Development and optimization of a plant-based sand fixer: Locust bean gum and its advanced materials

With soil wind erosion becoming an increasingly pressing issue, sand fixation technologies and approaches have advanced significantly. However, chemical sand fixers often exert detrimental effects on soil properties, necessitating efforts to research and develop a novel type of environmentally friendly sand fixer. In this study, acacia gum extracted from plants and sodium lignosulfonate from papermaking waste liquid were selected as raw materials to be co-mingled, and a biophilic plant-based sand fixer was developed. The results showed that the combination of acacia bean gum and sodium lignosulfonate strengthened the interaction with sand particles through hydrogen bonding, chemical adsorption, and cross-linking, thereby forming a stable composite structure. This further enhanced the cohesion with sand and improved its mechanical strength and stability. Soil effectively reduced soil moisture evaporation after spraying sand fixer. The seedling emergence rate of plants after spraying sand fixer ranged from 53.33 % to 60 %, which was higher than that after spraying equal amount of clear water (CK). Microscope images revealed that the sand-fixing material bridged the gaps between sand grains and progressively formed a cementation layer on their surfaces. This altered the flow characteristics of the sand and soil, imparting a degree of rigidity to the mixture. Furthermore, under a strong wind speed of 16 m/s, the wind erosion amount was <21 g·m^-2 over a 20-min period. This effectively protected the sand surface from wind erosion and demonstrated significant sand-fixing capability. The plant-based sand fixer could promote plant growth and modify the fundamental physical properties of sandy soil, holding potential as an environmental restoration material. Additionally, it should also serve as a novel approach for rapid sand fixation, laying the groundwork for the development of regional green prevention and control technologies.