Study on the Preparation and Properties of Impervious and Breathable Sand Based on Hydrophobic Theory

Land desertification, a severe global ecological and environmental problem, brings challenges to the sustainable utilization of land resources in the world. The purpose of this research is to use hydrophobic theory to prepare impervious and breathable sand, and to solve the problems of sandy soil that seeps easily and makes it difficult for vegetation to survive in desertified areas. The influences of coating material content, first-level and second-level rough structure on the impermeability and air permeability of impervious and breathable sand were studied. The research showed that, with the increase in coating material content, the impervious performance of the sample increased firstly and then decreased, and the air permeability rose continuously. The hydrostatic pressure resistance of the sample can reach an extreme value of 53 mm. The first-level rough structure of micron structure can greatly improve the hydrophobic performance, thus improving the impervious performance. The addition of micron calcium carbonate would improve the hydrostatic pressure resistance height of the sample to 190 mm. The sample would reach a superhydrophobic state in the condition of a first-level rough structure of a nano structure built by nano silica, and the contact angle was up to 152.0°, so that the hydrostatic pressure resistance height can rise to 205 mm. The best performance would be achieved under the condition of relatively less raw material with a second-level rough structure of micro-nano. At this point, the contact angle of the sample reached 152.8° and the hydrostatic pressure resistance height was up to 205 mm. At the same time, the air permeability index of the above four kinds of impervious and breathable sand met all planting requirements. The sample prepared can satisfy the demands of different degrees of impermeability and air permeability, and can be widely used in desertification control.