Fe_3O_4-TiO_2·nH_2O·Al吸附剂去除水中氟离子

以实验室制备的Fe_3O_4-TiO_2·n H_2O·Al吸附剂处理模拟和实际含氟废水,探讨了吸附剂用量、体系p H、吸附温度和吸附时间等因素对F-吸附效果的影响。结果表明:在初始F-浓度16.1 mg/L,起始p H 8.0,吸附剂投加量5 g/L,室温(约25℃)下吸附15 min时,模拟和实际废水的出水F-均可达到10 mg/L的《电镀污染物排放标准》和《污水综合排放标准》,且吸附剂的容量都在1.6 mg/g左右,显示Fe_3O_4-TiO_2·n H_2O·Al具有一定的实际应用价值。含氟水溶液初始p H对Fe_3O_4-TiO_2·n H_2O·Al吸附F-性能影响较大。在p H介于3.0~5.0时,吸附容量较大,过高或过低都会导致吸附容量降低。Fe_3O_4-TiO_2·n H_2O·Al吸附F-的过程为放热反应,升温不利于F-的吸附。该吸附剂吸附F-的过程为化学吸附,符合准二级动力学模型,等温线拟合接近Freundlich吸附等温线。     

以粉煤灰为原料制备高纯度NaP型分子筛

以工业固体废弃物粉煤灰为原料,经分级处理后提取其中的硅铝元素(Na_2SiO_3和NaAlO_2),通过水热合成法制备高纯度NaP型分子筛。考察了硅铝比、水硅比、晶化时间和晶化温度对NaP型分子筛制备的影响,采用XRD、SEM、FTIR和DTA-TG对NaP型分子筛的晶型、形貌、热稳定性进行分析表征,并考察了NaP分子筛对Cu~(2+)的吸附性能。实验结果表明,当H_2O/Si为120、Si/Al为1.0,晶化温度为115℃、晶化时间9h时,可得到高纯度NaP型分子筛。合成的NaP型分子筛可有效地吸附Cu~(2+),温度升高有助于分子筛吸附能力的提升,当吸附温度为45℃,吸附120min时,Cu~(2+)的最大去除率可达98.3%。     

分子筛对水中Pb2+的吸附行为及回收利用

以4A和13X分子筛为吸附材料,考察了分子筛投加量、废水pH值、Pb2+初始浓度和吸附时间对去除率的影响。结果表明,4A和13X分子筛投加量为0.16 g/L,废水pH为5,Pb2+初始浓度为30 mg/L时,吸附10 min后Pb2+去除率达到95%以上。通过吸附等温线和吸附动力学方程拟合,4A和13X分子筛对Pb2+的吸附过程均符合Langmuir吸附模型和Lagergren二级速率方程,计算出的饱和吸附容量Q0分别为714.3 mg/g和684.9 mg/g,二级反应速率常数k2分别为8.9×10-4g/(mg·s)和7.1×10-5g/(mg·s)。4A分子筛沉降性能较好,适宜回收;经过4次吸附-解吸仍保持88.7%的Pb2+去除率和493.2 mg/g的吸附容量,经解吸后的浓缩液中富含铅离子720.3 mg/L,富集倍数3.78,加入Na2S生成硫化物沉淀能够达到回收金属铅的目的。     

活性炭吸附-Fenton氧化处理高盐有机废水

采用活性炭吸附-Fenton氧化耦合工艺处理高盐度难降解有机废水的性能。考察了不同工艺参数对活性炭吸附及Fenton氧化对高盐有机废水处理效率的影响。结果表明,采用活性炭单独处理时,在pH=6.0,活性炭投加量为9.0g/L,吸附时间为60 min条件下,COD去除率最大,达到47.5%。活性炭吸附处理后,废水再采用Fenton氧化处理,在FeSO4.7H2O投加量为3.0 g/L,H2O2投加量为4.7 g/L,反应时间为30 min条件下,COD去除率最大,达到84.4%。整体而言,经过活性炭吸附和Fenton氧化处理后,废水COD由初始浓度13 650 mg/L降至560 mg/L,去除率达到95.9%。活性炭吸附-Fenton氧化耦合工艺适合高盐度难降解有机废水的处理。     

铁酸锰纳米材料吸附含Ni~(2+)电镀废水的性能研究

采用非表面活性剂水热法制备了铁酸锰(MnFe2O4)纳米材料吸附剂,研究了吸附时间、溶液pH和温度对MnFe2O4纳米材料吸附模拟含Ni 2+电镀废水和实际含Ni 2+电镀废水中重金属Ni 2+的吸附性能,并探讨了该材料的再生利用性能。结果表明,MnFe2O4纳米材料可有效吸附电镀废水中的Ni 2+,吸附平衡时间为600min。对20mg/L的模拟含Ni 2+电镀废水,投加4.5mg的的MnFe2O4纳米材料进行吸附处理,Ni 2+的吸附去除率高达98%左右;实际工程应用中,应保持电镀废水偏碱性、温度25℃;MnFe2O4纳米材料具有理想的再生利用性能,重复吸附5次后,吸附去除率仍可达82.24%,在实际废水处理中具有广阔的应用前景。     

