阳-非离子有机膨润土对水中硝基苯的吸附作用

分别用阳离子表面活性剂CTMAB、非离子表面活性剂Triton X-100及其混合物改性膨润土制得一系列的单阳离子、单非离子、阳-非离子有机膨润土.比较了它们对水中硝基苯的吸附性能及机理.结果表明,有机膨润土吸附水中硝基苯的等温吸附曲线呈线性,主要为分配作用所致,分配作用的大小由有机膨润土有机碳含量决定,并与改性时表面活性剂的种类、组成及配比有关;阳-非离子混合表面活性剂改性的有机膨润土有机碳含量(foc)高于相应的单阳离子和单非离子有机膨润土有机碳含量的和,因此,阳-非离子有机膨润土对水中硝基苯的吸附能力显著增强.     

共存有机物对毒死蜱在沉积物上吸附的影响

用批量平衡法研究了共存有机物对毒死蜱在沉积物上吸附行为的影响.结果表明,苯酚和芘对毒死蜱在沉积物上的吸附有竞争作用,其中苯酚的竞争能力较大.多种有机污染物共存时,毒死蜱在沉积物上的吸附仍然由分配作用决定.表面活性剂的浓度小于临界胶束浓度(CMC)时,十二烷基硫酸钠(SDS)能明显降低毒死蜱在沉积物上的吸附量,降低程度与SDS浓度呈负相关,而非离子表面活性剂Triton X-100能增加毒死蜱在沉积物上的吸附量,增加程度与Triton X-100浓度呈正相关.     

复合污染中Triton X-100在膨润土/水界面上的吸附行为

研究了水溶液中膨润土对非离子表面活性剂Triton X-100(X-100)的吸附,重点探讨了阳离子表面活性剂CPC、阴离子表面活性剂SDBS、中性无机盐NaCl及温度对膨润土吸附TX-100的影响.结果表明,Na基膨润土吸附TX-100的效果好于Ca基膨润土;低浓度CPC对膨润土吸附TX-100具有增强作用,当CPC初始浓度大于l0000 mg·L-1(平衡浓度Ce约为1CMC)时具有抑制作用,当CPC浓度低于3000 mg·L-1(Ce约为0.03CMC)时,TX-100吸附量与CPC浓度成线性正相关.SDBS能显著降低膨润土对TX-100的吸附,原因是溶液中SDBS与TX-100混合胶束的形成能阻止TX-100与膨润土硅氧表面间的氢键作用及在其表面形成胶束.NaCl的存在可以大大提高膨润土对TX-100的吸附,去除率由56%提高到99%以上.膨润土对TX-100的吸附随温度升高吸附量增大,其吸附热为12.68 kJ·mol-1,标准自由能的减小和熵值的增大是TX-100在膨润土上吸附的推动力.实验结果对用膨润土处理含表面活性剂废水具有一定的理论价值.     

生物表面活性剂皂角苷对菲在水和土壤间分配行为影响

文章比较研究了皂角苷(saponin)、Triton X-100以及二者的混合物对多环芳烃菲在土壤和水相间分配行为的影响。结果表明,在所选择的表面活性剂中,皂角苷对菲在水和土壤间的分配具有最强的增溶能力。在竞争吸附的作用下,随着加入的表面活性剂的量不同,菲在水和土壤间的分配行为也有差异。当表面活性剂的浓度较低时,促进菲在土壤上的吸附;当加入的表面活性剂的量超过其临界胶束浓度(CMC)时,菲在水和土壤间的分配系数随着表面活性剂浓度的增大出现持续减小的趋势。并且在相同浓度下,皂角苷和TritonX-100组成的混合表面活性剂的增溶能力比单独使用非离子表面活性剂Triton X-100强。同样在混合表面活性剂的协同增溶作用下,菲在水和土壤间的分配系数随着表面活性剂浓度的增加出现持续减小的趋势。     

