污泥-秸秆基活性炭的制备及其对渗滤液COD的吸附

以市政污泥与玉米秸秆为原料,采用化学活化法热解制备污泥-秸秆基活性炭,研究其物化性质、热解动力学特性及对渗滤液中COD的吸附性能。考察吸附剂投加量、吸附时间和溶液p H对COD去除率的影响,并用吸附等温线对吸附数据进行了拟合。结果表明,秸秆比例越高,活性炭的吸附碘值和BET比表面积越大,最大可达663 mg/g和902 m2/g;活性炭表面呈不规则的多孔状;秸秆比例为45%的活性炭在最佳实验条件下对COD的吸附去除率为82%;活性炭对COD的吸附符合Langmuir和Freundlich等温模型。     

磷酸活化植物基活性炭对水溶液中铅的吸附

以棉秆与互花米草为原料,采用磷酸活化法制备了低成本的植物基活性炭,通过静态实验研究了其对重金属铅的吸附性能。结果表明,在活化温度为500℃、活化时间为2 h条件下,制备的棉秆和互花米草活性炭比表面积为1 570m2/g和856 m2/g,含氧酸官能团含量分别为1.43 mmol/g和1.27 mmol/g。在25℃下,两种活性炭对重金属铅的Langmuir最大吸附量分别为119 mg/g和111 mg/g,吸附最佳pH为4.3,吸附平衡符合Freundlich方程,离子交换在吸附过程中发挥了重要作用。     

稻壳活性炭制备及其对磷的吸附

利用农业废弃物稻壳经炭化、活化、酸洗、水洗和干燥等工艺制备出一种富含微孔和中孔结构的稻壳活性炭,其BET比表面积达886.3 m2/g。通过正交实验优化了稻壳活性炭对磷吸附条件,并在该条件下进行了吸附等温和吸附动力学实验研究。结果表明,稻壳活性炭对磷的吸附等温曲线能较好符合Langmuir模型(R2=0.9284)和Freundlich模型(R2=0.9208),由Langmuir线性拟合方程可得稻壳活性炭对磷饱和吸附量达6.93 mg/g;稻壳活性炭对磷的吸附过程可用准二级动力学方程描述(R2=0.9968),吸附速度较快,颗粒内扩散为该过程控速阶段。稻壳活性炭作为一种易得、廉价、高效的填料,在农村分散型污水生态处理技术中,具有良好的应用前景。     

核桃壳炭化吸附废水中Cr(Ⅵ)的性能研究

采用氯化锌活化法制备生物质废物硬壳活性炭,工艺条件为:核桃壳与氯化锌溶液质量比为1∶1.5、氯化锌溶液质量分数50%、炭化温度300℃、炭化时间90 min、活化温度600℃、活化时间60 min。对产品比表面积、孔径和表征进行了分析,并探讨了该核桃壳活性炭吸附废水中六价铬的pH值、废水初始浓度、吸附时间、振动转速等影响因素。结果表明:制得的活性炭碘吸附值为1 038.33 mg/g,比表面积为645.36 m2/g,平均孔半径为1.37 nm。当活性炭用量为0.1 g,废水pH=3,吸附接触时间为1 h,取100 mL浓度为50 mg/L的含Cr6+废水时,处理吸附量可达48.57 mg/g。活性炭最大饱和吸附值为80.24 mg/g。吸附符合Langmuir等温模式,吸附等温方程式为Ce/Qe=0.0083+0.0121Ce。     

改性粉煤灰净化含磷废水的研究

采用改性粉煤灰对含磷废水进行净化,考察了pH、吸附剂用量、吸附时间和吸附温度对净化效果的影响。结果表明:(1)当pH为9时,磷净化率达到最大值。(2)当改性粉煤灰用量为30g/L时,磷净化率可达99.53%,磷净化后质量浓度为0.91mg/L,达到《污水综合排放标准》(GB8978—1996)中二级标准限值(1.0mg/L);当改性粉煤灰用量为40g/L时,磷净化率可达99.75%,磷净化后质量浓度为0.48mg/L,达到GB8978—1996中一级标准限值(0.5mg/L)。(3)改性粉煤灰对废水中磷的净化速度较快,吸附5min即可使吸附过程达到平衡;进一步提高吸附时间,磷净化率及净化后浓度几乎不再变化。(4)吸附温度对磷净化率的影响较小,当吸附温度为20～40℃时,磷净化率为97.00%～98.62%。(5)改性粉煤灰对磷的吸附等温线较符合Freundlich方程,且1/n=0.374,吸附过程易进行,改性粉煤灰可作为磷的吸附剂用于废水中磷的净化。     

