印染生化物化尾水反渗透回收特性

利用反渗透对印染生化物化尾水进行回收,考察了分离浓缩过程中,浓缩液和透过液水质随体积浓缩倍数(CF)变化情况,探讨印染生化物化处理尾水反渗透回收机制。研究结果表明,分离浓缩过程中,通量随CF的增加呈线性下降,CF为5时,降低了32.6%。透过液中COD未检出,浓缩液COD与CF呈近似线性关系。Na+、K+、Ca2+和Mg2+富集倍数随CF线性上升,但在高倍数下增大幅度反而降低;Fe、Mn和Al富集情况与主要无机阳离子相似,但程度略低。Cl-和SO2-4基本富集在浓缩液中,NO-3和NO-2也得到较好的富集,但截留率略低。透过液中无机离子主要为Na+和Cl-。     

兰州市冬季细颗粒中微量金属元素及无机可溶性离子来源分析

通过对兰州市区4个在线大气监测点冬季细颗粒成分进行测定,测得微量金属元素和无机可溶性离子分别占细颗粒浓度的1%、52%。微量金属元素中Pb的检出量最高,占本文所测微量金属元素总含量的39.3%;无机可溶性离子含量最高的是SO2-4,其次为NO-3、Na+,分别占本文所测9种无机可溶性离子的23.3%、20.5%和19.7%。采用富集因子法与因子分析法对微量金属元素来源进行分析,结果表明,微量金属元素的来源为燃煤源、风沙土壤源、金属加工,燃煤源成因率最高,为61.2%;采用因子分析法对无机可溶性离子来源进行分析,结果表明,无机可溶性离子的来源为二次转化、人为排放、土壤源(包括风沙土壤尘和道路扬尘),土壤源成因率最高,为49.5%。     

氮磷在水稻土不同发生层中的穿透性研究

为了解氮磷在不同类型水稻土发生层中的迁移特性,从浙江省宁波市和湖州市采集了27个水稻土主要发生层的原状土柱,通过饱和稳定流土柱运移试验,测定了氮和磷在不同发生层中的运移穿透曲线,用平均穿透点评估了NO-3-N、NH 4-N和PO3-4-P在各发生层中的穿透性.结果表明,氮和磷在各发生层中的穿透能力依次为:NO-3-N>NH 4-N>PO3-4-P;NO-3-N在各发生层中的穿透能力依次为:漂洗层(E层)>渗育层(P层)>表土层(A层)>腐泥层(M层)>潴育层(W层)>潜育层(G层)>犁底层(Ap层),NO-3-N的穿透能力主要与土壤饱和导水率有关,随饱和导水率增加而增强;NH 4-N穿透能力依次为:E层>P层>A层>W层>M层>Ap层>G层,NH 4-N穿透能力主要与饱和导水率和粘粒有关,迁移受粘粒明显阻滞;PO3-4-P穿透能力依次为:E层>W层>P层>M层>A层、Ap层>G层,PO3-4-P穿透能力主要受氧化铁等氧化物和粘粒的阻滞.     

改性活性炭对甲胺恶臭气体吸附研究

甲胺作为一种具有代表性的胺类恶臭气体,是工业中常见的原料与中间体,广泛存在于污水处理过程中。其嗅阈值为0.021mg/m3,稳定且难以生化降解,会影响人体健康。同时,居民区人口密集,工业区与市政设施在部分地区距离居民区较近,因此甲胺是急需治理的大气污染物之一。以方便高效且应用性强的氧化方式对活性炭进行改性并应用于气态甲胺处理。当达到穿透点(出口质量浓度为5mg/m3,穿透率约2%)时,HNO3改性活性炭最高穿透吸附量为517.30mg/g,是原始活性炭的45.7倍。通过对比改性前后活性炭的表面特征,并用吸附动力学数据研究了甲胺的吸附特性,表明甲胺在HNO3改性活性炭上的吸附是物理吸附和化学吸附的结合。当接近平衡时,吸附速率通过颗粒内扩散来控制。     

