颗粒物对乐果的吸附特征

研究了颗粒物（内蒙古土壤Y2、Y3、Y4和黄河水体表层沉积物Y1）对有机磷农药乐果的吸附规律,观察了颗粒物的性质如有机质、粘粒、CEC（阳离子交换量）和离子强度等因素对吸附行为的影响。结果表明,内蒙古4种颗粒物对乐果的吸附过程可用Freundlich等温式描述,吸附常数在1.4848～1.9550mL·g-1之间;影响颗粒物对乐果吸附的主要因素是CEC、离子强度和有机质,颗粒物对乐果的吸附量与颗粒物的CEC有着极显著的正相关关系,相关系数为0.9812,P〈0.01;随着离子强度的降低,4种颗粒物对乐果的吸附量增大;除黄河水体表层沉积物Y1外,颗粒物的有机质含量越高,对乐果的吸附能力就越强。     

有机酸作用下黄壤无机纳米微粒对Cd~(2+)吸附动力学特性

为探究有机酸对镉在纳米粒级土壤上的有效性及其形态的影响,基于超声—离心—冻融法,应用到四川省名山河流域老冲积黄壤中,获得纳米微粒(≤100 nm),分别研究不同分子量有机酸(柠檬酸、富里酸、EDTA)及其组合(柠檬酸+EDTA、柠檬酸+富里酸、富里酸+EDTA)对土壤纳米微粒吸附Cd~(2+)动力学特性的影响。结果表明,土壤纳米微粒对Cd~(2+)的动力学吸附量大小关系表现为:柠檬酸+EDTA富里酸柠檬酸+富里酸柠檬酸富里酸+EDTAEDTA。总的来看,EDTA的抑制作用最强,最能降低土壤纳米微粒对Cd~(2+)的吸附。     

河流渗滤系统中BTEX的吸附行为实验模拟研究

河流渗滤是一种自然净化过程,污染河水通过该过程在河流沉积层中发生物理、化学和生物作用,使得污染物浓度降低,入渗河水水质得到净化。为了研究BTEX污染河水通过河流渗滤系统时的吸附行为,进行了静态吸附模拟实验。结果表明BTEX 4种组分在3种河流沉积物样品中的吸附平衡均可以在48 h内完成。通过比较BTEX在3种不同河流沉积物样品中的吸附动力学曲线,可以发现BTEX在粉土中吸附速率最大,细砂中次之,粗砂中最小。BTEX在粉土和细砂中的吸附等温线符合Henry等温吸附方程,而在粗砂中符合Langmuir等温吸附方程。3种土壤中粉土和细砂具有较大的吸附容量,而粗砂吸附容量相对较小;粉土和细砂对苯的吸附能力最强,甲苯次之,乙苯和间二甲苯相对较小。从阻滞因子的计算结果来看,黄河花园口区采集的河流沉积物样品对BTEX各组分的迁移均具有较强的阻滞作用,在较高浓度范围内,河流渗滤系统能够通过吸附作用有效阻滞BTEX污染物,降低其对地下水的危害。     

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.     

广东主要母质发育水稻土对硅的吸附特性

Silicate adsorption in eight paddy soils developed from four different parent materials in Guangdong Province, China was examined to obtain fundamental knowledge of silicate adsorption to improve the efficacy of silicate fertilizer use in these areas. A correlation analysis showed that silicate adsorption did not obey the Langmuir equation （r = -0.664- 0.301） but did obey the Freundlich and Temkin equations （P〈0.01, r = 0.885-0.990）. When the equilibrium silicate concentration （Ci） was less than 45 mg SiO2 kg^-1, the adsorption capacity was in the following decreasing order of paddy soils： basalt-derived 〉 Pearl River Delta sediment-derived 〉 granite-derived 〉 sand-shale-derived. Stepwise regression and path analysis showed that for the investigated paddy soils amorphous MnO and Al2O3 were the two most important materials that affected silicate adsorption. Moreover, as Ci increased, amorphous Al2O3 tended to play a more important role in silicate adsorption, while the effects of amorphous MnO on silicate adsorption tended to decrease.     

