塿土对阴-非离子表面活性剂的吸附特征研究

以平衡吸附法研究了塿土对阴离子表面活性剂（SDS）、非离子表面活性剂（TritonX-100、Tween80和Brij35）的吸附特征,考察了pH、阴-非离子表面活性剂混合对塿土吸附表面活性剂的影响。结果表明,非离子表面活性剂在塿土上吸附等温线均呈L型,且均符合Freundlich和Langmuir方程;塿土对SDS的吸附等温线呈LS型,可用Freundlich方程来描述;塿土对4种表面活性剂吸附量的大小顺序为Tween80〉SDS〉Brij35〉TritonX-100。当阴-非离子表面活性剂一起进入土壤中,SDS-Brij35之间的相互影响不大;TritonX-100与SDS相互作用较大,无论二者以何种方式混合都会使TritonX-100在塿土上的吸附量增加,SDS的吸附量下降;SDS与Tween80之间的相互作用最大,混合后吸附量均下降,但Tween80吸附量降低的幅度最大。pH对非离子表面活性剂的吸附影响不大,而随着pH的增加,塿土对SDS的吸附百分率明显下降;在pH为8.0时,塿土对非离子表面活性剂的吸附百分率达到80以上。因此在选择合适的表面活性剂进行有机污染土壤修复和治理时,考虑土壤的特性和表面活性剂的结构是非常重要的。     

表面活性剂溶液清洗油污土壤试验研究

选用两种阴离子型表面活性剂十二烷基苯磺酸钠(LAS)和十二烷基硫酸钠(SDS)及两种非离子型表面活性剂Triton X-100和Tween 80,研究了临界胶束浓度(CMC)附近各表面活性剂溶液对柴油的增溶及一次性清洗油污土壤的能力。结果表明:在CMC附近,各表面活性剂对柴油的增溶能力大小顺序为SDSSDS>Triton X-100>Tween 80,两种阴离子型表面活性剂的清洗效果优于两种非离子型表面活性剂。     

十二烷基苯磺酸钠对乐果在水-气界面挥发动力学的影响研究

以有机磷农药乐果为研究对象,研究了不同浓度的阴离子型表面活性剂十二烷基苯磺酸钠（SDBS）存在时,乐果在水一气界面的挥发行为,以进一步认识农药的迁移转化规律,为复合污染水体中表面活性剂对有机物挥发的影响提供理论依据。研究结果表明：在试验条件下,乐果水溶液在水-气界面的恒温挥发过程符合一级动力学,并且其挥发行为受到表面活性剂的影响作用显著。不同浓度的表面活性剂对乐果挥发的影响不同,与未加入表面活性剂时乐果的挥发情况相比,当加入的SDBS浓度小于临界胶束浓度（CMC）时对乐果的挥发具有促进作用;当SDBS浓度超过CMC,乐果的挥发行为受到抑制,挥发速率开始变小。     

化学强化洗脱修复硫化铜矿区周边农田污染土壤中的铅锰

研究了非离子型表面活性剂辛烷基苯酚聚氧乙烯醚(Triton X-100)、聚氧乙烯失水山梨糖醇单油酸酯(Tween-80)与螯合剂二乙三胺五醋酸(DTPA)强化洗脱污染土壤中的铅和锰。单一洗脱实验结果表明,当DTPA浓度为26.7 mmol L-1时,DTPA对污染区的供试土壤中铅的去除率达到52.49%,锰的去除率达到21.94%;而Triton X-100和Tween-80单独洗脱时对铅锰的洗脱效果不佳,洗脱率均小于3%。复配洗脱实验结果表明,DTPA的浓度较低时,Triton X-100和Tween-80对DTPA洗脱重金属铅的作用表现为协同增溶。当DTPA浓度为3.3 mmol L-1时,当Triton X-100与DTPA复配时,污染土壤中铅的去除率由2.68%增加到83.35%;当Tween-80与DTPA复配时,污染土壤中铅的去除率由2.68%增加到24.72%。但当DTPA的浓度为6.7mmolL-1时,加入Triton X-100或Tween-80抑制了DTPA对铅的洗脱,表现为拮抗作用。Triton X-100、Tween-80分别与DTPA复配实验结果表明,Triton X-100和Tween-80不适合与DTPA复配洗脱供试土样中的锰。     

