复合表面活性剂对燃煤陶瓷窑炉黑烟润湿作用的研究

为了有效控制燃煤陶瓷窑炉黑烟的污染，根据理论和实验研究的结果，选择合适的润湿剂和助剂，研究了阴离子表面活性剂Y1、非离子表面活性剂F1与无机盐Z1复配后溶液表面张力的变化，筛选出了表面张力较小的配比。利用所选配比对燃煤陶瓷窑炉黑烟的润湿作用进行了Walker实验研究和理论分析。实验结果表明，0．5mmol／L Y1＋50mmol／L Z1＋0．03mmol／L F1的配比对黑烟的润湿作用较好。并对其润湿机理进行了探讨。     

湿法净化黑烟中添加剂对炭黑沉降性能的影响

湿法净化黑烟中炭黑颗粒物的关键在于降低吸收液的表面张力并以高性能絮凝剂使其从溶液中絮凝、沉降以利于分离。选用十六烷基三甲基溴化胺(CTAB)为主要表面活性剂,使之与十二烷基苯磺酸钠(SDBS)和月桂醇聚氧乙烯(9)醚(AEO-9)进行复配实验,研究了复配液的表面张力,再向最低表面张力的复配表面活性剂溶液中投加絮凝剂聚合氯化铝(PAC)和聚丙烯酰胺(PAM),探讨絮凝剂的添加对黑烟颗粒沉降和絮凝的影响.实验结果表明:同时添加表面活性剂CTAB,SDBS和PAC,并使之浓度分别为0.5 mmol/L,0.4 mmol/L和200 mg/L时,炭黑颗粒的沉降效果最好,沉降率高达94%,且絮凝体较大,沉降时间仅为2 min。     

产糖脂类生物表面活性剂菌株鉴定及发酵条件优化

从胜利油田污水中筛选出的产生物表面活性剂菌株Bbai-1,经过生理生化鉴定及16S rDNA系统发育学分析确定其属于类短短芽孢杆菌属(Brevibacillus parabrevis),由建立的该菌株的系统发育树可知菌株Bbai-1与其他类短短芽孢杆菌类同源性较低,是一个新的种.薄层色谱和红外光谱分析结果表明此菌株所产的生物表面活性剂为一种新型的糖脂类生物表面活性剂.通过产量和表面张力双重指标对菌株Bbai-1产生物表面活性剂的条件进行优化,确定了其最佳发酵温度为25℃、盐度为8 g/L、pH为7.5.在最佳发酵条件下,生物表面活性剂的产量可达0.9764 g/L.此糖脂类生物表面活性剂具有较高的降低表面张力能力,在浓度为其临界胶束浓度(120 mg/L)时,可将水溶液的表面张力从66.15 mN/m降低至27.62 mN/m.     

锰污染土壤根际微生物分离及耐Mn2+特性

为了研究锰污染土壤的生物修复,在湘潭锰矿不同植物根际土壤中分离得到7株真菌和8株细菌,依次命名为F1-7和B1-8。经耐锰性能测定,获得高耐锰性真菌3株,F3-5、细菌3株,B1、B2和B7。其中,F3耐锰浓度最高可达600mmol/L,细菌B7最高耐锰浓度为80 mmol/L。当Mn2+浓度小于300 mmol/L时,对3种真菌的生长均具有一定的促进作用,高于此浓度时,产生较大程度的抑制作用。在低Mn2+浓度(20~40 mmol/L)条件下,Mn2+对3种细菌的生长均表现出一定的促进作用,尤其是对B2作用明显。当Mn2+浓度逐渐增加到80 mmol/L时,抑制作用明显。在Mn2+浓度为300mmol/L时,F3对锰的吸附率约为60%,达到峰值。而在Mn2+浓度为60 mmol/L时,细菌B2对锰的吸附率约为70%,达最大值。     

