Synergetic effect of hydrochar on the transport of anatase titanium dioxide nanoparticles in the presence of phosphate in saturated quartz sand
作者：Cheng, XY (Cheng, Xueying)[ 1 ] ; Xu, N (Xu, Nan)[ 1 ] ; Huangfu, XX (Huangfu, Xinxing)[ 1 ] ; Zhou,
關鍵字：nanoparticles
論文來源：期刊
具體來源：ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
發表時間：2018年
The rapid development of nanomaterials has led to the unavoidable leakage and release of nanoparticles (NPs) into soil and the underlying groundwater. It is possible for chars and phosphate introduced into soil to improve crop soil properties by improving contact with NPs. In this study, the influences of hydrochar and/or phosphate on the anatase nTiO(2) transport behaviors were investigated under different conditions. The breakthrough curves (BTCs) and retention profiles were obtained by the saturated sand column experiments. The additional analysis of zeta potentials, sedimentation kinetics, Raman mapping, and the two-site kinetic attachment model (TSKAM) was conducted to explore the possible underlying mechanisms. The simultaneous presence of phosphate and hydrochar acted in a synergetic fashion to enhance the transport of nTiO(2) in a sand medium compared to the facilitated effect of single phosphate or hydrochar. The higher levels of hydrochar induce the more nTiO(2) in the high IC solution passing through the saturated sand columns in the co-presence of phosphate. It was attributed to the competitive adsorption of hydrochar with nTiO(2) to the sand site and the phosphate adsorption on nTiO(2) occurred simultaneously through the sand columns. The fitting results of BTCs using TSKAM showed that the value of k(2) for nTiO(2) (the irreversible attachment coefficient at site 2) was smaller than that of k(1d)/k(1) ( the first-order reversible detachment and attachment coefficient at site 1, respectively), suggesting irreversible retention of anatase nTiO(2) at site 1. The value of k(1d)/k(1) could be better used to explain the retention of nTiO(2) with combined phosphate and hydrochar. This study provides insight into the implications of phosphate and/or hydrochar for nTiO(2) transport in crop soil environments.