排序方式: 共有55条查询结果,搜索用时 15 毫秒
21.
云南省Palmer旱度模式的建立——2010年干旱灾害特征分析 总被引:1,自引:0,他引:1
2010年春季云南省发生了特大干旱灾害,造成了严重的经济损失。按照Palmer旱度模式的思路,利用云南省的气象和土壤数据,建立了云南省的Palmer旱度模式。通过将计算得到的Palmer指数值与云南省的实际旱涝灾情历史记录进行对比,发现所建立的Palmer旱度模式能够较好地反映云南省的旱涝情况。基于该模式对2010年云南特大干旱灾害进行了特征分析,结果表明,此次干旱灾害是云南省30年来干旱变化过程中的一次突变。而且结果显示,在2010年的云南干旱灾害中,严重干旱地区整体呈现东西走向的空间分布,极端干旱地区主要分布在云南省的东南部。 相似文献
22.
Hydroxylated polybrominated diphenyl ethers (HO-PBDEs) have received significant attention due to their toxicities and universal presence in the environmental matrices. However, their origins are not fully understood. We explored the feasibility of the generation of HO-PBDEs through photochemical processes from bromophenol, a commonly detected pollutant with anthropogenic source in freshwater and natural source in the marine environment. The results showed that when 2,4-dibromophenol (2,4-diBP) was irradiated in aquatic solutions under simulated sunlight, significant amounts of 2′-hydroxy-2,3′,4,5′-tetrabromodipheyl ether (2′-HO-BDE68) were rapidly formed as the dimeric product of 2,4-diBP. The formation of 2′-HO-BDE68 intensified with the increase of light intensity and with the initial concentration increase of 2,4-diBP, whereas it weakened with an increase in pH. Moreover, Fe(III) and fulvic acid played important roles in the formation of 2′-HO-BDE68. This study provides important insight into a possible source of HO-PBDEs from bromophenols in natural aquatic systems through photochemical approaches. 相似文献
23.
采用活性炭为催化剂,对微波辅助空气氧化水溶液中的五氯酚进行了处理研究。考察了活性炭投加量、微波功率、辐射时间和通气量对溶液中五氯酚的去除率的影响。结果表明,在通气量为0.2L/min,微波功率800W和微波辐射60min时,五氯酚的去除率可达到90%以上;对微波辐射前后的滤液进行紫外扫描和pH分析,可证实五氯酚被降解。 相似文献
24.
Thermal remediation of the soil contaminated with crude oil using microwave heating enhanced by carbon fiber (CF) was explored.
The contaminated soil was treated with 2.45 GHz microwave, and CF was added to improve the conversion of microwave energy into
thermal energy to heat the soil. During microwave heating, the oil contaminant was removed from the soil matrix and recovered by a
condensation system of ice-salt bath. The experimental results indicated that CF could e ciently enhance the microwave heating of
soil even with relatively low-dose. With 0.1 wt.% CF, the soil could be heated to approximately 700°C within 4 min using 800 W of
microwave irradiation. Correspondingly, the contaminated soil could be highly cleaned up in a short time. Investigation of oil recovery
showed that, during the remediation process, oil contaminant in the soil could be e ciently recovered without causing significant
secondary pollution. 相似文献
25.
Songwei Lin Yaobin Lu Bo Ye Cuiping Zeng Guangli Liu Jieling Li Haiping Luo Renduo Zhang 《Frontiers of Environmental Science & Engineering》2020,14(1):12
26.
生物滴滤法去除低浓度苯乙烯 总被引:3,自引:1,他引:2
通过装载改性聚乙烯填料的生物滴滤塔进行废气中的苯乙烯生物降解实验。结果表明,通过快速排泥法挂膜,该反应器可在较短周期内实现微生物的驯化。苯乙烯入口浓度和空床停留时间(EBRT)是影响反应器性能的重要因素,当EBRT分别为60、45、30和15 s以及对应的入口浓度分别为950、430、350和200 mg/m3时,可实现达标排放。循环喷淋液中的硝酸盐(亚硝酸盐)对生物滴滤池的影响十分明显,在初始阶段,亚硝酸根很快被耗尽,硝酸根则相对缓慢。当循环液中的TN从102.63 mg/L下降到24.24 mg/L时,滴滤池的去除效率由94.48%下降到43.16%,部分原因是降低NOx-的浓度减弱了反硝化作用对VOC碳源的利用。 相似文献
27.
腐殖酸和铁对阿特拉津光降解影响的研究 总被引:2,自引:0,他引:2
为考察除草剂在水体中的自净性能,对模拟太阳光(λ> 290 nm)下腐殖酸和铁元素对阿特拉津的光化学降解进行了研究。结果表明,单独辐照阿特拉津几乎不降解。在分别加入3、5和10 mg/L的腐殖酸时,阿特拉津的降解率分别为34.36 %、40.74%和15.66 %;在Fe(Ⅲ)投加量从0.01 mmol/L增加到0.2 mmol/L时,阿特拉津的降解率从24.36 %增加到34.97 %。而在当腐殖酸与铁共存时,阿特拉津降解率则进一步提高。紫外可见光谱和荧光光谱均表明,腐殖酸-铁络合物的形成及其光化学作用,促进了阿特拉津的降解。 相似文献
28.
Ibuprofen(IBU),a nonsteroidal anti-inflammatory drug,is becoming an important member of pharmaceuticals and personal care products(PPCPs)as emerging pollutants.To degrade IBU,magnetic Fe_3C nanoparticles embedded on N-doped carbon(Fe_3C/NC)were prepared as a catalyst by a sol–gel combustion method.As characterized,the Fe_3C/NC nanoparticles were composed of a NC nano-sheet and capsulated Fe_3C particles on the sheet.The Fe_3C/NC nanoparticles were confirmed an efficient catalyst for peroxymonosulfate(PMS)activation to generate sulfate radicals(SO_4~(·-)),single oxygen(~1O_2)and hydroxyl radicals(·OH)toward the degradation of IBU.The added IBU(10 mg/L)was almost completely removed in 30 min by using 0.1 g/L Fe_3C/NC and 2 g/L PMS.The catalyst was confirmed to have good ability and excellent reusability through leaching measurements and cycle experiments.A catalytic mechanism was proposed for the catalytic activation of PMS on Fe_3C/NC,which involves both Fe_3C reactive sites and N-doped carbon matrix as reactive sites in Fe_3C/NC.Moreover,the degradation pathway of IBU in the Fe_3C/NC-PMS system was proposed according to the detections of degradation intermediates. 相似文献
29.
以江苏某典型正规电子废弃物拆解厂为研究对象,在实测排放源数据的基础上,采用Calpuff大气扩散模式模拟其排放的多溴联苯醚(PBDEs)和重金属Pb、Cd大气浓度的区域与局部空间分布,进而对所排放PBDEs、Pb和Cd导致的健康风险进行评估.研究结果表明:在气象条件最为不利的情景下,污染物在东北、西南方向污染物扩散行为显著.PBDEs、Pb和Cd在区域空间范围的大气浓度最大值分别为3×10~(-6)、8.6×10~(-5)和3.6×10~(-6)μg·m~(-3),而局部范围的浓度则会高出一个数量级;其中BDE-209对于PBDEs的大气浓度贡献可达77%.在局部范围内,以HQ表达的PBDEs和Pb健康风险数值均在10~(-3)以下,非致癌健康风险极低;BDE-209和Cd的终生致癌风险最大值为1.10×10~(-12)与6.32×10~(-7),致癌风险可以忽略.该评估表明,正规操作的电子废弃物拆解厂的大气污染物不会对公共健康造成不可控风险. 相似文献
30.