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催化燃烧法处理聚对苯二甲酸乙二醇酯生产废气 总被引:3,自引:1,他引:3
采用催化燃烧法处理聚对苯二甲酸乙二醇酯生产过程排放的含乙醛、2-甲基-1,3-二氧戊烷、乙二醇的废气,用进口Pt Pd/Al2O3-CeO2球状催化剂作废气催化燃烧的催化剂。在催化燃烧反应器床层空速为20000h^-1、催化剂用量为935mL、反应器入口温度为250℃、进口废气总烃质量浓度为2555~5099mg/m^3的条件下,处理后废气的总烃质量浓度为1~38mg/m^3,远低于120mg/m^3的国家排放标准,且总烃去除率达到98.6%~100%,乙醛质量浓度小于99mg/m^3,低于125mg/m^3的国家排放标准。 相似文献
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采用Ca(ClO)2溶液在高效反应瓶中与模拟烟气进行脱硫脱硝实验,考察了模拟烟气中SO2和NOx的去除效果,以动力学为理论基础研究了Ca(ClO)2的脱硫脱硝性能。实验结果表明:在模拟烟气中SO2,NO,NO2的质量浓度分别为3700,1300,820 mg/m^3及Ca(ClO)2溶液浓度为0.35 mol/L的条件下,SO2去除率达到100%,NOx去除率达到67%。脱硫过程中吸收液中的ClO-是100%脱硫率的保障。Ca^2+吸收SO2的反应速率呈现一级反应的特征。得到的脱硫产物CaSO4·2H2O达到了工业石膏的品质要求。同时脱硫脱硝时NOx和SO2具有协同作用。 相似文献
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用电石渣浆制备烟气脱硫剂 总被引:2,自引:0,他引:2
采用电石渣浆经处理后配制成的电石渣试样作为脱硫剂,对除尘后锅炉烟气进行脱硫实验,在烟气巾s与c质量比约为1:30、吸收体系pH为7~8、温度为15℃的条件下,平均脱硫率达96.35%。采用电石渣浆上层清液作脱硫剂对锅炉烟气进行脱硫的工业试验,在烟气流速为2.8~4.2m/s、脱硫塔内nCa:n5=1.2:1、体系pH为7~8的条件下,平均脱硫率达90.66%,且脱硫塔出气口处SO2质量浓度明显低于GB13271-2001《锅炉大气污染物排放标准》。 相似文献
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ClO_2溶液去除烟气中NO的效果及工程应用 总被引:1,自引:0,他引:1
采用实验室规模喷淋脱硝装置对ClO_2溶液去除NO的效果及影响因素进行探讨,通过脱硝产物的测定对ClO_2溶液去除NO的能力及机理进行分析;在此基础上考察ClO_2溶液对供热厂燃煤锅炉烟气的实际脱硝效果。实验结果表明:在液气比为20L/m~3、反应温度为20℃,反应pH为4.0、进气NO质量浓度为250 mg/m~3,ClO_2质量浓度为200 mg/L的条件下,NO去除率达97%以上;ClO_2溶液可将NO氧化吸收为NO_3~-,氧化后产生的NO_x也可被NaOH溶液吸收转化为NO_2~-和NO_3~-;在ClO_2质量浓度为200~500 mg/L,反应pH为5.5~7.0的条件下处理初始NO质量浓度为212~230 mg/m~3的燃煤锅炉烟气,NO去除率为85.7%~94.6%,NO_x去除率为80.4%~88.8%,出口NO_x质量浓度低于46 mg/m~3,远低于GB 13271—2014规定的排放限值。 相似文献
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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. 相似文献
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C. L. Swanson R. L. Shogren G. F. Fanta S. H. Imam 《Journal of Polymers and the Environment》1993,1(2):155-166
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. 相似文献
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Application of Cellulose Microfibrils in Polymer Nanocomposites 总被引:1,自引:0,他引:1
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. 相似文献
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Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States 总被引:1,自引:0,他引:1
John J. Hutchens Jr. Darold P. Batzer Elizabeth Reese 《Water, Air, & Soil Pollution: Focus》2004,4(1):37-53
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. 相似文献
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Brian K. Gullett William P. Linak Abderrahmane Touati Shirley J. Wasson Staci Gatica Charles J. King 《Journal of Material Cycles and Waste Management》2007,9(1):69-79
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. 相似文献
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Nyberg Lars Lundström Ulla Söderberg Ulf Danielsson Rolf van Hees Patrick 《Water, Air, & Soil Pollution: Focus》2001,1(1-2):241-263
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. 相似文献
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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. 相似文献
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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. 相似文献
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S. H. Imam L. Chen S. H. Gordon R. L. Shogren D. Weisleder R. V. Greene 《Journal of Polymers and the Environment》1998,6(2):91-98
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. 相似文献