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氧化石墨烯和五价砷在改性多孔介质中的共迁移特征
引用本文:孟庆涛,管多,姜延吉,孙慧敏,殷宪强,王农.氧化石墨烯和五价砷在改性多孔介质中的共迁移特征[J].农业工程学报,2020,36(17):142-148.
作者姓名:孟庆涛  管多  姜延吉  孙慧敏  殷宪强  王农
作者单位:中国科学院西北生态环境资源研究院,兰州 730000;中国科学院大学,北京 100049;西北农林科技大学资源环境学院,杨凌 712100;西北农林科技大学资源环境学院,杨凌 712100;农业农村部环境保护科研监测所,天津 300191
基金项目:国家重点研发计划(2018YFC1800600);国家自然科学基金面上项目(41877018,41771260);陕西省重点研发项目(2018ZDXM-SF-030,2017SF-377)
摘    要:砷是农田土壤重金属污染的主要元素之一,在砷污染农田土壤的修复过程中往往忽视纳米颗粒能够使结合态的砷重新释放,导致有效态砷浓度升高,探究土壤中黏土矿物对氧化石墨烯(Graphene Oxide,GO)和五价砷(As(V))在多孔介质中迁移行为的影响,对进一步完善农田土壤砷修复理论以及提高农作物产量、保护人体健康具有重要意义。该研究利用蒙脱石和高岭石改性石英砂,通过砂柱迁移试验系统地研究了GO、As(V)和GO-As(V)在填加0%、10%、30%和50%的蒙脱石和高岭石改性石英砂柱中的迁移行为。研究结果表明,随着高岭石和蒙脱石改性石英砂填加比例的增加,GO和As(V)的迁移能力均呈降低趋势,且GO和As(V)在不同条件下的迁移曲线均存在显著差异(P0.05);GO在50%高岭石和蒙脱石改性石英砂柱中的回收率相对于石英砂柱分别下降了14%和17%,As(V)分别下降了15%和12%;在共迁移试验中,GO和As(V)在石英砂柱中回收率分别上升至99%和100%。分析表明,As(V)在蒙脱石改性石英砂柱中的迁移能力大于高岭石改性石英砂,而GO与之相反;当GO和与As(V)共迁移时,二者在介质中的迁移能力均大于其单独迁移。本研究表明GO、As(V)释放到土壤后,能够加速As(V)的迁移,造成土壤砷污染的扩大化。

关 键 词:重金属  土壤    氧化石墨烯  高岭石  蒙脱石  五价砷  迁移
收稿时间:2020/4/25 0:00:00
修稿时间:2020/7/22 0:00:00

Co-transport characteristics of graphene oxide and pentavalent arsenic in modified porous media
Meng Qingtao,Guan Duo,Jiang Yanji,Sun Huimin,Yin Xianqiang,Wang Nong.Co-transport characteristics of graphene oxide and pentavalent arsenic in modified porous media[J].Transactions of the Chinese Society of Agricultural Engineering,2020,36(17):142-148.
Authors:Meng Qingtao  Guan Duo  Jiang Yanji  Sun Huimin  Yin Xianqiang  Wang Nong
Institution:1.Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; 2.University of Chinese Academy of Sciences, Beijing 100049, China; 3. College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China;; 4. Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China;
Abstract:Arsenic is one of the main elements of heavy metal pollution in farmland soil. In the process of remediation of arsenic-contaminated farmland soil, it is often overlooked that nanoparticles can re-release the bound arsenic, leading to an increase in the effective arsenic concentration. Due to its high specific surface area and strong adsorption capacity, Graphene Oxide (GO) can be used as a carrier of pollutants to carry pollutants and migrate in groundwater environments. However, researches on the transport behavior of anions Arsenic (As(V)) and GO have not been reported. Clay minerals are more active solid components in the soil and play an important role in affecting the migration and transformation of pollutants. Exploring the influence of clay minerals in the soil on the transport behavior of GO and As(V) in porous media is of great significance for improving the theory and model of the fate and transport of nanoparticles and As(V) in the soil, and protecting the soil-groundwater environment. In this study, the influence of clay minerals on the transport behavior of GO and pentavalent As(V) in porous media was investigated. The montmorillonite and kaolinite were used to modify the quartz sand, and the surface characteristics of the modified quartz sand were characterized by a scanning electron microscope and energy dispersive spectrometer. The migration behavior of GO, As(V) and GO-As(V) in 0, 10%, 30%, and 50% montmorillonite and kaolinite modified quartz sand column was systematically studied by sand column transport experiment. The difference of the effect of different addition ratios on the transport of As(V) and GO was analyzed with the t-test (paired sample test), and the transport behavior of GO colloids in porous media was explained with Darjaguin-Landau-Verwey-Overbeek (DLVO) theory. The research results showed that the kaolinite particles coated on the surface of quartz sand were separated between particles, and the size was different. The montmorillonite particles coated on the surface of the quartz sand were stacked layer by layer in the shape of an amorphous sheet with a pore-shaped structure. GO and As(V) alone had high mobility in porous media. GO and As(V) both had high mobility in pure quartz sand column, and the recovery rates were 96% and 94%, respectively. The proportion of kaolinite and montmorillonite modified quartz sand added was increased to 10%, 30%, and 50%. The migration ability of GO and As(V) all showed a decreasing trend, there were significant differences in the migration curves of GO and As(V) under different conditions (P<0.05). The recovery rate of GO in the 50% kaolinite modified quartz sand column was 14% lower than that of the quartz sand column, and the recovery rate in the montmorillonite modified quartz sand column was reduced by 17%, while the As(V) decreased by 15% and 12% respectively. When both GO and As(V) existed in the solution, the Zeta potential of GO decreased from -21.3 to -26.7 mV. The presence of As(V) increased the negative charge carried on the GO surface and increased the repulsive force with the surface of the medium. On the other hand, it showed that GO could be used as a carrier of As(V) to carry As(V) for migration. Therefore, the migration ability of GO and As(V) in kaolinite and montmorillonite modified quartz sand was greater than their transport alone. The analysis showed that the mobility of As(V) in the montmorillonite modified quartz sand column was greater than that of kaolinite modified quartz sand, while the mobility of GO was opposite. When both GO and As(V) existed in the solution, the mobility of both in the medium was greater than their transport alone. The transport behavior of GO in packing modified quartz sand with different proportions was consistent with the DLVO theory. This study showed that they could accelerate the transport of As(V) and caused the expansion of soil arsenic pollution after GO and As(V) being released into the porous media.
Keywords:heavy metals  soils  water  graphene oxide  kaolinite  montmorillonite  As(V)  transport
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