新型类Fenton催化剂用于酸性红B染料废水处理的研究

为了解决Fenton试剂反应前后需要调节pH值、催化剂不能重复利用的问题,本实验以酸性红B溶液作为模拟染料废水,探索以硫铁矿烧渣作为非均相催化剂进行类Fenton反应的催化活性,研究了H2O2投加量、催化剂投加量、pH值、反应时间对酸性红B去除效果的影响。在双氧水(H2O2质量分数为30%)投加量为30 mL/L、催化剂投加量为30 g/L、pH值在1~11范围内,反应4 h,浓度为200 mg/L的酸性红B去除率均达到95%以上,且反应后pH值在中性范围。实验结果表明,该非均相类Fenton反应体系对pH的适用范围广,且催化剂易于沉淀分离,反应数次后依然保持较高催化活性,能重复利用。     

Fenton和类Fenton氧化处理地下水中BTEX及其动力学

研究比较Fenton试剂和类Fenton试剂氧化处理地下水中苯、甲苯、乙苯和二甲苯(BTEX)的效果及动力学.结果表明,Fenton氧化处理BTEX较类Fenton效果好,且反应过程中体系均处于强氧化环境,pH值维持在3左右;Fenton和类Fenton氧化去除BTEX过程均符合二级反应动力学方程:1/C=kt+1/C...     

Evaluation of plant availability of soil trace metals by chemical fractionation and multiple regression analysis

Soil samples with a range of chemical and physical properties were collected from 10 different rural regions of China. Trace metals (Ni, Co, Cu, and Pb) in the soils were partitioned by a sequential extraction procedure into Mg(NO(3))(2) extractable (F1), CH(3)COONa extractable (F2), NH(2)OH.HCl extractable (F3), HNO(3)?H(2)O(2) extractable (F4), and residual (F5) fractions. Chemical fractionation showed that F1 fraction of the metals was less than 1% and residue was the dominant form for Cu and Ni in all samples, and for Co in most of the samples. Significant interrelationships of the fractions varied considerably with the different metals. Winter wheat (Triticum aestivum L.) and alfalfa (Medicago sativa L.) had been grown on the soils in a pot-culture experiment under greenhouse conditions for 40 days. Metal availability to the plants was evaluated by simple and multiple regression analysis. The Mg(NO(3))(2) extractable Co (F1) was significantly correlated with Co concentrations in different parts of wheat and in the whole of alfalfa. For the other metals, the independent variables of the multiple regression models, chosen by stepwise selection, were given as: F1 and F2 + F3 + F4 for Ni; F1, F2 + F3 and F4 for Cu; and F3 + F4 for Pb. The results of this study demonstrate that the sequential extraction procedure, in conjunction with multiple regression models using a combination of correlated fractions as an independent variable, may be useful for the prediction of plant absorption of trace metals in soils.     

Treatment of odor by a seashell biofilter at a wastewater treatment plant

Biofilters are becoming an increasingly popular treatment device for odors and other volatiles found at wastewater treatment plants. A seashell media based biofilter was installed in April 2011 at Lake Wildwood Wastewater Treatment Plant located in Penn Valley, California. It was sampled seasonally to examine its ability to treat odorous compounds found in the air above the anaerobic equalization basin at the front end of the plant and to examine the properties of the biofilter and its recirculating water system. The odor profile method sensory panels found mainly sulfide odors (rotten eggs and rotten vegetable) and some fecal odors. This proved to be a useful guidance tool for selecting the required types of chemical sampling. The predominant odorous compounds found were hydrogen sulfide, methyl mercaptan and dimethyl sulfide. These compounds were effectively removed by the biofilter at greater than 99% removal efficiency therein reducing the chemical concentrations to below their odor thresholds. Aldehydes found in the biofilter were below odor thresholds but served as indicators of biological activity. Gas chromatography with mass spectrometry and gas chromatography with sensory detection showed the presence of dimethyl disulfide and dimethyl trisulfide as well, but barely above their respective odor thresholds. The neutrality of the pH of the recirculating water was variable depending on conditions in the biofilter, but a local neutral pH was found in the shells themselves. Other measurements of the recirculating water indicated that the majority of the bio-activity takes place in the first stage of the biofilter. All measurements performed suggest that this seashell biofilter is successful at removing odors found at Lake Wildwood. This study is an initial examination into the mechanism of the removal of odorous compounds in a seashell biofilter.

