The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and ...The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals.This paper explored for the first time the interaction mechanism between natural rubber latex(NRL)and bentonite suspensions(BTs)through a series of characterization experiments,as well as the potential applications in water-based drilling fluids(WBDF).The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient(k)and flow index(n)of BTs,and enhance the shear thinning performance of BTs as pseudo-plastic fluids.In addition,0.5 w/v%NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles,but also facilitated the compatibility of pressure loss and flow efficiency.The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles,and optimize the particle size distribution and flow resistance of WBDF under the"intercalation-exfoliation-encapsulation"synergistic interaction.Moreover,NRL can improve the rheological properties of WBDF at high temperatures(<150.C),and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake,which ultimately reduces the permeability of the cake and the filtration loss of WBDF.展开更多
Sorption of radioisotopes onto a stable colloidal phase may significantly enhance their transport in groundwater. The adsorption of cesium （Cs＋） and strontium （St^＋＋ ） from aqueous solutions onto commercial nat...Sorption of radioisotopes onto a stable colloidal phase may significantly enhance their transport in groundwater. The adsorption of cesium （Cs＋） and strontium （St^＋＋ ） from aqueous solutions onto commercial natural bentonite （NB） was studied as a function of contact time, temperature, bentonite mass and bentonite treatment （washing and heat treatment） on the uptake of these cations, independently. The heat treatment was 700 ℃ and washed bentonite samples termed by CB and WB respectively. Batch experiments results showed that the adsorptive capacity of NB at 293,298 and 308 K for Cs^＋ and Sr^＋＋ were 110,105, 104 and 35, 33.6, 31.8 mg/g respectively. The experimental results for strontium adsorption 293, 298 and 308 K fit well to a Langmuirian and Frendlich type isotherm but cesium adsorption fit better with Langmuir than Frendlich isotherm. Thermodynamic functions, the change of free energy （△G°）, enthalpy （△H°） and entropy （AS°） of adsorption were also calculated for each cation. These parameters showed that the adsorption of Cs^＋ and Sr^＋＋ onto N B was feasible, spontaneous and exothermic. The adsorption of Sr^＋＋ and Cs^＋ increases with increasing pH （pH 2-8） and follows pseudo-second order kinetics reaching equilibrium after an equilibration time of 300 and 5 min respectively. The adsorbed amount of Cs^＋ not affected by washing of NB but affected by the heat treatment. However the adsorbed amount of Sr^＋＋ on WB was higher than NB and CB.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.51991361 and Grant No.51874329)。
文摘The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals.This paper explored for the first time the interaction mechanism between natural rubber latex(NRL)and bentonite suspensions(BTs)through a series of characterization experiments,as well as the potential applications in water-based drilling fluids(WBDF).The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient(k)and flow index(n)of BTs,and enhance the shear thinning performance of BTs as pseudo-plastic fluids.In addition,0.5 w/v%NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles,but also facilitated the compatibility of pressure loss and flow efficiency.The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles,and optimize the particle size distribution and flow resistance of WBDF under the"intercalation-exfoliation-encapsulation"synergistic interaction.Moreover,NRL can improve the rheological properties of WBDF at high temperatures(<150.C),and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake,which ultimately reduces the permeability of the cake and the filtration loss of WBDF.
文摘Sorption of radioisotopes onto a stable colloidal phase may significantly enhance their transport in groundwater. The adsorption of cesium （Cs＋） and strontium （St^＋＋ ） from aqueous solutions onto commercial natural bentonite （NB） was studied as a function of contact time, temperature, bentonite mass and bentonite treatment （washing and heat treatment） on the uptake of these cations, independently. The heat treatment was 700 ℃ and washed bentonite samples termed by CB and WB respectively. Batch experiments results showed that the adsorptive capacity of NB at 293,298 and 308 K for Cs^＋ and Sr^＋＋ were 110,105, 104 and 35, 33.6, 31.8 mg/g respectively. The experimental results for strontium adsorption 293, 298 and 308 K fit well to a Langmuirian and Frendlich type isotherm but cesium adsorption fit better with Langmuir than Frendlich isotherm. Thermodynamic functions, the change of free energy （△G°）, enthalpy （△H°） and entropy （AS°） of adsorption were also calculated for each cation. These parameters showed that the adsorption of Cs^＋ and Sr^＋＋ onto N B was feasible, spontaneous and exothermic. The adsorption of Sr^＋＋ and Cs^＋ increases with increasing pH （pH 2-8） and follows pseudo-second order kinetics reaching equilibrium after an equilibration time of 300 and 5 min respectively. The adsorbed amount of Cs^＋ not affected by washing of NB but affected by the heat treatment. However the adsorbed amount of Sr^＋＋ on WB was higher than NB and CB.
