| With expansion of the oil industry chain, the reconstruction of petrochemicals industry along river and the development of oil transportation, handing, storage and processing, they promote local economy development rapidly, but also have a threat to the security of the ecological environment and water drinking of inhabitants. Oil spills in the river have some characteristics, such as fast oil spreading velocity, larger contaminative area, and serious pollution for river bank. Among existing techniques for the oil removal, mechanical recovery by sorbents is considered to be one of the most efficient techniques, which can reduce the harm of water pollution and avoid trans-boundary pollution. However, River have some characteristics in China, such as numerous in quantity, vast in territory, and complex in river bank, therefore, it is very important for the availability of high efficient-low cost oil sorbent and emergency countermeasures mode. In this work, stearic acid modified expanded perlite (SA-EP) and expanded perlite/fiber fabrics were prepared for emergency oil spill cleanup, due to the properties of expanded perlite such as inexpensive and available in the large scale. Oil sorption behavior of oil sorbents was investigated and oil sorption mechanism was discussed. Emergency countermeasure process of oil sorbents based on expanded perlite was analyzed by combining oil spill sorption model and pollution model, it is very meaningful for oil spill response in river as a reference.SA-EP was prepared by using solution-immersion method,2.0%(w/w) is regarded as an ideal loaded stearic acid amount through oil/water sorption test. The surface morphology and properties of expanded perlite of pre-and post modification were investigated applying Brunauer-Emmet-Teller surface area and pore distribution analysis, scanning electron microscopy, Fourier Transform Infrared spectrometer and hydrophobicity analysis. The results showed that surface area and pore size decreased after modification, and pore structure was unchanged, SA-EP was still fragmental structure. The intensity of the–OH group has considerably decreased, and new CH2-group provided further evidence that expanded perlite have been modified successfully by stearic acid. Hydrophobicity analysis showed that the surface of SA-EP was hydrophobic.The sorption behavior of expanded perlite of pre-and post modification showed that oil/water selectivity of SA-EP was improved significantly. The oil/water selectivity of expanded perlite as an adsorbent was investigated at different particle sizes, static and dynamic sorption condition and temperature, the results showed that unmodified expanded perlite have higher water sorption capacity than oil due to the existence of–OH group on the surface. Oil sorption behavior of unmodified expanded perlite is ascribed to physical capture. However, SA-EP has high oil sorption capacity and low water sorption capacity. Oil/water adsorption ratio of SA-EP is about195.5times as much as that of EP in dynamic sorption system.Langmuir, Freundlich, Koble-Corrigan and Temkin isotherm equations were applied to analyze the equilibrium sorption of oil onto SA-EP at different temperatures. Both linear and nonlinear regressive methods were used to obtain the relative parameters. It was found that Koble-Corrigan nonlinear fit was best. The adsorption thermodynamics was conducted which showed that the sorption is spontaneousand exothermic process. Low temperature was favor for oil sorption. Oil spill can be recovered by vacuum filtration. Oil recovery efficiency is74%at the first time, and then99%oil can be recovered with the increase of filtration cycles. Oil sorption capacity of desorbed sorbent maintain at85%of the first oil sorption capacity.Commercial acrylic fabric (AF), polypropylene nonwoven (PP), and silk stockings (SS), cotton cloth (CC), linen cloth(LC), and cotton and linen blended cloth (CLBC) were selected, and the oil/water selectivity and permeability of them were evaluated. The disposal process and method was proposed of collaborative oil sorption of expand perlite combined with fiber fabrics. The results showed that the oil removal efficiency increased as expanded perlite weight increased, however, oil sorption capacity of combined materials decreased when fiber fabrics remain unchanged. The optimum ratio of expanded perlite and fiber fabrics was0.5~1.0g/25cm2. Expanded perlite and fiber fabrics can complement each other when used together for oil sorption. The rate of desorption for combined materials follows three zones in each curve: initial stage of release, transition zone and steady-state period. Oil sorption capacity of combined materials increased until maximum sorption capacity was achieved with oil amount in the water increased. When oil film on water surface was very thin, PP and SS combined materials can adsorb water. The results are attributed to the penetration of hydrophobic fiber fabric which affects significantly the sorption behavior of combined material. Oil sorption capacity of combined materials increased significantly with time, the use of the sorption process over5min has no significant influence on oil sorption. Oil sorption capacity of combined materials increased significantly with temperature decreased, low temperature was favor for oil spill cleanup.The isotherms determined for three combined materials were found to fit the Koble-Corrigan equation very well, and pseudo-second order kinetic model could describe very well the sorption/desorption rate of sorbents. The oil sorption mechanism of combined materials included wetting, sorption and penetration of fiber fabrics and physical sorption of expanded perlite.The riverine oil spill pollution model and oil sorption model of oil sorbents based on expanded perlite was proposed. Accidential oil spill was pretended to accur in river, emergency response location and the quantity of oil sorbents was analyzed based on oil pollution and sorption model, it is very meaningful for oil spill response in river as a reference. |
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