吐温类表面活性剂在黑龙江黑土中的吸附特性研究

采用平衡振荡法,研究黑龙江黑土对吐温类非离子表面活性剂(Tween20、Tween40、Tween60和Tween80)的吸附特征及影响因素。结果表明,在试验浓度范围内,吐温类表面活性剂在黑土上的吸附随着平衡质量浓度的增加而增加;各表面活性剂的吸附等温线均呈"S"型,可用Freundlich吸附模型来描述;在同一平衡质量浓度下,Tween20和Tween40在黑土中的吸附量高于Tween60和Tween80的吸附量;有机质含量高的土壤S1对表面活性剂吸附能力高于有机质含量低的土壤S2。通过H2O2氧化去除黑土中的有机质后,对表面活性剂的吸附量与原土相比变化不大,表明土壤矿物质和有机质都是吸附表面活性剂的重要成分。黑土对Tween80的吸附量随着温度的增加而增加,但随着体系pH值的增加而呈现逐渐下降的趋势。     

阴/非表面活性剂对菲污染砂土柱淋洗研究

采用玻璃土柱法比较研究了1000、2000、3000和4000mg·L^-1的阴离子表面活性剂十二烷基苯磺酸钠（SDBS）、非离子表面活性剂聚氧乙烯山梨糖醇酐单油酸酯（Tween80）及不同质量配比的混合表面活性剂（SDBS-Tween80）（S∶T=1∶1、1∶2和1∶4）对砂土中菲的柱淋洗。结果表明,SDBS对菲的淋洗曲线总体上呈现先上升到峰值而后下降的变化规律,且呈锯齿形波动;而Tween80与SDBS-Tween80对菲的淋洗曲线具有相似的规律,即淋出液中菲浓度随表面活性剂淋洗液孔隙体积数增大呈现急剧增大、达到峰值后逐渐降低的趋势。淋洗结束时（菲流出浓度接近于0时）,不同浓度的Tween80和SDBS-Tween80对菲的总去除率均可达90.5%以上,而4000mg·L^-1的SDBS对菲的总去除率则仅为76.4%。此外,随着Tween80或SDBS-Tween80浓度增大,菲浓度峰值增大,开始有菲淋出时,菲浓度峰值以及菲流出浓度接近于0时对应的孔隙体积数均减小。菲浓度峰值与表面活性剂浓度呈正相关,累积孔隙体积数与表面活性剂浓度呈负相关。在淋出液累计孔隙体积数相同时,同种表面活性剂对菲的去除率与表面活性剂浓度呈正相关。     

表面活性剂对老化土壤中PAHs的生物有效性的影响

采用聚2,6-二苯基对苯醚(poly(2,6-diphenyl-p-phenylene oxide),Tenax-TA)提取和蚯蚓(Eisenia Fetida)富集实验研究曲拉通-100(聚乙二醇辛基苯基醚,Triton X-100)、吐温-80(聚氧乙烯脱水山梨醇油酸酯,Tween-80)和羟丙基-β环糊精(HPCD)表面活性剂对老化农田土壤中多环芳烃(PAHs)可提取组分以及生物有效性的影响。结果显示,表面活性剂可以显著增加PAHs的可提取性和在蚯蚓体内的蓄积浓度;和对照相比,增加可提取性42.3%~269%,蚯蚓体内的蓄积量增加10%~340%。研究表明在使用表面活性剂进行土壤修复时老化PAHs类污染物可能重新释放到环境中并带来环境风险。     

p,p′-DDT在黄河兰州段沉积物上的吸附/解吸特性及影响因素研究

采用批量平衡实验,研究了黄河兰州段沉积物对p,p′-DDT的吸附/解吸特性,并考察了环境因素温度、pH值、沉积物粒度等对吸附的影响。结果表明,p,p′-DDT在黄河兰州段沉积物上的吸附在24h内可以充分达到平衡。吸附过程是非线性的,Freundlich模型可以较好地描述吸附行为,分配作用和表面吸附作用同时存在;解吸过程存在明显滞后性,即解吸要比吸附困难。正交结果表明吸附质浓度和吸附剂浓度对p,p′-DDT在沉积物上的吸附量有显著影响,而温度、pH值、有机质含量、沉积物粒度影响不显著。     