土壤对铜的吸附-解吸特征及对土地利用的响应

用吸附平衡法研究黄河三角洲地区土壤对Cu2+的吸附和解吸特征,对比了农田和未利用地土壤吸附与解吸能力的差异,并分析了差异形成的原因。结果表明,土壤对Cu2+的吸附量随着平衡液Cu2+质量浓度的增加而增加,其吸附作用可用Langmuir,Temkin和Freundlich方程来拟合,以Langmuir方程拟合结果最佳。根据Langmuir方程计算出的两种土壤最大吸附量分别为3 961mg/kg和3 521mg/kg,农田土壤对Cu2+的吸附能力强于未利用地土壤;土壤Cu2+的解吸量远远小于土壤对Cu2+的吸附量,与农田土壤相比,未利用地土壤Cu2+的解吸有滞后现象;农田土壤和未利用地土壤Cu2+的解吸率变化范围分别为0.1%～0.35%和0.15%～1.8%,农田土壤的解吸率明显低于未利用地土壤。综合分析认为,两种土壤吸附—解吸特征的差异与农田土壤具有较高的有机质含量,从而在土壤胶体表面形成较多的吸附位点有关。     

Geochemistry of Coalbed Natural Gas (CBNG) Produced Water in Powder River Basin, Wyoming: Salinity and Sodicity

Extraction of natural gas from a confined coal aquifer requires the pumping of large amounts of groundwater, commonly referred to as produced water. Produced water from the extraction of coalbed natural gas is typically disposed into nearby constructed discharge ponds. The objective of this study was to collect produced water samples at outfalls and corresponding discharge ponds and monitor pH, electrical conductivity (EC), calcium (Ca), magnesium (Mg), sodium (Na), and alkalinity. Outfalls and corresponding discharge ponds were sampled from five different watersheds including Cheyenne River (CHR), Belle Fourche River (BFR), Little Powder River (LPR), Powder River (PR), and Tongue River (TR) within the Powder River Basin (PRB), Wyoming from 2003 to 2005. From Na, Ca, and Mg measurements, sodium adsorption ratios (SAR) were calculated, and used in a regression model. Results suggest that outfalls are chemically different from corresponding discharge ponds. Sodium, alkalinity, and pH all tend to increase, possibly due to environmental factors such as evaporation, while Ca decreased from outfalls to associated discharge ponds due to calcite precipitation. Watersheds examined in this study were chemically different form each other and most discharge ponds with in individual watersheds tended to increase in Na and SAR from 2003 to 2005. Since discharge pond water was chemically changing as a function of watershed chemistry, we predicted SAR of discharge pond water using a regression model. The predicted discharge pond water results suggested a high correlation (R ²?=?0.83) to discharge well SAR. Overall, results of this study will be useful for landowners, water quality managers, and industry in properly managing produced water from the natural gas extraction.     

Adsorption of 3H-Labeled 17-β Estradiol on Powdered Activated Carbon

Three source waters, two model waters (Ultrapure (natural organic matter (NOM)-free)) water and Suwannee River NOM isolate by reverse osmosis (SR-NOM)) and a natural water (Colorado River water (CRW)), were tested. Those waters were selected to represent a relatively hydrophobic NOM (SR-NOM) and a relatively hydrophilic NOM (CRW) based on their specific ultraviolet absorbance (SUVA = UVA₂₅₄/DOC) values. The adsorption of an estrogenic compound, 17β-estradiol (E2), on powdered activated carbons (PACs) was investigated. Kinetic and PAC dose-response experiments were performed with PACs at an initial concentration of 0.1 nM (27 ng L^?1). Additional experiments were also performed at various initial concentrations ranging from 0.025 nM (6.8 ng L^?1) to 5.0 nM (1360 ng L^?1) to determine the effects of initial concentration on E2 adsorption. In separate experiments, 17β-estradiol was introduced to PAC as a pure component, in binary mixtures with other salts (NaCl, Na₂SO₄, and CaCl₂), and under varying pH conditions (4.0, 7.5, and 11.0) to determine the effects of pH and background ions on E2 adsorption. Samples were measured by liquid scintillation counting using ³H radio-labeled E2. Without preconcentration, a method detection limit using the liquid scintillation counter was 0.005 nM (1.36 ng L^?1), respectively. Increasing contact time and PAC dose improved compound removal. Activated carbon is a viable technology for water treatment plants.     

