Catalytic activity of cerium-doped Ru/Al2O3 during ozonation of dimethyl phthalate

In this paper, factors influencing the mineralization of dimethyl phthalate (DMP) during catalytic ozonation with a cerium-doped Ru/Al₂O₃ catalyst were studied. The catalytic contribution was calculated through the results of a comparison experiment. It showed that doping cerium significantly enhanced catalytic activity. The total organic carbon (TOC) removal over the doped catalyst at 100 min reached 75.1%, 61.3% using Ru/Al₂O₃ catalyst and only 14.0% using ozone alone. Catalytic activity reached the maximum when 0.2% of ruthenium and 1.0% of cerium were simultaneously loaded onto Al₂O₃ support. Results of experiments on oxidation by ozone alone, adsorption of the catalyst, Ce ion’s and heterogeneous catalytic ozonation confirmed that the contribution of heterogeneous catalytic ozonation was about 50%, which showed the obvious effect of Ru-Ce/Al₂O₃ on catalytic activity. __________ Translated from China Environmental Science, 2006, 26(4): 445–448 [译自: 中国环境科学]     

Effect of preparation parameters on catalytic properties of Pt/graphite

Catalytic ozonation of aqueous solutions of oxalic acid was examined in the presence of graphite-supported platinum catalysts. The catalytic activity of graphite was significantly enhanced by loading platinum. The removal efficiency of oxalic acid was 3.0%, 47.6% and 99.3% for ozonation alone, graphite catalytic ozonation and Pt/graphite catalytic ozonation in 30 min under the experimental condition, respectively. The influence of support pretreatment, solvent, impregnation time, platinum loading amount and reduction temperature on the activity of Pt/graphite catalyst was investigated. The pretreatment of graphite support had no effect on activity improvement of Pt/graphite catalyst. Solvent and impregnation time also no great effect on the activity. Platinum loading amount and reduction temperature influenced the catalyst activity significantly. The optimal catalytic performance of Pt/graphite was obtained when 1.0% platinum loading and 623 K of reduction temperature was adopted. The Pt/graphite catalyst was used for five times with no significant decrease in its activity and more than 90% oxalic acid removal was obtained. __________ Translated from Environmental Science, 2007, 28(6): 1258–1263 [译自: 环境科学]     

N原子杂化石墨烯高效活化过一硫酸盐降解RBk5染料废水

过硫酸盐高级氧化技术使用过程中,活化剂的大量流失与其环境二次危害是影响该技术应用的主要限制因素.针对这一问题本研究采用改进的Hummers法结合水热法制备环境友好型的N原子掺杂石墨烯作为催化剂,活化过一硫酸盐(PMS)产生硫酸根自由基(SO4-·)和羟基自由基(·OH)降解活性黑5(RBk5)染料.利用傅立叶红外光谱,X-射线光电子能谱,拉曼光谱和透射电子显微镜对N原子掺杂石墨烯进行表征.对催化剂催化性能进行研究,考察了初始p H、催化剂投加量和PMS投加量等因素对降解过程的影响.结果表明,N元素掺杂能够有效提升石墨烯材料的PMS催化活性,且活性受N掺杂比例影响较大;废水的初始p H对降解效率无明显影响.催化剂投加量为1. 5 g·L-1,PMS投加量为0. 3 g·L-1的条件下,反应25min后RBk5染料废水的降解率可达到99%以上,反应过程符合一级反应动力学.自由基猝灭实验显示,N掺杂石墨烯/PMS体系降解RBk5为表面反应,SO4-·和·OH为降解RBk5的主要自由基.循环实验证明催化剂稳定性能良好.     