麦麸酯酶对有机磷及氨基甲酸酯类农药敏感性研究

为探讨麦麸酯酶在农残快速检测中应用的可行性,通过比色法研究了酶抑制法检测农残时表面活性剂对固蓝B盐显色体系的增敏作用及麦麸酯酶对乐果、敌敌畏、叶蝉联、西维因、丁硫克百威和甲基对硫磷等6种农药的灵敏度和最低检测限。结果表明,阴离子表面活性剂SDS在麦麸酯酶活性测定中具有增敏作用,当浓度为4.0%时可使显色体系相对吸光度值增加152.76%;叶蝉散对麦麸酯酶的最佳抑制时间为40min,其余5种农药均为30min。麦麸酯酶对6种农药的灵敏度大小顺序为:敌敌畏叶蝉散西维因甲基对硫磷丁硫克百威乐果,IC_(50)分别为0.136、0.375、0.641、1.366、2.361、2.651mg·L~(-1)。经溴水氧化的甲基对硫磷对麦麸酯酶的敏感性显著提高,其IC_(50)值达0.089mg·L~(-1)。综上所述,麦麸酯酶在快速检测有机磷及氨基甲酸酯类农药方面具有较高的灵敏度,且来源广泛,可满足酶抑制法用酶需要。本研究丰富了麦麸酯酶在农药残留快速检测中的应用。     

苏州河网区河道沉积物磷的吸附释放特征研究

研究了苏州河网区河道沉积物磷的吸附和释放行为,分析了沉积物的理化性质对磷吸附释放特征的影响,并探讨了其与上覆水水质的关系.结果表明,沉积物磷的饱和吸附量为191.1～771. 6 mg/kg,吸附能力强,但不同沉积物差异大;磷平衡浓度(EPC0)变化范围为0.013～0.183 mg/L,自然条件下沉积物对上覆水富营养化的发生起到了缓解作用;本底吸附磷(NAP)值范围为12.43～215.3 mg/kg,河道沉积物上自带的可解吸磷含量高;沉积物磷的吸附与释放过程均包括两个阶段,即前2 h为快速吸附或释放,10 h后,基本达到一种动态平衡;各因子相关性分析显示:沉积物中无机磷和铝含量是控制磷吸附与释放参数的最主要物理化学因子,磷的吸附与释放参数与CEC、有机质、粒度、铁铝等相关性不显著,可能是由研究对象本身的特点所决定,沉积物磷的吸附与释放是多个因素综合作用的结果.     

多源沉积物对地表水中磷铜锌浓度的影响

受多来源沉积物污染影响的水体中可溶性P,Cu,Zn实际浓度常明显低于按各自沉积物的比例与释放量计算的理论值。沉积物之间的性质差异越大,实际测定值与计算值之间的差异也越大。多来源沉积物水体中可溶性P,Cu,Zn的浓度主要受P,Cu,Zn释放能力最强或对P,Cu,Zn吸持能力最强的沉积物比例控制。     

天鹅湖沉积物对磷的吸附动力学及等温吸附特征

以荣成天鹅湖这一天然泻湖为研究对象,研究了6个样点沉积物对磷的吸附动力学曲线和等温吸附方程,并分析了沉积物理化性质与磷吸附参数间的关系.结果表明,天鹅湖不同区域沉积物对磷的吸附动力学均符合二级动力学方程,吸附反应主要在前10h内完成,且0～2h内反应迅速.根据Langmuir模型,6个样点沉积物对磷的理论吸附容量(Qmax)的范围为294.12～1 111.11 mg/kg,其中湖区北部和中部沉积物的吸附能力高于南部.沉积物对水体中磷的吸附解吸平衡浓度(EPC0)的变幅为0.002 ～ 0.033 mg/L,其与沉积物本底吸附态磷(NAP)呈较弱的正相关关系.本研究条件下,大部分样点的EPC0小于上覆水中磷的浓度,其中湖区西北部和东南部沉积物中磷具有向上覆水体释放的趋势.沉积物的NAP与总氮、有机质、活性铝和黏粒间均呈显著正相关,Qmax与铁铝结合态磷、有机质、活性铝和粉粒间呈显著的正相关关系.活性铝、有机质和粒度是影响沉积物磷吸附的主要因素.     

