垃圾渗滤液中砷的微波消解—石墨炉原子吸收光谱测定方法研究

优化并建立了垃圾渗滤液中砷的微波消解—石墨炉原子吸收光谱(GFAAS)测定方法,以实现复杂环境介质中砷的定量分析。GFAAS测定的最佳条件为灰化温度600℃、原子化温度2 200℃、基体改进剂Pd(10mg/L)8μL。微波消解最佳条件为消解液HNO_3∶H_2O_2(体积比)2.8∶0.2、消解温度166℃、消解时间38min。优化条件下,测得某垃圾填埋场垃圾渗滤液中砷质量浓度平均为176.80μg/L,加标回收率为91.7%～100.9%,相对偏差均小于5%,方法准确、可靠。     

微量金属元素及其配合物对厨余垃圾甲烷发酵的影响

生物可利用的微量金属元素不仅能够保证污染物以最大的速率转化，而且还可以使某些特殊的转化得以发生，并提高微生物对有毒污染物质的耐受能力。在研究厨余垃圾总固体浓度(total solid, TS)、接种量和C/N比对厨余垃圾厌氧发酵影响的基础上，重点探讨微量金属元素钴及其配合物丝氨酸对厨余垃圾厌氧发酵甲烷产量及关键酶含量的影响。结果表明，当TS为0.5%、接种污泥量为100 mL/L和C/N比为20∶1时，厨余垃圾厌氧发酵的甲烷产率较高，为367 mL/g COD；添加2 μmol/L的微量金属元素钴-配合物丝氨酸时，甲烷产率则提高到432 mL/g COD，相应地，辅酶M的含量由空白实验的41.21 μmol/g VSS提高到54.64 μmol/g VSS，辅酶F₄₂₀的含量由0.31 μmol/g VSS提高到0.48 μmol/g VSS。     

生物质活性炭的制备及其染料废水中的应用

以城市污水厂活性污泥为原料,用3 mol/L ZnCl2溶液活化,通入水蒸气作活化气制备活性炭吸附剂.实验结果表明,温度为600℃条件下,活化时间为1 h,制得的活性炭其碘吸附值为374.10 mg/g,比表面积为381.62 m2/g,孔容积为0.25 cm3/g,微孔容积为0.11cm3/g.并进一步将生物质活性炭应用于染料废水的处理,考察了吸附时间、活性炭投加量和pH对色度及TOC的脱除效果的影响.室温下,酸性大红GR染料废水初始浓度为300 mg/L,污泥活性炭的最佳投加量为2%(质量分数),吸附15min,废水色度脱除率可达99.6%,TOC去除率可达99.7%,利用等温吸附实验作吸附等温线,吸附等温线可以用Freundlich或Langmuir方程描述.     

湿热预处理对北京市典型餐厨垃圾生物制氢潜力的影响

采用北京市2种典型餐厨垃圾,研究不同湿热预处理温度(40、80、120和160℃)和时间(30、60、90和120 min)对2种典型餐厨垃圾理化性能的影响。在此基础上,阐明餐厨垃圾厌氧产氢潜力。结果表明,湿热预处理温度、时间对餐厨垃圾可浮油脱出量具有显著影响,ρ(SCOD)、ρ(TOC)与VS/TS呈负相关。餐厨垃圾处理厂的厨余垃圾经120℃湿热预处理30 min后,可浮油脱出量最大达17 m L·kg-1,ρ(SCOD)、ρ(TOC)分别为150.99、57.91 g·L-1;食堂的餐饮垃圾经160℃湿热预处理30 min后效果最佳,可浮油脱出量最高达99 m L·kg-1,ρ(SCOD)、ρ(TOC)分别为120.69、62.58 g·L-1。餐饮垃圾经160℃湿热预处理30 min,在中温(35±1℃)、高温(55±1℃)厌氧制氢,高温比产氢率和最大产氢速率分别可达40.58 m L·g-1VS、29.20 m L·h-1,与未经预处理组比提高0.78、2.02倍,中温产氢启动时间缩短1倍以上。可见,湿热预处理能显著改善餐厨垃圾理化性质,提高微生物的底物利用效率,提高餐厨垃圾厌氧制氢量及产氢效率。     