降雨促渗对地表径流污染物负荷影响模拟试验研究

建立模拟降雨装置，研究降雨条件下功能性材料与聚合物对降水土壤渗透性与地表径流污染负荷的影响。研究证实，沸石与PAM不仅能够促进降雨土壤水的人渗、延缓并减少地表径流．而且使土壤渗液和地表径流水质TSS、TN、TP、COD污染物负荷降低。以3kg／hm^2PAM、3kgPAM与7．5t／hm^2沸石、6kg／hm^2 PAM3种方式处理，径流COD负荷为对照的39．12％-69．76％、26．14％-46．63％和20．60％-28.09％；TN、TP与TSS负荷较对照分别减少44．36％-96．47％、66．63％-98．99％、93．71％-99．62％和50．46％～98．40％、83．30％～99．3l％、94．91％～99．72％和31．06％～77．23％、46．82％，86．22％、83．54％-95.33％。聚合物与功能性材料改良土壤是一种削减地袁降雨径流非点源污染的有效手段。     

NO模拟烟气水净化实验研究

通过模拟实验研究了在NO=120～480mL／Nm^3低浓度和含氧量5．5％、6．0％和20％体积浓度及常压与≤36℃条件下，以纯水净化难溶有害污染成分NO构成的模拟烟气。在相同的NO配气体积浓度10％，NO被净化吸收量随其流量的增加而增加，而吸收率η^LENO却下降了。常压大气中吸收率值为5．6％～20．6％；5．5％ O2时的吸收率值为1．3％～4．6％；添加少量氧化剂使O2达6．0％时的吸收率值为1．3％～16．7％。     

不同消毒剂对饮用水中可同化有机碳的影响

以某地表水为原水（TOC为5．3mg／L），研究了氯、氯胺和臭氧3种消毒剂对可同化有机碳（AOC）的影响。结果表明，投加1mg／L氯氧化30min就会使AOC升高近3倍。投加3种剂量（1、2、3mg／L）的氯胺，氧化30min时AOC增加不到1倍；氧化24h时AOC浓度均比30min时的高，这说明氯胺的作用机理与氯不同。投加臭氧2．0mg／L氧化30min时可使AOC增加2．4倍；当臭氧质量浓度大于2．0mg／L时，AOC开始下降，这说明一部分中间产物进一步被氧化成了二氧化碳和水。     

乙二胺还原的氧化石墨烯对镉离子的动态吸附

以乙二胺(EDA)还原氧化石墨烯(GO)制得一种吸附剂材料,即还原态氧化石墨烯(RGO)。考察了动态条件下Cd2+溶液的初始浓度、流速及吸附床高度对穿透曲线的影响,同时利用Bed-Depth-Service Time(BDST)模型对吸附床高度与穿透时间的关系进行线性拟合分析,研究了RGO对Cd2+溶液的动态吸附性能。结果表明,RGO可以有效地去除水溶液中的Cd2+,随着吸附床高度的增加,离子的去除率增大,穿透时间延长;当溶液初始浓度增大时穿透时间缩短,离子的去除率减小;而溶液的流速加快,穿透时间和去除率都相应减小。吸附床高度与穿透时间的关系可用BDST模型较好地进行描述,预测新的操作条件下的穿透时间与实验值误差均小于5%。     

粉状褐煤对水中草甘膦的动态吸附

采集内蒙霍林河煤矿褐煤样品,加工成粒径0.38~0.83 mm作为吸附剂,对模拟草甘膦废水进行动态吸附实验。考察了吸附柱高(3、5和10 cm)、草甘膦初始浓度(0.5%、0.75%和1.0%)、流速(1、2和3 m L/min)、pH(9、11和13)和离子强度(IS,0.001、0.01和0.1 mol/L)对草甘膦的吸附穿透曲线和传质区长度的影响。实验结果表明,降低柱高、增大初始浓度、提高流速、增加离子强度均会使穿透时间提前,pH变化对穿透时间影响很小;柱高、初始浓度、流速、IS和pH引起的传质区长度的平均变化率绝对值分别为0.675、6.300、1.625、47.727和0.263,可见,与柱高、初始浓度和流速相比,IS对传质区长度的影响较大,pH影响较小。低浓度条件下,吸附穿透曲线的实验数据符合BDST模型拟合条件(R20.99),在仅改变柱高或流速时,穿透时间理论值与实测值的最大误差均为5.71%,运用该模型能够准确地预测褐煤吸附柱的操作时间。     

