Application of Double-Dielectric Barrier Discharge Plasma for Removal of Pentachlorophenol from Wastewater Coupling with Activated Carbon Adsorption and Simultaneous Regeneration

Wastewater containing pentachlorophenol (PCP) was treated by granular activated carbon (GAC) adsorption and double-dielectric barrier discharge (D-DBD) plasma. A packed bed D-DBD reactor was applied for removal of PCP on GAC and GAC regeneration, where the discharge gap was filled with GAC. PCP degradation efficiency of 65% and GAC regeneration efficiency (RE) of 87% were achieved. Effects of discharge power, treatment time and O₂ flow rate on PCP degradation and GAC regeneration were investigated. Increasing discharge power, treatment time and O₂ flow rate were favorable for PCP degradation, and also contributed to GAC RE. C–Cl bonds in PCP were cleaved by D-DBD plasma. Effect of D-DBD plasma on physical and chemical properties of GAC during GAC regeneration process was characterized by N₂ adsorption and Boehm titration. This study is expected to demonstrate the feasibility of applying D-DBD plasma for efficient organic wastewater treatment by coupling with GAC adsorption.     

Electrochemical degradation of 2,4-Dinitrotoluene (DNT) from aqueous solutions using three-dimensional electrocatalytic reactor (3DER): Degradation pathway,evaluation of toxicity and optimization using RSM-CCD

2,4-Dinitrotoluene (2,4-DNT) has been found to be an important petrochemical compound, which is primarily employed for the synthesis of tolylene diisocyanate and the production of dyes, rubber, and explosives. Since this compound has high toxicity and carcinogenicity, the cautions should be considered when wastewater contaminated with DNTs and their derivatives is released into the environment. Thus, the object of the present study was the investigation of the 2,4-DNT degradation efficiency using the three-dimensional electrocatalytic reactor (3DER) with two different types of particle electrodes (granular activated carbon (GAC) and magnetized clinoptilolite zeolite (MCZ)@Fe₃O₄ nanoparticles)). Preparation of the graphite (G)/β-PbO₂ anode was done by electrochemically depositing PbO₂ layers on graphite sheets. The prepared graphite sheet and a stainless-steel 316 sheet (with the same dimensions) were employed as the anode and the cathode, respectively. Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), and energy-dispersive X-ray spectroscopy mapping (EDS-mapping) confirmed the successful preparation of G/β-PbO₂ anode. The surface morphology, chemical composition of MCZ@Fe₃O₄ nanoparticles as a particle electrode were determined by scanning electron microscope (SEM) and XRD pattern. To determine the optimal conditions, we employed the response surface methodology-based central composite design (RSM-CCD) method. According to observed results, higher efficiency of 3DER was obtained by increasing the reaction time and current density and decreasing pH and the pollutant concentration. Studies highlighted the initial 2,4-DNT concentration of 23.5 mg/L, current density 4.8 mA/cm², pH of 4.1, electrolysis time of 50 min, particle electrodes dose = 6 g/250 cc as optimum values of parameters. The 2,4-DNT degradation efficiencies using GAC and MCZ@Fe₃O₄ nanoparticles as particle electrodes under mentioned optimal conditions were 98.6% and 96.5%, respectively. Moreover, the chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies were 88.5% and 80.9% at the end of 50 min, respectively. Furthermore, results were indicative of an enhancement in average oxidation state (AOS) (from 1.27 to 2.36) and carbon oxidation state (COS) (from 1.27 to 3.68) in the 3DER process and a reduction in the COD/TOC ratio (from 1.81 to 1.09); these signposts the effectiveness of 3DER system for providing the biodegradability of 2,4-DNT. Considering the results, the 3DER could lead to suitable results for the degradation of wastewater containing DNT and resistant contaminants as pretreatment and has remarkable applicability for enhancing the biodegradability of wastewater.     

Efficient electrochemical incineration of phenol on activated carbon fiber as a new type of particulates

The feasibility of activated carbon fibers (ACFs) used as a new type of particle electrodes in 3-dimensional (3D) electrode for the electrochemical degradation of phenol wastewater was investigated for the first time. The surface morphology, textual properties and electrochemical behaviors of ACF were studied by scanning electron microscopy (SEM), N₂-BET sorption and cyclic voltammograms (CVs), respectively. Compared with the commercialized granular activated carbon (GAC), ACF particle electrodes exhibited higher electrochemical oxidation performance on the mineralization of target pollutant. The identification of intermediates indicated most of oxidation products were adsorbed onto the ACFs. The detection of hydrogen peroxide and hydroxyl radicals in the reaction system suggested that the reaction mechanism was direct anodic oxidation of pollutant on ACFs if the cathode did not contact the ACFs. The operative parameters including initial concentration of substrate, applied current density and the initial aqueous pH have been scientifically studied in search of the optimum condition. Based upon the obtained results, the ACFs longevity was tested in solution at pH 2.0, revealing relatively high electrooxidation capacity and long catalyst lifetime of ACFs in acid solution.     