表面活性剂对多壁碳纳米管吸附Pb~(2+)的影响

多壁碳纳米管(MWNT)在吸附有毒气体和重金属离子方面具有极高的应用价值.针对MWNT对水溶液中Pb2+的净化吸附进行了研究,从吸附量,吸附速率、动力学角度考察了表面活性剂、Pb2+浓度对MWNT吸附Pb2+的影响.结果表明,司班-60、吐温-20、阿拉伯树胶等表面活性剂的加入,促进了MWNT在溶液中的分散,导致在Pb2+摩尔浓度为3～18 mmol/L的Lang-muir和Freundlich等温吸附方程中的吸附常数(K)变大,使得MWNT对Pb2+的吸附速率和平衡吸附量都得到提高;随着溶液中Pb2+浓度的增大,MWNT对其吸附量渐至饱和,随后由于Pb2+的位阻作用.吸附量下降;在这3种表面活性剂中,由于司班-60具有相对较小的分子量,其分散的MWNT在Pb2+摩尔浓度为14 mmol/L时,吸附量最大,为230 mg/g.     

表面活性剂对Cd2+在沉积物上吸附行为的影响

以Cd2+为重金属代表,阴离子表面活性剂十二烷基苯磺酸钠(SDBS)、阳离子表面活性剂氯化十六烷基吡啶(CPC)、非离子表面活性剂辛基酚聚氧乙烯醚(TX-100)为表面活性剂代表,用实验模拟法研究了3种类型的表面活性剂对Cd2+在沉积物上吸附行为的影响.结果表明,不同种类的表面活性剂对Cd2+在沉积物上的吸附影响不同,SDBS对Cd2+的吸附影响可分为2个阶段,当SDBS初始质量浓度从0 mg/L增加到2 600 mg/L,Cd2+的吸附量从1.52 mg/g增至1.88 mg/g,增加了23.7%,随着SDBS初始浓度继续增加,Cd2+的吸附量开始下降,当SDBS初始质量浓度增至16 000 mg/L,Cd2+的吸附量降低至0.34 mg/g;CPC主要通过在溶液中电离出CP+,CP+与Cd2+竞争沉积物表面的吸附位从而抑制Cd2+的吸附,当CPC初始质量浓度从0 mg/L增加至16 000 mg/L,Cd2+的吸附量从1.50 mg/g降低至0.52 mg/g;TX-100能轻微抑制Cd2+在沉积物上的吸附,当TX-100初始质量浓度从0 mg/L增加到16 000 mg/L时,Cd2+吸附量从1.52 mg/g减少至1.35 mg/g.     

石油降解菌产表面活性剂的条件优化

为了了解陕北石油降解菌产表面活性剂的情况,对实验菌株CT-6以原油为唯一碳源时产表面活性剂的排油活性、表面张力和乳化性能进行了研究,并对实验菌株产表面活性剂的条件进行了优化.结果表明,排油圈直径达到8.0cm,表面张力降低到33 mN/m,乳化指数达89.9％,石油降解率达到68.0％;优化后的条件为:接种量10％、pH为8、温度28℃、转速220 r/min,该条件下,排油圈直径增加了13.1％,7d时乳化指数达到93.0％.     

一株产生物表面活性剂耐盐碱菌株的分离及鉴定

从黄河三角洲石油污染盐渍土中分离获得产生物表面活性剂的耐盐碱菌株,用于治理该地区的土壤污染问题。采用富集培养方法,分离得到4株优势菌,其中菌株BG降表面张力的能力最强。经生理生化实验和16SrRNA序列分析,鉴定菌株BG属于芽孢杆菌属(Bacillus sp.)。对该菌株产生物表面活性剂的性能进行研究,结果表明:菌株BG在37℃、180r/min下振荡培养48h,可将发酵液的表面张力由初始的58.4mN/m降低至25.1mN/m;温度对菌株BG产生物表面活性剂的影响较大,最适温度是37℃,此温度下菌株BG有良好的耐盐碱特性,显著降低发酵液表面张力。采用酸沉法提取了菌株BG产生的生物表面活性剂,鉴定为一种脂蛋白类物质,其中脂类和蛋白质质量分数分别为64.7%、35.3%。     

