Environmental sustainability in combating wind erosion: Chemical stabilization of sand dunes using acidic mulching

Abstract

Wind erosion and desertification are pressing environmental crises in arid and semi-arid regions, causing significant ecological damage through the formation of dunes and the redistribution of sand. This study investigates a chemical stabilization method for loose sand using acidic mulching liquids to mitigate these issues. Specifically, calcareous (Aragonitic) sand particles smaller than 300 micrometers were treated with diluted sulfuric and phosphoric acids (in water or alcohol) to create effective mulching solutions. The chemical reactions between the acids and the calcareous sand led to the formation of in-situ cements: dicalcium phosphate dihydrate (Brushite) from the reaction with phosphoric acid, and Gypsum from the reaction with sulfuric acid. These substances helped bind the sand particles, forming a solid crust on the sand surface. The study employed various tests to evaluate the effectiveness of the stabilization, including penetration resistance, unconfined compressive strength, wind erosion modulus, and analytical techniques such as XRD, FESEM, and XRF. The results indicated that the appropriate concentrations and volumes of these acids can successfully form a durable sand-cement crust, which effectively controls wind erosion. Wind tunnel experiments demonstrated a significant reduction in erosion, with the wind erosion modulus decreasing from 3975 g.m−2.min−1 for untreated sand to zero for sand stabilized with 35 % sulfuric acid. The findings offer a practical contribution to environmental management practices by introducing a feasible and impactful method to combat wind erosion and desertification in affected regions.

Keywords

• Stabilization
• Calcareous sand
• Sulfuric acid
• Phosphoric acid
• Dune
• Mulching liquid