Implications:?This paper presents a thorough examination of a seashell media biofilter, a sustainable treatment technology used to remove reduced sulfide compounds. The durable performance of the seashell biofilter ensures that odors will be adequately controlled, preventing odor nuisance to surrounding residences, which is an emerging problem faced by waste management facilities. The odor profile method technique used in this study can be applied in many situations by waste management facilities and regulatory air management organizations for source tracking in relation to prevention and management of odor complaints, respectively.     

絮凝与生物强化组合技术处理油田含聚污水

针对河南油田采油污水,室内选择4种常用无机絮凝剂与阳离子聚丙烯酰胺(CPAM)复配,筛选出最佳的絮凝剂用量:聚合氯化铝(PAC)用量为300 mg/L,CPAM用量为10 mg/L。研究了投加HPAM降解菌对油田含聚污水中COD的去除效果,优选出2株以聚合物(HPAM)为唯一碳源的降解菌,通过分子生物学16SrDNA鉴定,XL-1和XL-2菌分别为苏云金芽孢杆菌和溶血不动杆菌。实验结果表明,在温度为30℃,pH为7.5,降解72 h的条件下,XL-1菌的B/C增大了0.11,COD去除率提高了11.03%;XL-2菌的B/C增大了0.07,COD去除率提高了6.3%。油田污水经絮凝-生物强化组合工艺处理后,出水COD平均值为77.1 mg/L,总去除率为73.2%,絮凝段和生化段工艺的COD去除率分别为54.1%和19.1%,达到《污水综合排放标准(GB/T 8978-1996)》排放标准。     

混凝与芬顿工艺联用处理切削废液

为了处理常规物化和生化工艺难于有效处理的机械加工切削废液,采用了混凝与芬顿工艺联用对其进行降解处理的实验研究。结果表明,混凝与芬顿工艺联用对切削废液有明显的处理效果,尤其是COD和色度的去除率分别可达80.15%和96.88%。同时,比较了混凝/芬顿和芬顿/混凝不同联用方式对切削废液的处理效果,表明了混凝/芬顿工艺联用具有更好的处理效果和更低的运行成本。     

The flux and mass balance of PCDD/F in a MSW incineration full scale plant

PCDD/F are one of the most significant environmental concerns of municipal solid waste disposal through incineration processes. With the main purpose of evaluating their presence along the flue gas line and establishing a mass balance over the whole system, an extensive research study was performed on a full scale plant. Present paper reports the main results obtained, with particular reference to the PCDD/F concentration profiles and mass balance in the post-furnace region. where significant formation of these compounds might take place. PCDD/F mass fluxes evaluated in all the residues arising from the process are also reported.     

含磺胺嘧啶和酮基布洛芬的化学合成制药生产废水处理研究

含磺胺嘧啶(SD)和酮基布洛芬(KP)的化学合成制药生产废水对生物处理有较强的抑制作用.实验结果表明,通过对厌氧菌和好氧菌的驯化、筛选和复配,采用酸析作预处理,结合厌氧/好氧串联工艺可有效降低废水的COD、BOD5和NH3-N;经酸析和厌氧水解酸化处理后,COD去除率为85%,再经15 h的好氧处理,COD去除率可达94%,运行效果稳定.     

类Fenton氧化-絮凝耦合处理活性艳红K-2BP的研究

以H2O2为氧化剂、聚硅硫酸亚铁(PFSSⅡ)为催化絮凝剂,两者耦合形成类Fenton试剂氧化-絮凝处理活性艳红K-2BP废水.当PFSSⅡ的铁硅摩尔比为1∶3,H2O2和PFSSⅡ的投加量分别为10 mg/L和15 mg/L(以Fe2+计)时,活性艳红的脱色率可达到98%以上,且氧化反应速率符合三级反应速率方程.与传...     

