头孢拉定荧光猝灭法测定铁(Ⅲ)

基于铁（Ⅲ）对水溶液中头孢拉定（CEPC）的荧光猝灭作用,建立了测定微量铁（Ⅲ）的荧光分析方法。在以pH为3．0的盐酸为介质、最大激发波长为351nm、发射波长为431nm、CEPC质量浓度为0．11g／L的条件下,相对荧光强度与1gc呈良好的线性关系,测定铁（Ⅲ）浓度的线性范围为1．60×10^-6～6．30×10^-4mol／L,检出限为6．25×10^-7mol／L,相对标准偏差为2．10％（n=11）,加标回收率为94．3％～106．9％。该法具有良好的选择性,其他常见的共存离子不干扰测定,可直接用于测定环境水样中的铁（Ⅲ）含量。     

炉渣去除废水中六价铬

采用炉渣处理模拟含Cr（Ⅵ）废水,确定了炉渣去除Cr（Ⅵ）的适宜条件,并对去除机理及动力学规律进行了探讨。实验结果表明,对于初始质量浓度为10mg／L的含Cr（Ⅵ）废水,在室温、废水初始pH=1．00、炉渣加入量为8g/L、反应时间为240min的条件下,Cr（Ⅵ）去除率达99．2％。对于初始质量浓度低于50mg／L的含Cr（Ⅵ）废水,投加适量的炉渣,可使处理后出水中的Cr（Ⅵ）质量浓度降至排放标准以下。炉渣对Cr（Ⅵ）的去除机理主要是炉渣中溶出的Fe^2＋对Cr（Ⅵ）的还原作用,炉渣对Cr（Ⅵ）的吸附作用很小。炉渣对Cr（Ⅵ）的还原反应符合一级反应动力学规律,在pH分别为0．55,1．00,2．00的条件下,反应速率常数分别为6．0×10^-3,3．3×10^-3,4．0×10^-4min^-1．     

新型气体检测器

美国政府最近严格控制了甲烷和己烷的检测阈值。以前的法规允许仪器的检出上限（即下爆限）为4．400×10^-3,而现在更为强硬的标准要求这些组分的质量分数不大于1．000×10^-3。由于世界各国的管理部门均紧缩了暴露极限及相关法规,使得对低浓度气体的检测能力得到增强。     

Mn-Ce/Ti-Zr-柱撑膨润土催化剂低温选择性催化还原法脱硝

以改性的有机膨润土为原料,制备Ti、Zr共柱撑有机膨润土(Ti-Zr-OPILC),并通过浸渍法负载Mn、Ce,制备得催化剂Mn-Ce/Ti-Zr-OPILC,运用XRD、BET分析了催化剂的物理化学特性,并考察了催化剂对NO低温选择性催化还原反应的催化活性.实验结果表明:催化剂的比表面积得到很大提高,Mn和Ce在载体上分散性较好;在反应温度为220℃、体积空速为40 000 h-1、n(NH3)∶n(NO)为1、初始NO体积分数为0.06％、O2体积分数为3.6％时,对NO去除率高达95％以上.     

间歇式活性污泥反应器内短程同步硝化反硝化的研究

以絮状活性污泥为种泥,以模拟城市生活污水为处理废水,在间歇式活性污泥反应器（SBR）内进行污泥的驯化和培养,通过控制运行条件在SBR内成功实现了NO2-N的积累和短程同步硝化反硝化。实验结果表明,NO2-N积累阶段,控制温度（31±1）℃、曝气量40～45L／h、污泥泥龄9—15d,SBR内NO2-N积累率可达95％-96％。培养成熟的好氧颗粒污泥平均粒径为3—5mm,用其进行短程同步硝化反硝化实验,一个反应周期5h结束后SBR出水的COD,NO2-N,TN去除率分别达92％,95％,85％。     

膨胀颗粒污泥床反应器处理啤酒废水

对接种市政消化污泥的膨胀颗粒污泥床（EGSB）反应器的启动及启动成功后在35℃和15℃时的运行特性进行了研究。结果表明：EGSB反应器采用低进水COD、高有机负荷方式,46d快速启动成功;在35℃、HRT为3．4h、液体上升流速为2．80m／h的条件下,COD去除率均能保持在90．0％以上;温度在进水COD为450mg／L左右时对COD去除率影响不明显,但在1700mg／L左右时影响明显;EGSB反应器能在15℃的低温条件下稳定高效运行;在短时间内经历15℃→50℃→15℃的温度冲击和4．32kg／（m^3·d）到15．50kg／（m^3·d）的负荷冲击后能在8d和14d内快速恢复;经历35℃→17℃→35℃的温度冲击后,COD去除率的恢复没有出现滞后期。     