膨润土对复合污染中表面活性剂的吸附及机理

选取阳离子表面活性剂氯化十六烷基吡啶(CPC)、阴离子表面活性剂十二烷基苯磺酸钠(SDBS)及非离子表面活性剂Triton X-100(TX-100)为代表,研究了其在膨润土上的吸附行为,探讨了膨润土阳离子交换容量(CEC)、温度、盐度对CPC吸附的影响.结果表明,Na基膨润土对CPC的吸附性能最好,对SDBS基本无吸附,对TX-100的吸附介于两者之间.Na基膨润土对CPC的吸附是阳离子交换和疏水键缔合共同作用的结果,对TX-100的吸附主要是通过其与膨润土硅氧表面间的氢键作用,同时通过疏水键作用形成吸附双分子层;SDBS在Ca基膨润土上的吸附损失量先增大后减小,在1.5倍临界胶束浓度 (CMC)时达到极大值,主要机理是SDBS与膨润土中的Ca²⁺产生沉淀作用,而胶束具有再溶解沉淀的作用.膨润土对CPC的吸附量随着温度升高而降低,随着CEC的增大而增大,一定浓度NaCl的加入有利于其在膨润土上的吸附.     

芘污染黑土的表面活性剂洗脱修复研究

采用批量平衡振荡法研究了几种阴离子和非离子表面活性剂对黑土中芘的洗脱效果,以及不同因素对洗脱效果的影响。结果表明,非离子表面活性剂对芘的洗脱效果优于阴离子表面活性剂。将SDS和Triton X-100以不同质量配比混合后,可提高其洗脱效果,尤其在质量配比为3∶7时洗脱效果最好。不同固液比条件可影响Triton X-100对芘的洗脱,Triton X-100在低浓度时,固液比为1∶30时的洗脱效果最好;浓度大于5.0 g/L后,固液比为1∶10时的洗脱效果最好。Triton X-100对土壤中低浓度芘的洗脱效果要好于土壤中高浓度的芘。萘在土壤中的共存会降低Triton X-100对芘的洗脱率,萘浓度越高,芘的洗脱率越低。Triton X-100对不同类型土壤中芘的洗脱效果相差不大,对新疆荒漠土的洗脱效果好于哈尔滨黑土,这可能与土壤有机质含量有关。     

表面活性剂在土壤颗粒物上的吸附行为

对两种阴离子表面活性剂和两种非高子表面活性剂在土壤中的吸附行为进行了初步研究．结果表明．表面活性剂在土壤/水体系中的吸附过程很快．表面活性剂浓度接近或大于临界胶团浓度后,吸附等温线为线性．温度升高会降低阴离子表面活性剂的吸附而增加非离子表面活性剂的吸附．盐度对非离子表面活性剂吸附的影响不显著,但可略微增加阴离子表面活性剂的吸附量．实验结果对表面活性剂增效修复技术的应用有一定参考价值．     

Triton X-100在黄土上的吸附行为及影响因素

水土体系下,应用批实验法研究了Triton X-100在天然黄土上的吸附行为与平衡时间、Triton X-100浓度、溶液离子强度和pH值的关系.结果表明,Triton X-100在黄土中的吸附平衡时间约为30 min,其吸附动力学符合一级动力学模型,相应拟合参数Qe、k1、r2分别为3.041 mg·g-1、0.102 min-1、0.993 4.吸附等温线明显为非线性,在利用的4种等温吸附模型中,Sips模型对实验数据提供了最佳的拟合,其拟合参数Qmax和r2分别为3.202 mg·g-1和0.998 7.溶液离子强度和pH值对Triton X-100在黄土上的吸附有显著的影响,其吸附量随NaCl浓度的增加而明显增加,随pH增加而降低.     

Pb(NO3)2与CPC共存对沉积物吸附对硝基苯酚的影响

选取Pb(NO3)2、氯化十六烷基吡啶(CPC)、对硝基苯酚为代表污染物,试验了重金属与表面活性剂共存对有机物在沉积物上吸附行为的影响.结果表明:Pb(NO3)2的存在减弱了CPC的增强吸附效应,Pb(NO3)2和CPC共存对对硝基苯酚的吸附产生拮抗效应.在固定CPC初始浓度不变的情况下,拮抗效应随Pb(NO3)2初始浓度增大而加强.同时,拮抗效应也取决于CPC的浓度.当CPC初始浓度小于3 000mg/L(平衡浓度低于临界胶束浓度CMC)时,这种拮抗效应尤为明显;随着表面活性剂浓度的继续增加,拮抗效应减弱,并逐渐趋向于CPC的独立效应机理探讨表明,共存体系中,Pb2 与CPC在同一吸附点位不存在竞争吸附.     