百色市右江区大气PM10中水溶性无机离子的化学特征与来源

2010年10月至2011年9月采集百色市右江区大气PM10样品,分析PM10及其水溶性无机离子的化学特征与来源。结果表明:(1)百色市右江区大气PM10为13.89～319.44μg/m3,年均117.48μg/m3,年均值超过《环境空气质量标准》(GB 3095-2012)二级标准(100μg/m3)。百色市右江区大气可吸入颗粒物的污染主要出现在春冬季节。(2)水溶性无机离子浓度年均值依次为SO24->NO3->Cl->NH4+>K+>Na+>Mg2+>F-,SO24-、NO3-和Cl-浓度最高,分别占水溶性无机离子的57.7%、14.9%和14.5%。(3)百色市右江区大气PM10呈较强的酸性,高浓度的SO42-可能是导致百色市右江区大气PM10呈较强酸性的主要原因。(4)PM10的季节变化受气温和风速的影响极显著;气象因素对SO42-、NO3-、F-的影响不显著。(5)主因子分析表明,PM10中水溶性无机离子可能来自3个方面,Cl-和NO3-主要来自于当地低烟卤煤燃烧排放的烟气;Mg2+、K+和Na+主要来自于自然源;F-、SO24-和NH4+主要来自于混合源。     

Fluxes of ions in precipitation, throughfall and stemflow in an urban forest in Kuala Lumpur, Malaysia

A study was carried out to determine the chemical composition of bulk precipitation, throughfall and stemflow in an urban forest in Kuala Lumpur, Malaysia. The mean weekly rainfall recorded during the period of study was 63.2 mm. Throughfall, stemflow and canopy interception of incident precipitation were 77.1%, 1.2% and 21.7% respectively. Bulk precipitation, througfall and stemflow were acidic, the pH recorded being 4.37, 4.71 and 4.15 respectively. In all cases the dominant ions were NO3, SO4, Cl, NH4, K, Ca and Na. Of the ions studied Ca, K, Cl, SO4, Mg and Mn showed net increases in passing through the forest canopy, while NH4, Na, NO3, Zn, H and Fe showed net retention. This study shows that the urban environment of Kuala Lumpur contributes considerable amounts of materials to the atmosphere, as reflected by the high ionic contents in bulk precipitation, throughfall and stemflow.     

Interactions between precipitation and Scots pine canopies along a heavy-metal pollution gradient

Bulk precipitation and stand throughfall were collected during 1992-96 at distances of 0.5, 4 and 8 km from the Harjavalta Cu-Ni smelter, southwestern Finland. The amounts of heavy metals (Cu, Ni, Zn, Fe) and mineral nutrients in bulk precipitation and throughfall were highest at 0.5 km. Although the canopy coverage was low at 0.5 km, the amounts of heavy metals intercepted by the canopy were extremely high. The proportion of foliar leaching relative to the wash-off of dry deposition from the needle surfaces decreased on moving towards the smelter for all elements, except for K. The high rate of K leaching from the needle tissues close to the smelter demonstrated that the K throughfall flux has been greatly altered by the heavy pollution load.     

Fluxes of trichloroacetic acid through a conifer forest canopy

Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, approximately 1.4 x rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only approximately 1-2% of above-canopy deposition. On average, approximately 800 microg m(-2) of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of approximately 400 and approximately 300 microg m(-2) for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values ( approximately +/- 50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50-200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric origin into mature forest canopies, as has been shown for seedlings (in addition to uptake from soil via transpiration), and that annualized within-canopy elimination is similar to that in controlled-dosing experiments.     

Determination of herbicides in stemflow and throughfall of beeches (Fagus sylvatica L.) and in rainfall

