Synthesis And Applications Of Oleophilic Composites With Nitraria Seed Meals

Nitraria,a significant economic plant,is widely cultivated in the East Asian,North America,East Europe and other areas in the world,and its seeds are rich in fat.Nitraria seed meals(NSMs),the by-products of Nitraria seeds after oil extraction,have various advantages including that they are very inexpensive,incredibly abundant,completely biodegradable,and clearly renewable.However,great quantities of NSMs were mainly regarded as agricultural waste at present.In generally,NSMs are treated by discarding them outside,burying into underground or burning with fire,which bring serious harm to groundwater resources and atmosphere environment inevitably.To find the effective uses of excess waste NSMs,an eco-friendly oleophilic polymer and release carriers were successfully synthesized with NSMs.The obtained composite can overcome the shortcomings of traditional oleophilic polymers including high production cost,low absorbency,and poor loading-release property.The resultant composites were applied to oil recovery,water purification and agriculture.Also,the adsorption capability,loading property and reusability were investigated.The main research contents are listed as follows:(1)Preparation and properties evaluation of NSMs-g-P(MMA-co-BA)oil absorption resinThe NSMs-g-P(MMA-co-BA)resins with super hydrophobicity,high porosity and excellent oil-absorbency were synthesized via copolymerization using NSMs as raw material,methyl methacrylate(MMA)and butyl acrylate(BA)as co-monomers,benzoyl peroxide(BPO)as initiator and N,N'-Methylenebisacrylamide(MBA)as cross-linking agent.SEM and FTIR were used to characterize the structure.The effects of reaction conditions on resins and the absorption kinetics were studied.The results showed that NSMs-g-P(MMA-co-BA)is a kind of surface cross-linking compound where NSMs were dispersed as skeleton in composites.Optimal conditions for preparation of the resins were: the mass ratio of BA to MMA was 1:1,?(BPO)=0.7 %,?(MBA)=0.04 %,?(NSMs)=3.1 %,at 70 °C for 70 min.The maximum oil absorbency of NSMs-g-P(MMA-co-BA)under the above conditions was for chloroform,31.6 g/g;dichloromethane,36.7 g/g;toluene,24.4 g/g;ethyl acetate,18.5 g/g;carbon tetrachloride,32.4 g/g,at normal room temperature.The saturated oil absorption could be reached within about 50 min.The absorption kinetics experiments indicated that the pseudo-second-order kinetic equation was suitable for simulation of the adsorption processes and the absorption rate of the oil above was ethyl acetate > carbon tetrachloride > toluene > chloroform > dichloromethane.The maximum oil absorbency of the NSMs-g-P(MMA-co-BA)resins was for industrial engine oil 31.7 g/g,oil/water 24.7and water 0.09 g/g.(2)Removal of oil from water surface by novel composite NSMs-g-P(MMA-co-BA)super oil-absorbent resinNSMs-g-P(MMA-co-BA)with super oil-absorbent capability was prepared by grafting co-polymerization using NSMs as filler,methyl-meth-acrylate(MMA)and butyl-acrylate(BA)as monomers,N,N'-methylene-bis-acrylamide(MBA)as cross-linker and peroxide-benzoyl(BPO)as initiator.The structure of obtained products was analyzed using Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM),respectively.The oil absorbency,reusability,oil-retention capacity,thermodynamics and the removal of oil from surface of 0.9 wt % NaCl solutions were examined further.The results showed that NSMs-g-P(MMA-co-BA)can absorb lubrication up to 29.9 g/g,20.0 g/g for colza oil,18.2 g/g for diesel and 15.8 g/g for gasoline.The exhausted NSMs-g-P(MMA-co-BA)can be recollected and recovered through extraction or drying approach.More importantly,the oil sorption capacity of recovered NSMs-g-P(MMA-co-BA)only has a slight decline after six sorption cycles.The thermodynamic studies indicated that adsorption procedure with complex physical and chemical sorption is spontaneous and exothermic.In general,the present composite resins have exhibited potential applications in cleanup of oil spills because of their good hydrophobicity,lipophilicity and excellent network structure.Also,the findings of this study might provide a convenient and economic method for fast and selective removal of oil from surface of wastewater.(3)Lauric acid modified Nitraria seed meals as carriers for the controlled-release of deltamethrin pesticideTo alleviate the adverse effects of pesticide residues on environment,development of more safe,economical and reliable usage of pesticide is critically urgent.In the present study,a novel pesticide carrier(LA-NSMs)with the controlled-release properties was prepared via grafting esterification of lauric acid onto the Nitraria seed meal substrates.The structure of obtained products was characterized by Fourier transform infrared spectroscopy,scanning electron microscopy,and contact angle measurements,respectively.The surface characteristic about degree of esterification was determined.DEL was deliberately selected as sample pesticide to evaluate the loading and releasing efficiency of carrier.The loading experimental results show that the equilibrium loading capacity of DEL using LA-NSMs as carrier can reach about 1068 mg/g.Isotherm model studies show that the loading of DEL into LA-NSMs is mainly through multimolecular layer adsorption.Environmental factors like pH of soil,humidity of soil and environmental temperature show a significant effect on the controlled release performance of LA-NSMs&DEL.The highly hydrophobic property,excellent loading and controlled release ability of LA-NSMs make it a promising candidate in agricultural applications.