微电解协同氧化技术深度降解三氯乙烯和1,4-二恶烷复合污染

三氯乙烯(TCE)是地下水中分布较普遍且难以降解的一类污染物,具有密度大、迁移能力强、相对持久及生物难降解等性质,常见的地下水修复技术存在TCE去除效率低、成本高的问题。此外,在大多数TCE污染场地地下水中常发现有氯代烃稳定剂1,4-二恶烷(1,4-D)的伴生污染且难以综合去除。当前,基于过硫酸盐的高级氧化技术因其高效、经济、环境友好等优点备受青睐,是一种降解有机污染最有效的技术之一。研究以铁碳原电池(n ZVI/C)为活化剂,过氧化钙(CP)为增强剂,柠檬酸/过硫酸钠(CA/PS)为氧化剂构建了一种新型的微电解-氧化耦合技术体系(n ZVI/C/CP-CA/PS)探究水中高浓度TCE的降解。考察了不同修复体系类型、药剂投加比、间隔投放时间及反应温度对降解TCE的影响,并初步探究了耦合体系对TCE及1,4-D复合污染的去除效果。试验结果表明:在室温为20℃,间隔时间为3h,活化剂n ZVI/C、增强剂CP与氧化剂CA/PS摩尔投加比为35∶0.5∶26的条件下,初始质量浓度为10000μg/L的TCE经n ZVI/C/CP-CA/PS耦合体系处理6h后,出水浓度满足了《地下水质量标准》(GB/T14848—2017)中Ⅳ类水要求,去除率接近100%。降解机制说明TCE在活性炭吸附及n ZVI/C/CP原电池的还原脱氯作用下优先发生部分降解,随后通过原电池及其产物进一步活化CA/PS氧化剂产生·OH和SO_(4)·^(-)等强氧化性自由基起到深度降解的目的,从而使TCE的浓度进一步降低,且降解过程符合零级反应动力学。该试验表明n ZVI/C/CP-CA/PS耦合体系对高浓度TCE的降解兼具高效及经济双重优势,并在TCE及1,4-D复合污染场地的修复中具有较大的应用潜力,有助于推进该耦合体系在有机污染水处理行业的应用与发展。

微电解-生物接触氧化处理中药废水

扬州中药厂综合废水CODCr40 0～ 2 0 0 0mg L、水量 70～ 90m3 d。在清洁生产、清污分流的基础上采用微电解 生物接触氧化工艺处理后 ,废水排放达到 (GB8978 1996 )中一级标准 ,运行成本不超过 1 10元

微电解-水解酸化-生物接触氧化工艺处理抗生素废水

详细介绍了预处理 水解酸化 生物接触氧化工艺在某制药厂抗生素废水处理上的应用 。

混凝沉降—微电解—氧化—吸附法处理高COD_(Cr)气田水

气田水矿化度通常为几万至十余万mg/L ,CODCr值一般在 5 0 0mg/L左右 ,由于采气过程中各种油田化学剂的使用 ,可使CODCr值高达数千mg/L。文章以川中角 5 3井气田水为研究对象 ,实验研究了高CODCr值气田水的处理方法 ,首次将微电解技术用于气田水的处理 ,采用混凝沉降—微电解—氧化—吸附工艺处理高CODCr值气田水 ,并筛选出最佳工艺条件。实验结果表明 ,该法可使原水CODCr值从 15 6 7mg/L降至 15 0mg/L以下 ,出水各项指标均达到排放标准。

三维电解-微电解-电芬顿氧化处理阳极氧化染色废水工艺研究

本文研究了三维电解-微电解-电芬顿氧化法处理阳极氧化染色废水的影响因素,分别考察了初始pH值、电压、电解时间以及H_2O_2用量对废水脱色率的影响。结果表明,控制铁碳颗粒投加量为5 kg·L^(-1),初始pH值为5,电解电压为50 V,对染色废水电解反应时间为120 min,H_2O_2的添加比例为1/500时,可以使阳极氧化染色废水脱色率达到99.8%。实验验证了三维电解-微电解-电芬顿耦合为一体式反应处理阳极氧化染色废水可达到快速脱色的目的,且工艺简单,可操作性强,具有较好的应用前景。

