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1.
半胱氨酸合铁(Ⅱ)溶液同时脱除烟中SO2和NOx的研究   总被引:10,自引:0,他引:10  
研究用半胱氨酸合铁溶液同时脱除烟气中SO2和NOx,研究了「SO^2-3」对NOx脱除率的影响,半胱氨酸的再生。实验表明,烟气中SO2可以全部脱除;随「SO^2-3」的增加能增大半胱氨酸合铁(Ⅱ)溶液对NO的吸收。  相似文献   

2.
炉膛吸着制度射(FSI)与选择性非催化还原(SNCR)相结合同时脱除SO_2和NO,在夹带流反应器中进行实验研究。在800-1200℃下喷射石灰石/尿素吸着剂或石灰石/铵盐吸着剂能同时脱除SO_2和NO。石灰石/尿素吸着剂表现出最高的脱硫脱硝能力,当Ca/S=2和N/NO=2时,其SO_2和NO脱除率分别能达到90%和80%。主要的NO脱除是NH_3与NO反应生成N_2所致,少量的NO脱除率(10%)是在CaSO_4的催化下,CaO与NO反应生成Ca(NO_2)_2的结果。本文还考察了反应温度和时间对脱硫脱硝反应速度的影响。  相似文献   

3.
含灰含水烟气的脉冲放电脱除NO和NOx的研究   总被引:7,自引:0,他引:7  
脉冲放电脱除NO和NOx(NO+NO2)的实验表明,烟气中的飞灰对NOx具有2%-4%的吸附脱除作用,对脉冲放电又有抑制作用,使NO和NOx脱除具有降低的趋势,增加烟气含水量增强了飞灰粒子表面的化学吸附能力,使得在烟气含水量为15%和单位体积烟气注入能量小于3W.h/N,^3时,NO和NOx脱除率提高5%-15%。  相似文献   

4.
杜梅 《福建环境》1997,14(6):13-13
中性或碱性半胱酸亚铁溶液能吸收潮湿的烟道气中的NO半胱氨酸亚铁在烟道气中在由残余的O2氧化成中间产物(半胱氨酸铁)在中间物中存在电子转移反应,Fe^3+再生成Fe^2+,氧化产物胱氨酸用H2S和SO2转变成半胱氨酸,以清除烟道气中的NOx和SO2。  相似文献   

5.
水解聚合铝溶液中形态分布的定量模拟研究   总被引:27,自引:4,他引:27       下载免费PDF全文
通过Al-Ferron逐时络合比色法和 ̄(27)Al核磁共振(NMR)法,并应用“MINEQL”化学平衡模式计算法,对采用不同反应途径制得的聚合铝(PAC)溶液中的化学形态分布规律进行了定量模拟研究和对比。模式计算结果与两种实验定量分析结果都较为吻合,结果表明,在水解聚合铝溶液中较稳定的化学形态主要有五种:一种单体形态[al_a],即Al ̄(3+),Al(OH) ̄(2+),Al(OH)_2 ̄+;3种聚合形态[Al_b],即和以及一种溶胶或凝胶形态[Al_c],即Al(OH)_3(am).这些化学形态的分布和转化不仅取决于溶液的化学特征,而且也取决于制备方法的不同。  相似文献   

6.
应用超高压窄脉冲模拟治理工业烟气(常压、烟气温度180℃).CO_2、SO_2、NO_x分解率均在80%以上,把有害气体分解成单一原子组成的气体分子O_2、N_2和单质微粒S、C;同时收尘效率高达99%.是工业上治理烟气污染的高效、低成本的新技术。  相似文献   

7.
双碱法旋流板塔烟气脱硫工艺   总被引:18,自引:0,他引:18  
以旋流板塔为脱硫塔,对Na2CO3-Ca(OH)2双碱法烟气脱碱工艺进行了实验研究,对影响充率的主要因素进行考察,如再生液PH值,溶液中Na^2+浓度、SO^2-4浓度,液气比及气体中SO2初始浓度等。结果表明,选择以下工艺条件较为适宜:PH0=7-8,L/G=2-3L/同海高度  相似文献   

8.
对脉冲放电烟气除尘与脱除SO2和NOX进行实验研究与分析的结果表明,烟气中的飞灰对SO2和NOX吸附脱除2%~5%,吸附脱除量随着飞灰浓度和烟气含量的增加而增大。在单位体积烟气注入能量为4Wh/Nm3和烟气在反应器中停留时间小于3秒,飞灰与水蒸气的协同作用使SO2和NOX脱除率分别达到23%和33%。同时,脉冲放电使反应器对飞灰具有良好的协同作用,收集效率为97%。  相似文献   

9.
壳牌公司开发了从燃烧装置和化工厂排气中除去NOx的脱硝技术(SDS),并通过2000m3/h(标)小规模设备和100m3/h(标)大规模设备排气处理试验结果证明,处理效果非常理想,已被世界许多国家采用。处理原理和以前用片状催化剂多孔式脱硝技术相同。在催化剂上排气中的NOx同氨转化成对环境无害的H2O和N。使用该公司开发的基本由钛(Ti)和钒(V)组成的催化剂及侧流反应器除去排气中的NOx时,NOx分子扩散速度快,容易反应,即使在120~350℃低温下,不仅NOx脱除率高,而且运行成本既低又节能用…  相似文献   

10.
脉冲电晕烟气脱硫脱硝的化学动力学分析   总被引:13,自引:2,他引:13  
李谦  李劲 《环境科学学报》1998,18(3):236-241
对脉冲电晕等离子体条件下烟气SO2、NO气相氧化进行化学动力学模拟研究,结果表明,在气相反应中,SO2主要由OH基氧化脱除,大部分氧化物转化为H2SO4;NO的氧化则涉及与多种自由基(O,OH,HO2)及中性物种的反应,给出了SO2、NO气相氧化对主要自由基(OH基)浓度的依赖关系,以及典型实验上SO2气相净化所需的最优OH基产额,讨论了H2O和O2的行为和作用,及其含量对气象净化过程的影响;化学  相似文献   

11.
Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis (DGGE) and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity (both in gene richness and diversity index values) and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor (50 mg/kg) recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos (150 mg/kg) caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos (250 mg/kg) produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes (bands) responded differently to the impact of agrochemicals: four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.  相似文献   

12.
The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.  相似文献   

13.
In this study an effort has been made to use plant polyphenol oxidases; potato (Solanum tuberosum) and brinjal (Solanum melongena), for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.  相似文献   

14.
RemovalofheavymetalsfromsewagesludgebylowcostingchemicalmethodandrecyclinginagricultureWuQitang,NyirandegePascasie,MoCehuiF...  相似文献   

15.
A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field > tree land > fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT >1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.  相似文献   

16.
Single and joint effects of pesticides and mercury on soil urease   总被引:6,自引:3,他引:3  
The influence of two pesticides including chlorimuron-ethyl and furadan and mercury (Hg) on urease activity in 4 soils (meadow burozem and phaeozem) was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase (up to 13%-21%) in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship (P〈0.05) between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose (ED50) values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.  相似文献   

17.
A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several (halo)aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no (chloro)catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.  相似文献   

18.
Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.  相似文献   

19.
The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.  相似文献   

20.
Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus (P). In order to select suitable seed for P recovery from wastewater, three seeds including Apatite (AP), Juraperle (JP) and phosphate-modified Juraperle (M-JP) were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.  相似文献   

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