沸石分子筛和活性炭吸附/脱附甲苯性能对比

考察了甲苯在NaY型沸石分子筛(简写为NaY)、13X型沸石分子筛(简写为13X)、Hβ型沸石分子筛(简写为Hβ)、MCM-22型沸石分子筛(简写为MCM-22)和ZSM-5型沸石分子筛(简写为ZSM-5)上的吸附/脱附性能,同时与椰壳活性炭(AC)的吸附/脱附性能进行对比.结果表明,各吸附剂对甲苯的平衡吸附量大小依次为:AC>NaY>Hβ>13X>MCM-22>ZSM-5,甲苯从吸附剂表面脱附难易程度依次为:AC>NaY、13X>Hβ>MCM-22>ZSM-5>ZSM-5对甲苯的平衡吸附量和吸附强度都最小,这是由于甲苯无法进入ZSM-5的内部孔道造成的;在低甲苯质量浓度(<1 000 mg/m3)时.NaY平衡吸附量超过AC,因此NaY更适合应用在低浓度有机废气吸附治理中,Langmuir吸附方程比Freundlich吸附方程更符合沸石分子筛吸附甲苯的行为.     

天然Na基膨润土吸附处理高浓度PAM废水的研究

研究了PAM在天然钠基膨润土上的吸附行为，将其应用于含高浓度PAM（100～200 mg/L）的生产废水处理。静态条件下，膨润土的吸附平衡时间为1.5 h，最有效的吸附材料投加量为100 mg/100 mL水样。实验证明，低温度变化范围和弱酸、弱碱条件对PAM的吸附行为不产生显著影响。在最佳吸附动力学条件下，以活性炭做参比，利用实验的结论对化工厂中PAM生产废水进行吸附处理，结果表明，在对PAM废水中对PAM的吸附量分别可达到30.1和22.4 mg/g，膨润土是性价比较高的吸附处理材料。     

粉煤灰深度处理低浓度的磷

为了探讨低浓度磷吸附的方法,比较了粉煤灰、煤质活性炭和粉煤灰碎砖块颗粒这3种价廉易得的吸附材料的除磷效果。经对比确定以粉煤灰为吸附剂,研究了反应时间、粉煤灰投加量以及溶液p H对深度除磷效果的影响。同时为了解粉煤灰高效除磷原理,利用SEM和XRD对其表面形状、所含元素及其内部结构进行了表征。结果表明,粉煤灰比煤质活性碳和粉煤灰砖砖块颗粒的除磷效果更好,去除率高达98.9%;SEM和XRD表征结果显示,由于粉煤灰表面积较大、表面能高、含有Si—O—Si和Si—O—Al—O偶极键及铝、铁和钙的氧化物,使得粉煤灰对低浓度的磷有着高效的去除率;吸附磷后的粉煤灰表面形成了一层絮状物,经EDS分析显示其组成以钙磷沉淀为主;1 g粉煤灰对1 mg/L的磷酸盐溶液在p H=10、反应时间60 min时表现出最佳吸附性能。     

利用13X沸石分子筛净化含NH+4-N废水的实验研究

研究了13X沸石分子筛在静态和动态条件下对中低浓度含NH4^＋-N废水的吸附性能，包括影响吸附的主要因素、沸石对NH4^＋-N的吸附效果和沸石的再生等。静态实验结果表明，pH值为6．5～7．5，吸附时间35rain，吸附温度20～30℃的条件下，沸石对50mL NH4^＋-N初始浓度（C0）为80mg／L的废水吸附效果最佳，吸附过程符合Langmuir型吸附等温式，饱和吸附量为8．61mg／g。动态条件下，随水力停留时间增加，沸石对NH4^＋-N的吸附量上升，最大饱和吸附量可达24．20mg／g，吸附过程符合Thomas吸附模型。直接焙烧法对吸附后的沸石进行再生活化处理效果良好。实验证明，利用13X沸石净化中低浓度含NH4^＋-N废水具有良好的工业化应用前景。     

UV/H_2O_2-NaOH沉淀法处理铜-酒石酸络合体系模拟电镀废水的研究

含铜电镀废水中酒石酸等络合剂的存在,使得采用普通氢氧化物或硫化物沉淀法难以满足达标排放的要求。采用UV/H2O2-NaOH沉淀法处理铜-酒石酸络合体系模拟电镀废水,考察了光照时间、初始pH、H2O2投加量等因素对处理过程的影响。结果表明,对于铜-酒石酸络合体系(酒石酸质量浓度为418mg/L,CuSO4·5H2O质量浓度为196mg/L),得出的最佳处理条件为:光照时间70min,H2O2投加量1.07g/L,初始pH 3.0,出水中铜质量浓度可以低于0.3mg/L的排放标准,为后续工业化应用奠定了基础。     

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.     

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.     

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。     

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.