| In this study, agricultural waste pomelo peel was selected as raw material,stearic acid and oleic acid 、 acetic anhydride 、 styrene 、 magnetization and FTS(C10H4Cl3F17Si) were used to modify raw pomelo peel. The effect of the sample dose,oil added quantity, speed(oscillation frequency), temperature and salinity on the oil absorption capacity wre discussed. Moreover, oil retain and reuse of modified pomelo peel were also investigated. At the same time, the change of the microscopic morphology and functional groups of the material modified before and after were investigated by means of Fourier Infrared Spectroscopy(FT-IR), Scanning Electron Microscope(SEM), Vibration Magnetometer and so on. In this study, in order to understand the adsorption mechanism, the adsorption kinetics, adsorption isotherm and thermodynamics were investigated. The main conclusions were as follow:(1) The content of cellulose, hemicellulose, and lignin of the natural pomelo peel were 46.22%, 18.84% and 10.24% respectively; the contact angle of simulated seawater-natural pomelo peel was 135°, and the contact angle of oil-natural pomelo peel was 0°. The SEM photo showed that natural pomelo peel had honeycomb porous structure. FT-IR infrared spectrum showed that natural pomelo peel contained a large number of hydrophilic hydroxyl groups. The adsorption of natural pomelo peel in oil-water system was selective adsorption, which oil adsorption firstly. The water absorption capacity was 6 g/g in the purified water system during90 min. Moreover, the adsorption capacity of natural pomelo peel for diesel in the simulated seawater conformed to the Lagergren pseuo-second order kinetics equation, and the desorption of natural pomelo peel for diesel in the simulatedseawater conformed to the Lagergren pseuo-first order kinetics equation.The equilibrium time of adsorption and desorption were 11 min and 5 h, and the capacity of adsorption and desorption were 5.70 g/g and 0.49 g/g respectivly.(2)The adsorption capacity of stearic acid(oleic acid) modified pomelo peel for diesel and lubricating oil were 9.50 g/g(10.50 g/g) and 10.40 g/g(13.70 g/g)respectively, and both of them were higher than natural pomelo peel. For SEM, the surface of the oleic acid modified pomelo peel was more smooth than natural pomelo peel. Moreover, the FT-IR infrared spectra of 3408 cm-1, 1633 cm-1and 1751 cm-1showed that the oleic acid modified successfully natural pomelo peel.The oil adsorption process of stearic acid and oleic acid modified pomelo peel conformed to the quasi secondary dynamics equation. The oil absorption capacity of stearic acid and oleic acid modified pomelo peel decreased with the rise of temperature; The oil absorption capacity of stearic acid and oleic acid modified pomelo peel increased with the increase of salinity; The oil absorption capacity of stearic acid and oleic acid modified pomelo peel increased with the increase of rotational speed increases first and then decreased.(3) The best preparation conditions of acetylated pomelo peel were as follows:reaction temperature was 60 ℃, reaction time was 3 h and the dosage of DMAP was0.10 g. The results indicated that the adsorption of acetylated pomelo peel for diesel and lubricating oil in the oil-water system conformed to the Lagergren pseuo-second order kinetics equation, and the maximum adsorption capacity for diesel and lubricating oil were 14.45 g/g and 18.03 g/g respectively, and could be well retained and reuseable.The best preparation conditions of styrene grafted pomelo peel werw as follows:the reaction temperature was 70 ℃, the reaction time was 8 h, the dosage of styrene was 12 m L, the dosage of N, N-methylene double acrylamide was 0.01 g and the dosage of benzoyl peroxide was 0.50 g.The results indicated that the adsorption of styrene grafted pomelo peel for diesel and lubricating oil in oil-water system conformed to the Lagergren pseuo-second order kinetics equation, and the maximumadsorption capacity for diesel and lubricating oil were 19.94 g/g and 27.78 g/g respectively, and could be well retained and reuseable.(5) The best preparation conditions of magnetic pomelo peel were as follow: the dosage of ethylene glycol was 30 m L, the dosage of ferric chloride hexahydrate was0.40 g, the dosage of ammonium acetate was 3.40 g and the dosage of oleic acid was0.40 m L. SEM analysis indicated that the surface of the magnetic pomelo peel was rougher than the surface of the carbonized pomelo peel, and had many small holes which were distributed homogeneous. The infrared spectrum of the magnetic pomelo peel showed that it contained the Fe-O and the C=O of oleic acid, and proved that the oleic acid modified magnetic pomelo peel was preparated successfully. The magnetic performance measurement showed that the magnetic saturation values of the magnetic pomelo peel was 8.06 emu g-1, incidated that the magnetic pomelo peel could move by added a magnetic field. The result showed that the adsorption of the magnetic pomelo peel mainly belonged to the physical adsorption, and the maximum adsorption capacity for diesel were 27.98 g/g, and the adsorption of diesel was conformed to the Lagergren pseuo-second order kinetics equation and was applied to the Freundlich isotherm.(6)The best preparation conditions of FTS modified pomelo peel was as follow:WT:AT=1:1, the dosage of FTS was 0.20 m L, the reaction temperature was of 30 ℃,and the oscillation speed was 150 RPM. SEM analysis indicated that the FTS modified pomelo peel represented crude layer which was three-dimensional reticular structure. The adsorption equilibrium time of the FTS modified pomelo peel for diesel was 60 min, and the maximum adsorption capacity was 23 g/g. The adsorption of the FTS modified pomelo peel for diesel belonged to the physical adsorption, and the adsorption of diesel was conformed to the Lagergren pseuo-second order kinetics equation and was applied to the Langmuir isotherm. |
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