生物质炭施用及老化对石灰性紫色土中磺胺类抗生素迁移特征的影响

以长江上游低山丘陵区广泛分布的石灰性紫色土旱地的耕作层土壤为对象,采用室内批量平衡吸附试验和填装土柱穿透试验,研究了施用1%生物质炭及3年老化作用对2种磺胺类抗生素(磺胺嘧啶和磺胺二甲基嘧啶)吸附和迁移特征的影响。结果表明,Freundlich方程能更好地拟合抗生素在土壤中的等温吸附曲线,施用生物质炭提高了土壤对抗生素的吸附能力,吸附常数KF值依次为:老化1%施炭土新鲜1%施炭土对照土;土柱出流液的磺胺嘧啶和磺胺二甲基嘧啶相对浓度峰值均表现为:老化1%施炭土新鲜1%施炭土对照土,说明生物质炭的添加能有效减少控制紫色土中抗生素的淋失迁移,以对磺胺二甲基嘧啶的阻控效果较好;生物质炭老化3 a后土壤对抗生素的吸附作用与阻控效果均有所提高,主要归因于土壤pH的提高。     

名山河流域黄壤组分对微团聚体吸附解吸镉的影响

选取名山河流域4种土地利用方式（林地、水田、茶园、旱地）的黄壤为研究对象,采用平衡液等温吸附法和NH4OAC、EDTA溶液解吸法,研究土壤组分（有机质、游离氧化铁）对微团聚体吸附解吸Cd2＋的影响。结果表明：去除土壤组分前后,原土及各粒径微团聚体对Cd2＋的吸附量均随Cd2＋初始浓度增大而增大,吸附量均按以下次序递减：（〈0.002mm）〉2～0.25mm〉原土〉0.053～0.002mm〉0.25～0.053mm,与有机质、游离氧化铁、CEC呈极显著正相关。吸附减少量大小关系为：去除有机质〉去除游离氧化铁,有机质的贡献率大于游离氧化铁。Freundlich方程拟合效果最佳,达到极显著水平,分布系数Kd值与Cd2＋初始浓度呈曲线负相关。NH4OAC解吸率随原吸附Cd2＋初始浓度增大而增大,以最大解吸率计,递减规律为：0.25～0.053mm〉0.053～0.002mm〉原土〉2～0.25mm〉（〈0.002mm）;EDTA解吸率随原吸附Cd2＋初始浓度增大而减小,递减规律与NH4OAC解吸率相反。去除土壤组分后,NH4OAC解吸率上升,EDTA解吸率下降,茶园与旱地黄壤非解吸率减小,林地与水田黄壤非解吸率增大。去除土壤组分后,非专性吸附与吸附总量呈极显著正相关,专性吸附与吸附总量呈极显著负相关。     

土壤改良剂对黄河三角洲滨海盐碱土的改良效应

采用牛粪(A)、石膏(B)、秸秆(C)、保水剂(D)4种改良剂,通过4因素4水平正交设计方案,对黄河三角洲滨海盐碱土进行土壤改良试验,筛选出较好的改良方案,为黄河三角洲盐碱土的改良利用提供理论依据。研究结果表明:土壤pH和钠吸附比(SAR)随着改良时间增加呈下降趋势,土壤有机质、有效氮、有效磷、有效钾呈上升趋势;4种改良剂对盐碱土改良指标的贡献值存在差异,综合考虑最佳配方为A4B4C1D4,其土壤有机质、有效氮、有效磷、有效钾含量分别比对照增高113.93%,1 014.23%,828.32%,265.45%;其土壤pH和SAR比对照分别下降4.71%,33.37%。     

Classification of five pedons near Afgoi,Somalia

Five pedons representing the major soils on the Central Agricultural Research Station located on the Shabelle River floodplain near Afgoi (Somalia) were described and sampled. The samples were analyzed for particle-size distribution, pH, calcium carbonate equivalent, electrical conductivity and sodium adsorption ratio. According to Soil Taxonomy, three pedons were classified as Udic Chromusterts, very fine, isohyperthermic; one as a Udic Chromustert, fine isohyperthermic; and one as a Typic Ustifluvent, fine-loamy isohyperthermic. Four of the pedons were classified as Chromic Vertisols and the fifth as a Calearic Fluvisol according to legend of the FAO-Unesco soil map of the world.     

