用废甲醇催化剂制备活性氧化锌和五水硫酸铜

用ＮＨ４Ｃｌ和Ｈ２ＳＯ４为浸取剂，络合浸取废甲醇催化中的ＺｎＯ和ＣｕＯ，以制备活性ＺｎＯ和ＣｕＳＯ４．５Ｈ２Ｏ。浸取ＺｎＯ的适宜条件为：温度８５－１００℃，ＮＨＣｌ投加量为理论量的１．９－２．１倍，浸取时间为２０ｍｉｎ。     

从废甲醇合成催化剂中回收铜锌

将废RK-05甲醇合成催化剂经过煅烧、浸取、精制等工序回收其中的铜和锌。经正交实验得到煅烧废催化剂的最优工艺参数为:废催化剂筛目100目,煅烧温度950℃,煅烧时间60 min。最佳浸取工艺条件为:废催化剂加入量约4 g/L,浸取温度75℃,浸取剂用量与理论用量体积比2.0~3.0,浸取剂浓度4.0 mol/L,浸取时间10min。精制工序制备CuO的最佳工艺条件为:锌粒与滤渣质量比为1.00,反应时间3 h,煅烧温度450℃,煅烧时间4 h。制备ZnO的最佳工艺条件为:煅烧温度800℃,煅烧时间60 min。回收的产品CuO纯度为99.1%,满足GB/T674—2003《化学试剂粉状氧化铜》中优级品的标准。回收的产品ZnO纯度为99.6%,满足GB/T3185—1992《氧化锌(间接法)》中一级品的标准。     

碱熔法回收废催化剂中的钴、钼和铝

采用碱熔法从废钴钼催化剂中回收钴、钼和铝。该方法的工艺过程为 :将废催化剂与纯碱按质量比 1∶1 8混合 ,在焙烧温度 90 0℃条件下 ,焙烧 2h ;用 2倍于熔块的沸水浸取30min ;用稀硫酸调浸取液 pH至 6 ,浸取液中的铝形成氢氧化铝被回收 ;然后除盐并回收钼酸钠 ;使酸浸黑渣中的钴形成氢氧化钴并脱水氧化成为氧化钴。用该工艺回收铝、钼和钴 ,其回收率可达 95 %以上 ,回收产品的纯度可达 97%以上。     

氯化焙烧法回收铬渣中的铬

以CaCl2为氯化剂,碳粉为还原剂,采用氯化焙烧—盐酸浸取的方法处理铬渣,铬渣中的铬以CrCl3的形式被回收。在m(铬渣)∶m(碳粉)为10∶2.0、m(CaCl2)∶m(铬渣)为0.4、焙烧温度为1 200℃、焙烧时间为50min的条件下,Cr(Ⅲ)回收率为91.2%。采用本方法处理1g铬渣可回收CrCl3约0.033g。     

氟化物对酸浸取沸腾炉渣中铝的影响

采用酸浸取法、加入助溶剂浸取沸腾炉渣中的铝,考察了各种因素对铝浸出率的影响。实验结果表明：在球磨时间为30min、固液比（沸腾炉渣质量与酸体积之比）为1：7、硫酸浓度为4mol／L、浸取温度为107℃、浸取时间为120min的条件下,铝浸出率最高（为29．72％）;KF,NH4F,NaF,CaF2等作助溶剂可明显提高铝浸出率,且助溶剂为CaF：时的铝浸出率最高,CaF2与沸腾炉渣的质量比为0．08时的铝浸出率大于75％。     

用钡渣制取硫酸钡

用盐酸浸取钡渣，所得的氯化钡溶液再和硫酸反庆，得到硫酸钡沉淀，母液返回去浸取钡渣。浸取钡渣的适宜条件为：浸取时间５０ｍｉｎ、ｐＨ２－３、钡渣粒度１２０目、浸取温度４０－４５℃、液固比３：１。     

从废感光胶片中回收银

研究了以Fe3 -乙二胺四乙酸二钠-N a2S2O3体系为浸取剂从废感光胶片中回收银的方法,考察了浸出银的最佳工艺条件。实验表明,当浸取剂中FeC l3.6H2O质量浓度为35g/L、N a2S2O3.5H2O质量浓度为150g/L、pH为7、固液质量比为3∶10时,浸取剂可重复使用6次,胶片上银的浸出率可达99%以上;浸取液中的银采用硼氢化钠还原回收,粗银粉配以熔剂高温熔炼可得到纯度达99.78%的银,银回收率达96.88%,回收银后的浸取液可循环使用。     