超声波与Triton X-100联合修复芘污染土壤的研究

该文研究了超声波联合非离子表面活性剂Triton X-100修复芘污染土壤的效果及不同因素对修复效果的影响。结果表明:增加处理次数有助于提升土壤中芘的去除率,3次处理总去除率较1次处理提高了30%。Triton X-100浓度的增加,可提高污染土壤中芘的去除率,且Triton X-100浓度为10.0 g/L时较2.0 g/L时去除率提高了18.90%。水土比为12∶1时,芘去除率达到峰值,水土比过高或过低芘去除率都会降低。随着超声时间的增加去除率呈现先升高后降低的趋势,超声时间为20 min时,对土壤中浓度为0.4 g/kg的芘去除率达到最高的75.30%。相同条件下对低浓度芘污染土壤的处理效果好于高浓度污染土壤,芘浓度为0.1 g/kg的土壤去除率比1.0 g/kg的土壤上升了46.70%。该研究结果表明超声波和表面活性剂联合处理技术具有一定的应用于土壤修复的价值和潜力。     

Adsorption of mixed cationic-nonionic surfactant and its effect on bentonite structure

The adsorption of cationic-nonionic mixed surfactant onto bentonite and its effect on bentonite structure were investigated. The objective was to improve the understanding of surfactant behavior on clay mineral for its possible use in remediation technologies of soil and groundwater contaminated by toxic organic compounds. The cationic surfactant used was hexadecylpyridinium bromide (HDPB), and the nonionic surfactant was Triton X-100 (TX100). Adsorption of TX100 was enhanced significantly by the addition of HDPB, but this enhancement decreased with an increase in the fraction of the cationic surfactant. Part of HDPB was replaced by TX100 which decreased the adsorption of HDPB. However, the total adsorbed amount of the mixed surfactant was still increased substantially, indicating the synergistic effect between the cationic and nonionic surfactants. The surfactant-modified bentonite was characterized by Brunauer-Emmett-Teller specific surface area measurement, Fourier transform infrared spectroscopy, and thermogravimetric-derivative thermogravimetric/differential thermal analyses. Surfactant intercalation was found to decrease the bentonite specific surface area, pore volume, and surface roughness and irregularities, as calculated by nitrogen adsorption-desorption isotherms. The co-adsorption of the cationic and nonionic surfactants increased the ordering conformation of the adsorbed surfactants on bentonite, but decreased the thermal stability of the organobentonite system.     

Water solubility enhancements of pyrene by single and mixed surfactant solutions

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Arsenic retention and transport behavior in the presence of typical anionic and nonionic surfactants

The massive production and wide use of surfactants have resulted in a large amount of surfactant residuals being discharged into the environment,which could have an impact on arsenic behavior.In the present study,the influence of the anionic surfactant sodium dodecyl benzene sulfonate(SDBS) and nonionic surfactant polyethylene glycol octylphenyl ether(Triton X-100) on arsenic behavior was investigated in batch and column tests.The presence of SDBS and Triton X-100 reduced arsenic retention onto ferrihydrite(FH),enhanced arsenic transport through FH coated sand(FH-sand) columns and promoted arsenic release from the FH surface.With coexisting surfactants in solution,the equilibrium adsorbed amount of arsenic on FH decreased by up to 29.7% and the adsorption rate decreased by up to 52.3%.Pre-coating with surfactants caused a decrease in the adsorbed amount and adsorption rate of arsenic by up to 15.1% and 58.3%,respectively.Because of the adsorption attenuation caused by surfactants,breakthrough of As(Ⅴ) and As(Ⅲ) with SDBS in columns packed with FH-sand was 23.8% and 14.3%faster than that in those without SDBS,respectively.In columns packed with SDBS-coated FH-sand,transport of arsenic was enhanced to a greater extent.Breakthrough of As(Ⅴ) and As(Ⅲ) was 52.4% and 43.8% faster and the cumulative retention amount was 44.5% and 57.3% less than that in pure FH-sand column systems,respectively.Mobilization of arsenic by surfactants increased with the increase of the initial adsorbed amount of arsenic.The cumulative release amount of As(Ⅴ) and As(Ⅲ) from the packed column reached 10.8% and 36.0%,respectively.     

