The Hall effect in Ni0.8Co0.2-SiO2 granular films which were fabricated by ion beam sputtering technique was studied. The saturated Hall resistivity reached 6.3μΩ·cm in an applied field of 9.5×105 A/m at room temperature when NiCo volume fraction x is near the metal-insulator transition threshold. The temperature dependence of resistivity in these samples with different NiCo compositions was also investigated. It showed-lg T dependence in low x samples, which gradually showed metallic as x increased. Transmission electron microscopy and vibrating sample magnetometer were used to study the microstructures and magnetic properties, the dependence of transport properties on microstructure was also discussed.
Magnesium oxide slurry is used for sulfur dioxide removal in regenerative magnesia scrubbing flue gas desulfurization(FGD) system.Magnesia is regenerated from desulfurization by-products through pyrolysis process and is applied in the system as recycling agent.A thermal power plant desulfurization by-products were analyzed,the plant desulfurization by-product contents 0.842 g MgSO3 per-gram of dry residue,has great recovery value.Investigated the pyrolysis conditions of the by-product such as pyrolysis temperature and heating time.Under the condition that pyrolysis temperature is 750 ℃ and heating time is 2 h,the recovery rate of MgO can reach 59.8%.Confirmed that the exhalation rate of sulfur occupied 6.0% of the theoretical value when pyrolysis temperature is below 750 ℃ and reached 24.0% when pyrolysis temperature is 900 ℃.Pyrolysis temperature should be controlled to reduce the exhalation of sulfur during the pyrolysis process of the by-products.
Cetylpyridinium bromide-modified polystyrene resin(R-CPB) was synthesized as packing material for treating oily wastewater.The oil removal mechanism was studied by resin surface wettability measurement and oil droplet Zeta potential test.The results indicate that the resin surface wettability is significantly altered and the hydrophilicity is decreased while the lipophilicity is increased.R-CPB influences the Zeta potential of oil droplets and therefore enhances the demulsification process.Under the same condition,R-CPB demonstrates a better oil and turbidity removal capacity than the un-modified polystyrene resins and a better oil removal stability than activated carbon,which shows a good future for application.
Fabric peat was modified by hexadecyltrimethylammonium bromide for sorption of bisphenol A from water.The surface properties of modified fabric peat were characterized and its sorption capacity of bisphenol A was also investigated.The modified fabric peat was found to be more organophilic,the organic carbon content and zeta potential of modified fabric peat increased from 43.85% to 49.94% and-42.5 mV to-32.6 mV respectively.The sorption isotherms followed Langmuir model and Freundlich model.Through modification,the sorption constant increased from 0.018 L/mg to 0.054 L/mg and the equilibrium sorption capacity increased by over 220%.The sorption kinetics followed pseudo-second order model and the sorption rate of modified fabric peat was much quicker.It was also found that the equilibrium sorption capacity of modified fabric peat increased with the increase of cation concentration in water.In addition,it was found that pH influence the sorption process significantly.Results suggested that the enhanced hydrophobicity and less negatively charged surface are the most important reasons for the significantly improved sorption capacity of modified fabric peat for bisphenol A.
The influence of clay minerals from superficial deposit of Yangtze estuary on diesel and heavy oil dispersion were studied.The results found that the size distribution of particulate matter,the content of particle and the type of oil were important parameters.High ratio of micro-sized particle and particle content was proved to be good for oil dispersion.The suspended particles could be aggregated with oil droplet in short time.More heavy oil was dispersed by particles than diesel.Increase of salinity in a specific range can improve oil dispersion.
Recovery of cobalt and copper from nitric acid leaching solution of cemented carbide scrap was studied.Three active metals(Al,Fe and Zn) were used as reduction reagent to displace cobalt and copper.The test results on hydrolyzation and secondary displacing show that when iron was first removed by hydrolyzation and displaced with zinc powder under optimum conditions of 80 ℃,pH =2,4 h stirring time,the recovery rate of Co and Cu was 94% and 98%,respectively.
Stearic acid was used to embed calcium peroxide under anhydrous conditions in order to prepare an oxygen slow-release composite that supplies oxygen for water environment remediation.The infrared spectroscopy and scanning electron microscopy confirmed that stearic acid could effectively embed calcium peroxide,and the surface of oxygen slow-release composite was more closely and flat than before.Based on the tests in aseptic and oxygen-free water,it was found that the oxygen release rate decreased with the stearic acid concentration increase,and the pH value also leveled off.The results from the simulation sediment showed that with calcium peroxide dosage of 720 g/m2,the oxygen slow-release composite(stearic acid content of 1.2%) maintained the dissolved oxygen concentration around 5.0 mg/L within 42 d at 25 ℃,and pH value gradually reduced from 8.7 to 7.7 relying on sediment self-buffering,which was conducive to microbial growth and inhibition of endogenous pollutants release.
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