| 1 | Multiple effects of nitrate amendment on the transport, transformation and bioavailability of antimony in a paddy soil-rice plant system显示文摘Nitrate(NO3^(-))is known to be actively involved in the processes of mineralization and heavy metal transformation;however,it is unclear whether and how it affects the bioavailability of antimony(Sb)in paddy soils and subsequent Sb accumulation in rice.Here,the effects of NO3^(-)on Sb transformation in soil-rice system were investigated with pot experiments over the entire growth period.Results demonstrated that NO3^(-)reduced Sb accumulation in brown rice by 15.6%compared to that in the control.After amendment with NO3^(-),the Sb content in rice plants increased initially and then gradually decreased(in roots by 46.1%).During the first 15 days,the soil p H increased,the oxidation of Sb(Ⅲ)and sulfides was promoted,but the reduction of iron oxide minerals was inhibited,resulting in the release of adsorbed and organic-bound Sb from soil.The microbial arsenite-oxidizing marker gene aox B played an important role in Sb(Ⅲ)oxidation.From days 15 to 45,after NO3^(-)was partially consumed,the soil p H decreased,and the reductive dissolution of Fe(Ⅲ)-bearing minerals was enhanced;consequently,iron oxide-bound Sb was transformed into adsorbed and dissolved Sb species.After day 45,NO3^(-)was completely reduced,Sb(V)was evidently reduced to Sb(Ⅲ),and green rust was generated gradually.Thus,the available Sb decreased due to its enhanced affinity for iron oxides.Moreover,NO3^(-)inhibited the reductive dissolution of iron minerals,which ultimately caused low Sb availability.Therefore,NO3^(-)can chemically and biologically reduce the Sb availability in paddy soils and alleviate Sb accumulation inrice.This study provides a potential strategy for decreasing Sb accumulation in rice in the Sb-contaminated sites. | Xiaofeng Zhang Tongxu Liu Fangbai Li Xiaomin Li Yanhong Du Huanyun Yu Xiangqin Wang Chuanpin Liu MiFeng Bing Liao | 2021 | Journal of Environmental Sciences2021，33，2： | 6 |
| 2 | Effect of Rubber Particle Modifi cation on Properties of Rubberized Concrete显示文摘To improve the combination of cement matrix and waste tire rubber particles in concrete, the rubber particles were treated with acrylic acid(ACA) and polyethylene glycol(PEG) for grafting hydrophilic groups on their surfaces. The X-Ray photoelectron spectroscopy(XPS) and surface contact angle were used to characterize the hydrophilicity and surface functional group of rubber particles. The effect of rubber particle modifi cation on fresh/hardened properties of rubberized concrete was studied. The experimental results show that the contact angle between rubber particle surface and water decreases when rubber particle is modifi ed. Compared with the unmodifi ed rubberized concrete(RC), the unit weight of modifi ed rubberized concrete(MRC) changes slightly. However, the slump, air-entrainment, compressive strength, flexural strength, and impact performance of MRC are obviously improved. Under good condition of slump, the water-cement ratio of the MRC can be reduced from 0.4 to 0.38. And the compressive strength and fl exural strength of the MRC(10% rubber particle content) can be increased by 25.9% and 26.4%, respectively. | 张海波 GOU Mifeng LIU Xiaoxing 管学茂 | 2014 | Journal of Wuhan University of Technology(Materials Science)2014，29，4： | 6 |
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