Tao Huan-yu,Ge Hui,Shi Jianghong,Liu Xiaowei,Guo Wei,Zhang Mengtao,Meng Yaobin,Li Xiao-yan
Abstract In this study, the effect of biochar (BC) derived from Litchi chinensis Sonn. and its modification, including Ca-biochar (Ca-BC) and Fe–Mn-biochar (Fe–Mn-BC), on the transportation of oestrone (E1) in water and soil was investigated. Fe–Mn-BC showed better adsorption ability than other types of biochar (BC, Ca-BC) under different conditions (humic acid, pH, ionic strength) in an aqueous environment. The maximum mass of sorbent at 298 K increased from 1.12 mg g −1 (BC) to 4.18 mg g −1 (Fe–Mn-BC). Humic acid had a greater impact on aqueous E1 adsorption on these biochars than did the pH and ionic strength. Fe–Mn-BC as a soil amendment had a great control of E1 transport in soil, and no leachate of E1 was observed in the column experiment. E1 mobility showed strong retardation in amended soil with Ca-BC ( R f = 11.2) compared with raw soil ( R f = 7.1). These results suggested that Fe–Mn-BC was more effective in controlling E1 transportation, and Fe–Mn-BC could be used as an alternative and inexpensive adsorbent to reduce E1 contaminants from water and soil. Graphic abstract
Qianqian Geng,Jingchan Xie,Xin Wang,Mengling Cai,Hui Ma,Hanwen Ni
A water-soluble inclusion complex for butachlor was prepared by complexation with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD). Phase solubility results indicated a 1:1 stoichiometric ratio with an apparent stability constant of 864.3 M–1 in the obtained solid complex. The formation of the complex was confirmed by 1H nuclear magnetic resonance, Fourier transform infrared, and differential scanning calorimetry spectra. Coupled with the molecular docking results, butachlor was considered to be completely included in HP-β-CD cavity. Butachlor complexation with HP-β-CD decreased its adsorption capacity and enhanced its mobility in soil. The inclusion complex displayed better herbicidal activities than free butachlor. The 96 h median lethal concentration values of the inclusion complex and free butachlor was 2.30 and 0.65 mg L–1, respectively, for zebrafish, indicating that the complexation could significantly reduce toxicity to fishes. The present study provides an approach to develop environment-friendly formulations using CDs for herbicides.
The small particle size of nanoplastics allows them to migrate through soil and make them highly bioavailable, posing a potential threat to groundwater. Measures are urgently needed to reduce the migration of nanoplastics in soil. However, there is limited research available on this topic. In this study, two types of iron-modified biochar (magnetic corncob biochar (MCCBC) and magnetic walnut shell biochar (MWSBC)) were selected and their effects on the transport of polyvinyl chloride nanoplastics (PVC-NPs) in natural sandy soil columns under different ionic types and strengths were investigated. The results show that the transport of PVC-NPs in single sandy soil columns was rapid and efficient, with the estimated breakthrough rate of 85.10%. However, the presence of MCCBC and MWSBC (0.5%, w/w) significantly inhibited the transport of PVC-NPs in sandy soil columns ( p < 0.05), and MCCBC had a stronger inhibitory effect on the transport of PVC-NPs than MWSBC. This can be attributed to the fact that the adsorption of PVC-NPs on adsorbents followed the order as: MCCBC > MWSBC > sandy soil. The retention of PVC-NPs by MCCBC and MWSBC is determined by ionic type and ionic strength. The presence of coexisting ions enhanced the inhibitory effect of iron-modified biochar on the transport of PVC-NPs, with the following order: Ca 2+ > SO2- 4 > Cl − > NO- 3. The inhibitory effect of MCCBC and MWSBC on the transport of PVC-NPs in soil columns increased with increasing ionic strengths. Furthermore, MCCBC and MWSBC inhibited the migration of PVC-NPs in a rainwater-soil system. The mechanisms by which MCCBC and MWSBC affect the transport of PVC-NPs in soil columns were considered to enhancing adsorption and decreasing soil pore volume. The results provide new insights into the management of soil nanoplastic pollution.
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