废无汞碱性电池极性材料制备锰锌铁氧体磁性纳米颗粒

以硝酸浸取废无汞碱性电池极性材料,再加入硝酸铁及蔗糖生成前驱体,最后通过焙烧制得锰锌铁氧体磁性纳米颗粒。优化了酸浸和焙烧条件,采用FTIR和DTA-TG技术研究了前驱体的形成和热解过程,采用XRD、FTIR、TEM技术和振动样品磁强计对锰锌铁氧体进行了表征。结果表明:废无汞碱性电池极性材料酸浸的最佳条件为H_2O_2加入量3%(w)、液固比10 mL/g、稀硝酸浓度4 mol/L、浸取温度40℃,该条件下浸取10 min锰和锌的浸出率均可达100%;所得前驱体为葡萄糖酸盐,其最佳焙烧条件为焙烧温度450℃、焙烧时间2 h;最佳条件下所得锰锌铁氧体为尖晶石型Mn_(0.5)Zn_(0.5)Fe_2O_4,其颗粒为球形、大小均匀,且磁性能优良。     

废甲醇催化剂的回收和利用

介绍了利用废甲醇催化剂生产活性氧化锌和五水硫酸铜的方法，试验结果表明，最佳工艺条件为：催化剂粒度80目；酸浸反应的硫酸浓度3．6则mol/L，100g原料中硫酸用量325mL；净化反应的pH控制在5—5．5，温度85℃；活性氧化锌煅烧温度800℃；铜粉焙烧温度600℃，通风量0．8L／min，焙烧时间2．5h；硫酸铜生产过程中，反应温度为60—80℃，时间2h。该方法具有工艺简单、操作方便、产品质量好的特点，并可减少环境污染，变废为宝，具有较好的经济效益。     

废SCR催化剂中钒和钨的有机酸浸出

在对废SCR催化剂组成进行分析的基础上,采用草酸和酒石酸两种有机酸浸取废SCR催化剂中的V和W。实验结果表明：草酸对V、W的浸出率均大于酒石酸;在草酸浓度为1.00 mol/L、浸取温度为80 ℃、液固比为10 mL/g、浸取时间为180 min时,V和W的浸出率分别为63.50%和13.12%;在酒石酸浓度为0.5 mol/L、浸取温度为100 ℃、液固比为10 mL/g、浸取时间为180 min时,V和W的浸出率分别为44.00%和9.00%。酸性浸出未改变SCR催化剂中TiO₂的晶型,剩余残渣中依然保留着TiO₂骨架,可继续作为催化剂载体使用。     

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.     

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。     

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.     

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.     

High Immobilization of NH4+ in Danish Heath Soil Related to Succession,Soil and Nutrients: Implications for Critical Loads of N

During recent decades heathlands havechanged into grasslands in regions with high atmosphericnitrogen deposition. In regions with intermediatedeposition level (e.g., Denmark) changes have been lesspronounced which may be due to delay or decrease inresponse of the ecosystem. The mor layer (O horizon) mayplay an important role for this delay due to high sinkstrength for N. In this study, the capacity for netNH₄ ⁺ immobilization and mineralization wasstudied during short- and long-term incubations (2–36 days)of mor samples from Danish dry inland heaths. High short-term capacity for net NH₄ ⁺ immobilization wasfound to be a general characteristic of Danish heath morlayers both under heather (Calluna vulgaris) andcrowberry (Empetrum nigrum ssp nigrum), the latterdominating late stages in heathland succession. The netNH₄ ⁺ immobilization was higher under youngcompared to old or dead vegetation, and higher on lessnutrient poor soils than on extremely nutrient poor soils.The addition of N, P and C stimulated CO₂ productionand net NH₄ ⁺ immobilization, but not net Nmineralization. The immobilization of ¹⁵NH₄ ⁺caused release of dissolved organic N, increased N anddecreased C/N ratio in the microbial biomass, and indicatedgrowth of microorganisms with other metabolic abilitiesthan the indigenous population. No evidence was obtained ofstabilization of immobilized ¹⁵NH₄ ⁺ intosoil organic matter during the experiment. On background ofthe results and current knowledge it was concluded that therecognition of the high capacity for net NH₄ ⁺immobilization in mor layers does not allow for a raiseof critical loads for N for northern dry inland heaths.     

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.