Preparation and Study of Properties of High-Efficiency Salt-Blocking Materials for Saline-Alkali Soil Reconstruction System

Abstract:

In order to improve saline-alkali soil， a superhydrophobic particle material with an excellent waterproof and salt-blocking performance was prepared， which was used to build a saline-alkali soil reconstruction system with a water-storage mode. Substrate material and desert sand were modified with a hydrophobic coating. The influences of resin content and micro-/nano-material content on the hydrophobicity， impermeability and breathability of the material were studied. A self-designed mini soil-column was used to simulate the migration process of underground saline water， and the waterproof and salt-blocking properties of the prepared materials were explored. The results show that when resin， hydrophobic CaCO₃ and nano-SiO₂ contents were 1.0 %， 0.8 % and 0.2 %， respectively， the material achieved a water contact angle of 153.6°， a water-resistant height of 230 mm， and maintained a good air permeability. The mini soil-column simulation test indicates that the material has a strong inhibition effect on the water evaporation and the upward movement of salt， with an evaporation-inhibiting rate of 50 % to 70 % and a salt-blocking rate of more than 99 %， which maintains 97.5 % after 20 test cycles.

Key words:saline-alkali soil improvement;superhydrophobic materials;waterproof and salt-blocking;evaporation-inhibition