Synthesis of nanoiron by microemulsion with Span/Tween as mixed surfactants for reduction of nitrate in water

Denitrification of nitrate in groundwater using iron nanoparticles has received increasing interest in recent years. In order to fabricate iron nanoparticles with homogeneously spherical shape and narrow size distribution, a simple and “green” method was developed to synthesize iron nanoparticles. The conventional microemulsion methods were modified by applying Span 80 and Tween 60 as mixed surfactants. The maximum content of water in the Water-in-oil (W/O) microemulsion and its appropriate forming conditions were found, and then the microemulsion system consisting of saturated Fe²⁺ solution was used to synthesize α-Fe ultrafine particles by redox reaction. The nanoparticles were characterized by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the average diameter of the particle is about 80–90 nm. The chemical activity of the obtained iron nanoparticles was studied by the denitrification experiment of nitrate. The results show that under the experimental conditions, iron removed most of the 80 mg/L nitrate within 30 min. The mass balance of nitrate reduction with nanoscale Fe indicates that endproducts are mainly ammonia. Two possible reaction pathways for nitrate reduction by nanoscale iron particles have been proposed in this work. __________ Translated from Chemical Journal of Chinese Universities, 2006, 27(4): 672–675 [译自: 高等学校化学学报]     

Mo源改性石墨相氮化碳(g-C3N4)活化过一硫酸盐可见光降解罗丹明B的性能研究

分别以钼酸钠（MA）和乙酰丙酮钼（MC）作为钼（Mo）源,采用热聚合法合成不同类型Mo-C₃N₄材料（MACN和MCCN）,并通过XRD、SEM、XPS、UV-Vis DRS等表征技术探究不同Mo源的引入对g-C₃N₄晶体结构和光学性质的影响.结果表明,Mo的引入增大了g-C₃N₄的晶格间距,以MC为Mo源合成的MCCN催化剂具有更大的比表面积、更宽的可见光响应范围和更低的能带宽度.将所合成的催化剂应用于耦合过一硫酸盐（PMS）可见光催化降解罗丹明B （RhB）研究,发现在催化剂浓度为0.5 g·L^-1、PMS浓度为1 mmol·L^-1、罗丹明B浓度为10 mg·L^-1的条件下,MCCN-4/PMS/Vis催化体系在25 min内对RhB的降解率高达94.1%,分别是MCCN-4/Vis和单独PMS催化体系的5.6和19.2倍,并且RhB光催化降解过程符合一级动力学方程.为进一步探索MCCN/PMS/可见光（Vis）催化体系的最佳工艺条件,系统考察了Mo的掺杂量、催化剂投加量、PMS浓度、污染物浓度、pH值等实际因素对RhB降解效果的影响.同时,循环实验表明,MCCN-4复合催化剂具有良好的稳定性和可重复性,3次循环之后仍保持89.1%的RhB降解率.此外,捕获实验和电子自旋共振测试（ESR）结果表明,在MCCN/PMS/Vis催化体系下,光生空穴（h⁺）和超氧自由基（·O₂^-）作为主要活性物种参与了RhB的降解.     

低温等离子体结合锰基催化剂去除乙酸乙酯的研究

利用固态法和溶胶-凝胶法分别制备了钙钛矿（LaMnO₃）和八面体分子筛（OMS）两种锰基催化剂,在不同工况（输入电压、初始浓度、停留时间和催化剂放置量）条件下考察了等离子体催化对乙酸乙酯的降解特性.结果发现,锰基催化剂的加入显著提高了乙酸乙酯的去除率,减少了副产物的生成,并且OMS的催化活性高于LaMnO₃;此外,乙酸乙酯去除率随着电压的升高而增加,随着污染物初始浓度的增大而减少,并随停留时间的增长而变大;催化剂放置量为0.2 g时催化效果最佳.OMS催化剂在等离子体催化长期运行过程中表现出较好的稳定性.基于X射线衍射（XRD）、X射线光电子能谱（XPS）、H₂程序升温还原（H₂-TPR）、比表面积测试（BET）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）等手段对锰基催化剂物理化学性质的分析表明,OMS具有较高的催化活性主要归功于其拥有更高比例的Mn⁴⁺/（Mn³⁺+Mn⁴⁺）和吸附氧（O_ads）/晶格氧（O_latt）.     

