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1.
从含镍二壬基萘磺酸-煤油溶液中反萃取镍   总被引:1,自引:0,他引:1  
采用简单反萃取法回收含镍二壬基萘磺酸(DNNSA)-煤油溶液中的镍。考察了反萃剂种类、反萃时间、反萃温度、油水比(负载镍的有机相与反萃剂的体积比)、反萃剂浓度等对反萃率的影响。实验结果表明,在硫酸作为反萃剂、反萃剂浓度为0.3mol/L、反萃时间为10min、反萃温度为30℃、油水比为3的工艺条件下,反萃率达81.5%。反萃取后得到的DNNSA可多次重复用于含镍废水的萃取处理,Ni2+萃取率基本保持不变。  相似文献   

2.
采用自制的SSX萃取剂对FeCl3蚀刻液膜电解阴极液(简称废液)中的Ni2+进行萃取回收。考察了萃取pH、SSX萃取剂含量、萃取相比(SSX萃取剂与废液的体积比)、萃取时间、萃取次数对Ni2+萃取率的影响,以及反萃剂HCl溶液浓度、反萃相比(反萃剂与萃取液的体积比)、反萃时间对Ni2+反萃率的影响。实验结果表明: 当SSX萃取剂质量分数20%、萃取pH 2.0、萃取相比1.0、萃取时间10 min、1次萃取时,Ni2+萃取率可达74.56%;当反萃剂HCl溶液浓度6.0 mol/L、反萃相比1.5、反萃时间10 min时,Ni2+反萃率达93.10%;再生后的SSX萃取剂重复使用4次后,Ni2+的累积萃取率达91.00%,萃取剂中Ni2+的质量浓度可达14.94 g/L;反萃液经浓缩、结晶处理可制备电镀用NiCl2产品。  相似文献   

3.
利用醋酸废水制取醋酸钙镁盐   总被引:4,自引:1,他引:4  
喻新平 《化工环保》2002,22(4):224-227
用三辛胺萃取醋酸废水中的醋酸,加入白云石灰乳反萃、可制得环保型除冰剂醋酸钙镁盐(CMA)。研究了萃取剂组成,剂水比,萃取温度,萃取时间,搅拌速度对萃取效率的影响,确定了反萃的操作条件。试验表明:采用该法处理稀醋酸,工艺简单、醋酸利用率高。  相似文献   

4.
从苯酐生产废水中萃取富马酸   总被引:1,自引:0,他引:1  
用三辛癸胺和三辛胺为萃取剂,在无稀释剂的条件下,对苯酐生产废水中的富马酸进行了络合萃取研究。研究结果表明,萃取剂的负荷量与相比呈递减的幂函数关系,三辛癸胺比三辛胺的络合酸度大;温度对萃取处理效果有明显影响,温度为10~40℃时,萃取剂的负荷量随着温度的升高而增加,但温度过高易造成乳化,最佳操作温度为30~40℃;用氢氧化钠溶液再生萃取剂,最佳反萃操作条件为:振荡时间60s、相比(水/油,体积比)2、温度60℃、碱液质量浓度12g/L;萃取剂9次循环萃取和再生使用过程中,萃取率稳定在71 8%±1 7%,再生效率稳定在94 3%±1 9%,9次循环后萃取剂的损失量为4%;从每吨废水中可回收富马酸4 8kg,可获益24元。  相似文献   

5.
J酸生产废液冷冻分离的研究   总被引:3,自引:0,他引:3  
采用冷冻分离法处理J酸生产过程中产生的酸性废液,具有设备简单、能耗小、处理费用低的特点。该法的主要步骤:①将废液冷冻至-10——20℃,使其中的Na_2SO_4结晶析出,然后进行过滤去除;②将滤液进行换热、浓缩后,送回原生产工序循环使用。采用该法处理这种酸性废液,不但可消灭这种污染源,而且回收了资源。  相似文献   

6.
萃取法回收钛白水解废酸中的硫酸   总被引:4,自引:2,他引:4  
李潜  朱红力 《化工环保》2003,23(4):225-228
提出了以三异辛胺作萃取剂、H2O作反萃取剂从钛白水解废酸中萃取回收硫酸的新工艺。考察了萃取剂浓度、相调节剂浓度、相比及温度对萃取和反萃取的影响,并进行了模拟试验。在以40%三异辛胺、25%仲辛醇和35%航空煤油(均为质量分数)为萃取有机相,相比为2,以H2O为反萃剂,相比为1.5的条件下,质量浓度为146.02g/L的废酸经8级萃取和6级反萃取,硫酸回收率达到91.81%,产品酸质量浓度达119.73g/L。  相似文献   

7.
国外动态     
萘酚生产废水含有大量无机盐(Na_2SO_4、Na_2SO_3)和有机物(β-萘磺酸和其他)。采用电渗析法可以有效地净化该废水,并能得到氢钣化钠和硫酸。实验是在装有离子膜、铂钛阴极和阳极的三室电渗析器内进行。离子膜牌号为 MK-40和 MA-40,电流密度为0.08—0.12安/厘米~2。电解4~5小时,无机盐去除率达97—99%,有机物去除率达95—98%(按 COD 计)。净化后的废水可回用。阴极电解液硫酸(70克/升)和阳极电解液氢氧化钠(60克/  相似文献   

