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881.
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使用半连续式不锈钢搅拌反应釜,研究了质量分数30%的乙醇胺(MEA)水溶液(CO2负载量0.4 mol·mol-1)的热降解-氧化降解循环过程,旨在探讨循环过程对MEA降解的影响,以及SO2对MEA热降解、氧化降解和循环过程产生的影响.其中,热降解的实验条件为120℃,降解时间为2周,在密闭反应器内进行;氧化降解的实验条件为55℃,约121.59 kPa,向溶液中持续通入模拟烟气,总气量为7.5 L·min-1,其中包括2%CO2、0~150 ppm SO2和空气.实验结果表明,在先进行热降解再进行氧化降解的过程中,MEA的热降解产物N-(2-羟乙基)乙二胺等会在氧化降解的过程中发生进一步反应,且原本氧化降解中生成的亚硝酸根会有部分进一步被氧化,生成硝酸根.在循环过程中,MEA的整体降解程度比单独进行热降解、氧化降解实验中有所提高.研究表明,添加亚硫酸根会加剧热降解中的氨气生成量,而在氧化降解中,SO2又表现出了明显的抑制作用.在循环过程中,这两者均有体现,SO2仍起到一定的抑制降解的作用. 相似文献
884.
Influence of sunlight on the proliferation of cyanobacterial blooms and its potential applications in Lake Taihu, China 总被引:2,自引:0,他引:2
To learn the relationship between sunlight intensity and cyanobacterial proliferations for the further control of the heavy blooms, enclosure experiment were conducted in Meiliang Bay, Lake Taihu by regulating the natural light intensities with different shading ratio (0% (full sunlight), 10%, 25%, 50% and 75% of original natural sunlight intensities) from September to November in 2010. The results indicated that phytoplankton biomass (mean) decreased significantly when the shading ratios reached 50% or more. Higher shading ratios (e.g. 75%) were very efficient in controlling the average and total cyanobacterialbloom biomass, while 50% shading ratio was proven very effective either in controlling the peak value of phytoplankton biomass or postponing the occurrence of cyanobacterial blooms in Lake Talhu. In addition, phytoplankton composition and photosynthesis efficiency were also affected by altering the shading ratios, and in turn, they might also act on phytoplankton growth. Based on the results from the present study, intermediate shading strategies such as regulation of water level or turbidity through the hydrology regulations would probably be an effective and efficient method in controlling cyanobacterial blooms in large and shallow lakes. 相似文献
885.
随着近几年中小城市发展进程的加快,城市中日益暴露出各方面的问题与弊端,污水治理问题显得尤为突出和严重。污水排放大量增加对我国中小城市水环境造成了严重的污染和破坏,因此对污水处理技术的选择与考量十分迫切。基于我国国情,我国是发展中国家,财力有限。因此用于基础设施上的资金在大城市和中小城镇之间的分配比重严重失衡,中小城镇污水的处理率相对较低。这就决定了中小城镇在选择污水处理技术时,首先要考虑的因素必须是经济、高效、节能和简便易行。 相似文献
886.
电芬顿反应原理研究进展 总被引:6,自引:0,他引:6
电芬顿法作为一种新型电化学氧化技术,因其强氧化能力以及环境友好的特性引起了国内外的广泛关注.电芬顿反应通过电极产生H2O2和(或)Fe2+,进行一系列反应生成具有强氧化能力的羟基自由基·OH.为了提高电子传递速度,产生更多芬顿试剂,国内外学者研发出不同类型的电芬顿反应器.通过分析电芬顿反应中·OH浓度与有机物浓度间的关系,大多数学者在准一级反应动力学基础上确定了反应常数,然而,目前其应用仍只停留在实验室阶段,电芬顿技术的效率及机理仍需要进一步研究改进. 相似文献
887.
888.
为研究动载下高密度全尾砂胶结充填体(HTB)的稳定性,制备直径为50 mm×25 mm的HTB试件,进行静态单轴压缩试验。首次采用分离式霍普金森杆(SHPB)装置研究HTB的动态力学性质,通过观察冲击试验后试件的破坏程度,来评判高应变率下试件的稳定性。结果表明:HTB试件波阻抗较小,对弹性应力波传播有较强的阻尼作用;在冲击载荷下,试件最大应变率可达305 s-1,动态抗压强度随着应变率的增加而增大,最大动态抗压强度为17 MPa;HTB试件的稳定性与应变率密切相关,当应变率低于10 s-1时,试件稳定性较好;当应变率为10~39 s-1时,试件产生一定的损伤裂纹,但尚有一定的残余强度;当应变率大于39 s-1时,试件完全失稳。 相似文献
889.
Ammonia volatilization from a Chinese cabbage field under different nitrogen treatments in the Taihu Lake Basin, China 总被引:5,自引:0,他引:5
Ammonia(NH_3) volatilization is a major pathway of nitrogen(N) loss from soil-crop systems.As vegetable cultivation is one of the most important agricultural land uses worldwide,a deeper understanding of NH_3 volatilization is necessary in vegetable production systems.We therefore conducted a 3-year(2010–2012) field experiment to characterize NH_3 volatilization and evaluate the effect of different N fertilizer treatments on this process during the growth period of Chinese cabbage.Ammonia volatilization rate,rainfall,soil water content,p H,and soil NH_4~+were measured during the growth period.The results showed that NH_3 volatilization was significantly and positively correlated to topsoil p H and NH4+concentration.Climate factors and fertilization method also significantly affected NH_3 volatilization.Specifically,organic fertilizer(OF) increased NH_3 volatilization by 11.77%–18.46%,compared to conventional fertilizer(CF,urea),while organic–inorganic compound fertilizer(OIF) reduced NH_3 volatilization by 8.82%–12.67% compared to CF.Furthermore,slow-release fertilizers had significantly positive effects on controlling NH_3 volatilization,with a 60.73%–68.80% reduction for sulfur-coated urea(SCU),a 71.85%–78.97% reduction for biological Carbon Power~#174; urea(BCU),and a 77.66%–83.12% reduction for bulk-blend controlled-release fertilizer(BBCRF)relative to CF.This study provides much needed baseline information,which will help in fertilizer choice and management practices to reduce NH_3 volatilization and encourage the development of new strategies for vegetable planting. 相似文献
890.
It remains unclear whether dicofol should be defined as a persistent organic pollutant. Its environmental persistence has gained attention. This study focused on its degradation by cellulase. Cellulase was separated using a gel chromatogram, and its degradation activity towards dicofol involved its endoglucanase activity. By analyzing the kinetic parameters of cellulase reacting with mixed substrates, it was shown that cellulase reacted on dicofol and carboxyl methyl cellulose through two different active centers. Thus, the degradation of dicofol was shown to be an oxidative process by cellulase. Next, by comparing the impacts of tert-butyl alcohol (a typical OH free-radical inhibitor) on the removal efficiencies of dicofol under both cellulase and Fenton reagent systems, it was shown that the removal of dicofol was initiated by OH free radicals produced by cellulase. Finally, 4,4′-dichloro-dibenzophenone and chloride were detected using gas chromatography mass spectrometry and ion chromatography analysis, which supported our hypothesis. The reaction mechanism was analyzed and involved an attack by OH free radicals at the orthocarbon of dicofol, resulting in the degradation product 4,4′-dichloro-dibenzophenone. 相似文献