Effects of sediment components and TiO2 nanoparticles on perfluorooctane sulfonate adsorption properties

Purpose

Here, the roles of sediment components in perfluorooctane sulfonate (PFOS) adsorption onto aquatic sediments and relevant adsorption mechanisms were investigated in terms of adsorption isotherms and influences of TiO₂ nanoparticles (NPs) contamination.

Materials and methods

Due to the complexity of the sediments, instead of randomly selecting different component sediments, the selective dissolution method was used to better explore the effects of sediment compositions, such as sediment organic matter (SOM) and ferric oxides (dithionite–citrate–bicarbonate [DCB] Fe), and TiO₂ NPs pollution on PFOS adsorption. Mathematical equations (Freundlich, Langmuir, and Temkin) were used to describe the adsorption behavior of PFOS on different sediments and adsorption mechanisms of multiple pollutant interactions. Moreover, the characterization methods of zeta potential, nitrogen (N₂) adsorption–desorption, and scanning electron microscopy (SEM) analysis, as well as Fourier transform infrared (FT-IR) spectroscopy, explained effects of the sediment components and TiO₂ NPs on PFOS adsorption properties in view of physicochemical theories.

Results and discussion

The adsorption isotherms of PFOS on six tested sediments were all nonlinear (Freundlich model, R² = 0.992~1.000). The Freundlich sorption affinities (K_F) of PFOS on S (original sediments), S1 (sediment organic matter (SOM)-removed S), and S2 (ferric oxides (DCB Fe)-removed S1) were 0.232, 0.179, and 0.120, respectively. Both SOM and DCB Fe influenced the physicochemical properties of the sediments, e.g., zeta potential, specific surface area, and permanent negative charge. The addition of TiO₂ NPs increased the K_F of PFOS for S, S1, and S2 by approximately 9.9%, 14.5%, and 26.7%, respectively, by increasing the zeta potential and specific surface area (S_BET, S_ext, and S_micro) and by changing the water and oil properties of the three sediments. However, the addition of TiO₂ NPs decreased the linearity of the sorption isotherm (1/n). FT-IR spectroscopy showed that hydrophobicity, ion exchange, surface complexation, and hydrogen bonding interactions (non-fingerprint region) could all play a role in PFOS sorption onto tested sediments. However, the hypothesis of hydrogen bonding to promote PFOS adsorption on sediment layer silicates (fingerprint region) should be studied further.

Conclusions

The content of both SOM and DCB Fe affected the physicochemical properties of sediment. Both SOM and DCB Fe showed a positive relationship with sorption of PFOS on sediment. The addition of TiO₂ NPs increased PFOS sorption by altering the sediment surface properties. Hydrophobic interactions certainly impelled and ligand and ion exchange and hydrogen bonding (non-fingerprint region) could promote PFOS sorption on the sediments.

     

Surfactant Enhanced Desorption of TNT from Soil

Surfactant enhanced desorption of 2,4,6-trinitrotoluene (TNT) from contaminated soils at a military site was investigated. Anionic (SDS and DOWFAX 8390), cationic (CTAC and CTAB), and nonionic (Tween 80 and Brij 35) surfactants were first tested at concentrations ranging from 0.1 to 1%. The anionic and nonionic surfactants were further tested at concentrations of up to 10%. Anionic surfactants, particularly SDS, provided the best desorption of TNT from the soil. There was not any increase in TNT desorption for both the nonionics and cationics at concentrations ranging between 0.1 to 1% and the extent of desorption was found to be lower than the TNT desorption only by water. The competition of the negatively charged soil surfaces for the positively charged cationics and the neutral nonionic surfactants may constitute the underlying reason. TNT was significantly desorbed when the concentrations of Tween 80, DOWFAX 80 and SDS were increased up to 10%.     

Adsorption of Bisphenol A on Sediments in the Yellow River

Bisphenol A is widely used for the production of epoxy resins and polycarbonate plastics, and it has been found in many wastewaters or surface waters. Adsorption of bisphenol A on sediments sampled from several representative hydrologic stations of the Yellow River was studied, and some factors that may affect the sorption of bisphenol A were analyzed using the LC-MS/MS following solid-phase extraction. The results show that neither linear nor Freundlich isotherms is fit to the experimental data due to the high carbonate content in sediments. Bisphenol A has greater adsorption after the elimination of the carbonate in the sediment, and the adsorption of bisphenol A on the treated sediment can be described by both the linear and the Freundlich isotherms. The adsorption amount of bisphenol A is related to both the total organic carbon and dissolved organic carbon of sediments. The effects of Ca^{2 +} and K⁺ on the adsorption of bisphenol A were also studied. It is found that Ca²⁺ and K⁺ showed different effects on the adsorption of bisphenol A because of their different valences.     