采用等离子体气化工艺从含氯废物中回收氯并产合成气

美国Dow Coming公司的硅制品制造厂将采用一套等离子体废物处理工艺,用于循环利用化学废物,以帮助该厂减少每年4×10^11 Btu（合4．22×10^11kJ）的天然气消耗量以及75％的总排放量。该技术的所有者综合环境技术公司（ITE）声称,该装置标志着等离子体技术在化工企业的首次应用。在初始阶段,将采用等离子体强化熔炉（PEM）消解医学废物及化学废物。     

亚甲基蓝褪色催化动力学光度法测定痕量Cu^2＋

研究了在聚乙二醇-200（PEG-200）活化下,Cu^2＋催化H2O2氧化亚甲基蓝的褪色反应,建立了亚甲基蓝褪色催化动力学光度法测定痕量Cu^2＋的方法。在25mL容量瓶中,加入1．00mL pH为11．68的氨水溶液、2．00mLH2O2溶液（质量分数15％）、1．00mL亚甲基蓝溶液（质量浓度0．20mg／mL）、3．00mL PEG～200溶液,76℃恒温反应5min后冷却,测定吸光度,根据加Cu^2＋溶液和不加Cu^2＋溶液的吸光度差值与Cu^2＋质量浓度绘制了工作曲线,并由试样的吸光度差值确定痕量Cu^＋含量。该法的测定波长为664nm,检出限为5．4×10^-6 g／L,最大相对标准偏差为2．58％,回收率为97．5％～104．5％。     

改性粉煤灰吸附-高级氧化法处理奥里油废水

将氯化铁改性粉煤灰（简称改性粉煤灰）吸附处理与高级氧化和生物处理等技术进行优化组合,以期得到简便而有效的处理奥里油废水（简称废水）的组合工艺。研究结果表明：在废水COD平均为4600mg／L、改性粉煤灰加入量为50g／L、废水pH为7～9、吸附时间为1h的条件下,COD去除率达30％。采用“改性粉煤灰一次吸附-湿式均相催化氧化-厌氧生物过程-改性粉煤灰二次吸附”组合工艺处理废水时,改性粉煤灰不但具有较好的预处理效果,且还有较好的后处理能力;湿式均相催化氧化的催化剂用量少（Cu（NO3）2为2．0g／L）、操作条件温和（2．5MPa,180℃,pH5—7,1h）;厌氧生物过程中不需特殊筛选的菌种,易操作控制;经该组合工艺处理后,废水COD从4600mg／L降至55mg／L,COD去除率为98．4％,达到GB8978-1996《污水综合排放标准》的一级排放标准。     

TiO2-xNx光催化氧化苯甲酸的研究

采用悬浮态光催化反应体系,以氙灯为光源,自制纳米TiO2-xNx为催化剂,考察了苯甲酸光催化氧化过程中TiO2-xNx质量浓度、反应体系初始pH和苯甲酸初始质量浓度对苯甲酸溶液中TOC去除率的影响。实验结果表明：最佳催化剂质量浓度为0．30g／L;TiO2-xNx的等电点为pH=5．3,在酸性条件下（pH=2．0）更有利于苯甲酸在催化剂表面的吸附,以及光生电子与O2反应生成·OH的进行;随苯甲酸初始质量浓度增加,TOC去除率降低,反应速率也相应地降低。TiO2-xNx比P25型TiO2表现出更强的浓度适应能力。     

Distribution of Cd,Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequentialextractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn incase of stemwood harvesting, and of Cd, Cu and Zn in the case ofwhole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd inthe biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in thebiomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters ofthe A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil.     

