球磨纳米生物质炭在饱和多孔介质中的迁移与滞留机制  

Mechanisms of Transport and Retention of Ball-milled Nano-biochar in Saturated Porous Media

作　　者：樊建新[1] 唐文巧 吴兴钰 石姣 FAN Jianxin;TANG Wenqiao;WU Xingyu;SHI Jiao(School of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]重庆交通大学河海学院,重庆400074

出　　处：《土壤》2024年第4期849-856,共8页Soils

基　　金：国家自然科学基金项目(41977337);重庆市自然科学基金项目(CSTB2022NSCQ-MSX0394);重庆市研究生科研创新项目(CYS23492)资助。

摘　　要：利用球磨纳米生物质炭模拟老化产生的纳米生物质炭,通过一维柱迁移试验研究了不同背景溶液离子强度(IS)、pH和流速对球磨纳米生物质炭在饱和多孔石英砂介质中迁移与滞留行为的影响,并运用对流弥散模型拟合穿透与滞留曲线得到沉积速率系数等运移参数,结合DLVO理论研究影响作用机制。结果表明:背景溶液IS降低,pH和流速升高,球磨纳米生物质炭的迁移率明显提高。这是由于在低IS和高pH条件下,球磨纳米生物质炭和石英砂的电负性增加,从而增强了两者之间的静电斥力,同时球磨纳米生物质炭之间具有更好的分散性,有助于球磨纳米生物质炭的迁移;在高流速条件下,球磨纳米生物质炭在石英砂柱中的滞留时间因为平流扩散而减短,同时水流剪切作用力增大不利于颗粒在石英砂上的吸附,有助于球磨纳米生物质炭的迁移。Ball-milled nano-biochar was used to simulate the nano-biochar produced in aging process in this study,and one-dimensional column transport experiments were carried out to investigate the effects of ionic strengths(IS),pH and flow velocity of different background solutions on the transport and retention characteristics of ball-milled nano-biochar in quartz sand porous media.The convective dispersion model and DLVO theory were used to fit the breakthrough and retention curves,and the transport parameters such as deposition rate coefficients were obtained.The results showed that the transport rate of ball-milled nano-biochar was significantly increased under low IS,high pH and high flow velocity conditions.Due to the negative increases of Zeta potentials of both ball-milled nano-biochar and quartz sand under low IS and alkaline environments,which enhanced the electrostatic repulsion between them.In addition,the high dispersion of ball-milled nano-biochar in alkaline environment enhanced the migration of ball-milled nano-biochar.Moreover,the residence time of ball-milled nano-biochar in quartz sand column was decreased with the increase of water flow velocity due to advection diffusion.Meanwhile,the increase of shear force took a disadvantage on the sorption of nanoparticles on quartz sand.

关 键 词：球磨纳米生物质炭 柱试验 迁移与滞留 作用机制 DLVO理论 迁移模型 

分 类 号：X53[环境科学与工程—环境工程]