黄河三角洲柽柳周边土壤钠吸附比分布特征及影响因素分析

  目的  黄河三角洲是极具特色的滨海盐生湿地,为探究该区域关键木本植物柽柳周围土壤钠吸附的特征及其影响因素。  方法  运用同心圆布点采样和相关分析等方法,对黄河三角洲柽柳周边土壤盐分离子、钠吸附比的空间分布及离子相互关系进行了分析。  结果  Cl?和Na+是柽柳周边土壤盐分构成的主要离子。Na+、Cl?和Mg2+在距离柽柳较近的表层土壤中含量较少,其含量随土壤深度增加而上升,呈现底聚现象,在距离柽柳较远的土壤中呈现表聚现象。Ca2+、SO₄2?和K+的表聚现象不受距离柽柳远近的影响。相关分析表明,柽柳周边土壤钠吸附比与Cl?、Na+、K+和Mg2+离子关系密切,与Na+的相关性最强。在0 ~ 40 cm土层中,距离柽柳100 cm以内的钠吸附比远低于150 cm以外区域。钠吸附比的变异系数随土层加深而减小,深层土壤钠吸附比与盐离子的相关性均不显著。  结论  柽柳对钠吸附比的影响在100 cm以内的0 ~ 40 cm土层中更为显著。土壤盐分与钠吸附比的空间分布受柽柳冠幅范围、植物根系吸收、凋落物堆积和降水淋溶等作用的影响。     

Competitive adsorption between phosphate and carboxylic acids: quantitative effects and molecular mechanisms

The competitive adsorption at the water‐goethite interface between phosphate and a carboxylic acid, either oxalate, citrate, 1,2,3,4‐butanetetracarboxylic acid (BTCA), mellitate or Suwannee River Standard Fulvic Acid 1S101F (FA), was investigated over a wide pH range (3–9) by means of batch experiments and attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy. The quantitative results from the competitive adsorption measurements show that the efficiency of the organic acids in competing with phosphate was in the order oxalate < citrate < BTCA ≅ FA < mellitate. Oxalate showed no detectable effect, whereas the effect in the mellitate system was strong, and the aggregative results indicate that an increasing number of carboxylic groups favours competitive ability towards phosphate. The infrared spectroscopic results show conclusively that competition for goethite surface sites between carboxylic acids and phosphate is not a ligand‐exchange reaction between inner‐sphere surface complexes. Instead, ligands capable of multiple H‐bonding interactions are required to out‐compete and desorb surface complexes of phosphate. The fact that partially protonated organic acids are the most efficient emphasizes the importance of both H‐accepting carboxylate groups and H‐donating carboxylic acid groups for the competitive effect.     

Use of Biopolymeric Membranes for Adsorption of Paraquat Herbicide from Water

The use of membranes prepared with alginate and chitosan to adsorb paraquat aqueous solution was evaluated as a potential alternative technique for remediation of contaminated water. Production of bilayer membranes was based on the electrostatic interaction between alginate (a polyanion) and chitosan (a polycation). Herbicide adsorption experiments were performed using three different membranes, consisting of pure alginate, pure chitosan, and a chitosan/alginate bilayer. Adsorption was characterized using the Langmuir and Freundlich isotherm models, as well as by applying pseudo-first order and pseudo-second order kinetic models. The potential use of the membranes in environmental applications was evaluated using water collected from the Sorocabinha River in S?o Paulo State, Brazil. The results indicated that interactions between the membranes and the herbicide were strongly related to the type of biopolymer and the physical?Cchemical characteristics of the herbicide.     

Effect of surface heterogeneity on phosphorus adsorption onto mineral particles: experiments and modeling

Purpose

Adsorptive interaction at the solid-water interface plays an important role in the fate and behavior of phosphorus (P) in rivers and lakes and the resulting eutrophication. This study aims to investigate the contributions of heterogeneous morphology to P adsorption onto mineral particles.

Materials and methods

The dominant minerals in Yellow River sediment, quartz, k-feldspar, and calcite are investigated with adsorption experiments and microscopic examinations. Taylor expansion is applied to quantitatively characterize the heterogeneous surface morphology.

Results and discussion

The results reveal that locally concave or convex micro-morphology characterized by the second derivative term of the Taylor expansion, F ₂, can be related to adsorption capacity due to its effect on surface-charge density and distribution. The distribution of adsorbed P as a function of F ₂ was determined for selected particles composed of each of the pure minerals and was fit to a Weibull distribution. Each mineral was characterized by F _2a , the weighted average value of F ₂, and Weibull distribution factors, and correlated with sorption isotherms. The developed relationships were used to accurately predict adsorption onto individual particles as well as pure mineral samples.