8.
络合萃取法处理2-萘酚生产废水   总被引:1,自引:0,他引:1       下载免费PDF全文
采用络合萃取法处理2-萘酚生产废水,比较了分别以三辛胺、十二烷基二甲基胺(十二叔胺)、三烷基胺作为萃取剂的萃取效果,其中三辛胺萃取效果最佳,三烷基胺次之,十二叔胺的萃取效果最差。处理2-萘酚生产废水的最佳工艺条件为:以三辛胺作为萃取剂,萃取剂加入量为8.5%,废水pH为1.0。在此最佳工艺条件下废水的COD去除率可达97.2%。采用NaOH溶液反萃取后的萃取剂用于第二次萃取,COD去除率为96.4%,再反萃取后用于第三次萃取,COD去除率为94.9 %。萃取剂可重复使用。  相似文献   

9.
采用多级冷冻法处理含油废水。实验结果表明:在初始废水中COD和ρ(NH3-N)分别为36 400 mg/L和73 mg/L的条件下,经过8级冷冻处理,COD和ρ(NH3-N)分别降至430 mg/L和2 mg/L,去除率分别可达98.82%和97.72%;在相同COD的条件下,ρ(NH3-N)较高时,COD去除率较高,由此可见无机盐离子(如NH4+)的存在有利于有机物的去除。  相似文献   

10.
DSD酸氧化缩合废水浓缩液回用试验研究   总被引:4,自引:1,他引:4  
研究了DSD酸氧化缩合废水浓缩液回用到原生产过程的可行性。对DSD酸氧化缩合废水可采用萃取技术分离出其中97%的有机物,反萃产生的4-8倍的浓缩液返回到DSD酸生产中的氧化缩合单元后,可提高DNS酸的收率约7.43%,且不会明显影响产品的纯度,浓缩液8次循环磁用试验的结果表明,虽然DSD酸氧化缩合废水的COD从15000-20000mg/L提高到20000-29000mg/L,但没有显著持续增长的趋势,表明反应液中副产物的浓度得到了有效的控制。  相似文献   

11.
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   

12.
The major forest nonpoint source control programs in the West are largely regulatory, either under forest practices acts (California, Idaho, New Mexico, Nevada, Oregon, and Washington) or a streamside management act (Montana). These programs and the specific rules they enforce continue to undergo intensive scrutiny. Still, the questions are the same for these regulatory programs as for states that base nonpoint source control on voluntary BMPs (Arizona, Colorado, Utah, Wyoming). Are the rules or BMPs being applied, and are they effective in reducing nonpoint source pollution to levels that protect beneficial uses of water? The level of debate about forestry in the West has resulted in detailed monitoring and research to answer these questions. In the past, state agencies have assumed levels of BMP compliance based on the percent of operations without enforcement actions. These estimates are being replaced by statistically valid and reproducible monitoring of forest practices rules and BMP compliance levels. BMP effectiveness is being assessed using both qualitative and quantitative methods. This can involve field assessments, process-based research, and control watershed studies. Some trend monitoring is also beginning. With the regional implementation rate for forestry BMPs at about 94% and rising, it is likely that effectiveness testing will continue to be a priority and consume the majority of assessment resources for this region.  相似文献   

13.
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   

14.
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   

15.
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。  相似文献   

16.
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   

17.
Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m-2 yr-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO4 -2, NO3 -, and NH4 + in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO4 -2 and NO3 - decreased (average ± standard deviation) by 22±7 and 12±7 mol L-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca2+ + Mg2+ (17±7 mol L-1) and H+ (4±6 mol L-1), and an increase in HCO3 -(10±10 mol L-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L-1), Ca2+ + Mg2+ (9±6 mol L-1), and H+ (6±5 mol L-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO4 -2 and NO3 - in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance.  相似文献   

18.
Stuchlík  E.  Appleby  P.  Bitušík  P.  Curtis  C.  Fott  J.  Kopáček  J.  Pražáková  M.  Rose  N.  Strunecký  O.  Wright  R. F. 《Water, Air, & Soil Pollution: Focus》2002,2(2):127-138
Starolesnianske pleso is a small and shallow acid lake in the High Tatra Mountains, situated at 2000 m above sea level, on granitic bedrock, with sparse and thin soil cover. When detailed measurements began in the 1980s Starolesnianske pleso had pH below 5 and only one species of cladoceran zooplankton, the ubiquitous Chydorus sphaericusPalaeolimnological investigations show changes in cladoceran zooplankton and chironomid zoobenthic assemblages since about 1920 and a major change in 1970–1980. The dynamic acidification model MAGIC was used to reconstruct changes in water chemistry over the past 150 years. The results from MAGIC agree well with the sediment record; pH levels gradually decreased from 6.5 in the mid-1800s to about 5.6 in 1920 (first response in biota) to below 5.0 by 1970, and concentrations of inorganic aluminium rose dramatically beginning about 1960. In the 1990s the lake water chemistry showed clear signs of reversal in acidification brought about by a major decline in S deposition.  相似文献   

19.
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   

20.
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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