Study On The Fog Collection Performance Of Superhydrophobic Grids And Electrostatic Interaction

With the development of society and population growth,the problem of freshwater scarcity has become increasingly serious,and the development and utilization of freshwater resources through effective means has become an urgent issue.In nature,the water mist in the atmosphere is rich in freshwater resources,in addition to the problem of water evaporation from human production activities,which also generates large water mist resources.Thus,the effective exploitation of freshwater resources can be achieved by capturing water mist from the air,alleviating the increasing water scarcity.First,we use a superhydrophobic coating to reinforce the fog collection effect of the stainless steel mesh.The zeolite coating was grown in situ on the surface of stainless steel by hydrothermal reaction,and further modified with perfluorodecyltrichlorosilane(FDTS)to prepare a stable superhydrophobic grid.The effects of hydrothermal reaction time and hydrophobic modification time on the surface morphology,chemical composition,and water contact angle were investigated.Furthermore,the water mist collection performance and mechanism of the mesh under different wetting conditions and the stability of superhydrophobic coatings were investigated.The results show that the surface of the stainless steel mesh has the best micro-nano-level roughness after hydrothermal for 24 h and modification for 24 h,and more F-containing groups are grafted,the surface contact angle reaches 155°.The adhesion to water droplets was extremely low.Therefore,the grid has good super-hydrophobicity.The mist collection experiment shows that the superhydrophobic mesh can greatly reduce the mesh clogging and improve the aerodynamic efficiency of the mesh.Compared with the untreated stainless steel mesh,the drop-off time of the droplets is greatly reduced,the collection rate is 4200 mg/(cm~2·h),an increase of up to 93%.In addition,the superhydrophobic grid has good stability.After soaking in 1 mol/L HCl,1 mol/L NaOH and3.5wt.%NaCl solution for 48 hours,the grid still shows good hydrophobicity and the water mist collection rate is about 4200 mg/(cm~2·h).After 60 wear cycles on 2000 mesh sandpaper,the contact angle can still reach 145°,and the water mist collection rate is 4000 mg/(cm~2·h).Then,the fog collection performance driven by the electric field was studied.Through the construction and testing of the experimental device,the effects of operating voltage,gas velocity and mist volume on the recovery rate and energy consumption of the device were investigated.And the performance of the device in series and parallel was further investigated.The results show that the device has a simple structure and was mainly composed of spur-type corona electrodes,cylindrical grounding electrodes and rectifying grids.The number and length of corona electrode burrs increase,the stronger the electrode discharge performance;The increase in the height of the ground electrode is beneficial to improve the recovery rate.The distance(Δ)between the corona pole tip and the rectifier grid is reduced,and the breakdown voltage of the electric field is reduced.As the operating voltage increases,the recovery rate increases and the energy consumption increases;The increase in gas velocity will cause the recovery rate to decrease,and there is no obvious change in energy consumption.When the voltage is constant,the higher the mist volume,the lower the collection rate and the lower the energy consumption.In different environments,the device can achieve a recovery rate of more than 80%,and the energy consumption is only 1-4 kW·h/m~3,which has the characteristics of high yield and low energy consumption.In addition,the device can be further designed in series and parallel.The series system can further reduce energy consumption while maintaining a high recovery rate.Good parallel performance can realize the modular use of the device,and make reasonable adjustment design according to the specific fog volume,gas velocity,working area,etc.,to meet the collection of water mist under various conditions.