表面活性剂清洗处理重度石油污染土壤

为了优化表面活性剂清洗处理重度石油污染土壤的方法和具体洗脱条件参数，采集山东省东营市胜利油田污染土壤，研究了阴离子-非离子混合表面活性剂对该土壤中石油类污染物的去除效果。应用化学热洗原理，主要考查了表面活性剂配比、投加量、清洗温度及清洗助剂对去除效果的影响。实验得到的清洗处理最佳条件为：使用LAS与TX-100质量比为8∶2的组合表面活性剂，总表面活性剂浓度为3 g/L，助剂硅酸钠浓度为5 g/L，75℃条件下搅拌1 h。清洗后土壤含油量从20%下降到4.6%，去除率达到76.9%。废水回用实验表明，清洗处理的废水对土壤中石油烃类物质仍有一定的去除效果。废水回用比从30%到100%时，对土壤中石油烃的去除率都可达到55%以上。对废水进行二次回用时仍能去除18.8%的污染物。     

糖脂类生物表面活性剂去除污染含水层中石油烃的研究

研究了糖脂类生物表面活性剂对石油烃的增溶,并将其用于污染含水层中石油烃的去除。结果表明:石油烃溶解度随着糖脂类生物表面活性剂浓度的增大而增大,糖脂类生物表面活性剂质量浓度为1 200mg/L时,石油烃溶解度达10 077.7mg/L;界面张力随着糖脂类生物表面活性剂浓度的增加而减小,糖脂类生物表面活性剂质量浓度为1mg/L时,界面张力为34.3mN/m,糖脂类生物表面活性剂质量浓度为800mg/L时,界面张力为5.2 mN/m。采用糖脂类生物表面活性剂对污染含水层进行清洗处理,在固液比(质量体积比)为1g∶2mL的体系中,糖脂类生物表面活性剂质量浓度为3 000mg/L,120r/min、10℃下振荡12h,石油烃去除率达70.82%。污染含水层柱冲洗结果表明,糖脂类生物表面活性剂质量浓度分别为1 200、3 000mg/L时,10倍孔隙体积的表面活性剂冲洗后,分别从污染砂样中去除41.81%和63.30%的石油烃。     

添加剂对炭黑颗粒润湿和沉降性能的影响

为提高湿式除尘装置对炭黑颗粒物的去除效率，通过向吸收液中添加复配表面活性剂以提高吸收液对炭黑的润湿性，投加絮凝剂使进入吸收液的炭黑颗粒发生凝聚和沉降，从而使吸收液得以循环利用。其中表面活性剂的复配以非离子表面活性剂月桂醇聚氧乙烯（9）醚（AEO-9）为主，与十二烷基苯磺酸钠（SDBS）、十六烷基三甲基溴化胺（CTAB）和壬酚基聚氧乙烯醚（TX-10）分别复配，筛选出复配效果最好的一组复配液；然后投加絮凝剂，探讨絮凝剂的加入对吸收液中炭黑颗粒物絮凝沉降的影响。结果表明，在AEO-9浓度为0．05mmol／L，TX-10浓度为0．09mmol／L时，吸收液的表面张力最小，为36．75mN／m；投加无机絮凝剂聚合氯化铝（PAC）浓度为100mg／L时，经15min沉降，炭黑的沉降率可达88．1％，上清液中悬浮颗粒的平均粒径为6．36μm。     

The effect of surface-active solutes on water flow and contaminant transport in variably saturated porous media with capillary fringe effects

Organic contaminants that decrease the surface tension of water (surfactants) can have an effect on unsaturated flow through porous media due to the dependence of capillary pressure on surface tension. We used an intermediate-scale 2D flow cell (2.44 x 1.53 x 0.108 m) packed with a fine silica sand to investigate surfactant-induced flow perturbations. Surfactant solution (7% 1-butanol and dye tracer) was applied at a constant rate at a point source located on the soil surface above an unconfined synthetic aquifer with ambient groundwater flow and a capillary fringe of approximately 55 cm. A glass plate allowed for visual flow and transport observations. Thirty instrumentation stations consist of time domain reflectometry probes and tensiometers measured in-situ moisture content and pressure head, respectively. As surfactant solution was applied at the point source, a transient flow perturbation associated with the advance of the surfactant solution was observed. Above the top of the capillary fringe the advance of the surfactant solution caused a visible drainage front that radiated from the point source. Upon reaching the capillary fringe, the drainage front caused a localized depression of the capillary fringe below the point source because the air-entry pressure decreased in proportion to the decrease in surface tension caused by the surfactant. Eventually, a new capillary fringe height was established. The height of the depressed capillary fringe was proportional to height of the initial capillary fringe multiplied by the relative surface tension of the surfactant solution. The horizontal transport of surfactant in the depressed capillary fringe, driven primarily by the ambient groundwater flow, caused the propagation of a wedge-shaped drying front in the downgradient direction. Comparison of dye transport during the surfactant experiment to dye transport in an experiment without surfactant indicated that because surfactant-induced drainage decreased the storage capacity of the vadose zone, the dye breakthrough time to the water table was more than twice as fast when the contaminant solution contained surfactant. The extensive propagation of the drying front and the effect of vadose zone drainage on contaminant breakthrough time suggest the importance of considering surface tension effects on unsaturated flow and transport in systems containing surface-active organic contaminants or systems, where surfactants are used for remediation of the vadose zone or unconfined aquifers.     

