土壤理化性质对Fe0还原硝基苯的影响

采用零价铁(Fe0)还原降解土壤中的硝基苯，考察土壤理化性质对还原效果的影响。结果显示，当2 g土壤中NB含量约为2.5 ×10-6mol/g，铁粉用量为50 mg，土壤含水量为75％时，控温25℃条件下反应1 h，硝基苯在松砂土和中壤土中的还原率分别可达到82.9％和91.1％。硝基苯在2种土壤中的还原率表现出中壤土...     

土壤理化性质对Fe~0还原硝基苯的影响

采用零价铁（Fe0）还原降解土壤中的硝基苯,考察土壤理化性质对还原效果的影响。结果显示,当2 g土壤中NB含量约为2.5×10-6mol/g,铁粉用量为50 mg,土壤含水量为75%时,控温25℃条件下反应1 h,硝基苯在松砂土和中壤土中的还原率分别可达到82.9%和91.1%。硝基苯在2种土壤中的还原率表现出中壤土〉松砂土的规律;土壤微生物和土壤有机质含量升高有利于反应进行;粒径偏小的中壤土中硝基苯还原较彻底。NB在土壤中的老化时间对Fe0还原效果影响较小。     

零价铁对土壤中对氯硝基苯的还原作用

在常温常压下,利用零价铁(Fe0)还原土壤中的对氯硝基苯(p-CNB),研究反应产物随时间的变化以及反应条件对还原率的影响.实验结果表明,Fe0能够有效将土壤中的p-CNB还原成对氯苯胺(p-CAN),反应过程中先生成中间产物对氯亚硝基苯(p-CNSB),然后再进一步还原生成p-CAN.p-CNB还原率受到反应时间,土壤初始pH、温度、铁粉用量和土壤含水率等条件的影响.当p-CNB约为2.5×10-6mol/g,土壤初始pH为6.8,铁粉用量为50 mg,土壤含水率为75%时,在恒温生化培养箱中温度为(25±1)℃条件下,反应5 h后p-CNB还原率达到97.43%.     

土壤中零价铁还原3-氯硝基苯的作用

利用零价铁在常温常压下对土壤中的3-氯硝基苯的还原，对反应物和产物随时间的变化及反应的各个影响因素进行了研究。实验结果表明，零价铁能够有效地将3-氯硝基苯还原为3-氯苯胺，反应过程中没有检测到脱氯产物。其反应速率随铁粉用量、反应体系含水量的增加以及反应温度的升高而升高，随土壤初始pH值的升高而降低。在土壤中3-氯硝基苯含量约为2.5×10^-6 mol/g，铁粉使用量为25 mg/g，反应体系中含水量为0.75 mL/g，pH值为6.8时，在恒温生化培养箱(25±1)℃反应5 h后，3-氯硝基苯的还原率达到92.75％。     

利用高炉瓦斯泥-H_2O_2处理硝基苯废水

以高炉瓦斯泥为铁源,通过其在酸性条件下与H2O2形成Fenton/类Fenton反应体系来处理硝基苯废水,考察了p H、H2O2用量、高炉瓦斯泥用量及反应时间对硝基苯降解率的影响,并对降解机理进行了分析表征。实验结果表明,在p H为3、高炉瓦斯泥用量为0.5 g/L、H2O2用量为10 m L/L、反应时间为60 min的条件下,100 mg/L的硝基苯溶液中硝基苯的降解率达87.88%;硝基苯先被氧化生成硝基苯酚、硝基苯二酚、对苯醌等中间产物,然后再进一步氧化生成二氧化碳和水达到降解的目的。     

超声波/零价铁降解对硝基苯胺的试验研究

对在超声波、零价铁和超声波/零价铁(U/Fe0)等体系中对硝基苯胺的降解规律进行了研究。研究结果表明,对硝基苯胺在超声波作用下,降解规律符合一级反应动力学模型,但超声波对高浓度的对硝基苯胺降解效果较差。在U/Fe0体系中,超声波和零价铁对降解对硝基苯胺具有协同作用,对硝基苯胺降解速率显著提高。降解机理显示,对硝基苯胺在零价铁表面上发生原电池反应,被还原为对苯二胺,在超声波作用下进一步降解。在U/Fe0体系中添加Cu2+,形成Fe/Cu原电池,可进一步促进对硝基苯胺的降解速率,降解效率优于铸铁屑形成的Fe/C原电池。     

