Distinguishable Transport Behavior of Zinc Oxide Nanoparticles in Silica Sand and Soil Columns
As part of ongoing risk assessments of ZnO nanoparticles (nZnO) in the natural environment,transport behaviors of nZnO in soil need investigation.This work comparatively studied the transport and retention behavior of nZnO in silica sand versus soil,where the effect of input concentration (C0 = 34 ~ 430 mg L-1) and ionic strength (IS =1~50 mM) were investigated.In silica sand,nZnO were highly mobile,especially at low C0 and the efflux of nZnO generally decreased with increasing C0 at all tested IS.Conversely,at low C0,n ZnO were almost entirely immobile in soil and the efflux of nZnO increased with C0 at all tested IS.In both media,the retention profiles (RPs) were generally hyper-exponentially shaped suggesting nZnO easily deposited near the column inlet.As indicated by DLVO calculations,previously deposited nZnO on the silica sand surface acted as new deposition sites due to the lower energy barrier (Φmax) between nZnO-nZnO than between nZnO-silica sand.However,previously deposited nZnO in soil could enhanceΦmax between the soil surface and nZnOwhich resulted in unfavorable sites for nZnO deposition.The two-site kinetic attachmentmodel provided good descriptions for the breakthrough curves of nZnO.Detachment wasmore significant than attachment in silica sand (k1d N k1a),whereas soil surface attachment of nZnO were strong and irreversible (k1a N k1d).The straining interaction parameter (k2str) increased with increasing C0 in silica sand,but decreased with C0 in soil.Such differences were mainly responsible for the various transport behaviors of nZnO in silica sand and soil.
ZnO nanoparticles transport silica sand soil concentration modeling
Peide Sun Altantuya Shijirbaatar Jing Fang Gary Owens Daohui Lin Keke Zhang
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, P. Environmental Contaminants Group, Mawson Institute, University of South Australia, Mawson Lakes, Sou Department of Environmental Science, Zhejiang University, Hangzhou 310058, P. R. China
国内会议
杭州
英文
189-198
2014-11-13（万方平台首次上网日期，不代表论文的发表时间）