复合金属氧化物Sn-Sb-Mn/陶瓷粒子电极体系的电催化性能

通过热分解法制备了复合金属氧化物Sn-Sb-Mn/陶瓷粒子电极, 分别采用扫描电子显微镜(SEM)、能量色散X 射线能谱(EDS)、X射线衍射(XRD)和N2吸附-脱附等技术对电极的形貌、晶相组成、比表面积和孔径分布进行了表征. 考察了该三维粒子电极系统的析氧特性, 采用循环伏安法分析了三维系统的电催化性能, 并且进行了电化学催化降解苯酚的试验. 结果表明, 制备的陶瓷粒子电极涂层比表面较大、孔结构发达, 有利于电催化反应; 电催化降解主要发生在电化学析氧区; 粒子电极系统对苯酚降解作用显著, 明显高于二维电极系统, 苯酚的去除率为92.3%, 总有机碳(TOC)的去除率为66.7%. 研究结果表明, 该三维粒子电极系统具有优良的电催化性能.     

Ni^2＋／TiO2介孔材料光催化降解造纸废水影响因素的研究

溶胶-凝胶法合成了不同Ni掺杂量的Ni2 /TiO2介孔复合材料.用X射线衍射(XRD)、透射电子显微镜(TEM)、红外(FT - IR)光谱和N2吸附脱附等对产物结构进行了表征.考察了Ni掺杂量、催化剂的用量、初始pH、外加氧化剂等因素对光催化降解造纸废水的影响.结果表明: Ni2 /TiO2介孔复合材料光催化降解造纸废水的最佳反应条件为:Ni掺杂量为2%、催化剂用量1.5g/L、初始pH=4、通氧;光照4 h后,废水色度去除率达100%; 12 h后,废水CODCr去除率达到83.4%.     

Electrochemical Degradation of o-Chloronitrobenzene by Three-dimensional Electrodes

Degradation of o-chloronitrobenzene wastewater was experimentally investigated at a three-dimensional electrode(TDE) with granular activated carbon as the particle electrode, graphite as the anode, and stainless steel plate as the cathode. The kinetic model of o-chloronitrobenzene degradation was studied, and the effects of pH, electrolysis time, particle electrode, electrolyte concentration, and initial concentration of the solution on degradation efficiency were investigated to determine the optimal operating conditions. The degradation of o-chloronitrobenzene by oxidation at the TDE was monitored by chemical oxygen demand(COD) measurements, UV-Vis absorption, and high performance liquid chromatography(HPLC). COD degradation by electrochemical degradation followed pseudo-first order kinetics with respect to the concentration of o-chloronitrobenzene solutions. Optimal reaction conditions included 15 g of activated carbon as the particle electrode, 400 mg/L o-chloronitrobenzene solution containing 0.10 mol/L Na₂SO₄, pH=3, and 60 min of electrolysis. The UV-Vis absorption spectra and HPLC results illustrate that the benzene ring in o-chloronitrobenzene was rapidly broken down to form aliphatic substances through electrochemical degradation. COD degradation was approximately 98.5% at optimal conditions.     

3,5-Dinitrosalicylic Acid Adsorption Using Granulated and Powdered Activated Carbons

Some nitroaromatic compounds are found in wastewater from industries such as the weapons industry or the wine industry. One of these compounds is 3,5-dinitrosalicylic acid (DNS), widely used in various tests and frequently found as an emerging pollutant in wastewater and to which the required attention has not been given, even though it may cause serious diseases due to its high toxicity. This study investigated the adsorption of DNS using granulated activated carbon (GAC) and powdered activated carbon (PAC) at different temperatures. The results show that in equilibrium, the adsorption takes place in more than one layer and is favorable for the removal of DNS in both GAC and PAC; The maximum adsorption capacity was obtained at 45 °C, with values of 6.97 mg/g and 11.57 mg/g, respectively. The process is spontaneous and exothermic. In addition, there was a greater disorder in the solid-liquid interface during the desorption process. The predominant kinetics using GAC (7.14 mg/g) as an adsorbent is Elovich, indicating that there are heterogeneous active sites, and when PAC (10.72 mg/g) is used, Pseudo-second order kinetics predominate, requiring two active sites for DNS removal. External mass transfer limitations are only significant in GAC, and ATR-FTIR studies in PAC demonstrated the participation of functional groups present on the adsorbent surface for DNS adsorption.     