超声波／零价铁降解对硝基苯胺的试验研究

对在超声波、零价铁和超声波／零价铁(U／Fe^0)等体系中对硝基苯胺的降解规律进行了研究。研究结果表明。对硝基苯胺在超声波作用下，降解规律符合一级反应动力学模型，但超声波对高浓度的对硝基苯胺降解效果较差。在U／Fe^0体系中，超声波和零价铁对降解对硝基苯胺具有协同作用，对硝基苯胺降解速率显著提高。降解机理显示，对硝基苯胺在零价铁表面上发生原电池反应，被还原为对苯二胺，在超声波作用下进一步降解。在U／Fe^0体系中添加Cu^2 ，形成Fe／Cu原电池，可进一步促进对硝基苯胺的降解速率，降解效率优于铸铁屑形成的Fe／C原电池。     

铁炭微电解法降解1-丁基-3-甲基咪唑四氟硼酸盐的研究

1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)是一种常用的离子液体,被越来越多地应用于精细化学品及药物的合成。由于其对水生生物有毒性的影响且难于生物降解,提出了采用铁炭微电解法来降解[BMIM]BF4,并探讨了影响处理效果的主要因素、工艺条件及其反应动力学。结果表明,影响铁炭微电解降解[BMIM]BF4的因素按从小到大的顺序为:炭铁比、反应时间、pH;铁炭微电解降解[BMIM]BF4的最佳工艺条件是:铁粉用量3 g/L、水样pH2.5、炭铁比2、反应时间为60~90 min;在此条件下,[BMIM]BF的去除率可以达到80%以上,且该降解反应为二级反应。     

铁炭微电解法降解布洛芬的研究

药品和个人护理用品(PPCPs)是一类新兴有机污染物,对环境存在潜在的威胁,已引起国内外的广泛关注。以典型PPCPs物质-布洛芬(2-(4-异丁基苯基)丙酸)作为研究对象,采用铁炭微电解法对其进行降解处理,考察了影响布洛芬去除效率的主要因素,确定了各影响因素的最佳操作条件为:离子浓度0.8 g/L,反应时间120 min,铁屑用量1.5 g/L,铁炭质量比2∶1,pH为4.0;在此条件下,布洛芬去除率可达80%以上,布洛芬降解过程符合一级反应动力学。     

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),H2O_2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。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

不同泥源对厌氧氨氧化反应器启动的影响

采用2套上流式生物膜反应器,分别接种少量厌氧氨氧化污泥和大量硝化污泥,考察其对厌氧氨氧化反应器启动的影响。污泥接种入反应器后,测得接种厌氧氨氧化污泥的反应器(R1)内MLSS为0.22 g/L,另一个反应器(R2)MLSS为2.7 g/L。与直接接种厌氧氨氧化污泥相比,R1经过72 d的运行才显现出厌氧氨氧化特性。经过114 d的培养,前者氮去除速率由0.23 kg/(m3.d)提升到5.29 kg/(m3.d),总氮去除率大于89%;R2的氮去除速率由0.01 kg/(m3.d)提升到1.1 kg/(m3.d),总氮去除率大于84.6%。说明普通污泥启动需要一个较长的筛选过程,直接接种少量的厌氧氨氧化污泥比接种普通的污泥能够更快启动厌氧氨氧化反应器。     