选矿废水的回用处理研究与实践

铅锌矿泡沫浮选废水含有大量Pb2 + 离子和有机硫化物 ,经过混凝沉淀和活性炭吸附 ,去除其中的悬浮物、重金属离子和部分COD、降低其起泡性 ,然后回用生产。回用实践证明 ,选矿废水经过上述工艺处理后 ,其浮选选别指标与洁净水基本一致     

Distribution of PAHs and trace metals in urban stormwater sediments: combination of density fractionation,mineralogy and microanalysis

Sediment management from stormwater infiltration basins represents a real environmental and economic issue for stakeholders due to the pollution load and important tonnages of these by-products. To reduce the sediment volumes to treat, organic and metal micropollutant-bearing phases should be identified. A combination of density fractionation procedure and microanalysis techniques was used to evaluate the distribution of polycyclic aromatic hydrocarbons (PAHs) and trace metals (Cd, Cr, Cu, Ni, Pb, and Zn) within variable density fractions for three urban stormwater basin sediments. The results confirm that PAHs are found in the lightest fractions (d?d??3) whereas trace metals are equally distributed within the light, intermediary, and highest fractions (d?d?d?d?>?2.8 g cm^?3) and are mostly in the 2.3?d??3 fraction. The characterization of the five fractions by global analyses and microanalysis techniques (XRD and MEB-EDX) allowed us to identify pollutant-bearing phases. PAHs are bound to the organic matter (OM) and trace metals to OM, clays, carbonates and dense particles. Moreover, the microanalysis study underlines that OM is the main constituent responsible for the aggregation, particularly for microaggregation. In terms of sediment management, it was shown that density fractionation is not suitable for trace metals but could be adapted to separate PAH-enriched phases.     

Treatment of chlorinated solvents by TiO2 photocatalysis and photo-Fenton: influence of operating conditions in a solar pilot plant

Titanium dioxide photocatalysis (using 20 0mg l(-1) of TiO2), under aerobic and anaerobic conditions, and photo-Fenton (2 and 56 mg l(-1) iron) were applied to the treatment of different NBCS (non-biodegradable chlorinated solvents), such as dichloroethane, dichloromethane and trichloromethane dissolved in water at 50 mg l(-1). All the tests were performed in a 35-l solar pilot plant with compound parabolic collectors (CPCs) under natural illumination. The two solar treatments were compared with attention to chloride release and TOC mineralisation, as the main parameters. Photo-Fenton was found to be the more appropriate treatment for these compounds, assuming volatilisation as a drawback of photocatalytic degradation of NBCS dissolved in water. In this context, several operating parameters related to NBCS degradation, e.g., treatment time, temperature, hydrogen peroxide consumption and volatility of parent compounds are discussed. The correct choice of operating conditions can very often diminish the problem of volatilisation during treatment.     

上海市餐厨垃圾处理管理思路剖析

根据<上海市餐厨垃圾处理管理办法>,分析了加强餐厨垃圾处理管理的思路,包括对物流、资金流和信息流的控制,从而实现餐厨垃圾产生环节、收集运输环节、处置环节的有效监管,维护公共卫生安全.     

Microbial in situ degradation of aromatic hydrocarbons in a contaminated aquifer monitored by carbon isotope fractionation

We present an approach for characterizing in situ microbial degradation using the 13C/12C isotope fractionation of contaminants as an indicator of biodegradation. The 13C/12C isotope fractionation of aromatic hydrocarbons was studied in anoxic laboratory soil percolation columns with toluene or o-xylene as the sole carbon and electron source, and sulfate as electron acceptor. After approximately 2 months' of incubation, the soil microbial community degraded 32 mg toluene l(-1) and 44 mg o-xylene l(-1) to less than 0.05 mg l(-1), generating a stable concentration gradient in the column. The 13C/12C isotope ratio in the residual non-degraded fraction of toluene and o-xylene increased significantly, corresponding to isotope fractionation factors (alphaC) of 1.0015 and 1.0011, respectively. When the extent of biodegradation in the soil column was calculated based on the measured isotope ratios (R(t)) and an isotope fractionation factor (alphaC=1.0017) obtained from a sulfate-reducing batch culture the theoretical residual substrate concentrations (C(t)) matched the measured toluene concentrations in the column. This indicated that a calculation of biodegradation based on isotope fractionation could work in systems like soil columns. In a field study, a polluted, anoxic aquifer was analyzed for BTEX and PAH contaminants. These compounds were found to exhibit a significant concentration gradient along an 800-m groundwater flow path downstream of the source of contamination. A distinct increase in the carbon isotope ratio (delta13C) was observed for the residual non-degraded toluene (7.2 per thousand ), o-xylene (8.1 per thousand ) and naphthalene fractions (1.2 per thousand ). Based on the isotope values and the laboratory-derived isotope fractionation factors for toluene and o-xylene, the extent to which the residual substrate fraction in the monitoring wells had been degraded by microorganisms was calculated. The results revealed significant biodegradation along the groundwater flow path. In the wells at the end of the plume, the bioavailable toluene and o-xylene fractions had been almost completely reduced by in situ microbial degradation. Although indane and indene showed decreasing concentrations downstream of the groundwater flow path, suggesting microbial degradation, their carbon isotope ratios remained constant. As the physical properties of these compounds are similar to those of BTEX compounds, the constant isotope values of indane and indene indicated that microbial degradation did not lead to isotope fractionation of all aromatic hydrocarbons. In addition, physical interaction with the aquifer material during the groundwater passage did not significantly alter the carbon isotope composition of aromatic hydrocarbons.     

