水体中常见无机阳离子对TiO_2薄膜光催化还原Cr(Ⅵ)的影响

选择了6种水体中常见的阳离子(Na+、Mg2+、Ca2+、Al3+、Cu2+、Ni2+),分别考查了其对TiO2薄膜光催化还原Cr(Ⅵ)的影响;从光吸收、无机离子本身的性质对光生电子的捕获及传递等讨论了上述离子影响TiO2薄膜光催化还原Cr(Ⅵ)的反应速率的原因。结果表明:由于其不能捕获光生电子,Na+、Mg2+、Ca2+本身对TiO2薄膜光催化还原Cr(Ⅵ)的反应速率影响不大;Al3+吸引电子能力较强,成为光生电子和Cr(Ⅵ)之间的桥梁,促进了Cr(Ⅵ)的还原;浓度为1 mmmol/L时,Cu2+显著地促进了Cr(Ⅵ)的光催化还原,其主要原因是Cu2+捕获光生电子的能力很强,起到了催化剂的作用,而浓度大于10 mmol/L时,Cu2+形成单质Cu以及对紫外光的吸收都使促进作用降低;Ni2+未充满的d轨道具有获得并传递光生电子的能力,也促进了Cr(Ⅵ)的还原;在浓度同为1mmol/L时,对Cr(Ⅵ)光催化还原的促进作用依次为:Cu2+Al3+Ni2+Na+、Ca2+、Mg2+。     

工业废水中多金属离子的吸附净化

以含有Si、Al、Ca、C元素的矿物材料作为基质,经特定条件处理后造粒成型加工成轻质多孔Si-Al-Ca-C结构的吸附材料。研究了该吸附材料对工业废水中多种金属离子的吸附性能,探讨了影响吸附性能的因素。研究结果表明,在一定条件下,Si-Al-Ca-C吸附材料对工业废水中Al3+、Ca2+、Mn2+、Cu2+、Fe3+、Mg2+、As3+和Zn2+的净化率分别高达99.34%、99.82%、98.26%、98.16%、97.76%、97.01%、100%和89.09%。金属离子残留浓度分别为0.152、0.07、0.012、0.02、0.119、0.311、0和0.259 mg/L,均低于国家污水综合排放标准(GB8978-1996)一级标准。     

镁铝类水滑石原位共沉淀法处理含镍模拟废水的研究

通过原位共沉淀法处理含镍模拟废水,探讨了反应时间、体系pH、镍与镁的摩尔比(Ni/Mg)、二价离子与三价离子的摩尔比((Ni+Mg)/Al)和Ni 2+初始浓度对Ni 2+去除效果的影响。实验结果表明,Ni 2+能通过镁铝类水滑石原位共沉淀法被除去。体系pH、Ni/Mg、(Ni+Mg)/Al和Ni 2+初始浓度均对Ni 2+去除率影响较大,而反应时间对其影响不大。在反应时间为1～2h、pH=8.5、Ni/Mg=0.25、(Ni+Mg)/Al=2.0时,可获得最高的Ni 2+去除率(99.84%),产物经X射线衍射(XRD)分析确定具有层状双氢氧化物(LDHs)结构。     

常州市春季大气PM2.5中金属元素的分析及污染特征

建立了微波消解-电感耦合等离子体质谱(ICP-MS)法,同时测定大气PM2.5中K、Na、Ca、Mg、Fe、Al、Zn、Si、Ti、V、Cr、Mn、Co、Ni、Cu、As、Cd和Pb等18种金属元素的分析方法.样品用HNO3+H2O2(5∶1)经微波消解系统进行前处理.该方法操作方便,酸用量少,由于是密闭消解,对环境污染也少.经过反复调试,确定了仪器最佳操作条件.结果表明,各种元素标准曲线的线性相关系数均在0.9990以上,方法检出限在0.07 μg/L ～1.16 mg/L之间,精密度实验中各元素的RSD均小于7.53％,回收率在91.38％～117.53％之间.该方法能够快速有效地实现多元素同时测定,检测线性范围宽,测试结果准确可靠,可以应用于大气颗粒物中多种金属元素的测定.采用富集因子分析法对常州市大气中PM25做来源分析表明,常州市大气PM25中,大部元素的富集因子都大于10,其中,Ni、Cu、Zn、As、Cd、Co和Pb在各个采样点的富集因子都非常高,表明主要来自于人为污染.     

淀粉基黄原酸盐处理重金属废水的条件优化研究

采用淀粉基黄原酸盐处理含重金属的电镀废水 ,对淀粉基黄原酸盐的用量、pH值和反应时间等条件进行了研究。结果发现 ,1L含氰电镀废水 (含Cr3+15mg/L、Cu2 +3mg/L、Ni2 +9.2mg/L和Zn2 +6mg/L) ,加入 1g淀粉基黄原酸盐 ,调节 pH为 8,搅拌 1h ,过滤 ,处理后的废水中Cr3+、Cu2 +、Zn2 +和Ni2 +残余浓度分别为 0 .0 8mg/L、0 .0 1mg/L、0 .1mg/L和 0 .0 8mg/L。含有重金属盐的残渣 ,可用硝酸处理 ,以回收重金属     

