浓度及中间转化产物对蒽、菲生物降解特征的影响研究

研究了蒽、菲的浓度及其不同时段产生的中间转化产物对蒽、菲生物降解特征的影响。结果表明，芽孢杆菌FCN4对蒽、菲均有良好的降解能力，且菲的降解速度大于对蒽的降解速度，蒽、菲浓度分别小于150mg／L，175mg／L时，随浓度增加，生物降解速率增加，反应均表现为一级反应。大于该相应浓度值时，降解速度随浓度增加而减小。在反应早期，外加中间产物明显地对蒽、菲生物降解产生抑制作用。24h内降解转化出的中间产物，对24h内，FCN4降解蒽、菲的抑制作用能明显地通过实验证明。     

大中型沼气工程技术讲座(五)沼气的脱硫与工程运行管理

1沼气脱硫1.1沼气成分的生理特性可以从生理反应来分析沼气成分对人或牲畜的危害程度。生理反应是指一定量(浓度)的气体,在一定的时间内,对人或重68kg以上的动物所产生的生理反应。对于体重轻的动物反应较快,体重重的动物则反应较慢。国家环境卫生标准规定,H2S气体含量在居民区的空气中不得超过0.00001mg/L;在工厂车间不得超过0.01mg/L;在城市煤气中不得超过0.02mg/L。因为H2S含量达0.6mg/L时可使人在0.5～1h内致死,含量在1.2～2.8mg/L时可使人立即致死。各处理厂沼气中H2S的含量排列顺序如下:城粪处理厂沼气中含有7.56～7.59mg/L屠宰…     

水中邻苯二甲酸酯类内分泌干扰物的去除方法

叙述了去除水中邻苯二甲酸酯类物质的主要方法——生物降解、微波辐照处理、光催化氧化处理、活性炭降解、臭氧氧化法，指出，催化臭氧化法是去除邻苯二甲酸酯类的研究方向。     

酵母菌对Cr(Ⅵ)的生物吸附作用研究

以固定化酵母菌作为生物吸附剂,吸附重金属离子铬,研究了用不同载体包埋的酵母菌在不同条件下对Cr(Ⅵ)的吸附影响.实验结果表明,1:2的PVA-SA固定的酵母菌在pH=2.0,Cr(Ⅵ)浓度为5 mg/L,菌体浓度为40 mg/L,室温条件下吸附60 min时,对Cr(Ⅵ)的吸附效率为91.17％.     

熔模铸造空心叶片用陶瓷型芯浆料分析

通过溶解过滤方法对某外来陶瓷浆料进行分离后，利用红外光谱（IR）、气相-质谱联用色谱（GC-MS）对增塑剂部分进行分析，结果表明其主要成分为低温石蜡，熔点50℃，并含有少量邻苯二甲酸二乙酯；利用激光粒度仪、电镜和EDS对粉体部分进行分析，结果表明基体为石英粉，矿化剂为锆英粉。该陶瓷浆料的分析结果对公司陶瓷型芯的研究具有重要的推进作用。     

氨氮对餐厨垃圾厌氧发酵产氢的影响

研究了以尿素作为氮源时对餐厨垃圾厌氧发酵产氢的影响.研究结果表明,随着尿素添加量的增大,体系中氨氮的浓度逐渐增大,当氨氮浓度在3.58～7.89g/L的范围内,对氢气的产生有促进作用;氨氮浓度超过7.89g/L时,体系的氢气产量开始下降,氨氮浓度为6.24g/L时得到最大氢气产率(126.8mL/g VS);然而,当氨氮浓度超过5.93g/L时,体系反应的延迟时间超过了13.64h,因此综合考虑氢气产量和产氢效率,应该控制反应过程中氨氮的浓度低于6g/L.反应后,液相中的主要产物是乙酸和丁酸,随着尿素投加量的增大,体系中丁酸的浓度逐渐减少,乙酸的浓度增大,但两者的浓度和所占总有机酸的比例都约为80%,没有明显变化;丙酸和戊酸含量较少,且变化不大.     