A combination of ion exchange and electrochemical reduction for nitrate removal from drinking water. Part II: electrochemical treatment of a spent regenerant solution.

The process of electrochemical treatment of a solution after strong basic anion exchanger regeneration was studied. The goal of the study was to reduce the nitrate content in the solution to allow its use in a closed loop. Diaphragmless, flow-through cells in a recirculation mode with and without a fluidizing bed of inert particles in the interelectrode space equipped with copper (Cu) cathodes and activated titanium anodes were used. The temperature was maintained at 20 degrees C. To assess the influence of recirculation of the regenerant solution on the quality of the treated water, the effect of the addition of copper ions to the solution, postelectrolysis cathode treatment, and enhanced mass transfer on the electrolysis results with respect to current efficiency and residual nitrate and nitrite concentration were investigated using an artificial solution. On the basis of the experimental results, a laboratory-scale unit for selective nitrate removal was designed and constructed that integrated ion exchange and electrochemical cell to one assembly. The process of recirculation of regenerant solution was tested using groundwater.     

Mineralization of dinitrotoluenes and trinitrotoluene of spent acid in toluene nitration process by Fenton oxidation

Fenton's reagent, UV/H2O2 and UV/Fenton's reagent were employed to mineralize dinitrotoluene (DNT) isomers and 2,4,6-trinitrotoluene (TNT) of spent acid in toluene nitration process. The bench-scale experiments were conducted to elucidate the influence of various operating variables on the performance of removal of total organic compounds (TOC) from spent acid, including reaction temperature, concentration of ferrous ion and H2O2 dosage. It is remarkable that organic compounds were completely mineralized by Fenton oxidation, of which removal efficiency is superior to that of UV/H2O2. Nevertheless, it makes slight difference between Fenton oxidation and UV/Fenton oxidation. According to the spectra identified by gas chromatograph/mass spectrometer (GC/MS), it is proposed that oxidative degradation of DNT isomers leads to o-, m-, p-mononitrotoluene (MNT) and 1,3-dinitrobenzene respectively. Besides, the oxidation of 2,4,6-TNT gives the 1,3,5-trinitrobenzene intermediate. Apparently, Fenton oxidation is promising for purification of spent acid industrially.     

Assessment of heavy metal pollution from a Fe-smelting plant in urban river sediments using environmental magnetic and geochemical methods

Environmental magnetic proxies provide a rapid means of assessing the degree of industrial heavy metal pollution in soils and sediments. To test the efficiency of magnetic methods for detecting contaminates from a Fe-smelting plant in Loudi City, Hunan Province (China) we investigated river sediments from Lianshui River. Both magnetic and non-magnetic (microscopic, chemical and statistical) methods were used to characterize these sediments. Anthropogenic heavy metals coexist with coarse-grained magnetic spherules. It can be demonstrated that the Pollution Load Index of industrial heavy metals (Fe, V, Cr, Mo, Zn, Pb, Cd, Cu) and the logarithm of saturation isothermal remanent magnetization, a proxy for magnetic concentration, are significantly correlated. The distribution heavy metal pollution in the Lianshui River is controlled by surface water transport and deposition. Our findings demonstrate that magnetic methods have a useful and practical application for detecting and mapping pollution in and around modern industrial cities.     