The pesticide contamination of water samples collected in and nearby a beech forest in northern Germany was evaluated. For this purpose, a method for the collection of water samples from stemflow and throughfall of beeches (Fagus sylvatica L.) and rainfall was developed in response to the demands for the analysis of organic contaminants in water samples. Furthermore a sensitive and selective multiresidue method was developed to determine 18 pesticides, frequently used in Germany, in aqueous samples. The samples collected were taken from the stemflow, the crown throughfall and the rainfall between May and November 2001. Analysis based on reversed-phase liquid chromatography with a pneumatically assisted electrospray mass spectrometer followed a solid phase extraction using C-18 extraction cartridges. Isoproturon, metolachlor, prosulfocarb and terbuthylazine were found during and shortly after their application period. In rainfall metolachlor, terbuthylazine and prosulfocarb were detectable in concentrations between 5 and 65 ng l(-1) and isoproturon in concentrations between 20 and 360 ng l(-1) respectively. In most of the samples, concentrations of those four pesticides were higher and detectable for a longer time in stemflow than in rainfall. Crown throughfall samples were collected from the end of August to November. Absolute deposition of isoproturon to forest soil were up to 70 times higher in comparison to rainwater samples.     

Contribution of canopy leaching to sulphate deposition in a Scots pine forest

Radioactive sulphate (35SO4) was applied to the soil below a Scots pine forest on 23 June 1989, and its movement into the canopy and into throughfall and stemflow was measured over 4 months. The specific activity, Bq (mg S)(-1), of the canopy increased monotonically; uptake by current-year (1989) expanding needles was initially twice as fast as by older needles or live twigs. By 10 October the canopy average specific activity was 62 Bq (mg S)(-1). The specific activity of net throughfall (throughfall + stemflow - rain), deduced from measurements from six throughfall collectors, six stemflow collectors and two rain collectors, fell rapidly from 12.6 Bq (mg S)(-1) in late July to <1 Bq (mg S)(-1) in mid-August. The results suggest (assuming rapid equilibration of 35S with sulphate in soil) that root-derived sulphate contributed c. 3% of sulphate in net throughfall and that dry deposition of SO2 and sulphate particles contributed c. 97% of the 0.56 g S m(-2) measured in net throughfall over the period. Simultaneous measurements of SO2 at canopy height and of NH3 above and within the canopy gave mean concentrations of 5.9 and 0.86 microg m(-3), respectively, sufficient to account for the sulphate measured in net throughfall only if codeposition of NH3 and SO2 occurred to canopy surfaces. The large values of specific activity observed in July, however, indicate that throughfall composition may be closely related to recent soil input of sulphate, and that equilibrium cannot be safely assumed. The possibility of a significant contribution of soil-derived sulphate to sulphate deposition in net throughfall cannot be ruled out on the basis of this experiment.     

Throughfall chemistry and canopy interactions in a Sitka spruce plantation sprayed with six different simulated polluted mist treatments

Throughfall chemistry was studied in a mature Sitka spruce plantation in order to investigate canopy interactions, such as nitrogen absorption, cation leaching, and neutralization of rainfall passing through the canopy. The plantation had been exposed to six different simulated mist treatments including N (NH(4)NO(3)) and S (H(2)SO(4) at pH 2.5) in four replicated blocks since 1996. Throughfall and rainfall were collected from May to September 2000. The results showed that 30-35% of the applied N was retained by the canopy. There were linear relationships between the loss of H(+) and increased K(+), Mg(2+) and Ca(2+) deposition through the canopy. However these increases in K(+), Mg(2+) and Ca(2+) deposition accounted for only about 50% of total neutralization of the acidity. The relationship between the anion deficits in throughfall and the loss of H(+) implied that weak organic acid anions were involved in the neutralization of the acidity in throughfall.     

Spatial variability of throughfall fluxes in a spruce forest

The spatial variability of throughfall deposition of H(+), Ca(2+), Mg(2+), Na(+), K(+), Cl(-), NO(3)(-), NH(4)(+), O(4)(2-) to a Norway spruce (Picea abies (L.) Karst.) forest was intensively examined during the period October 1986 to October 1987. Large systematic spatial variability of the atmospheric deposition within the forest was observed. The flux of throughfall water was higher away from the trunk compared to the flux close to the trunk. In contrast to this, the deposition of all substances was considerably higher close to the trunk compared to the deposition at the periphery of the canopy. A linear decrease in deposition as a function of the distance from the nearest tree trunk was found. Further, the deposition varied quite dramatically between trees according to their size. The observed spatial variability in throughfall may be due to variabilities in the processes taking part in altering the distribution and composition of the precipitated water as it moves through the canopy. The influence of these processes of precipitation, wash-off, dry deposition and canopy exchange is discussed, and it is found that both increased dry deposition and canopy exchange in the tree tops contribute to the higher solute fluxes found close to the tree trunk.     