微电解—生物接触氧化法处理假发制品废水

采用了微电解—生物接触氧化法处理色度高、酸性大且可生化性差的假发制品废水。工程实践表明,微电解工艺作为预处理系统,不仅收到了良好的脱色效果,还显著地提高了废水的可生化性,降低了运行成本,出水各项指标均达到国家GB8978—1996一级排放标准。

微电解-芬顿-水解酸化-接触厌氧-ABFT-混凝工艺处理甾体类制药废水

采用微电解-芬顿-水解酸化-接触厌氧-ABFT-混凝沉淀工艺处理甾体类制药废水,主要介绍了废水的处理工艺流程、工程设计、调试运行和处理效果。经过该工艺处理后的废水COD、NH3-N、TP及甲苯的去除率,分别为98.53%、95.20%、92.40%、99.58%,出水各项指标满足《化学合成制药工业水污染排放标准》(GB21904-2008)的要求。

Structure and corrosion resistance of modified micro-arc oxidation coating on AZ31B magnesium alloy

A hydrophobic surface was fabricated on a micro-arc oxidation (MAO) treated AZ31 Mg alloys via surface modification with myristic acid. The effects of modification time on the wettability of the coatings were investigated using the contact angle measuring device. The surface morphologies and structure of the coatings were evaluated using SEM, XRD and FT-IR. The corrosion resistance was investigated by potentiodynamic polarization curves and long-term immersion test. The results showed that the water contact angle (CA) increases gradually with modification time from 0 to 5 h, the highest CA reaches 138° after being modified for 5 h, and the number and size of the micro pores are decreased. The modification method hardly alters crystalline structure of the MAO coating, but improves the corrosion resistance based on the much positive potential and low current density. Moreover, the corrosion resistance and hydrophobicity can be enhanced with increasing the alkyl chain. The wetting and spreading for the alkylcarboxylate with low surface energy become easier on the micro-porous surface, and alkylcarboxylate monolayer will be formed through bidentate bonding, which changes the surface micropores to a sealing or semi-sealing structure and makes the MAO coating dense and hydrophobic. All the results demonstrate that the modification process improves the corrosion protection ability of the MAO coating on AZ31B Mg alloy.

Optimization of dual electrolyte and characteristic of micro-arc oxidation coating fabricated on ZK60 Mg alloy

Micro-arc oxidation （MAO） process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 to develop compact, smooth and corrosion-resistant coatings on ZK60 Mg alloy by single factor experiments. The microstructural characteristics of coatings were investigated by X-ray diffractometry （XRD） and scanning electron microscopy （SEM） coupled with energy dispersive X-ray spectroscopy （EDS）. Test of mass loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The effect of every element in the dual electrolyte system on voltage—time responses during MAO process and the coating characteristic were also analyzed and discussed systematically via single factor experiments. The results reveal that the main components of NaAlO 2 and Na 3 PO 4 as well as additives of NaOH, NaB4O7 and C6H5Na3O7 demonstrate different effects on MAO process and coating characteristics. By means of single factor experiments, an optimized dual electrolyte system was developed, containing 17.5 g/L NaAlO 2, 5.0 g/LNa3 PO4, 5.0 g/L NaOH, 3.0 g/L NaB4O7 and 4.2g/LC6H5Na3O7 .

Plasma electrolytic oxidation of zircaloy-4 alloy with DC regime and properties of coatings

The plasma electrolytic oxidation（PEO） coatings on zircaloy？4 alloy were prepared in silicate,phosphate and pyrophosphate electrolyte systems or their combination by DC current regime.The proper processing parameters were determined and the coatings were evaluated by electrochemistry technique,micro-hardness,SEM and XRD.The results show that the coating prepared in pure silicate system is uneven and after the addition of phosphate solution,the homogeneity of the coating is still poor.The coating prepared in pure pyrophosphate electrolyte system is homogeneous,but its hardness value is low.After the addition of silicate into the pyrophosphate electrolytic system,both the uniformity and hardness of the coating are improved.The XRD results show that the phase compositions are m-ZrO2 and t-ZrO2,the addition of silicate is beneficial to the formation of t-ZrO2.The results of polarization curves show that the coatings prepared in pyrophosphate and the mixture of pyrophosphate and silicate have better corrosion resistance.

