Study On Solar-enhanced Oil Absorption Characteristics Of Graphene-coated Sponge

With the development of economic globalization,oil transportation by sea has become one of the important ways of economic exchanges between countries.With the increase of oil transportation by sea year by year,oil leakage also occurs frequently.If not handled properly,it will cause great harm to the ecological environment.At present,among various methods for oil pollution treatment,physical adsorption method is considered to be the most potential method for oil pollution treatment due to its high efficiency,recyclability and no secondary pollution.However,the existing adsorbents have disadvantages such as low cycle efficiency,low adsorption capacity and failure on highly viscous crude oil.Therefore,in order to solve the problem of surface oil pollution treatment,it is urgent to synthesize adsorbent materials with high oil absorption rate,reusability,environmental friendliness and low cost,and develop a method suitable for adsorbing high viscosity oil pollution.In addition,since the adsorbents are mostly porous media with high porosity,the study on the effects of internal flow characteristics of porous media is helpful to reveal the mechanism of adsorption of oil stains by adsorbents,thus improving oil absorption rate and oil absorption capacity.The main research contents are as follows.For the preparation of porous media adsorbent,firstly Graphene oxide(GO)solution was prepared by improved Hummers method,and then graphene-coated melamine foam(rGO-MS)adsorbent was prepared by soaking and HI thermal reduction using melamine foam as the substrate.The morphology and composition of rGO-MS adsorbent were characterized by scanning electron microscopy and Raman spectroscopy,and its hydrophobicity and light absorption ability were tested.It was found that rGO-MS adsorbent was hydrophobic and oleophilic material.Due to the effect of surface graphene,it also had good photo-thermal properties,and the absorption rate of sunlight could reach 91%.In the experimental study of solar energy enhanced rGO-MS adsorbent for oil absorption,firstly,the theoretical analysis of liquid permeability in porous media was carried out.The influence mechanism of temperature on oil diffusion in porous media was analyzed in combination with the thermal property test results of silicone oil at different temperatures.It was found that the increase of temperature promoted adsorption by greatly reducing the viscosity of oil.Subsequently,a solar energy enhanced oil adsorption experiment platform was designed and built,using silicone oil and high viscosity crude oil as experimental oils,and introducing solar energy to enhance the absorption of high viscosity crude oil.The results show that the adsorbent has strong adsorption capacity,recovery capacity,and can be recycled many times.Solar energy has a significant promoting effect on the adsorption.For seepage simulation in porous media,the Quartet Structure Generation Set(QSGS)was used to establish the physical model of porous media.Then,Lattice Boltzmann Method(LBM)Shan-Chen multiphase flow model was used to simulate the displacement flow,and the effects of Re number,gas-liquid surface tension coefficient and wettability of solid phase were investigated.The results show that the displacement efficiency can be improved by selecting the appropriate displacement speed and increasing the wettability of adsorbent to the displacement phase,while the gas-liquid surface tension coefficient has little effect on the results.