The discharge of pyridine bearing wastewater into water bodies without a prior satisfactory treatment would pose significant public health risk as well as serious threat to the aquatic ecosystems. In this study, a nat...The discharge of pyridine bearing wastewater into water bodies without a prior satisfactory treatment would pose significant public health risk as well as serious threat to the aquatic ecosystems. In this study, a natural shale from Yichang, China is investigated to determine its potential as a low-cost adsorbent for trace pyridine removal from wastewaters. The prepared shale samples without surface modification are characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Kinetics and isotherms of pyridine from aqueous solutions onto shale are investigated on the basis of the experimental data. It is found that the shale samples with well-developed porosity are mainly composed of illite, quartz, calcite, chlorite and sericite. Several kinetic models (viz. pseudo-first-order, pseudo-second-order, two-constant rate, intra-particle diffusion and Elovich) as well as isotherm models (Langmuir, Freundlich and Temkin) are applied to test the experimental data for pyridine removal. The kinetics of the adsorption of pyridine by shale follows a pseudo-second-order rate law with the adsorption data being best described by the Freundlich isotherm model. The preliminary study shows that natural shale obtained from sedimentary basins may be used as a potential low-cost adsorbent for the removal of trace pyridine from effluents.展开更多
In this paper,a viscoelasticity-plastic damage constitutive equation for naturally fractured shale is deduced,coupling nonlinear tensile-shear mixed fracture mode.Dynamic perforation-erosion on fluid re-distribution a...In this paper,a viscoelasticity-plastic damage constitutive equation for naturally fractured shale is deduced,coupling nonlinear tensile-shear mixed fracture mode.Dynamic perforation-erosion on fluid re-distribution among multi-clusters are considered as well.DFN-FEM(discrete fracture network combined with finite element method)was developed to simulate the multi-cluster complex fractures propagation within temporary plugging fracturing(TPF).Numerical results are matched with field injection and micro-seismic monitoring data.Based on geomechanical characteristics of Weiyuan deep shale gas reservoir in Sichuan Basin,SW China,a multi-cluster complex fractures propagation model is built for TPF.To study complex fractures propagation and the permeability-enhanced region evolution,intersecting and competition mechanisms between the fractures before and after TPF treatment are revealed.Simulation results show that:fracture from middle cluster is restricted by the fractures from side-clusters,and side-clusters plugging is benefit for multi fractures propagation in uniformity;optimized TPF timing should be delayed within a higher density or strike of natural fractures;Within a reservoir-featured natural fractures distribution,optimized TPF timing for most clustered method is 2/3 of total fluid injection time as the optimal plugging time under different clustering modes.展开更多
文摘The discharge of pyridine bearing wastewater into water bodies without a prior satisfactory treatment would pose significant public health risk as well as serious threat to the aquatic ecosystems. In this study, a natural shale from Yichang, China is investigated to determine its potential as a low-cost adsorbent for trace pyridine removal from wastewaters. The prepared shale samples without surface modification are characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Kinetics and isotherms of pyridine from aqueous solutions onto shale are investigated on the basis of the experimental data. It is found that the shale samples with well-developed porosity are mainly composed of illite, quartz, calcite, chlorite and sericite. Several kinetic models (viz. pseudo-first-order, pseudo-second-order, two-constant rate, intra-particle diffusion and Elovich) as well as isotherm models (Langmuir, Freundlich and Temkin) are applied to test the experimental data for pyridine removal. The kinetics of the adsorption of pyridine by shale follows a pseudo-second-order rate law with the adsorption data being best described by the Freundlich isotherm model. The preliminary study shows that natural shale obtained from sedimentary basins may be used as a potential low-cost adsorbent for the removal of trace pyridine from effluents.
基金Supported by the National Natural Science Foundation of China(52192622,52204005,U20A20265)Sichuan Outstanding Young Scientific and Technological Talents Project(2022JDJQ0007).
文摘In this paper,a viscoelasticity-plastic damage constitutive equation for naturally fractured shale is deduced,coupling nonlinear tensile-shear mixed fracture mode.Dynamic perforation-erosion on fluid re-distribution among multi-clusters are considered as well.DFN-FEM(discrete fracture network combined with finite element method)was developed to simulate the multi-cluster complex fractures propagation within temporary plugging fracturing(TPF).Numerical results are matched with field injection and micro-seismic monitoring data.Based on geomechanical characteristics of Weiyuan deep shale gas reservoir in Sichuan Basin,SW China,a multi-cluster complex fractures propagation model is built for TPF.To study complex fractures propagation and the permeability-enhanced region evolution,intersecting and competition mechanisms between the fractures before and after TPF treatment are revealed.Simulation results show that:fracture from middle cluster is restricted by the fractures from side-clusters,and side-clusters plugging is benefit for multi fractures propagation in uniformity;optimized TPF timing should be delayed within a higher density or strike of natural fractures;Within a reservoir-featured natural fractures distribution,optimized TPF timing for most clustered method is 2/3 of total fluid injection time as the optimal plugging time under different clustering modes.
