值为138.11,概率(P)值<0.000 1,变异系数(CV)为2.26%,信噪比为49.124,这些指标均在合理范围内,故该模型可信度和准确性较高,预测性能好。