Preparation And Fluid Transmission Performance Of Janus Fabrics

The rapid development of global industry and frequent oil spills have produced a large amount of oily wastewater,posing a serious threat to the earth’ s ecological environment and human life safety,the treatment of oil-contaminated water is already a global problem.Due to the asymmetric wettability or wettability gradient on both sides,Janus porous membrane can separate oil with different density from oil-water mixture by changing the transmembrane direction of oil-water mixture,which has attracted great attention in the field of oil-water separation.At present,there are few researches on how the hydrophobic/hydrophilic layer of Janus membrane affects fluid transport.1)In this paper,cotton fabrics were used as substrates,and Janus fabrics with asymmetric wettability were prepared by hydrophobization modification of octadecyl trimethoxysilane and oxidation treatment of KMnO4 solution.By increasing the oxidation time of KMnO4 solution,the appearance color of Janus fabrics gradually deepened,the hydrophilicity and thickness of hydrophilic surface gradually increased,but the wettability of hydrophobic surface almost remained unchanged,and the prepared Janus fabrics could not conduct unidirectional transmission.2)For the water prewetted fabrics with oxidation time of 0,1,2 and 4 h,when the hydrophobic layer was broken,the water penetration time is increased by 195.2%,178.9%,156.4%and 122.9%,respectively,compared with the pristine cotton fabric,when the underwater oleophobic layer was broken,the penetration time of carbon tetrachloride increased by 6.6%,23.8%,30.4%and 41%,respectively,and the penetration time of dichloromethane increased by 14.7%,39.2%,54.8%and 71%,respectively.For water,the longer the oxidation time,the slower the transmission;for heavy oil,the longer the oxidation time,the faster the transmission.3)Using COMSOL Multiphysics,the permeation flux test models of water,carbon tetrachloride and dichloromethane were constructed.The simulation and experimental results prove that the acceleration of fluid transmission is caused by the decrease in the internal flow resistance of the fabric after the built-in lyophobic layer(hydrophobic layer or underwater oleophobic layer)of the fabric pre-wetted by water is broken by water or oil,and the thicker the lyophobic layer,the smaller the fluid flow resistance and the faster the transmission.In addition,the hydrophobic layer of Janus fabric prewetted with water is fixed upward,when the water breaks through the hydrophobic layer,the light oil-water mixture can be separated;the hydrophilic layer of Janus fabric prewetted with water is fixed upward,when the oil breaks through the underwater oleophobic layer,the heavy oil-water mixture can be separated,and the separation efficiency is above 98%.It shows that the prepared Janus fabrics can separate the oil-water mixture with high efficiency under the fluid transmission performance.Figure[34]Table[8]Reference[101]...