Utilizing surfactants to control the sorption, desorption, and biodegradation of phenanthrene in soil-water system

An integrative technology including the surfactant enhanced sorption and subsequentdesorption and biodegradation of phenanthrene in the soil-water system was introduced and tested. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactant- enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guarding agricultural production. After planting, residual surfactants combined with added nonionic surfactant could also promote thedesorption and biodegradation of residual phenanthrene, thus providing a cost-effective pollution remediation technology.0ur results showed that the cationic-nonionic mixed surfactantsdodecylpyridinium bromide (DDPB) and Triton X-100 (TX100) significantly enhanced soil retention of phenanthrene. The maximum sorption coefficient Kd* of phenanthrene for contaminated soils treated by mixed surfactants was about24.5 times that of soils without surfactant (Kd ) and higher than the combined effects of DDPB and TX100 individually, which was about 16.7 and 1.5 times Kd , respectively.0n the other hand, TX100 could effectively remove phenanthrene from contaminated soils treated by mixed surfactants, improving the bioavailability of organic pollutants. Thedesorption rates of phenanthrene from these treated soils were greater than 85% with TX100 concentration above2000 mg/L and approached 100% with increasing TX100 concentration. The biodegradation rates of phenanthrene in the presence of surfactants reached over 95% in30days. The mixed surfactants promoted the biodegradation of phenanthrene to some extent in 10-22days, and had no obvious impact on phenanthrene biodegradation at the end of the experiment. Results obtained from this study provide some insight for the production of safe agricultural products and a remediation scheme for soils slightly contaminated with organic pollutants.     

Sorption and transport studies of cetyl trimethylammonium bromide (CTAB) and Triton X-100 in clayey soil

Surfactants are soil washing agents and facilitators for subsurface remediation of hydrocarbon spills.It is important to understand the sorption and transport behavior of surfactants for enhanced soil remediation.The adsorption and desorption isotherms of cetyl trimethylammonium bromide (CTAB) and Triton X-100 with sand and kaolinite have been quantified.Kaolinite clay had the highest sorption capacity compared to blasting sand.Transport parameters such as diffusion coefficient (D) and retardation factor (R) of the above mentioned surfactant solutions were determined in clayey soils (82.5% sand and 17.5% kaolinite mixture) with near zero and 0.1 g/L ionic strength.NaCl was used as the electrolyte solution.Convection-Diffusion equation was used to model the breakthrough curves of the surfactants.Bromide ion was chosen as the tracer material in order to characterize the column.CTAB and Triton X-100 were used to flush the perchloroethylene (PCE) contaminated soil.The effectiveness of CTAB and Triton X-100 in flushing the PCE from the contaminated soil was quantified.     

Mobilization of arsenic from contaminated sediment by anionic and nonionic surfactants

The increasing manufacture of surfactants and their wide application in industry,agriculture and household detergents have resulted in large amounts of surfactant residuals being discharged into water and distributed into sediment. Surfactants have the potential to enhance arsenic mobility, leading to risks to the environment and even human beings. In this study, batch and column experiments were conducted to investigate arsenic mobilization from contaminated sediment by the commercial anionic surfactants sodium dodecylbenzenesulfonate(SDBS), sodium dodecyl sulfate(SDS), sodium laureth sulfate(AES)and nonionic surfactants phenyl-polyethylene glycol(Triton X-100) and polyethylene glycol sorbitan monooleate(Tween-80). The ability of surfactants to mobilize arsenic followed the order AES SDBS SDS ≈ Triton X-100 Tween 80. Arsenic mobilization by AES and Triton X-100 increased greatly with the increase of surfactant concentration and p H, while arsenic release by SDBS, SDS and Tween-80 slightly increased. The divalent ion Ca~(2+) caused greater reduction of arsenic mobilization than Na~+. Sequential extraction experiments showed that the main fraction of arsenic mobilized was the specifically adsorbed fraction. Solid phase extraction showed that arsenate(As(V)) was the main species mobilized by surfactants,accounting for 65.05%–77.68% of the total mobilized arsenic. The mobilization of arsenic was positively correlated with the mobilization of iron species. The main fraction of mobilized arsenic was the dissolved fraction, accounting for 70% of total mobilized arsenic.