Pd/TiO2对水体中2,4-二氯酚的催化加氢脱氯研究

分别采用沉淀-沉积法和浸渍法合成了Pd/TiO2催化剂,采用透射电镜(TEM)、X射线衍射(XRD)和电感耦合等离子体发射光谱(ICP-AES)对材料进行了表征,并对2,4-二氯酚的催化加氢脱氯反应进行了研究.结果表明,2种方法制备的催化剂在加氢脱氯反应中均具有较好的效果,沉淀-沉积法制备的催化剂活性更高,当反应物初始浓度为3.11 mmol.L-1,pH为12,催化剂用量为50 mg时,45 min内2,4-二氯酚可以完成脱氯过程.酸性条件有利于反应的进行.当催化剂用量在15～80 mg时,反应初活性没有明显变化,因此催化反应过程不受传质阻力的影响.当反应物初始浓度在0.62～3.11 mmol.L-1时反应初活性随浓度的提高显著增加,但进一步增加反应物的浓度时初活性没有明显提高,因此2,4-二氯酚在催化剂上的加氢脱氯行为符合Langmuir-Hinshelwood模型,表明2,4-二氯酚的加氢脱氯受表面吸附所控制.     

Degradation of 4-aminophenol by hydrogen peroxide oxidation using enzyme from Serratia marcescens as catalyst

This paper reports on the degradation of 4-aminophenol using hydrogen peroxide as oxidizer and the enzyme from Serratia marcescens AB 90027 as catalyst. The effecting factors during degradation and the degrading mechanism were studied. Also, the location of the enzyme in the cell, which could catalyze the degradation of 4-aminophenol, was analyzed. The results showed that to degrade 50 mL of 4-aminophenol whose concentration was 500 mg/L, the optimal conditions were: volume of H₂O₂ = 3 mL, temperature = 40–60°C and pH = 9–10. In the degradation process, 4-aminophenol was first converted to benzoquinone and NH₃, then organic acids including maleic acid, fumaleic acid, and oxalic acid were formed, and then finally CO₂ and H₂O were generated as final products. The enzyme that could catalyze the degradation of 4-aminophenol was mainly extracellular enzyme. Translated from Environmental Chemistry, 2006, 25(2): 141–144 [译自: 环境化学]     

纳米Fe/Co催化降解土霉素效果及影响因素研究

为探究液相还原法制备的纳米Fe/Co催化剂的类芬顿催化效果,以单因素分析法研究了pH、OTC（土霉素）初始质量浓度、H₂O₂摩尔浓度和催化剂用量对纳米Fe/Co催化剂催化性能的影响,并通过SEM（扫描电子显微镜）和BET（比表面积测试仪）对纳米Fe/Co催化剂进行表征,进一步研究了纳米Fe/Co催化剂对OTC模拟废水的催化降解效果.结果表明:①纳米Fe/Co催化剂可以有效地改善催化体系的pH使用范围,在pH为3.0~11.0范围内,纳米Fe/Co催化剂对浓度为100 mg/L OTC的去除率（94.0%）高于纳米Fe催化剂（85.0%）;低浓度OTC有利于提高污染物的去除率,而高浓度的OTC有利于提高反应速率;H₂O₂摩尔浓度为200 mmol/L时,纳米Fe/Co催化剂对OTC的去除率最高（93.8%）;纳米Fe/Co催化剂用量为6 g/L时,其对OTC的去除率最高（92.8%）.②纳米Fe/Co催化剂粒径为20~30 nm,比表面积较高,为121.3 m2/g.③纳米Fe/Co催化剂在重复利用13次后OTC去除率仍在50.0%以上,其重复利用性能良好.研究显示,纳米Fe/Co催化剂对OTC废水具有较好的催化性能、重复利用性能以及较宽的pH使用范围,可为含抗生素废水处理提供理论支撑.      