类芬顿催化剂强化去除喷漆废水COD的研究

目前环保行业中,喷漆废水的处理因其COD浓度高、可生化性极差而成为一个难点。研究在使用类芬顿催化剂后对喷漆废水COD的去除率,结果表明,原水水质COD=7690mg/L,传统芬顿反应后COD=4960mg/L,处理效率为35.5%,经类芬顿催化剂使用后COD=1740mg/L,处理效率为77.3%,约是相同实验条件下传统芬顿反应的2倍,明显强化了传统芬顿反应的处理效率。     

影响固定床烟气脱硫因素的实验研究

以CaO粉末做吸收剂,通过固定床干法脱硫实验,分别研究了温度、进口浓度、Ca/S摩尔比、吸收剂粒径和停留时间等各因素对脱硫效率的影响,结果表明：当T= 825℃、Ca/S=2.82、粒径为75μm、进口浓度Cin=1783 mg/m3、tR=0.4 s时,脱硫效率可达89.6%,出口SO2浓度为185 mg/m3,低于国家标准规定的260 mg/m3.     

某分散染料化工废水的处理工程实例

针对某染料化工废水的高浓度、高盐分、高生物毒性的特点,采用中和-MVR除盐-电解-氧化-混凝沉淀-水解酸化-A/0-二沉池-混凝沉淀-BAF生物滤池的联合处理工艺对其进行处理.结合稳定运行结果显示,CODCr、SS、NH3-N、苯胺类的平均去除率分别为91.8％、96.6％、94.2％和98.6％,平均出水浓度分别为409 mg/L、29 mg/L,7 mg/L和4mg/L,满足且优于污水处理厂的接管标准,且出水水质稳定.     

低水力负荷下培养的好氧颗粒污泥释磷特性

为研究在低水力负荷下培养的好氧颗粒污泥的破胞释磷特性,以厌氧颗粒污泥为接种污泥,使用SBR反应器在水力负荷为0.4~1.02kg/(m~3·d)的条件下培养具有脱氮除磷能力的好氧颗粒污泥,设置静置、热解、酸解、碱解和搅拌五种条件,分析每种条件下其上清液中磷氮浓度的变化趋势并得出最佳释磷条件。结果表明,在静置条件下PO_4~(3-)-P净增长可达到5.02mg/L;热解条件下在60℃时PO_4~(3-)-P净增长可达到36.057mg/L;酸解条件下当pH=3时PO_4~(3-)-P净增长可达到12.097 mg/L;碱解条件下pH=10时PO_4~(3-)-P净增长可达到19.732mg/L;搅拌条件下在100r/min时PO_4~(3-)-P净增长可达到约23.641mg/L。对比分析五种不同条件可知,温度和碱解对低水力负荷下培养的好氧颗粒污泥破胞释磷的影响最大。研究成果为减少污泥量及磷的资源回收提供了理论依据。     

Carbazole based D-A-π-A chromophores for dye sensitized solar cells: Effect of the side alkyl chain length on device performance

A series of Carbazole based Donor-Acceptor-π Bridge-Acceptor (D-A-π-A) dyes that contain different alkyl side chains with different lengths have been synthesized. Electrochemical and optical properties of these dyes were demonstrated by impedance spectroscopy, cyclic voltammetry, UV–Vis absorption and fluorescence spectroscopy, respectively. Herein, we report PV performance of dye-sensitized solar cells depending on the molecular structure of the dyes in terms of comparison of alkyl chain length on the carbazole moiety using an ionic liquid based electrolyte under standard AM 1.5 illumination. The results demonstrate that the dye containing alkyl chain with 4C atoms exhibited better performance compared to alkyl chains with 2C, 6C and 12C atoms.     