Fe-Mn-Cu-Ce/Al2O3 as an efficient catalyst for catalytic ozonation of bio-treated coking wastewater: Characteristics,efficiency, and mechanism

It is important to develop a catalyst that has high catalytic activity and can improve the degradation efficiency of refractory organic pollutants in the catalytic ozonation process. In this study, Fe-Mn-Cu-Ce/Al₂O₃ was synthesised via impregnation calcination for catalytic ozonation of bio-treated coking wastewater. The physical and chemical characteristics of the catalysts were analysed using X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller nitrogen adsorption–desorption methods. The effects of catalyst dosage, pH, and reflux ratio on the degradation efficiency of wastewater were examined in laboratory-scale experiments. The chemical oxygen demand (COD) removal rate of bio-treated coking wastewater was estimated to be 52.76 % under optimal conditions. The experiments on the catalytic mechanism demonstrated that the surface hydroxyl formed by the Lewis acid sites on the surface of the catalyst can react with ozone as the active site forming the active oxygen (·OH, ·O₂^–, and ¹O₂), thereby efficiently degrading the organic pollutants in coking wastewater. Furthermore, a pilot-scale experiment on the catalytic ozonation of bio-treated coking wastewater was carried out using an Fe-Mn-Cu-Ce/Al₂O₃ catalyst, while the effects of the initial pollutant concentration, ozone concentration, and gas flow on the COD removal rate were studied on a pilot scale. It was found that the COD removal rate of the wastewater was ～ 60 % under optimal parameters. After the treatment, the wastewater steadily reached the coking wastewater discharge standard (COD < 80 mg/L), while the operating cost of catalytic ozonation reached ～ 0.032$/m³, thereby paving the way toward economic engineering applications. The COD degradation kinetics in the bio-treated coking wastewater followed pseudo-second-order kinetics. Three-dimensional fluorescence and gas chromatography–mass spectrometry revealed that macromolecular organic pollutants in the bio-treated coking wastewater were greatly degraded. In summary, Fe-Mn-Cu-Ce/Al₂O₃ exhibited good reusability, high catalytic activity, and low cost and has a wide application prospect in the treatment of coking wastewater.     

Application of polyaniline as an efficient and novel adsorbent for azo dyes removal from textile wastewaters

In this work, application of polyaniline coated onto wood sawdust (PAni/SD) for the removal of methyl orange (MO) as a typical azo dye from aqueous solutions is introduced. The effects of some important parameters such as pH, initial concentration, sorbent dosage, and contact time on the uptake of MO solution were also investigated. In order to get a better comparison, adsorption experiments were also carried out using commercial grade of granulated activated carbon (GAC) and sawdust without coating (SD) at the same time. It was found that PAni/SD can be used to remove azo dyes such as MO from aqueous solutions very efficiently. Experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Kinetic parameters for the adsorption of MO dyes for the selected adsorbents are also reported. In order to study the possibility of desorption for frequent application, chemical regeneration of the used adsorbents was also investigated. Desorption or recovery of dye and regeneration of adsorbent (PAni/SD) was found to be quite possible and of high performance. Application of modified sawdust with polyaniline for the removal of azo dye is very promising for textile wastewater treatment.     

Photocatalytic degradation of acid blue 74 in water using Ag–Ag2O–Zno nanostuctures anchored on graphene oxide

Water pollution due to industrial effluents from industries which utilize dyes in the manufacturing of their products has serious implications on aquatic lives and the general environment. Thus, there is need for the removal of dyes from wastewater before being discharged into the environment. In this study, a nanocomposite consisting of silver, silver oxide (Ag₂O), zinc oxide (ZnO) and graphene oxide (GO) was synthesized, characterized and photocatalytically applied in the degradation (and possibly mineralization) of organic pollutants in water treatment process. The Ag–Ag₂O–ZnO nanostructure was synthesized by a co-precipitation method and calcined at 400 °C. It was functionalized using 3-aminopropyl triethoxysilane and further anchored on carboxylated graphene oxide via the formation of an amide bond to give the Ag–Ag₂O–ZnO/GO nanocomposite. The prepared nanocomposite was characterized by UV–Vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), energy dispersive X-ray spectrometry (EDX), Fourier transformed infrared spectroscopy (FTIR), and Raman spectroscopy. The applicability of Ag–Ag₂O–ZnO/GO nanocomposite as a photocatalyst was investigated in the photocatalytic degradation of acid blue 74 dye under visible light irradiation in synthetic wastewater containing the dye. The results indicated that Ag–Ag₂O–ZnO/GO nanocomposite has a higher photocatalytic activity (90% removal) compared to Ag–Ag₂O–ZnO (85% removal) and ZnO (75% removal) respectively and thus lends itself to application in water treatment, where the removal of organics is very important.     