流动注射-火焰原子吸收法快速测定水样化学需氧量

采用流动注射-火焰原子吸收法(FI-FAAS)测定水样化学需氧量.以KMnO4作氧化剂、葡萄糖作基准物质,在95 ℃反应,生成的Mn(Ⅱ)在线分离吸附于阳离子交换树脂微型柱上,用3 mol/L HCl洗脱后,送至火焰原子吸收检测器检测.在反应盘管长500 cm、反应时间30 s的条件下,测定化学需氧量的线性范围为8.00～200.00 mg/L,检出限为2.30 mg/L;采样频率为24次/h,Cl-质量浓度至100 mg/L无干扰,Mg2 质量浓度至1 000 mg/L无干扰;对50.00 mg/L的化学需氧量标样重复测定7次,相对标准偏差为3.37%.用该法测定河水、池塘水和轻度污染工业废水的化学需氧量,获得了与重铬酸盐法(标准方法)基本一致的测定结果.     

高碘酸钾分光光度法测定电解锰渣中的Mn（Ⅱ）

实验定量研究了存在Ca2＋、Mg2＋和Fe3＋时,应用高碘酸钾分光光度法测定Mn2＋的准确性,旨在探讨应用该方法准确测定电解锰渣中Mn（Ⅱ）的可行性。结果发现Ca2＋浓度超过320 mg/L时,测定过程中会产生大量絮状乳白色沉淀,对Mn2＋的测定结果产生干扰。经过16 h的自然沉降,干扰被彻底消除。Mg2＋在浓度为0~192 mg/L范围内对Mn2＋浓度的测定不产生干扰。同时,Fe3＋的存在对Mn2＋浓度的测定产生灵敏的干扰,使用掩蔽剂氟化钾可以减少Fe3＋的干扰,但却不能彻底消除Fe3＋的干扰。提出了在电解锰行业中,没有彻底地消除Ca（Ⅱ）或Fe（Ⅲ）的干扰因素前,需要更为精确地测定Mn（Ⅱ）的浓度,不建议使用高碘酸钾分光光度法。     

K+、Ca2+、Mg2+对高盐肝素废水处理的影响

高盐废水的生物处理效率因盐分对活性污泥系统的抑制作用而受到很大的限制。寻求降低盐抑制作用,提高生物处理效率的方法和技术是目前研究的热点。针对SBR工艺处理高盐肝素钠生产废水的活性污泥,从金属离子间的拮抗效应出发,研究了K+、Ca2+和Mg2+3种金属离子对污泥性能的影响。结果表明,K+、Ca2+和Mg2+添加量分别为40、50和150 mg/L时,COD去除率比对照组分别提高了2.8%、8.0%和3.8%,其余添加量下无明显改善;K+、Ca2+和Mg2+添加量分别为100、200和20 mg/L时,氨氮去除率比对照组分别提高了39.8%、9.8%和28.4%,其中Ca2+对氨氮去除效果的改善能力最差,同时在最佳添加量下讨论了这3种金属离子对污泥浓度以及污泥沉降速率的影响。     

SCR脱硝尿素中微量元素的质谱法测定

建立了电感耦合等离子体质谱(ICP-MS)法测定SCR脱硝尿素中Na、Mg、Al、P、K、Ca、Cr、Fe、Ni、Cu、Zn、Pb等12种微量元素的分析方法.通过向碰撞/反应池(CRC)系统中引入氦气消除多原子离子质谱干扰,采用混合内标元素45Sc、89Y、209Bi消除基体效应.结果表明,各元素在一定范围内线性关系良好,方法的检出限为0.2～23.6 ng/L,样品的加标回收率在89.6％ ～ 108.4％之间,RSD在1.6％ ～3.8％之间.方法能准确测定SCR脱硝尿素中的多个微量元素,可用于SCR脱硝尿素的质量控制和安全评价.     

重金属污染土壤的草酸和EDTA混合淋洗研究

采用不同浓度的草酸(oxalic acid,OX)和乙二胺四乙酸(EDTA)混合的淋洗方法研究重金属污染土壤的最佳混合淋洗方式,探讨了液固比、淋洗时间及pH对淋洗效果的影响,并分析了0.2 mol/L OX+0.2 mol/L EDTA处理前后土壤中重金属形态的变化。结果表明,采用0.2 mol/L OX+0.2 mol/L EDTA混合的淋洗法可同时去除多种重金属,且对Cu、Zn、Ni和Cr的去除率明显高于单用OX和EDTA,去除率分别为Cu 41.29%、Zn 84.73%、Ni 54.2%和Cr 66.01%。0.2mol/L OX+0.2 mol/L EDTA在液固比为5∶1、淋洗时间为4 h、pH为6时可分别达到最佳淋洗效果,且分别为Cu 62.59%、Zn 93.48%、Ni 55.95%和Cr 71.57%;Cu 50.47%、Zn 86.67%、Ni 61.53%和Cr 72.68%;Cu 44.40%、Zn 81.82%、Ni68.76%和Cr 74.93%。形态分析结果表明,0.2 mol/L OX+0.2 mol/L EDTA能较好地改变土壤中重金属形态的分布。     

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.     

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.     

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.     

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     

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.