Treatment of chitin-producing wastewater by micro-electrolysis-contact oxidization

The technique of micro-electrolysis-contact oxidization was exploited to treat chitin-producing wastewater. Results showed that Fe-C micro-electrolysis can remove about 30% CODcr, raise pH from 0.7 to 5.5. The CODcr removal efficiency by biochemical process can be more than 80%. During a half year抯 operation, the whole system worked very stably and had good results, as proved by the fact that every quality indicator of effluent met the expected discharge stan-dards; which means that chitin wastewater can be treated by the technique of micro-electrolysis, contact oxidization.

Effects of sintering temperature on microstructure and performance of Ti-based Ti-Mn alloy anodic material

A novel Ti-based Ti-Mn composite anode used for electrolytic manganese dioxide(EMD) fabrication was developed by a two-step heating manganizing technique.The effects of sintering temperature on the manganized microstructure and the performance of the composite anode were studied by scanning electron microscopy(SEM),mechanical properties tests at room temperature and electrochemical methods.The results show that the thickness of the diffusion layer increases with the increase of sintering temperature up to 1 100 °C;whereas,the surface Mn content increases and reaches the maximum at 1 000 °C and then decreases thereafter.Lower surface Mn content is beneficial for the enhanced corrosion resistance and lowered open cell voltage in electrolytic process.The new anode prepared under the optimized conditions has been applied in industry and exhibits superior economic benefits to conventional Ti anodic materials.

Experimental study on micro-electrolysis technology for pharmaceutical wastewater treatment

Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of pharmaceutical wastewater. The results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis.

Preparation of micro/nano-structured ceramic coatings on Ti6Al4V alloy by plasma electrolytic oxidation process

In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)process on Ti6Al4V alloy in NaF electrolyte.The influence of NaF concentration(0.15-0.50 mol/L)on the PEO process,microstructure,phase composition,corrosion resistance and thickness of the coatings was investigated using scanning/transmission electron microscopy,energy dispersive spectroscopy,atomic force microscopy,X-ray diffractometer,and potentiodynamic polarization.The results demonstrated that Ti6Al4V alloy had low PEO voltage(less than 200 V)in NaF electrolyte,which decreased further as the NaF concentration increased.A micro/nano-structured coating with 10-15μm pits and 200-800 nm pores was formed in NaF electrolyte;the morphology was different from the typical pancake structure obtained with other electrolytes.The coating formed in NaF electrolyte had low surface roughness and was thin(<4μm).The NaF concentration had a small effect on the phase transition from metastable anatase phase to stable rutile phase,but greatly affected the corrosion resistance.In general,as the NaF concentration increased,the surface roughness,phase(anatase and rutile)contents,corrosion resistance,and thickness of the coating first increased and then decreased,reaching the maximum values at 0.25 mol/L NaF.

Anodic behavior and microstructure of Al/Pb-Ag-Co anode during zinc electrowinning

In order to study the anodic behavior and microstmctures of A1/Pb-Ag-Co anode during zinc electrowinning, by means of potentiodynamic investigations, scanning electron microscopy （SEM） and X-ray diffraction （XRD） analyses, the mechanism of the anodic processes playing on the surface of A1/Pb-0.8%Ag and A1/Pb-0.75%Ag-0.03%Co anodes prepared by electro-deposition from methyl sulfonic acid bath for zinc electrowinning from model sulphate electrolytes have been measured. On the basis of the cyclic voltammograms obtained, information about the corrosion rate of the composite in PbO2 region has been concluded. The microstructures were also observed by means of SEM and XRD which showed Pb-0.75%Ag-0.03%Co alloy composite coating has uniform and chaotic orientation tetragonal symmetry crystallites of PbSO4, but Pb-0.8%Ag alloy composite coating has well-organized orientation crystallites of PbSO4 concentrated in the certain zones after 24 h of anodic polarization. It is important that Al/Pb-0.75%Ag-0.03%Co anode oxide film consists of non-conductive dense MnO2 and PbSO4 and a, fl-PbO2 penetrated into which, in fact, are the active centers of the oxygen evolution after 24 h of anodic polarization.