填埋场中亚硝酸还原酶测定条件的优化

填埋垃圾中的含氮化合物经一系列生物脱氮作用,最终使得填埋场中的氮素得以消减,在这一过程中亚硝酸还原酶起着十分重要的作用。以填埋场中的填埋垃圾为研究对象,在土壤亚硝酸还原酶测定方法的基础上,对亚硝酸还原酶活性测定条件进行了优化。结果表明,填埋垃圾中的亚硝酸还原酶活性测定的最优条件为:垃圾样品风干温度25℃,2mL的1%NaNO2溶液和2.5 mL的1%葡萄糖溶液,抽气5 min,置于25℃的培养箱中培养24 h。优化后的测定条件相对标准偏差(RSD)小于1.27%,表明该方法具有较高的灵敏度和精密度。     

应用超临界水气化技术的垃圾渗滤液资源化制氢技术研究

利用超临界水气化技术从垃圾渗滤液中制取H_2,当垃圾渗滤液总有机碳(TOC)和TN初始质量浓度分别为3 207~14 810、530~1 480mg/L时,分析了温度、压力、反应时间和催化剂Na2CO3对气化产物中H_2摩尔分率和产率的影响,以及TOC、TN去除率的变化趋势。结果表明:(1)随着温度的升高,H_2摩尔分率、产率和TOC、TN去除率均提高,500℃时分别达到55.60%、94.73mol/kg、71.89%、36.65%。H_2主要来源于蒸汽重整及水气转换反应。(2)压力的升高不利于H_2的产生,而有利于CH4的获得。(3)适宜的反应时间为5min。(4)催化剂Na2CO3的投加增加了气相产物中H_2摩尔分率和产率,有利于H_2的获得;TN去除率增加,但TOC去除率却下降。     

鼓泡反应器中液相络合催化同时脱硫脱硝的研究

在鼓泡反应器中考察了[Co(en)3]2+同时吸收去除SO2和NO的影响因素,实验结果表明,pH值和脱硫剂种类是影响乙二胺合钴同时脱除NO和SO2的最重要影响因素,烟气中的氧促进乙二胺合钴吸收NO和SO2,烟气中的SO2,CO2和NO2对乙二胺合钴吸收NO具有抑制作用。在实验条件温度为20℃,pH为13.0,[Co(en)3]2+浓度为0.025 mol/L,加入1 g NH3.H2O的脱硝率更好,连续吸收60 min,脱硝率均保持在93.5%,加入NaOH和NH3.H2O的脱硫效果最好。乙二胺合钴络合同时脱除NO和SO2完全可以在一个装置中完成。     

过硫酸钾去除水中的TCE

以地水中的氯代烃污染物三氯乙烯(TCE)为目标污染物,以过硫酸钾溶液为氧化剂,探讨了不同条件下过硫酸钾对TCE的去除效果。实验结果表明,在40℃,过硫酸钾初始浓度为2.43 g/L条件下,反应2 h后,TCE的去除率就可达到96.8%;过硫酸钾对TCE的去除符合一级反应动力学方程,速率常数(K)为1.3364 h-1,半衰期(t1/2)为0.51 h;过硫酸钾对TCE的去除速率在pH为中性附近时最大,其后无论pH升高或降低去除速率均减小;受温度和pH影响较明显,并且反应温度越高,受pH的影响越明显;随离子强度的增加而减小;反应活化能为119.6 kJ/mol;过硫酸钾溶于水生成过硫酸根离子(S2O28-),S2O28-会进一步生成硫酸根自由基(SO4-.),在碱性条件下,SO4-.与OH-反应会进一步生成羟基自由基(.OH)。过硫酸钾对于TCE的去除主要源自SO4-.和.OH的强氧化性。     

锌冶炼废渣浸出液硫化法除砷的研究

以硫化钠为沉淀剂,将锌冶炼废渣浸出液中的砷以硫化砷的形式沉淀析出,实验考察了浸出液酸度、硫化钠加入量、反应时间等因素对除砷效率的影响.实验结果表明,当浸出液中游离H2SO4浓度为3 mol/L,Na2S·9H2O投加量为16.1 g/L(浸出液),反应时间为30 min时,浸出液中的砷去除率达到99.3%,较好地解决了...     

垃圾降解过程中淀粉酶活性测定条件优化

垃圾填埋场中垃圾降解初期,淀粉酶活性对于垃圾填埋场中碳素的转化过程和垃圾填埋场生物学特性的研究有重要意义,而且也可作为垃圾填埋场稳定化机制研究的重要指标之一.以模拟垃圾填埋系统的垃圾为研究对象,通过正交实验(L25(56))对淀粉酶活性的测定条件进行了优化研究.结果表明:(1)正交实验结果表明,对淀粉酶活性测定的影响大...     

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     

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.     

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.     

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.     

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。     

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.     

Visualisation of the complexity of EUSES

The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters (inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation, on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency. The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters), and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity to 961, and the maximal dimension is 21.     

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.