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
This paper focused on the sessile droplet freezing and ice adhesion on aluminum with different wettability （hydrophilic, com- mon hydrophobic, and superhydrophobic surfaces, coded as HIS, CHS, SHS, respectively） ove...This paper focused on the sessile droplet freezing and ice adhesion on aluminum with different wettability （hydrophilic, com- mon hydrophobic, and superhydrophobic surfaces, coded as HIS, CHS, SHS, respectively） over a surface temperature range of -9℃ to -19℃. It was found that SHS could retard the sessile droplet freezing and lower the ice adhesion probably due to the interfacial air pockets （IAPs） on water/SHS interface. However, as surface temperature decreasing, some IAPs were squeezed out and such freezing retarding and adhesion lowering effect for SHS was reduced greatly. For a surface temperature of-19℃, ice adhesion on SHS was even greater than that on CHS. To discover the reason for the squeezing out of lAPs, forces applied to the suspended water on IAPs were analyzed and it was found that the stability of IAPs was associated with surface mi- cro-structures and surface temperature. These findings might be helpful to designing of SHS with good anti-icing properties.展开更多
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.
基金supported by the National Natural Science Foundation of China(Grant Nos.21203089 and 51263018)International Science and Technology Cooperation Program of China(Grant No.2012DFA51200)+1 种基金Science and Technology Project of Jiangxi Province(Grant No.20123BDH80015)the Open Fund of Jiangsu Key Laboratory for Biomass-based Energy and Enzyme Technology(Grant No.JSBEET1224)
文摘This paper focused on the sessile droplet freezing and ice adhesion on aluminum with different wettability （hydrophilic, com- mon hydrophobic, and superhydrophobic surfaces, coded as HIS, CHS, SHS, respectively） over a surface temperature range of -9℃ to -19℃. It was found that SHS could retard the sessile droplet freezing and lower the ice adhesion probably due to the interfacial air pockets （IAPs） on water/SHS interface. However, as surface temperature decreasing, some IAPs were squeezed out and such freezing retarding and adhesion lowering effect for SHS was reduced greatly. For a surface temperature of-19℃, ice adhesion on SHS was even greater than that on CHS. To discover the reason for the squeezing out of lAPs, forces applied to the suspended water on IAPs were analyzed and it was found that the stability of IAPs was associated with surface mi- cro-structures and surface temperature. These findings might be helpful to designing of SHS with good anti-icing properties.