太阳光照射浮石负载二氧化钛降解氨氮废水

采用溶胶-凝胶法制备了Ti O_2,并使Ti O_2负载在浮石上制备Ti O_2/浮石光催化剂。用X射线荧光光谱(XRF)、电镜扫子显微描(SEM)和傅里叶红外光谱(FT-IR)表征浮石、Ti O_2及Ti O_2/浮石。在太阳光照射下,用Ti O_2/浮石处理模拟氨氮废水,以废水中氨氮降解率为标准,考察影响氨氮降解因素。结果表明,Ti O_2成功固定在浮石表面,负载率为3.71%;废水中氨氮降解率随太阳光照射时间、废水p H值、催化剂Ti O_2/浮石含量增加而增大。当初始氨氮浓度为500 mg/L、太阳照射180 min、废水p H=11、催化剂Ti O_2/浮石剂量为20 g/L时,氨氮降解率达82.0%,氨氮除去率86.8%,降解产物中未发现污染成分NO_2~-和NO_3~-产生。催化剂再生/催化3次,每次再生后氨氮降解率约下降10.0%。该方法快速、简单、低消耗和产生二次污染少,能有效地降解废水中的氨氮。     

Enhanced three-dimensional electrochemical process using magnetic recoverable of Fe3O4@GAC towards furfural degradation and mineralization

Furfural is as one of the major environmental pollutants in different industrial effluents such as refinery and petrochemical, paper, cardboard and oil refining. This toxic chemical is irritant and causes allergy for skin, eyes and mucous membranes. This study was developed to investigate the efficiency of a three-dimensional electrochemical process in the presence of granular activated carbon magnetized with Fe₃O₄ (Fe₃O₄@GAC) particle electrodes for removal of furfural from aqueous solution. The particle electrodes structural and morphological featured were determined via BET, VSM, XRD, FE-SEM and FTIR techniques. The experiments were performed based on central composite design (CCD) and the role of influencing factors including reaction time, pH, voltage and initial furfural concentrations at five levels were evaluated. The Quadratic model with high correlation coefficient = 0.9872 (R² and (R²_Adj = 0.9724)) was suggested for experimental data analysis. The performance of electrochemical oxidation towards furfural degradation was enhanced substantially after adding Fe₃O₄@GAC. The highest furfural removal efficiency (98.2%) was achieved under optimal conditions (furfural: 201 mg/L, electrolysis time: 69 min, voltage: 19 V, and pH: 5.0). Besides, over 78 and 74 % of COD and TOC were removed by Fe₃O₄@GAC-based three-dimensional process, respectively. Based on the COD/TOC ratio and average oxidation state (AOS) index, a significant increase was observed in the biodegradability of intermediates of furfural after treatment. Results showed that three-dimensional electrochemical process with particle electrodes is a promising technology for efficient removal of furfural, even at high concentrations. Results of Liquid chromatography–mass spectrometry (LC-MS) analysis and degradation pathway showed that furfural could be oxidized to compounds with smaller molecular masses, which eventually converted to carbon dioxide and water.     

Study on the electrocatalytic degradation of 4-chlorophenol on PbO<Subscript>2</Subscript>–ZrO<Subscript>2</Subscript> composite electrode and its electrochemical property