Removal of hydrocarbons from wastewater using treated bark

This paper explores the possibility of removing hydrocarbons (HCs) and trace elements from synthetic and industrial effluents using treated bark as biosorbent. Coniferous bark was treated either chemically (Tc) or biologically (Tb) to eliminate soluble organic compounds of bark. The removal efficiency (RE) of the HCs from a synthetic oil-water mixture containing spent diesel motor oil exceeds 95% using 2 g/L of treated bark mixed with a synthetic oil-water mixture containing 2 g/L of spent oil. Under these conditions, the retention capacity (RC) was approximately 1 g HC/g dry substrate. The sorption reaction seems to be quasi-instantaneous, and the retention capacity of spent oil on treated bark increases as the temperature augments. This implies that the retention mechanism is related to the capillary action. Results of Fourier transform infrared (FTIR) spectroscopy indicate that spent oil is mainly composed of alkanes. They also suggest that no chemical bonds between Tc and spent oil were established. Measurement of the surface tension of spent oil and the wetting index of the bark suggests that only spent oil will be retained by the substrate. Treatment of an industrial effluent containing 14.4 g/L of total HCs was performed using Tc. It was possible to remove 97% of HCs and retain some trace elements such as Al, Ca, Fe, Mg, S, and so on.     

Measuring and modeling the composition and temperature-dependence of surface tension for organic solutions

Surface tensions for a wide variety of pure organic and mixed organic/salt solutions were measured at 25 and 5 °C using the Wilhelmy plate method. Langmuir adsorption parameters for the organic compounds were extracted by fitting the surface tension data to the Szyszkowski equation. In a mixed organic/salt solution, the surface tension was primarily controlled by the organic component, even when the mass ratio of salt to organic in solution exceeded threefold. Excellent agreement was found between measured surface tension values at 5 °C and those predicted by the Szyszkowski equation using Langmuir adsorption parameters extracted at 25 °C. This finding may have important implications for cloud formation studies where the onset of activation often occurs at temperatures below 25 °C.     

Removal of Hydrocarbons from Wastewater Using Treated Bark

ABSTRACT

This paper explores the possibility of removing hydrocarbons (HCs) and trace elements from synthetic and industrial effluents using treated bark as biosorbent. Coniferous bark was treated either chemically (Tc) or biologically (Tb) to eliminate soluble organic compounds of bark. The removal efficiency (RE) of the HCs from a synthetic oil-water mixture containing spent diesel motor oil exceeds 95% using 2 g/L of treated bark mixed with a synthetic oil-water mixture containing 2 g/L of spent oil. Under these conditions, the retention capacity (RC) was ~1 g HC/g dry substrate. The sorption reaction seems to be quasi-instantaneous, and the retention capacity of spent oil on treated bark increases as the temperature augments. This implies that the retention mechanism is related to the capillary action.

Results of Fourier transform infrared (FTIR) spectros-copy indicate that spent oil is mainly composed of al-kanes. They also suggest that no chemical bonds between

Tc and spent oil were established. Measurement of the surface tension of spent oil and the wetting index of the bark suggests that only spent oil will be retained by the substrate. Treatment of an industrial effluent containing 14.4 g/L of total HCs was performed using Tc. It was possible to remove 97% of HCs and retain some trace elements such as Al, Ca, Fe, Mg, S, and so on.     