Picric Acid Degradation in Sediments from the Louisiana Army Ammunition Plant

Picric acid is an explosive historically produced and disposed at the Louisiana Army Ammunition Plant (LAAP) in northern Louisiana. The potential for natural degradation of picric acid was investigated by creating picric-acid slurries with four LAAP sediments of variable composition and monitoring for up to 98 days. The concentrations of picric acid decreased rapidly in all slurries during the first day, attributed to adsorption, followed by slower decreases in some samples due to degradation. Degradation in unsterilized slurries was nearly complete within 80 days for two of the four sediments. Increases in nitrite and nitrate concentration over time were proportional to the loss of picric acid and indicate that at least two of the three nitrite groups were removed from the picric acid molecule. The absence of significant concentrations of compounds with a mass greater than 100 amu in the final solutions suggests that all three nitrite groups were removed. No correlation was found between the degree of degradation and grain size, clay content, organic content, carbonate content, or a suite of element concentrations in the sediment. Degradation in sterilized samples was minimal for all sediment slurries, indicating microbial activity as the primary mechanism of degradation.     

荣成天鹅湖湿地沉积物对磷的吸附特征及影响因子分析

在荣成天鹅湖湿地的典型区域选取代表性样点,研究表层沉积物对水体中磷的吸附特征,并分析了环境因子、沉积物组成对磷吸附的影响.结果表明,当上覆水中磷浓度低于0.40 mg/L时,沉积物对磷的吸附量很低或呈负吸附状态;在高磷浓度条件下,等温吸附曲线可用改进的Langmuir模型来很好地拟合.本研究条件下湿地沉积物对磷的吸附容量(Q_(max))变幅为181.8～1 000.0 mg/kg.临界磷平衡浓度(EPC_0)变化在0.043～0.479 mg/L之间.沉积物对磷的最大吸附量与其本身的理化性质关系密切,主要影响因素为粘粒含量和粘土矿物种类,氧化铁铝和有机质含量起次要作用.环境因子对磷吸附的影响作用明显,各因子的影响顺序为:扰动>温度、盐度>pH.不同区域相比,湿地北部沉积物的吸附能力远高于南部砂质土.且后者的吸附特性更易受到环境因子的影响.     

湖泊沉积物中水溶性有机质对吸附磷的影响

以分别属于不同营养水平的五里湖和东太湖沉积物为研究对象,通过吸附试验,研究了水溶性有机质(DOM)对沉积物吸附磷酸盐等温线和动力学曲线的影响。结果表明:(1)DOM没有改变沉积物吸附磷动力学曲线的基本趋势,在前10 h内,沉积物对磷的吸附具有较大速度,20 h后基本达到吸附平衡;DOM提高了沉积物吸附磷的速度,特别是提高了0-0.5 h内的吸附速度,其中东太湖沉积物由82.34 mg kg-1h-1增加到97.18 mg kg-1 h-1,五里湖沉积物由12.21 mg kg-1h-1增加到59.17 mg kg-1h-1;(2)DOM明显改变了沉积物吸附磷等温线,对沉积物吸附磷具有促进作用,提高了沉积物吸附磷的效率,其中东太湖沉积物,DOM使其对磷的吸附效率由123.3 L kg-1增加到164.8 L kg-1,五里湖沉积物,DOM使其对磷的吸附效率由94.56 L kg-1增加到206.3 L kg-1;(3)DOM对有机质含量较高、严重污染的五里湖沉积物吸附磷的影响大于对有机质含量较低、中营养水平的东太湖沉积物的影响。     

土壤/沉积物中天然有机质对疏水性有机污染物的吸附作用

通过对土壤/沉积物中天然有机质的组成分析,阐述了天然有机物在吸附疏水性有机污染物过程中所起的重要作用,其中包括可溶性有机质的增溶作用和不溶性有机质的吸附作用。本文着重探讨了天然有机质结构的异质性对吸附作用的影响,导致吸附等温线的非线性,从而从土壤/沉积物有机质的微观结构上进一步解释了非线性吸附机理。