The Study On Preparation And Mechanism Of Fiber-based Oil Sorption Materials

With the rapidly increasing production and consumption of oils in China’s economy, plenty of water pollution has caused by oil spills. Therefore, it has important practical significance to study efficient oil absorbent material. An ideal oil absorbent material should have the following properties: high selectivity, high buoyancy, low cost, good recyclability and biodegradability. In this study, commercial polypropylene fibers and raw kapok fibers were selected for preparing efficient oil absorbent materials via different methods: commercial polypropylene fibers modified via grafting process, raw kapok fibers modified by physical, chemical and biological modification methods. At the same time, the change of functional groups, microscopic morphology, surface wettability of the modified material were investigated by Fourier Infrared Spectroscopy(FT-IR), Scanning Electron Microscope(SEM), contact angle(CA) etc.. In order to understand the oil adsorption mechanism, adsorption kinetics and adsorption isotherm were also preliminarily investigated. The main conclusions were as follow:(1) Polypropylene fiber-grafted polybutylmethacrylate(PP-g-PBMA) oil absorbent were prepared by suspension polymerization. The oil sorption capacity of PP for diesel, soybean oil, and lubricating oil is 11.43, 15.93, 22.32 g/g, respectively. By contrast, the oil sorption capacity of PP-g-PBMA for above three oils can reach 25.74, 33.56, and 38.90 g/g, respectively. It can be observed that PP-g-PBMA shows a fast adsorption rate and 80% of the maximum adsorption capacity was obtained during the initial 30 s, and the saturated oil adsorption capacity can be reached within 5 min.(2) The content of cellulose, hemicellulose, and lignin of the raw kapok fibers were 66.75%, 15.09% and 8.10% respectively. FT-IR infrared spectrum showed that natural kapok fibers contained a large number of hydrophilic hydroxyl groups. The SEM images showed that kapok fiber has smooth surface smooth and unique hollow tubular structures. XPS analysis indicated that kapok fiber is mainly composed of the C and O elements. Water and oil contact angle of kapok fibers were 114.7° and 0°, respectively. Kapok fibers absorbed oil quickly and the saturated oil adsorption capacity can be reached within 5 min. Kapok fiber adsorption capacity for diesel oil, soybean oil and lubricating oil were 27.55 g/g, 38.28 g/g and 43.57 g/g, respectively. The results showed that adsorption kinetics was well described by the Lagergren pseuo-second order kinetics equation.(3) Dip coating and chemical modification methods were successfully applied to prepare FTS(1H,1H,2H,2H-perfluorodecyltrichlorosilane) modified graphene coated kapok fibers(FGRKF), and the best preparation conditions of FTS modified kapok fibers was also discussed. Si-O-Si and C-F functional groups were found by FT-IR. C, O, Si and F elements were detected by XPS analysis, which proved that the graphene and FTS were successfully coated on the surface of kapok fiber. The oil sorption capacity of FGRKF for diesel oil, soybean oil and lubricating oil were can reach 50.74 g/g, 61.08 g/g, 68.26 g/g, respectively. After eight cycles, more than 85% of the original oil sorption capacity of FGRKF still remained.(4) Superhydrophobic CeO2 modified kapok fiber(SCMKF) oil absorption materials were prepared using a chemical modification method. The oil sorption capacity of SCMKF for diesel oil, soybean oil and lubricating oil were can reach 48.65 g/g, 58.17 g/g, 62.57 g/g, respectively. The saturated oil adsorption capacity of SCMKF for above three oils can be reached within 3 min, and the oil absorption process was conformed to the Lagergren pseuo-second order kinetics equation and Freundlich isotherm. At the same time, SCMKF showed good recyclability.(5) Aspergillus niger Cellulose enzyme modified kapok fiber(ANCMKF) were successfully prepared using biological modification, and the response surface method was introduced to design the best preparation conditions. The best preparation conditions of ANCMKF were as follows: enzyme dosage of 0.04 g, reaction temperature of 45.6 oC, and reaction time of 5.41 h. The oil sorption capacities of ANCMKF for diesel oil, soybean oil and lubricating oil were can reach 41.10 g/g and 54.11 g/g and 60.45 g/g, respectively. The results indicated that the adsorption of ANCMKF for diesel oil, soybean oil and lubricating oil conformed to the Lagergren pseuo-second order kinetics equation.(6) The production cost of FGRKF, SCMKF and ANCMKF was 11065, 9495 and 8825 yuan/ton. Compared with the oil sorption capacities, reusability and cost of modified kapok fibers, ANCMKF is promising and eco-friendly as a candidate for removal of spilled oil.