三价铁改性活性炭对水中微量砷的吸附特性

研究了三价铁改性对不同活性炭(颗粒和粉末)对水中砷的吸附特性的影响。结果表明,三价铁改性有效提高了活性炭对不同形态砷的吸附性能。其中,对于2种活性炭,As(Ⅲ)和As(Ⅴ)的最佳铁离子改性浓度分别为0.1和0.05 mol/L。此时,通过Langmuir等温线方程拟合得到:粉末和颗粒活性炭对As(Ⅲ)的最大吸附量qm分别为2.38 mg/g和9.39 mg/g;而对As(Ⅴ)的qm分别为5.12 mg/g和2.32 mg/g。此外,当溶液的p H从3升高到9的过程中,吸附量先增加后有所下降,当p H为7时,改性前后的活性炭对砷的吸附量达到最高。     

长柄扁桃核壳活性炭的制备及表征

以长柄扁桃核壳为原料采用磷酸活化法制备活性炭，分别研究了温度、时间、浸渍比和磷酸浓度对活性炭吸附性能的影响；进而采用氮气吸附曲线和SEM对最佳工艺条件下的活性炭进行了表征。结果表明，长柄扁桃核壳是一种优质的活性炭原料；当温度为400℃，活化时间2 h，浸渍比2：1，磷酸浓度60%时，得到产率为46.46%，碘吸附值和亚甲基蓝吸附值分别为1 073 mg/g、255 mg/g，比表面积高达1 740 m²/g，中孔率为73.12%的孔隙发达的高中孔率活性炭。     

响应面法优化磷酸改性秸秆生物炭的制备

以秸秆为原料,磷酸为活化剂制备改性生物炭,利用基于Box-Behnken中心组合的响应面法对生物炭制备条件进行优化。根据响应面分析,热解温度、保留时间和磷酸质量分数对生物炭的吸附性能有显著影响,浸渍比影响不显著;保留时间与浸渍比、磷酸质量分数与浸渍比的交互作用对生物炭吸附能力也有显著影响。根据响应面法获得生物炭制备的最优条件为:热解温度884.32℃、保留时间82.61min、磷酸质量浓度40.74%、浸渍比1.74,此时生物炭最大碘吸附预测值为1 099mg/g,与验证实验实测结果(1 063mg/g)仅相差3.28%,表明响应面回归模型预测结果可靠。响应面法优化后制得的生物炭具有更高比表面积与总孔容,因此具有更高的吸附性能。     

改性竹活性炭去除汞离子

采用溴化钾、碘化钾和硫磺对竹活性炭掺杂改性,利用电感耦合等离子体发射光谱仪测定滤液中汞离子浓度,用除汞效率和吸附容量评价活性炭对溶液中汞离子的吸附性能,探讨其吸附机理。结果表明,掺杂改性明显提高了竹活性炭的除汞性能。原竹活性炭的除汞效率为78.6%,吸附容量为2.210 mg/g;经碘化钾、溴化钾和硫磺掺杂改性后的竹活性炭除汞效率分别为94.3%、93.8%和88.8%,吸附容量分别为2.830、2.813和2.663 mg/g;经溴化钾(碘化钾)和硫磺联合改性的竹活性炭对水溶液中汞离子的吸附性能性能又有提高,其中以先载硫后载溴化钾的方法除汞效果最好,除汞效率达96.6%,吸附容量为2.898 mg/g。     

电吸附活性炭电极制备及电吸附特性

电极的材料和制备是电吸附技术的核心。本研究进行了活性炭电极的制备、改性和表征,并分析其电吸附特性。结果表明,物理化学改性活性炭电极比表面积可达748.54 m2/g,分别是物理改性、化学改性活性炭电极的1.22和12.16倍,电吸附效果最佳。其对Na Cl紊态电吸附效果是物理改性活性炭电极的1.28倍,化学改性活性炭电极的3.75倍。对Na Cl紊态电吸附单位吸附量为7.19 mg/g,是静态吸附的8.78倍。对Na Cl、Na2SO4和Na3PO4紊态电吸附单位吸附量依次为5.94、11.83和21.47 mg/g,单位吸附量和吸附平衡时间随着被吸附离子的负电荷增加而增加。紊态电吸附过程符合一级动力学,吸附过程是由扩散机制控制的、伴随着电场作用的慢吸附过程。     

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.     

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。     

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.     

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.     

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.     

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