人工智能助力臭氧催化剂SrFexZr1-xO3的开发

将人工智能应用于催化臭氧氧化催化剂SrFe_xZr_1-xO₃的开发过程,采用共沉淀法制备了50种不同配方的催化剂,考察聚乙二醇（PEG）投加量、煅烧时间、老化时间、氨水投加量和铁掺杂量对SrFe_xZr_1-xO₃催化剂催化臭氧降解间甲酚反应活性的影响.同时,利用人工神经网络（ANN）和响应面（RSM）对催化剂合成条件与TOC去除率和间甲酚转化率的关系进行拟合,训练集中ANN的R²值分别为0.91和0.97,高于RSM的R²值0.35和0.41;在4组测试集上ANN的均方误差（MSE）分别为9.87和17.67,远小于RSM的23.89和28.87.结果表明,ANN模型对催化剂制备过程的复杂体系具有更好的拟合和泛化能力.在ANN训练好的模型中通过枚举法寻找最优合成条件为：PEG投加量为19.00%,煅烧时间为1.25 h,老化时间为26.50 h,氨水投加量为6.21 mL,铁掺杂量为3.37%,所得催化剂为SrFe_0.13Zr_0.87O₃-B.最佳反应条件下,间甲酚转化率和TOC去除率分别达到98.52%和17.21%,优于空白组的73.46%和1.86%.     

Effects of environmental factors on the production and release of matrix-bound phosphine from lake sediments

Effects of pH, temperature, and oxygen on the production and release of phosphine in eutrophic lake sediments were investigated under laboratory tests. Results indicated that the elimination of matrix-bound phosphine was accelerated under initial pH 1 or 12. Phosphine levels could reach maximum under initial pH 10. The contents of phosphine increased with the addition of alkali under pH 4–12. The rates of phosphine production and release from lake sediments varied with temperature. 20°C was the most favorable temperature for the production of matrix-bound phosphine. Oxygen showed little effect on matrix-bound phosphine. Matrix-bound phosphine concentrations in lake sediments were concluded to be dependent on a balance of natural generation and depletion processes. Translated from Acta Scientise Circumstantiae, 2005, 25(5): 681–685 [译自: 环境科学学报]     

Removal of benzotriazole by heterogeneous photoelectro-Fenton like process using ZnFe2O4 nanoparticles as catalyst

ZnFe2O4 nanoparticles(ZFNPs) were developed as catalyst for the degradation of benzotriazole(BTA) by heterogeneous photoelectroFenton(PE-Fenton) like process.ZFNPs were prepared by a co-precipitation process and then characterized with transmission electron microscopy(TEM),X-ray fluorescence(XRF),X-ray diffraction(XRD) and BET surface area.Using such ZFNPs as catalyst,the degradation of BTA was investigated.Due to the high catalytic activity of ZFNPs,PE-Fenton like process showed efficient degradation of BTA.The influencing factors such as pH,dosage of ZFNPs,applied potential and initial concentration of BTA were systematically investigated.Under the optimum conditions,91.2% of BTA was removed after 180 min treatment.     

阴极电场增强活性炭纤维-臭氧体系去除水中硝基苯

通过对电流强度、反应液初始pH值、电解质种类及浓度等因素分析,探究了电增强活性炭纤维-臭氧体系对水中硝基苯的去除效果和机制.结果表明,与活性炭纤维-臭氧体系比较,电增强活性炭纤维-臭氧体系对硝基苯的去除效率显著提升.电增强活性炭纤维-臭氧体系中电流强度对体系影响不显著,臭氧浓度对水中硝基苯的去除效率有一定影响,反应初始液的pH值对活性炭纤维催化臭氧体系的影响较大.水中无机盐如硫酸钠、硝酸钠及氯化钠的存在会抑制活性炭纤维催化臭氧.此外,单独臭氧对活性炭纤维有破坏作用,降低了活性炭纤维对反应的促进效果,外加阴极电场时,不仅活性炭纤维对有机物的去除效果显著提升,而且保证了活性炭纤维结构不被臭氧所破坏.     

Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

Enhanced biological phosphorus removal (EBPR) is a commonly used and sustainable method for phosphorus removal from wastewater. Poly-β-hydroxybutyrate (PHB), polyphosphate, and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation organisms. The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release, which is very important for controlling the performance of EBPR. To obtain the mechanism and kinetic character of anaerobic phosphorus release, a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit of the biological phosphorus removal system in this study. The results showed that the volatile suspended solid (VSS) had an increasing trend, while the mixed liquid suspended sludge (MLSS) and ashes were reduced during the anaerobic phosphorus release process. The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms is exhausted. Under the condition of lower initial HAc-COD, HAc became the limiting factor after some time for anaerobic HAc uptake. Under the condition of higher initial HAc-COD, HAc uptake was stopped because of the depletion of glycogen in the microorganisms. The mean ratio of Δρ _P/Δρ _PHB, Δρ _GLY/Δρ _PHB, Δρ _P/ΔCOD, was 0.48, 0.50, 0.44, and 0.92, respectively, which was nearly the same as the theoretical value. The calibrated kinetic parameters of the HAc-uptake and phosphorus-release model were evaluated as follows: Q _HAc,max was 164 mg/(g · h), Q _P,max was 69.9 mg/(g · h), K _gly was 0.005, and KCOD was 3 mg/L. An apparently linear correlation was observed between the ratio of Δρ _P/ΔCOD and pH of the solution, and the equation between them was obtained in this study. Translated from Acta Scientiae Circumstantiae, 2005, 25(9), 1164–1169 [译自: 环境科学学报]     

Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

Batch experiments were carried out to investigate the promotive effect of pyridine on indole degradation under denitrifying conditions. The seed sludge was obtained from a local coal-coking wastewater treatment facility and was acclimated in the laboratory. Indole and pyridine were supplemented to the synthetic wastewater at different ratios. The optimum ratio of chemical oxygen demand (COD) to nitrate (C/N) was 8.4–8.9 for both denitrification and indole and pyridine degradation. At a temperature of 28°C and pH of 7.0–7.5, the nitrate reductase activity (NRA) was in the best state. The addition of pyridine could promote NRA and the degradation of indole. When the initial concentration of indole was 150 mg/L, the concentration ratio of indole to pyridine was in the range of 1–10. Under optimum C/N conditions, the degradation of indole could be described with pseudo-zero-order kinetics. There was no accumulation of nitrite during the reaction. When the concentration ratio of pyridine to indole was less than 0.25 with an increase in the pyridine proportion, there were more significant augment rates for NRA and the degradation of indole than the situation when the concentration ratio was more than 0.25. __________ Translated from Environmental Science, 2006, 27(2): 300–304 [译自: 环境科学]     

Adsorptive behaviors of humic acid onto freshly prepared hydrous manganese dioxides

This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO₂(s) (δMnO₂), and investigated the feasibility of employing δMnO₂ for humic acid removal from drinking water. Effects of such parameters as molecular mass of humic acid, kinds of divalent cations on adsorptive behaviors and possible mechanisms involved were investigated. This study indicated that humic acid with higher molecular mass exhibited more tendency of adsorbing onto δMnO₂ than that with lower molecular mass. Ca²⁺ facilitated more humic acid adsorption than Mg²⁺; UV-Vis spectra analysis indicated higher capabilities of Ca²⁺ coordinating with acidic functional groups of humic acid than that of Mg²⁺. Additionally, ζ potential characterization indicated that Ca²⁺ showed higher potential of increasing gz potential of δMnO₂ than Mg²⁺. Ca²⁺ of 1.0 mmol/L increased ζ potential of δMnO₂ from −37 mV (pH 7.9) to +7 mV (pH 7.2), while 1.0 mmol/L Mg²⁺ increased to lower value as −9 mV (pH 6.5), correspondingly. Fourier transform infrared (FTIR) spectra demonstrated the adsorption of humic acid onto δMnO₂, showing the important roles of-COO⁻ functional groups and surface Mn-OH in the adsorption of humic acid onto δMnO₂. Translated from Acta Scientiae Circumstantiae, 2005, 25(3): 351–355 [译自: 环境科学学报]     

