| Oily wastewater is widely found in petroleum,chemical,metallurgical,mechanical and textile industries.Hundreds of millions of tons of oil waste water in the world are discharged into the river,lake and sea each year,causing serious waste of resources and environmental pollution,which poses a serious threat to the living environment of human beings.Deep bed filtration is a kind of advanced treatment technology for low concentration oily wastewater,especially for oil pollutants with particle size less than 10?m.The wettability of the filter material determines the degreasing effect to a certain extent.The hydrophobicity of the filter material are stronger,and the oil removal ability is stronger.Conversely,the oil removal ability is worse.Therefore,the oil removal efficiency of the filtration process can be improved by increasing the hydrophobicity of the filter material surface.There are two ways to improve the hydrophobicity of the surface of the filter,one is to graft low surface energy on the surface of the filter material,to change the hydrophobicity of the material,and the other is to construct a rough structure on the surface of the filter material,so that the hydrophobicity is strengthened and the superhydrophobic surface is formed.At present,the matrix of super hydrophobic materials used for oil and water separation is mostly steel wire mesh and sponge materials,but there are still some shortcomings,such as the harsh preparation conditions,the poor stability of the prepared superhydrophobic materials,and the limitation of the size,shape and material in the process of oil and water separation.Use.Quartz sand is a commonly used natural,cheap and stable filter material,which can be used to screen its particle size to meet different needs.In the process of sewage treatment,the quartz sand filter material can be filled in the filter bed according to the actual treatment needs.However,the surface of the quartz sand filter is hydrophilic,and the oil removal efficiency still has a greater lift space when the oily wastewater is treated.Therefore,this paper uses the traditional quartz sand filter as the matrix,using OTS?Octodecyltrichlorosilane?and ZnO nanoparticles to surface modification,and preparation of high hydrophobic and super hydrophobic two kinds of quartz sand modified filter material.The modified filter material has more oil removal efficiency than that of the unmodified quartz sand filter,because the composite coating and the quartz sand filter matrix are combined with the stable physical or chemical effects,so the super hydrophobic quartz sand filter material has strong stability.The method is simple and practical,and does not use complex instruments.It provides a better filter material for filtering oily wastewater.The main specific work of this article is as follows:?1?Research on the preparation of high hydrophobic quartz sand filter material.By self assembly technology,the OTS with low surface energy is modified on the surface of quartz sand filter material,and the quartz sand filter material has a physical and chemical effect in the ethanol solution of OTS.Through a series of reactions,such as hydrolysis,adsorption,condensation,and so on,the filter material of quartz sand is in the form of Si-O-Si bond at the end.A stable and orderly monolayer of molecular membrane is formed on the surface.The contact angle between the hydrophobic quartz sand filter material and the water is 133.2 degrees,showing high hydrophobicity.?2?Study on the preparation of super hydrophobic quartz sand filter.A polydopamine layer with a certain degree of roughness and strong adhesion was prepared on the surface of quartz sand filter material by dopamine on almost all surfaces under the weak alkali condition.Then the nano Zinc Oxide particles were attached to the surface of the quartz sand filter by the adhesion ability of the polydopamine layer.During this process,nano Zinc Oxide produced adhesion and agglomeration on quartz sand filter surface and formed micro nano structure on the surface of quartz sand filter material.The micro and nano structure formed by nano Zinc Oxide particles synergistically with the rough structure of the dopamine layer,which increases the roughness of the surface of the quartz sand filter.On this basis,the surface modified by OTS is modified to reduce the surface free energy of the filter,and the surface modified quartz sand filtration is prepared.The material,and the water contact angle of 154 degrees,showing the superhydrophobic.?3?Characterization of hydrophobic quartz sand filter media by scanning electron microscopy?SEM?,electron spectroscopy?XPS?and infrared spectroscopy?FTIR?.By analyzing the results of scanning electron microscopy,the surface of the natural quartz sand filter material has smooth surface,many angles,irregular boundary arrangement,staircase fracture and obvious crystal structure characteristics.The surface of the high hydrophobic quartz sand filter material is smooth and smooth,and the staircase fracture depth decreases,and a layer of OTS is attached to its surface.The alkane organic monolayer,the edge angle of the super hydrophobic quartz sand filter is obviously reduced,the boundary is more smooth and the ladder like fracture vanishes.The surface adheres to the polydopamine film,the nano Zinc Oxide particles and the white micro nanostructures formed by the agglomeration.The results of XPS photoelectron spectroscopy analysis show that the natural quartz sand filter material is mainly composed of SiO2 form of Si and O elements,which contains a small amount of C element impurities,and the high hydrophobicity quartz sand filter material increases the Cl element in the surface composition,and the content of C element increases obviously,and the surface composition of super hydrophobic quartz sand filter material increases Cl and N yuan.The content of C elements increased significantly.The results of FTIR infrared spectrum analysis show that the surface of the natural quartz sand filter material has a hydroxyl in the form of Si-OH.In the process of surface modification of the two surface modification methods,the condensation reaction between the OTS and the hydroxyl group on the surface of the quartz sand filter,the-OH is consumed,OTS and quartz sand filter material.The combination of chemical bonds has successfully covered an organic monolayer film with low surface energy on the surface of quartz sand filter.?4?Static adsorption experiment.The experimental results show that high hydrophobicity quartz sand filter material increases the static adsorption capacity of oil and vegetable oil by 33%and 27%compared with the non surface modified quartz sand filter material,and the static adsorption capacity of oil and vegetable oil is increased by 54%and45%by the super hydrophobic quartz sand filter,and the static adsorption capacity is positively related to the hydrophobicity.?5?The experiment of centrifugal adsorption of oil containing wastewater.The experimental results show that the removal rate of centrifugal adsorption of oil and vegetable oil wastewater by high hydrophobicity quartz sand filter material is 15.09%and19.37%,and the removal rate of centrifugal adsorption of oil and vegetable oil containing wastewater by super hydrophobic quartz sand filter material is 33.48%and 27.77%,There is a positive correlation between the adsorption capacity of the heart and the hydrophobicity.?6?Stability test of surface modified quartz sand filter material.The experimental results show that super hydrophobic quartz sand filter can still maintain super hydrophobic ability under strong acid condition and ultrasonic oscillation.Under strong alkali conditions,the superhydrophobic property is reduced to a certain extent due to the destruction of micro nano structure under strong alkali conditions.With the increase of air exposure time,super hydrophobic quartz sand filtration.The hydrophobicity of the material is weakened,but it can basically stabilize at 136 degrees and still has strong hydrophobicity. |
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