Enhanced desorption of phenanthrene from contaminated soil using anionic/nonionic mixed surfactant

A new approach using an anionic/nonionic mixed surfactant, sodium dodecyl sulphate (SDS) with Triton X-100 (TX100), was utilized for the desorption of phenanthrene from an artificial contaminated natural soil in an aim to improve the efficiency of surfactant remediation technology. The experimental results showed that the presence of SDS not only reduced the sorption of TX100 onto the natural soil, but also enhanced the solubilization of TX100 for phenanthrene, both of which resulted in the distribution of phenanthrene in soil-water systems decreasing with increasing mole fraction of SDS in surfactant solutions. These results can be attributed to the formation of mixed micelles in surfactant solution and the corresponding decrease in the critical micelle concentration of TX100 in mixed solution. The batch desorption experiments showed that the desorption percentage of phenanthrene from the contaminated soil with mixed solution was greater than that with single TX100 solution and appeared to be positively related to the mole fraction of SDS in surfactant solution. Thus, the anionic/nonionic mixed surfactants are more effective for the desorption of phenanthrene from the contaminated soil than a single nonionic surfactant.     

Bench-scale visualization of DNAPL remediation processes in analog heterogeneous aquifers: surfactant floods and in situ oxidation using permanganate

We have conducted well-controlled DNAPL remediation experiments within a 2-D, glass-walled, sand-filled chamber using surfactants (Aerosol MA and Tween 80) to increase solubility and an oxidant (permanganate) to chemically degrade the DNAPL. Initial conditions for each remediation experiment were created by injecting DNAPL as a point source at the top of the chamber and allowing the DNAPL to migrate downward through a water-filled, heterogeneous, sand-pack designed to be evocative of a fluvial depositional environment. This migration process resulted in the DNAPL residing as a series of descending pools. Lateral advection across the chamber was used to introduce the remedial fluids. Photographs and digital image analysis illustrate interactions between the introduced fluids and the DNAPL. In the surfactant experiments, we found that DNAPL configured in a series of pools was easily mobilized. Extreme reductions in DNAPL/water interfacial tension occurred when using the Aerosol MA surfactant, resulting in mobilization into low permeability regions and thus confounding the remediation process. More modest reductions in interfacial tension occurred when using the Tween 80 surfactant resulting in modest mobilization. In this experiment, capillary forces remained sufficient to exclude DNAPL migration into low permeability regions allowing the excellent solubilizing properties of the surfactant to recover almost 90% of the DNAPL within 8.6 pore volumes. Injection of a potassium permanganate solution resulted in precipitation of MnO2, a reaction product, creating a low-permeability rind surrounding the DNAPL pools. Formation of this rind hindered contact between the permanganate and the DNAPL, limiting the effectiveness of the remediation. From these experiments, we see the value of performing visualization experiments to evaluate the performance of proposed techniques for DNAPL remediation.     

Adsorption behavior of light green anionic dye using cationic surfactant-modified wheat straw in batch and column mode

An agricultural by-product, natural wheat straw (NWS), was soaked in 1 % cationic surfactant (hexadecylpyridinium bromide, CPB) solution for 24 h (at 293 K), and modified wheat straw (MWS) was obtained. Analysis of FTIR, XFR, and nitrogen element showed that CPB was adsorbed onto surface of NWS. Then, MWS was used as adsorbent for the removal of light green dye (LG, anionic dye) from aqueous solution. The experiment was performed in batch and column mode at room temperature (293 K). Sodium chloride (up to 0.1 mol/L) existed in solution was not favor of LG dye adsorption. The equilibrium data were better described by Langmuir isotherm, and adsorption capacity of q _m from Langmuir model was 70.01?±?3.39 mg/g. In fixed-bed column adsorption mode, the effects of initial LG concentration (30, 50, 70 mg/L) and flow rate (6.5, 9.0, 14.5 mL/min) on adsorption were presented. Thomas and modified dose–response models were used to predict the breakthrough curves using nonlinear analysis method, and both models can fit the breakthrough curves. Theoretical and experimental breakthrough curves were drawn and compared. The results implied that MWS can be used as adsorbent material to remove LG from aqueous solution.