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971.
Effects and mechanisms of meta-sodium silicate amendments on lead uptake and accumulation by rice 总被引:1,自引:0,他引:1
Mingliu Zhao Yuting Liu Honghong Li Yifan Cai Ming Kuang Wang Yanhui Chen Tuanhui Xie Guo Wang 《Environmental science and pollution research international》2017,24(27):21700-21709
The objectives of this research were to study the effects of Na2SiO3 application on the uptake, translocation, and accumulation of Pb in rice and to investigate the mechanisms of Pb immobilization by Na2SiO3 in paddy rice soils and rice plants. Pot experiments were conducted using a Cd-Pb-Zn-polluted soil and Oryza sativa L. ssp. indica cv. Donglian 5. L3-edge X-ray absorption spectroscopy was used to identify Pb species in soils and roots. The results showed that the application of Na2SiO3 increased soil pH and available soil Si but decreased DTPA-extractable Pb in the soil. High dose of Na2SiO3 (12.5 g/kg) reduced the Pb level in brown rice as it inhibited Pb transfer from soil to rice grains, especially Pb transfer from the root to the stem. The Pb X-ray absorption near-edge spectroscopic analysis revealed that application of high dose of Na2SiO3 increased Pb-ferrihydrite and PbSiO3 precipitates in the soil and in the root while it reduced Pb-humic acids (Pb-HAs) in the soil and Pb-pectin in the root. The decrease in Pb availability in the soil can be partly attributed to increase the precipitation of PbSiO3 and the association of Pb2+ with Fe oxides in the soil. The inhibition of the root-to-stem translocation of Pb was partially due to the precipitation of PbSiO3 on the root surfaces or inside the roots. 相似文献
972.
973.
针对破乳剂成分与结构对油田采出水破乳脱稳的影响机制仍不明确的问题,依据新疆油田二元驱实际采出水组成配制模拟二元复合驱采出水,考察有机破乳剂种类和结构及无机电解质对其破乳脱稳的影响.结果表明,合成有机破乳剂的起始剂种类对破乳脱稳的影响较大,起始剂含量具有一定影响,而EO/PO比的影响相对较小.PAC和Al2(SO4)3的破乳脱稳效果最好,投加量500 mg/L时均能将剩余含油量降低到10 mg/L以下;而FeSO4和ZnSO4次之,NH4Cl较差.破乳剂通过电性中和及与HPAM形成的协同絮凝作用,促进了油滴的碰撞聚并,达到了较好的破乳脱稳效果. 相似文献
974.
通过溶胶-凝胶法制备了同时具有可见光(Vis)光催化和Fenton催化双重活性的Co-TiO2催化剂。通过对比Vis/Co-TiO2/KHSO5、Co-TiO2/KHSO5和Vis/Co-TiO23种体系对苯酚的降解效果,Vis/Co-TiO2/KHSO5表现出明显的Fenton-光催化协同作用。进一步研究pH值、KHSO5与苯酚摩尔比(nKHSO5∶nC6H6O)和Co-TiO2投加量(mCo-TiO2)对Fenton-光催化协同降解苯酚效果的影响。结果表明,pH=6.9、nKHSO5∶nC6H6O=10∶1、mCo-TiO2=1.0 g/L时,降解率达100%。最后,结合XRD、XPS和UV-DRS等手段和催化活性实验数据分析了Vis/Co-TiO2/KHSO5体系的催化机理。 相似文献
975.
三明市酸、碱降水成因研究 总被引:4,自引:0,他引:4
三明市属福建省内陆山区,在东、西相差仅四公里的两个测点,常常一边下硫酸盐型酸雨,一边下钙盐型碱雨这一特殊降水过程。从离子成分、离子浓度比进行分析,并从局地污染源、气象等因素就其成因作了探索性研究,将影响降水pH值的污染因子进行灰色关联优势分析。结果表明,三明市降水污染相当严重,在重视酸性降水污染的同时,也不应忽视污染更为严重的碱性降水 相似文献
976.
Xuan Huang Jing Zheng Min Chen Yangyu Zhao Chunlei Zhang Lifu Liu Weiwei Xie Shuqiong Shi Yuan Wei Dongzhu Lei Chenming Xu Qichang Wu Xiaoling Guo Xiaomei Shi Yi Zhou Qiufang Liu Ya Gao Fuman Jiang Hongyun Zhang Fengxia Su Huijuan Ge Xuchao Li Xiaoyu Pan Shengpei Chen Fang Chen Qun Fang Hui Jiang Tze Kin Lau Wei Wang 《黑龙江环境通报》2014,34(4):335-340
977.
Zheng-Tong Xie Ian P. Castro 《Atmospheric environment (Oxford, England : 1994)》2009,43(13):2174-2185
Large-eddy simulations (LES) with our recently developed inflow approach (Xie, Z.-T., Castro, I.P., 2008a. Efficient generation of inflow conditions for large-eddy simulation of street-scale flows. Flow Turbul. Combust., vol. 81(3), pp. 449–470.) have been used for flow and dispersion within a genuine city area – the DAPPLE site, located at the intersection of Marylebone Rd and Gloucester Pl in Central London. Numerical results up to second-order statistics are reported for a computational domain of 1.2 km (streamwise) × 0.8 km (lateral) × 0.2 km (in full scale), with a resolution down to approximately one meter in space and one second in time. They are in reasonable agreement with the experimental data. Such a comprehensive urban geometry is often, as here, composed of staggered, aligned, square arrays of blocks with non-uniform height and non-uniform base, street canyons and intersections. Both the integrative and local effect of flow and dispersion to these geometrical patterns were investigated. For example, it was found that the peaks of spatially averaged urms, vrms, wrms and <u′w′> occurred neither at the mean height nor at the maximum height, but at the height of large and tall buildings. It was also found that the mean and fluctuating concentrations in the near-source field is highly dependent on the source location and the local geometry pattern, whereas in the far field (e.g. >0.1 km) they are not. In summary, it is demonstrated that full-scale resolution of around one meter is sufficient to yield accurate prediction of the flow and mean dispersion characteristics and to provide reasonable estimation of concentration fluctuations. 相似文献
978.
979.
980.
研究了以城市垃圾中3种典型的固体有机废弃物——锯木屑、纸张和塑料的热解产物(分别简称木炭、纸炭和塑料热解物)为原料,水蒸气为活化剂制备废弃物基活性炭时钙化物含量对活化过程、活性炭吸附性能(以碘值表征)及其孔结构的影响。结果表明,钙化物可加快活化反应的速度,且钙化物含量在1.5%时活化反应速度即已不再随钙化物含量的增加而增加;活性炭的吸附性能则随钙化物含量的增加而减少,同时钙化物对活性炭的孔径分布基本无影响,但降低了活性炭的比表面积、微孔孔容及中孔孔容;钙化物的2种前驱体(即CaO和Ca(OH)2)对活化过程具有相同的催化作用。 相似文献