PbO₂–ZrO₂ composite electrodes were prepared by anodic electrodeposition in the lead nitrate solution. The electrochemical property of this electrode was studied by cyclic voltammetry, polarization curves and open-circuit potential–time curves. The results show that PbO₂–ZrO₂ composite electrodes possess higher oxygen evolution overpotential and better anti-corrosion performance than traditional PbO₂ electrodes. Electrocatalytic oxidation of 4-chlorophenol (4-CPs) in aqueous solution was studied to evaluate the applications of this electrode in environmental protection. The influence of experimental parameters on the COD removal efficiency was studied on PbO₂–ZrO₂ composite electrodes as a function of the current density, initial concentration of the 4-CPs, initial pH, supporting electrolyte concentration and electrolysis time. The results show that the 4-CPs removal efficiency in 0.1 mol L^–1 Na₂SO₄ solution containing 8 mmol L^–1 4-CPs could reach 89.2% with the current density at 200 mA cm^–2 and pH value at 6.5 after 4 h. Compared with traditional PbO₂ anodes, the PbO₂–ZrO₂ composite electrodes show higher instantaneous current efficiency with degradation of 4-CPs. The experimental results demonstrate that the PbO₂–ZrO₂ composite electrodes possess the excellent electrocatalytic activity in refractory pollutants degradation.     

Enhanced Photocatalytic Degradation of Synthetic Dyes and Industrial Dye Wastewater by Hydrothermally Synthesized G–CuO–Co<Subscript>3</Subscript>O<Subscript>4</Subscript> Hybrid Nanocomposites Under Visible Light Irradiation

To enhance the degradation of colour and chemical oxygen demand using photocatalytic activity, Graphene–CuO–Co₃O₄ hybrid nanocomposites were synthesized using an in situ surfactant free facile hydrothermal method. The photocatalytic degradation of synthetic anionic dyes, methyl orange (MO) and Congo red (CR), and industrial textile wastewater dyes under visible light irradiation was evaluated. The synthesized nanocomposite was characterized structurally and morphologically using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscope, and Fourier transform infrared spectroscopy. Evaluation of the colour indicated complete removal at 15 min of irradiation for the MO and CR dyes, with 99% degradation efficiency. The reaction time for the primary effluent wastewater dye was 60 min for 81% dye removal. In contrast, a longer reaction time was required to meet the national discharge regulation for the raw wastewater dye, 300 min for 60% dye removal. The mechanism for dye degradation using the Graphene–CuO–Co₃O₄ hybrid nanocomposite was elucidated using the Langmuir–Hinshelwood model, and the rate constant and half-life of the degradation process were calculated. The results demonstrate that photocatalytic degradation using a hybrid nanocomposite and visible light irradiation is a sustainable alternative technology for removing colour from wastewater dye.     

Assessing the Influence of Electrode Polarity on the Treatment of Poultry Slaughterhouse Wastewater

Electrochemical methods have been increasingly gaining popularity in the field of wastewater treatment. However, the performance of these methods can be highly affected by the polarity direction as determined by the electrodes arrangement (anode to cathode or cathode to anode); as well as the characteristics of the wastewater to be treated as determined by the type of wastewater. The presented research work investigated the relationship between polarity direction and the removal of pollutants from poultry slaughterhouse wastewater using titanium and aluminium electrode materials. In the first case, the wastewater was exposed to the Ti (anode)-Al (cathode) combination, whereas in the second case the wastewater was subjected to the Al (anode)-Ti (cathode) arrangement. The two cases were designed to see if the polarity direction of the chosen electrode materials affected the removal of pollutants. The removal efficiencies were computed as a ratio of the remaining concentration in the treated effluent to the concentration before treatment. It was observed that the production processes generate highly fluctuating wastewater in terms of pollution loading; for instance, 422 to 5340 Pt-Co (minimum to maximum) were recorded from color, 126 to 2264 mg/L were recorded from total dissolved solids, and 358 to 5998 mg/L from chemical oxygen demand. Also, the research results after 40 min of retention time showed that both electrode arrangements achieved relatively high removal efficiencies; Whereby, the aluminium to titanium polarity achieved up to 100% removal efficiency from turbidity while the titanium to aluminium polarity achieved a maximum of 99.95% removal efficiency from turbidty. Also, a similar phenomenon was observed from total dissolved solids; whereby, on average 0 mg/L was achieved when the wastewater was purified using the aluminium to titanium arrangement, while on average 2 mg/L was achieved from the titanium to aluminium arrangement. A little higher removal efficiency discrepancy was observed from ammonia; whereby, the aluminium to titanium arrangement outperformed the titanium to aluminium arrangement with average removal efficiencies of 82.27% and 64.11%, respectively.     