Effects of nitrite on phosphate uptake in anaerobic-oxic process

An anaerobic-oxic (A/O) biological phosphorus removal reactor was operated to study the effect of nitrite on phosphate uptake. The phosphorus uptake profile was determined under different operating conditions. The results indicated that in addition to oxygen and nitrate (DPB_Na, nitrate denitrifying phosphorus removal), to some extent, nitrite could also serve as an electron acceptor to achieve nitrite denitrifying phosphorus removal (DPB_Ni). The quantity and rate of phosphorus uptake of DPB_Ni, however, were evidently lower than that of DPB_Na. The experiment results revealed that nitrite would bring toxic action to phosphate-accumulating organisms (PAOs) when NO₂ ⁻-N ⩾ 93.7 mg/L. The nitrite existing in the anoxic reactor made no difference to the quantity and rate of denitrifying phosphorus removal, but it could reduce the consumption of nitrate. Moreover, the data showed that the aerobic phosphate uptake of DPB_Ni was lower than that of anaerobic phosphorus-released sludge in a traditional A/O process. However, there was not much difference between these two kinds of sludge in terms of the total phosphorus uptake quantity and the effluent quality. Translated from Environmental Science, 2006, 27(4): 701–703 [译自: 环境科学]     

Simultaneous sorption of aqueous phenanthrene and phosphate onto bentonites modified with AlCl3 and CTMAB

The purpose of this work is to synthesize a new type of bentonite sorbent that can simultaneously remove both organic compounds and phosphate from water. Inorganic-organic bentonites (Al-CTMAB-Bent) were synthesized by modifying bentonites with both AlCl₃ and cetyltrimethyl ammonium bromide (CTMAB). Simultaneous sorption of aqueous phenanthrene and phosphate onto Al-CTMAB-Bent was examined. Removal rates of phenanthrene and phosphate from water reached 96.3% and 90.2%, respectively, at their respective initial concentrations of 1 mg/L and 5 mg/L and the added amount of Al-CTMAB-Bent was 1.25 g/L. The residual turbidity of the Al-CTMAB-Bent suspension decreased 81.4% compared to that of organobentonite suspension after a 1 h settling time. Thus, inorganic-organic bentonite can be used to treat wastewater containing both organic pollutants and phosphate. Translated from Environmental Science, 2006, 27(1): 91–94 [译自: 环境科学]     

Bi-TiO2纳米管阵列电极对水中硝酸盐的去除

为研究电化学技术对硝酸盐氮的去除作用,本实验以TiO₂纳米管（TiO₂-NT）为基体,利用电沉积法制备了Bi-TiO₂纳米管阵列电极（Bi-TNA）.同时,采用X-射线衍射仪（XRD）、扫描电子显微镜（SEM）对电极涂层表面形貌和晶体结构进行表征,并分析了电流密度、pH、初始浓度对硝态氮去除、亚硝态氮和氨氮转换、总氮去除及氮气选择性的影响.最后分析了Bi-TNA电极对硝态氮去除的动力学模型.结果表明,在单因素水平下,最佳操作条件为：硝态氮浓度为50 mg·L^-1,电流密度为30 mA·cm^-2,pH值为8.5.Bi-TNA电极对硝态氮的还原过程都遵循一级反应动力学.     

Effects of cathode potentials and nitrate concentrations on dissimilatory nitrate reductions by Pseudomonas alcaliphila in bioelectrochemical systems

The effects of cathode potentials and initial nitrate concentrations on nitrate reduction in bio- electrochemical systems （BESs） were reported. These factors could partition nitrate reduction between denitrification and dissimilatory nitrate reduction to ammonium （DNRA）. Pseudomonas alcaliphilastrain MBR utilized an electrode as the sole electron donor and nitrate as the sole electron acceptor. When the cathode potential was set from -0.3 to -I.1 V （vs. Ag/AgC1） at an initial nitrate concentration of 100 mg NO~-N/L, the DNRA electron recovery increased from （10.76 ± 1.6）% to （35.06 ± 0.99）%; the denitrification electron recovery decreased from （63.42 ± 1,32）% to （44.33 ± 1.92）%. When the initial nitrate concentration increased from （29.09 ± 0.24） to （490.97 ± 3.49） mg NO3-N/L at the same potential （-0.9 V）, denitrification electron recovery increased from （5.88 ± 1.08）% to （50.19 ±2.59）%; the DNRA electron recovery declined from （48.79 ±1.32）% to （16.02 ± 1.41）%. The prevalence of DNRA occurred at high ratios of electron donors to acceptors in the BESs and denitrification prevailed against DNRA under a lower ratio of electron donors to acceptors. These results had a potential application value of regulating the transformation of nitrate to N2 or ammonium in BESs for nitrate removal.