Starch-plastic materials—Preparation,physical properties,and biodegradability (a review of recent USDA research)

Recent starch-plastic research at the National Center for Agricultural Utilization Research is reviewed and related worldwide efforts are noted. Properties of starch that influence its formulation and performance in plastics are discussed. Methods are given for preparation of starch-poly(methyl acrylate) graft copolymer, starch-poly(ethylene-co-acrylic acid), and starch-poly(ethylene-co-acrylic acid)-polyethylene plastics. Their physical properties are discussed, as is degradability by enzymes or amylolytic organisms from soil, ponds, and streams.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Application of Cellulose Microfibrils in Polymer Nanocomposites

Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers were added at low concentrations (2–10% w/w) to polymer gels and films as reinforcing agents. Significant changes in mechanical properties, especially maximum load and tensile strength, were obtained for fibrils derived from several cellulosic sources, including cotton, softwood, and bacterial cellulose. For extruded starch plastics, the addition of cotton-derived microfibrils at 10.3% (w/w) concentration increased Young’s modulus by 5-fold relative to a control sample with no cellulose reinforcement. Preliminary data suggests that shear alignment significantly improves tensile strength. Addition of microfibrils does not always change mechanical properties in a predictable direction. Whereas tensile strength and modulus were shown to increase during addition of microfibrils to an extruded starch thermoplastic and a cast latex film, these parameters decreased when microfibrils were added to a starch–pectin blend, implying that complex interactions are involved in the application of these reinforcing agents.     

四氮唑废水处理工艺设计

高浓度、高盐分的四氮唑生产废水通过三效蒸发浓缩,馏出液经铁炭氧微电解和混凝预处理,再采用水解酸化一接触氧化一反应二沉主体组合工艺进行处理。研究了该工艺所需构筑物和设备的设计与选型。该工艺在正常运行条件下,处理后出水pH6～9,COD 302mg／L,BOD5 108mg／L,SS30mg／L,色度36倍,水质达到GB8978--1996（污水综合排放标准》三级标准。     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Characterization of air emissions and residual ash from open burning of electronic wastes during simulated rudimentary recycling operations

Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15 and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits, designating this ash as a hazardous waste.     

Does Soil Acidification Affect Spruce Needle Chemical Composition and Tree Growth?

In 1994, a large survey of soil chemistry was undertaken in thecounty of Värmland in central Sweden (Lundström et al., 1998).The southern part of the county was affected by soilacidification whereas there were no such indications in thenorthern part. To investigate the influence of soil chemistryon the trees at the specific sites, the survey was continued byan analysis of needle chemistry (Norway spruce) which wasundertaken at 150 of the 180 sites, and of tree growth at 65 ofthe 180 sites. Growth was expressed as a ratio between expectedgrowth, estimated with a national, empirical growth model, andthe growth observed in the field. In statistical analyses,using rank correlation, PCA and PLS, there were only weakindications of an influence of soil chemistry on needlechemistry and on tree growth. A moderate correlation betweennitrogen and sulphur in needles was found, which wasinterpreted as an effect of deposition and of processes in thetree canopy. No obvious regional pattern of the growth ratiowas found, in contrast to the clear pattern of soilacidification. The statistical analysis could not with anycertainty point out any of the soil chemistry variables asespecially important for the tree growth ratio.     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment

Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV < 30% starch < 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by ¹H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.     

Historical Weathering Based on Chemical Analyses of Two Spodosols in Southern Sweden

Chemical weathering losses were calculated for two conifer stands in relation to ongoing studies on liming effects and ash amendments on chemical status, soil solution chemistry and soil genesis. Weathering losses were based on elemental depletion trends in soil profiles since deglaciation and exposure to the weathering environment. Gradients in total geochemical composition were assumed to reflect alteration over time. Study sites were Horröd and Hasslöv in southern Sweden. Both Horröd and Hasslöv sites are located on sandy loamy Weichselian till at an altitude of 85 and 190 m a.s.l., respectively. Aliquots from volume determined samples from a number of soil levels were fused with lithium metaborate, dissolved in HNO₃, and analysed by ICP – AES. Results indicated highest cumulative weathering losses at Hasslöv. The weathering losses for the elements are in the following order:Si > Al > K > Na > Ca > MgTotal annual losses for Ca+Mg+K+Na, expressed in mmol_c m^-2 yr^-1, amounted to c. 28 and 58 at Horröd and Hasslöv, respectively. Variations between study sites could not be explained by differences in bulk density, geochemistry or mineralogy. The accumulated weathering losses since deglaciation were larger in the uppermost 15 cm than in deeper B horizons for most elements studied.