Evaluation of the presence of drugs of abuse in tap waters

A total of seventy samples of drinking water were tested for non-controlled and illicit drugs. Of these, 43 were from Spanish cities, 15 from seven other European countries, three from Japan and nine from seven different Latin American countries. The most frequently detected compounds were caffeine, nicotine, cotinine, cocaine and its metabolite benzoylecgonine, methadone and its metabolite EDDP. The mean concentrations of non-controlled drugs were: for caffeine 50 and 19 ng L⁻¹, in Spanish and worldwide drinking water respectively and for nicotine 13 and 19 ng L⁻¹. Illicit drugs were sparsely present and usually at ultratrace level (<1 ng L⁻¹). For example, cocaine has mean values of 0.4 (Spain) and 0.3 ng L⁻¹ (worldwide), whereas for benzoylecgonine, these mean values were 0.4 and 1.8 ng L⁻¹, respectively. Higher concentrations of benzoylecgonine were found in Latin American samples (up to 15 ng L⁻¹). No opiates were identified in any sample but the presence of methadone and EDDP was frequently detected. Total mean values for EDDP were 0.4 ng L⁻¹ (Spain) and 0.3 ng L⁻¹ (worldwide). Very few samples tested positive for amphetamines, in line with the reactivity of chlorine with these compounds. No cannabinoids, LSD, ketamine, fentanyl and PCP were detected.     

Mechanisms of biodegradation of dibenzoate plasticizers

Biodegradation mechanisms were elucidated for three dibenzoate plasticizers: diethylene glycol dibenzoate (D(EG)DB), dipropylene glycol dibenzoate (D(PG)DB), both of which are commercially available, and 1,6-hexanediol dibenzoate, a potential green plasticizer. Degradation studies were done using Rhodococcus rhodochrous in the presence of pure alkanes as a co-substrate. As expected, the first degradation step for all of these systems was the hydrolysis of one ester bond with the release of benzoic acid and a monoester. Subsequent biodegradation of the monobenzoates of diethylene glycol (D(EG)MB) and dipropylene glycol (D(PG)MB) was very slow, leading to significant accumulation of these monoesters. In contrast, 1,6-hexanediol monobenzoate was quickly degraded and characterization of the metabolites indicated that the biodegradation proceeded by way of the oxidation of the alcohol group to generate 6-(benzoyloxy) hexanoic acid followed by β-oxidation steps. This pathway was blocked for D(EG)MB and D(PG)MB by the presence of an ether function.The use of a pure hydrocarbon as a co-substrate resulted in the formation of another class of metabolites; namely the esters of the alcohols formed by the oxidation of the alkanes and the benzoic acid released by hydrolysis of the original diesters. These metabolites were biodegraded without the accumulation of any intermediates.     

混凝试验搅拌器的研制

影响混凝效果的因素众多,混凝沉淀烧杯试验是进行水的混合、絮凝、沉淀工艺研究、设计和生产指导的最有效方法之一,阐述了智能型混凝试验搅拌器的设计原理和技术性能.     

生物质快速热裂解主要参数对生物油产率的影响

以松木木屑为原料,在自制的小型流化床上,开展了生物质热裂解温度、生物质粒径和进料速率对生物油产率的影响实验研究.结果表明,在热裂解温度分别为450、475、500、525和550℃条件下,当热裂解温度为500℃时,生物油产率最高,平均产率达到53.33%（质量百分比）.反应温度越高,炭产量越低,不可冷凝气体产量越高,气体发热值越高;粒径＜1 mm的生物质其粒径对生物油产率影响不大;生物质进料速率增加时,生物油产率增加.本研究为生物能的利用提供了新的途径.     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

产油微藻培养与回收的关键技术研究进展

寻找廉价而高效的替代原料是实现生物柴油产业化的关键所在.微藻以含油量高、生长周期短、环境适应能力强、生物产量高等优点,有望成为一种极具潜力的生物柴油生产原料.然而,目前尚存在微藻培养低效成本高和微藻回收效率低两大难题.综述了微藻培养与回收过程中的关键技术,并对存在的两大难题及其改进技术进行了详细的探讨.最后,总结并展望了微藻培养、回收技术未来的发展趋势.     

造纸废水混凝处理中SFT助凝替代性研究

中小造纸厂废水处理常用PAC作混凝剂 ,PAM作助凝剂。由于PAM成本很高 ,影响了处理设备的投运率。用超细滑石粉 (SFT)替代PAM助凝 ,与混凝剂PAC配合 ,其混凝处理效果基本相当 ,但是处理成本降低 0 .10元 /m3 。由于SFT属环境无害材料 ,不会给排泥带来二次污染