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| Removal capacity of silver nanoparticles by different carbon-based materials |
| Received:December 05, 2017 |
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| KeyWord:carbon-based materials;silver nanoparticles;removal;sorption mechanisms |
| Author Name | Affiliation | E-mail | | LIU Long-fei | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer, College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | LIU Yan-li | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer, College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | LI Cheng-liang | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer, College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | chengliang_li11@163.com | | LI De-yun | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer, College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | QU Zhao-ming | National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer, College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | |
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| Abstract: |
| In the present study, silver nanoparticles (Ag NPs) with good stability were synthesized, and we investigated their adsorption characteristics of biochar (BC), multi-walled carbon nanotubes (CNTs), and graphene (GP). The effects of environmental factors (ionic strength, ionic species, and solution pH) on the Ag NPs adsorption were also researched. The results showed that the pseudo-second order model better simulated the Ag NPs diffusion process. The Ag NPs adsorption rate was controlled by internal diffusion and other processes, and the adsorption equilibrium was reached within 240 min. The Langmuir model better reflected the isotherms of Ag NPs on carbon-based materials than the Freundlich model, and the Ag NPs adsorption capacities of BC, CNTs, and GP were 69.15, 87.78 mg·g-1, and 121.21 mg·g-1, respectively. The Ag NPs adsorption amount was not affected significantly by the increasing strength of Na+, while increasing Ca2+ strength had a completely opposite result. The pH value of the electrolyte solution had a strong influence on Ag NPs adsorption. Acidic conditions promoted the adsorption of Ag NPs, and alkaline conditions obviously inhibited the process. BC adsorbed Ag NPs by complexation, ion exchange, precipitation, and electrostatic interaction, while CNTs and GP fixed the Ag NPs mainly through electrostatic interaction and Van der Waals forces. These results would be beneficial for an environmental risk assessment of Ag NPs. |
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