Degradation of Phenol by Hydroxyl Radicals on Different Coating Lead Dioxide Electrodes

Lead dioxide electrodes on Ti substrates were prepared by thermal-deposition or electro-deposition. The amount of hydroxyl radicals generated at the electrodes prepared by the above-mentioned two methods was compared with that at the electrodes mingled with Bi or La prepared by electro-deposition. The experimental results indicate that the highest concentration of hydroxyl radicals generated by thermal-deposition, electro-deposition mingled with nothing, electro-deposition mingled with Bi or La was 0.781, 1.048, 1.838 or 2.044 μmol/L, respectively. When phenol was electrolyzed on the four electrodes at a current density of 30 mA/cm2, the removal efficiency of phenol after electrolysis for 1.5 h was 87.30%, 93.55%, 97.95% or 98.70%, TOC removal efficiency after electrolysis for 5 h was 86.76%, 94.26%, 98.53% or 99.60%, respectively. Through the degradation experiments of phenol, the amount of hydroxyl radicals was responsible for the removal efficiency of phenol. The electro-catalytic characteristics were investigated by SEM, the generation amount of hydroxyl radicals, the degradation degree of phenol and the stability and conductivity of the electrodes were also investigated. The experimental results indicate that the four electrodes all show good electro-catalytic characteristics; the electro-catalytic characteristics of the electrode mingled with La were superior to those of the other three ones, and the electrochemical degradation of phenol followed one-step reaction dynamics.     

Treatment of CNC industry wastewater by electrocoagulation technology: an application through response surface methodology

ABSTRACT

Removal of COD, and several toxic heavy metals (Cu²⁺ and Ni²⁺) from CNC (metalworking fluid) wastewater was investigated using electrocoagulation method (EC) with Fe and Al electrodes. The interaction effects of the current density, reaction time and initial pH were analyzed and were correlated to assess the removal efficiencies for COD, copper, and nickel. Coefficient of determination (R²) and adjusted R² was found to be higher than 96.81% and 92.77; 99.01% and 89.94 for all responses at Fe and Al electrodes, respectively. Removal efficiencies were determined to be 95.72%, 96.03%, 95.22% and 97.11%, 98.51%, 92.49% for COD, copper and nickel at iron and aluminum electrodes, respectively under optimum operating conditions. The operational cost of the EC process for COD, copper, and nickel removal, were found to be 2.54, 3.36, 2.50 €/m³ for iron electrode and 7.16, 8.95, 8.50 €/m³ for aluminum electrode at optimum conditions, respectively. The results provide that The EC process seems to be an effective treatment method for removing COD and several trace heavy metals from the CNC machine (metalworking fluid) wastewater.     

Photolysis of organic pollutants in wastewater with 206 nm UV irradiation

A new-type UV light source(206 nm) was explored for the degradation of organic pollutants in wastewater for the first time.The degradation performances of triphenyltin chloride(TPTCl),dimethyl phthalate(DMP),as well as rhodamine B(RhB) were investigated.The results indicated that removal efficiency of 50 mg/L RhB,60 mg/L DMP and 120 mg/L TPTCl can reach 88.6%, 92.5%and 89.4%for 60 min,50 min and 75 min,respectively.By comparison of removal efficiency,we found 206 nm is superior to 253.7 nm UV in wastewat...     

Boron-doped diamond electrodes for the mineralization of organic pollutants in the real wastewater

The presence of recalcitrant organic compounds in wastewater poses a serious threat to the ecosystem and human health. Electrochemical advanced oxidation processes constitute a promising way for the mineralization of persistent organic compounds. They are commonly used for the transformation of organic pollutants into more biodegradable compounds or their complete removal from water. In this review, we present the recent advances in the use of boron-doped diamond (BDD) electrodes in the anodic oxidation process for the mineralization of real wastewater. First, the characteristic properties of BDD electrodes are discussed followed by the degradation mechanism. In addition, an overview on the application of BDD electrodes for mineralization of real wastewater is provided.     

Keggin型Ni-Mo-Zr杂多酸盐的合成、表征及催化超声降解性能

采用水热合成法制备了Keggin型结构的Ni-Mo-Zr杂多酸盐,并利用红外光谱（IR）和X射线衍射仪（XRD）对合成的产物进行了表征。以酸性绿B（AGB）为目标物,研究了在超声波辐射下,Ni-Mo-Zr杂多酸盐的投加量、染料废水初始浓度、pH值等因素对降解效果的影响。实验结果表明：新合成的杂多酸盐具有Keggin型结构,当催化剂的投加量为0.8 g/L,染料废水的初始浓度为10 mg/L,初始pH=5时,用 40 kHz超声频率辐射60 min,染料废水的降解率最高可达90.2%。通过动力学分析,降级反应符合一级反应动力学模型,降解速率随初始浓度的增加而减小。