Microstructural, corrosion and mechanical behavior of two-step plasma electrolyte oxidation ceramic coatings

Plasma electrolytic oxidation(PEO)is considered as a cost effective and environmentally friendly surface treatmentprocess for improving surface properties of light alloys.The formation of ceramic coatings on Ti6Al4V alloy was reported bytwo-step PEO process and its structural,electrochemical and mechanical properties with the coated samples were compared byone-step PEO process in an alkaline electrolyte.The structural properties were studied using field-emission scanning microscope(FESEM)and X-ray diffraction(XRD).Electrochemical studies were carried out using linear polarization method and in additionmechanical behaviors were investigated by means of Knoop microhardness and nanoindentation method.Results showed that thesecond step process resulted in an increase of both porosity percentage and average pore diameter on the surface.The two-stepprocess resulted in a small increase of thickness from about12.5to13.0μm.Electrochemical test results showed that applying thesecond step resulted in the decrease of both polarization resistance from1800.2to412.5kΩ/cm2and protection efficiency from97.8%to90.5%.Finally,the nanoindentation results indicated that the PEO coatings became softer but more ductile after applyingthe second processing step in acidic electrolyte.

硅基磁性纳米SiO_(2)微球的制备与表征

采用Stober法,以Fe3O4为磁核,制备出粒径为250-300 nm的磁性SiO2-Fe3O4复合微球。详细介绍了Stober法制备微球的实验过程,并对所制得的复合微球做了X射线衍射（XRD）结构分析、扫描电子显微镜（SEM）形貌表征以及振动样品磁强计（VSM）磁性性能测试分析。此外,还在金属氧化物半导体（MOS）电容结构的基础上,结合SiO2-Fe3O4复合微球的独特结构,制作了一种新型电解液-二氧化硅-微球-半导体（ESSS）电容结构化学传感器,并在不同pH值溶液下,分别测试了ESSS电容的电容-电压（C-V）曲线,测试结果初步证实了ESSS电容结构用作化学传感器的可行性。

含硝基苯及其衍生物染料废水的处理

采用铁炭微电解-过氧化氢氧化还原法处理含硝基苯、硝基苯胺类的染料废水。实验探索了电解时间、pH值、氧化剂投加量和氧化反应时间对废水COD去除率的影响,以确定最佳工艺条件。

Microarc oxidation coating fabricated on AZ91D Mg alloy in an optimized dual electrolyte

Microarc oxidation （MAO） process was conducted on AZ91D magnesium alloy in an electrolyte composed of NazSiO3, NaAlO2, NaEB4O7, NaOH, C3H803 and C6H5Na307 by AC pulse electrical source. The surface and cross-sectional morphologies, film thickness, chemical composition and structure of the coatings were characterized by scanning electron microscopy（SEM）, layer thickness metry, energy disperse spectroscopy（EDS） and X-ray diffraction（XRD）. The corrosiofi resistances of the coatings in a 3.5% NaC1 neutral solution were evaluated by electrochemical impedance spectroscopy （EIS） and potentiodynamic polarization test. The results showed that an optimized electrolyte with a composition of 15 g/L NazSiO3, 9 g/L NaA102, 2 g/L NazB407, 3 g/L NaOH, 5 mL/L C3H803 and 7 g/LC,HsNa307 was developed by means of orthogonal experiment. The coating obtained in the optimized electrolyte had a dense structure and revealed a lower current density, decreased by two orders of magnitude as compared with the magnesium substrate. Meanwhile, the corrosive potentials of the coated samples increased nearly by 73 inV. EIS result showed that the corrosion resistance of the coating was mainly determined by the inner dense layer. The coating primarily contained elements Mg, Al, O and Si and XRD analyses indicated that the coating was mainly composed of MgO, Mg2SiO4 and MgAl204.

含硝基苯类衍生物的废水处理

采用铁炭微电解—双氧水氧化还原法处理含硝基苯、硝基苯胺类化合物的染料废水。探索了微电解时间,氧化还原的pH值、氧化剂投加量和氧化反应时间对废水CODCr去除率的影响,确定了最佳工艺条件:电解时间45min,电解液pH=3.0,过氧化氢投加量在30～50mg·L-1,氧化反应时间控制在1.5～2.0h。此工艺条件对处理该类含硝基苯类化合物的废水具有较佳的降低CODCr的效果。