A comparative study of gel polymer electrolytes based on PVDF-HFP and liquid electrolytes, containing imidazolinium ionic liquids of different carbon chain lengths in DSSCs

The photoelectrochemical characteristics of titanium dioxide (TiO₂)-based dye-sensitized solar cells (DSSCs) containing gel polymer electrolyte (GPE) and organic liquid electrolyte (OLE) were studied in detail. GPE was prepared by adding poly(vinyidene fluoride-co-hexafluoro propylene) (PVDF-HFP) to imidazolinium ionic liquids (IILs) of the type, 1-methyl-3-alkyl imidazolinium iodides (alkyl is C_nH_2n+1, where n=3–10) in methoxy propionitrile (MPN) and the OLE contained the above molten salt in MPN. The IILs were synthesized in the laboratory and characterized by ¹H nuclear magnetic resonance spectroscopy (NMR). The conductivities (σ) of both GPE and OLE decrease with increase in chain length (n) of the alkyl group of IILs; however, the effect is more drastic in the former case. The performance of the DSSCs containing OLE increases with the increase in alkyl chain length of IIL from C3 to C7, whereas, there is a linear decrease in the efficiency of the DSSCs incorporated with GPE containing IIL of alkyl chain length from C3 to C10. The change in short circuit current density (J_SC) determines the cell efficiency as the V_OC of the DSSCs remains almost the same with increase of alkyl chain length of IILs for both the electrolytes. The change in J_SC values and the consistency of the V_OC of the DSSCs for both the electrolytes may be explained on the basis of increase in viscosity of IILs from C3 to C10 and the dominating role of the 4-tertiary butyl pyridine (TBP), respectively, on the phenomenon of charge recombination.     

Research Interfacial Properties of the Novel Lignosulfonates

Abstract

The interfacial tensions between the crude oil and the novel modified lignosulfonate solutions were measured by a spinning drop interfacial tension apparatus. Some effects that influence on IFT were discussed. With the increase of alkyl chain length or the number of lipophilic groups introduced, the interfacial activity of the modified lignosulfonate increases, and the optimum surfactant concentration required to reach ultra-low IFT decreases. Excellent activity at the interface of crude oil and the solutions was observed. The interfacial tensions of the modified lignosulfonates could be ultra-low over a wide range of surfactant concentration and alkali concentration without the addition of other surfactants. They are capable of being the principal surfactant in enhanced oil recovery (EOR).     

Electrolyte properties of 1-alkyl-2,3,5-trimethylpyrazolium cation-based room-temperature ionic liquids for lithium secondary batteries

The physicochemical and electrochemical properties of three 1-alkyl-2,3,5-trimethylpyrazolium cation-based room-temperature ionic liquids with various alkyl chain lengths were investigated. The temperature dependences of density, viscosity, and ionic conductivity were obtained by precise measurements. Electrolyte properties of these room-temperature ionic liquids were also examined from the viewpoint of their uses in lithium secondary batteries ([LiCoO₂ positive electrode|electrolyte|lithium metal negative electrode]). It was found that the alkyl chain length affects the charge–discharge performances of cells.     

Study on the partially cross-linked poly(styrene-b-(ethylene-co-butylene)-b-styrene) anion exchange membrane remotely (spaced hexyl) grafted double cation separated by different alkyl groups

In order to improve the alkali stability and OH⁻ conductivity of Poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)-based anion exchange membranes (AEMs), double cations with different alkyl intervals are remotely grafted onto the SEBS skeleton with hexyl as a linker through reactions such as acylation and ketone reduction. Then, SEBS-0.8Cn-0.2C6 cross-linked membranes were prepared to study the effect of the length of the alkyl chain between the dications on the ion transport and other properties. The OH⁻ conductivity of SEBS-0.8C4-0.2C6 cross-linked membrane can reach 85.27 mS cm⁻¹ at 80 °C, and the peak power density can reach 225 mW cm⁻² at a current density of 450 mA cm⁻². As the dicationic spacer alkyl chains became longer, the swelling rate and water uptake of the membranes increased, resulting in significant improvements in mechanical properties and chemical stability. After soaking in 2 M NaOH solution at 80 °C for 1200 h, the conductivity of SEBS-0.8C6-0.2C6 decreased by only 5.76%. Optimizing the side chain structure of SEBS skeleton can effectively improve the comprehensive performance of AEM.     