Conclusions

Mineral particles have complex surface morphology, which affects the interface P adsorption. Micro-morphological characterization of F ₂ and F _2a can be used to predict adsorption onto the pure minerals, and this study provides physical basis for predicting adsorption on sediment particles composed of these minerals.

     

Mobilization Potential of Heavy Metals: A Comparison Between River and Lake Sediments

Toxic metals introduced into aquatic environments by human activities accumulation in sediments. A common notion is that the association of metals with acid volatile sulfides (AVS) affords a mechanism for partitioning metals from water to solid phase, thereby reducing biological availability. However, variation in environmental conditions can mobilize the sediment-bound metal and result in adverse environmental impacts. The AVS levels and the effect of AVS on the fate of Cu, Cd, Zn, Ni in sediments in the the Changjiang River, a suboxic river with sandy bottom sediment and the Donghu Lake, a anoxic lake with muddy sediment in China, were compared through aeration, static adsorption and release experiments in laboratory. Sips isotherm equation, kinetic equation and grade ion exchange theory were used to describe the heavy metal adsorb and release process. The results showed that AVS level in the lake sediment are higher than that of the river. Heavy metals in the overlying water can transfer to sediments incessantly as long as the sediment remains undisturbed. The metal release process is mainly related to AVS oxidation in lake sediment while also related to Org-C and Fe–Mn oxyhydroxide oxidation in river sediment. The effect of sulfides on Zn and Ni is high, followed by Cd, and Cu is easy bound to Org-C. AVS plays a major role in controlling metals activity in lake sediment and its presence increase the adsorption capacity both of the lake and river sediments.     

Effects of Coal-Bed Methane Discharge Waters on the Vegetation and Soil Ecosystem in Powder River Basin, Wyoming

Coal-bed methane (CBM) co-produced discharge waters in the Powder River Basin of Wyoming, resulting from extraction of methane from coal seams, have become a priority for chemical, hydrological and biological research during the last few years. Soil and vegetation samples were taken from affected and reference sites (upland elevations and wetted gully) in Juniper Draw to investigate the effects of CBM discharge waters on soil physical and chemical properties and on native and introduced vegetation density and diversity. Results indicate an increase of salinity and sodicity within local soil ecosystems at sites directly exposed to CBM discharge waters. Elevated concentrations of sodium in the soil are correlated with consistent exposure to CBM waters. Clay-loam soils in the study area have a much larger specific surface area than the sandy soils and facilitate a greater sodium adsorption. However, there was no significant relation between increasing water sodium adsorption ratio (SAR) values and increasing sediment SAR values downstream; however, soils exposed to the CBM water ranged from the moderate to severe SAR hazard index. Native vegetation species density was highest at the reference (upland and gully) and CBM affected upland sites. The affected gully had the greatest percent composition of introduced vegetation species. Salt-tolerant species had the greatest richness at the affected gully, implying a potential threat of invasion and competition to established native vegetation. These findings suggest that CBM waters could affect agricultural production operations and long-term water quality.     

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。     

人工布设基质对农田排水沟水质的影响

本研究选择宁夏灵武农场的典型排水支沟进行人工布设基质,在沟中布设土壤、炉渣、秸秆、锯末4种基质处理及铲草处理和对照(不做任何处理),研究分析了基质对农田排水沟水质的影响。对基质的组分分析表明,锯末显著地吸附盐分和全氮,吸附量分别达0.4 g.kg 1和0.3 g.kg 1,土壤、炉渣、秸秆均明显地释放盐分,释放量为5.3~50.8 g.kg 1;秸秆显著地释放有机碳,释放量达54.0 g.kg 1;4种基质对全磷吸附效果不明显。水质分析表明,除秸秆处理和对照外,盐分(TDS)在其他处理下显著减少,而化学需氧量(COD)、总氮(TN)、总磷(TP)、NO3-N和NH4+-N浓度在锯末和土壤处理下均有不同程度的减小。对于整条试验沟道,农田退水中TDS、TN、TP的浓度随着在沟道迁移距离的增加呈明显减小的趋势,至出水断面时浓度分别为0.60~0.80g.L 1、0.24~0.33 mg.L 1和0.04~0.09 mg.L 1。田间沟道试验说明,农田排水沟能有效地截留农田退水污染物,选择适合的基质进行人工布设实际可行,有助于发挥农田排水沟的生态功能。