The effect of alkyl chain length on the degradation of alkylimidazolium- and pyridinium-type ionic liquids in a Fenton-like system

Background, aim, and scope  Ionic liquids are regarded as essentially “green” chemicals because of their insignificant vapor pressure and, hence, are a good alternative to the emissions of toxic conventional volatile solvents. Not only because of their attractive industrial applications, but also due to their very high stability, ionic liquids could soon become persistent contaminants of technological wastewaters and, moreover, break through into natural waters following classical treatment systems. The removal of harmful organic pollutants has forced the development of new methodologies known as advanced oxidation processes (AOPs). Among them, the Fenton and Fenton-like reactions are usually modified by the use of a higher hydrogen peroxide concentration and through different catalysts. The aim of this study was to assess the effect of hydrogen peroxide concentration on degradation rates in a Fenton-like system of alkylimidazolium ionic liquids with alkyl chains of varying length and 3-methyl-N-butylpyridinium chloride. Materials and methods  The ionic liquids were oxidized in dilute aqueous solution in the presence of two different concentrations of hydrogen peroxide. All reactions were performed in the dark to prevent photoreduction of Fe(III). The concentrations of ionic liquids during the process were monitored with high-performance liquid chromatography. Preliminary degradation pathways were studied with the aid of ¹H NMR. Results  Degradation of ionic liquids in this system was quite effective. Increasing the H₂O₂ concentration from 100 to 400 mM improved ionic liquid degradation from 57–84% to 87–100% after 60 min reaction time. Resistance to degradation was weaker, the shorter the alkyl chain. Discussion  The compound omimCl was more resistant to oxidation then other compounds, which suggests that the oxidation rates of imidazolium ionic liquids by OH· are structure-dependent and are correlated with the n-alkyl chain length substituted at the N-1-position. The level of degradation was dependent on the type of head group. Replacing the imidazolium head group with pyridinium increased resistance to degradation. Nonetheless, lengthening the alkyl chain from four to eight carbons lowered the rate of ionic liquid degradation to a greater extent than changing the head group from imidazolium to pyridinium. 1H-NMR spectra show, in the first stage of degradation, that it is likely that radical attack is nonspecific, with any one of the carbon atoms in the ring and the n-alkyl chain being susceptible to attack. Conclusions  The proposed method has proven to be an efficient and reliable method for the degradation of imidazolium ionic liquids by a Fenton-like reagent deteriorated with lengthening n-alkyl substituents and by replacing the imidazolium head group with pyridinium. The enhanced resistance of 1-butyl-3-methylpyridinium chloride when the resistance of imidazolium ionic liquids decreases with increasing H₂O₂ concentration is probably indicative of a change in the degradation mechanism in a vigorous Fenton-like system. H-NMR spectra showed, in the first stage of degradation, that radical attack is nonspecific, with any one of the carbon atoms in the ring and the n-alkyl chain being susceptible to attack. Recommendations and perspectives  Since ionic liquids are now one of the most promising alternative chemicals of the future, the degradation and waste management studies should be integrated into a general development research of these chemicals. In the case of imidazolium and pyridinium ionic liquids that are known to be resistant to bio- or thermal degradation, studies in the field of AOPs should assist the future structural design as well as tailor the technological process of these chemicals     

Fe0还原、芬顿氧化及其耦合技术去除染料厂剩余污泥中的AOX

染料废水中含有大量难生物降解的卤代有机物合成中间体,合成卤代有机物在废水的生物处理过程中容易被吸附到剩余污泥中,如不能妥善处理会引起生态健康风险。研究了零价铁还原、芬顿氧化及其组合技术对染料企业剩余污泥中AOX（可吸附有机卤代物）的去除效果,优化了处理条件,解析了去除机理。结果表明,铁粉投加量为5 g·L-1,厌氧反应30 d时,零价铁还原对污泥中AOX降解率仅为24.7%;Fe2+投加量0.059 mol·L-1,H2O2投加量0.89 mol·L-1,芬顿氧化1.5 h时,污泥中AOX去除率提高至73.7%;投加2 g·L-1的铁粉,还原30 d后再进行芬顿反应,则污泥中AOX去除率可达到90.3%。GC-MS分析结果表明,污泥中的主要AOX物质为2,6-二氯-4-硝基苯胺,该物质经过零价铁还原与芬顿氧化组合工艺处理后,比直接芬顿氧化能得到更有效的去除。