Throughfall below grassland canopies: a comparison of conventional and ion exchange methods

Sampling of canopy fluxes (throughfall and stemflow) below low structured vegetation with a small-scale, intricate canopy architecture is difficult, and representative sampling with most methods is questionable. In the present study, two sampling methods for canopy fluxes below grassland vegetation are compared. Method I sampled canopy fluxes of moisture inefficiently, because stemflow volumes were not quantitatively included. Canopy fluxes of ions calculated with method I necessitated assumptions on equal concentrations in actually sampled throughfall and non-sampled stemflow. Method II sampled canopy fluxes of ions quantitatively, because the total volume of throughfall and stemflow percolated through a mixed bed of ion exchange resins below the canopy. Ion-specific differences between the two methods were observed. For ions with foliar leaching, such as K+ and Ca2+, higher canopy fluxes were recorded with method II than with method I. In contrast, for ions with foliar uptake, such as NH4+ and NO3-, canopy fluxes were found to be less with method II than with method I. Canopy fluxes of inorganic nitrogen below Mesobrometum grassland were 2.35 and 1.52 kmol(c) ha(-1) year(-1) for methods I and II, respectively, and 2.85 and 7.90 kmol(c) ha(-1) year(-1) for K+. It is argued that these differences result from under-estimated (foliar leaching) or over-estimated (foliar uptake) concentrations in stemflow by the first method. Canopy fluxes for SO4(2-) were not statistically different, indicating that canopy exchange of SOx was quantitatively unimportant, and that both methods estimated atmospheric input equally well.     

Research on the impact of forest stand structure on atmospheric deposition

Dry and wet deposition onto thirty forest stands in relation to stand structure is studied by sampling throughfall and bulk precipitation. Nine measurement sites are situated in Pseudotsuga menziesii stands, ten in Pinus sylvestris and eleven in Quercus robur stands. All stands are situated within a radius of 1.2 km to assure a more or less equal air pollution load. In each stand, detailed forest structure inventories are made to determine aerodynamic roughness, collecting efficiency and surface area parameters. Measurements to data cover a four month period (April-July 1990). First results show relatively high throughfall deposition in Pseudotsuga menziesii stands. Lowest throughfall fluxes are recorded for Quercus robur and intermediate values for Pinus sylvestris stands. There are indications of a relatively strong canopy exchange in Quercus robur stands during the measurement period. Many results from forest stand structure inventories are not available yet. However, a strong relation is observed between throughfall deposition in Pseudotsuga menziesii stands and total crown volume.     

Atmospheric deposition and canopy exchange processes in heathland ecosystems

The aims of the present study were to determine canopy exchange processes and to quantify total atmospheric deposition of sulphur and nitrogen in heathland. The study was carried out in dry inland heath vegetation, dominated by Calluna vulgaris, in two nature reserves in the eastern part of the Netherlands. Atmospheric deposition was determined with throughfall-stemflow measurements, adapted for low vegetation. Throughflow measurements (sum of throughfall and stemflow) in artificial Calluna canopies showed co-deposition of SOx and NHy upon heathland vegetation. In the real Calluna canopy, a significant part of the deposited ammonia/ammonium was directly assimilated by the Calluna shoots, especially in wet periods. The concentrations of potassium, calcium and magnesium in throughflow, after passage through the Calluna canopy, increased significantly compared with bulk precipitation. The amount of cations lost from the canopy were in good agreement with the observed ammonium uptake by the Calluna. A field experiment demonstrated that losses of the above-mentioned cations can be doubled by application of ammonium sulphate. It was shown that interception deposition is an important component of the atmospheric deposition of sulphur and nitrogen upon Calluna heathland; bulk precipitation amounted to only c. 35-40% of total atmospheric input. Total atmospheric deposition of sulphur and nitrogen in the investigated heathlands was 1.5-2.1 (27-33 kg S ha(-1) yr(-1)) and 2.1-3.1 kmolc ha(-1) yr(-1) (30-45 kg N ha(-1) yr(-1)), respectively. It is concluded that the present atmospheric nitrogen deposition is a continuous threat for the existence of heathlands in Western Europe.