New perylene derivative dyes for dye-sensitized solar cells

We have studied the influence of the spacer alkyl chain length of perylenemonoimide (PMI) dyes on the device performance in dye-sensitized solar cells (DSSCs). We observed that the dyes with longer and brunched alkyl chains exhibit higher efficiencies in DSSCs. In line with these statements we now report the highest efficiency obtained under standard conditions for a perylene imide derivative with PMI-DA1 that performs 300 mV open circuit voltage, 9.79 mA/cm² short-circuit current and 1.61% overall conversion efficiency.     

Solar cells made from polymers containing Dithieno[3,2-b:2′,3′-d]pyrrole with different side chain lengths

Polymer solar cells made from poly(2,6-bis(3-dodecylthiophen-2-yl)-N-alkyl-dithieno[3,2-b:2′,3′-d]pyrrole) (PDTPBT) with different side chain lengths as donors and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as the acceptor were investigated. After optimization with thermal treatments, the device made from PDTPBT with a longer alkyl side chain (P1) delivers a power conversion efficiency (PCE) of 1.06%, which is much higher than that made from PDTPBT with a shorter side chain (0.26%). Atomic force microscopy (AFM) and modeling results show that the polymer with longer side chain produces much better uniform nanostructure with less pinhole than the polymer with a short side chain, resulting in lower interfacial resistance for higher short circuit current and reduced cathode penetration into the active layer for lower charge recombination rate, and further leading to higher power conversion efficiency.     

Synthesis and Properties of a Novel Fluorescent Surfactant

Abstract

A novel kind of fluorescent surfactant by having a hydroxyl coumarin group and a sulfonate group attached to the same alkyl chain has been synthesized. The determined critical micelle concentration (CMC) values and surface tensions (γ_cmc) at CMC for the fluorescent surfactant are in good agreement with the conventional surfactants. Ultraviolet absorption and fluorescence parameters of the product against the variation of the pH values are studied. The results indicate that the absorption and fluorescence intensity attribute to the interaction between the product and OH^?. These properties make them very promising for applications of determining the interface properties.     

On the calculation of heat,mass and momentum transport in coaxial jets and mixing layers

This communication deals with the determination of mass, momentum and heat transport in turbulent mixing layers and with the determination of momentum transport in concentric round jets. Mixing length, k/? and k/ω models are employed in the calculations. The constants appearing in these models are evaluated to yield the correct spreading rate, mean axial velocity, concentration and temperature profiles. A single-point probability density function (pdf) has been employed to calculate heat and mass transport in mixing layers. It is shown that the concentric jet mean velocity profiles are accurately predicted if the constants multiplying the production terms in the ?^? and ω^? equation have values of 1.52 and 1.50. These constants have to be taken equal to 1.44 and 3.80 for mixing layers. The calculated turbulent Schmidt/Prandtl number is 0.70 for mixing layers.     

Influence of alkyl dihalide gelators on solidification of dye-sensitized solar cells

Quasi-dye-sensitized solar cells were prepared by using ionic liquid-type electrolytes and gelators consisting of polyvinylpyridine and alkyl dihalides. Gelation occurred by the reaction of polyvinylpyridine and alkyl dihalides. When the chain length of the dihalides was varied, the short-circuit current (J_sc) increased with an increase in the chain length. However, the open-circuit voltage (V_oc) and fill factor (ff) slightly decreased. The increase in J_sc was brought about by the decrease in the interfacial resistances between the gel electrolyte and the counter electrode. In addition, the increase in the J_sc was explained by increases in the apparent diffusion coefficient of I⁻/I₃⁻ when the chain length increased. Decreases in V_oc and ff were explained by back-electron transfers from TiO₂ to iodine in the electrolytes. V_oc of the cells solidified by alkyldiiodide was lower than that solidified by alkyldichloride or alkyldibromide. It was explained by negatively shifted redox potential of I⁻/I₃⁻, compared with those for Cl⁻/Cl₂ or Br⁻/Br₂.