Erosion resistance of treated dust soils based on the combined enzymatically induced carbonate precipitation and polyacrylic acid

Abstract

The majority of cities worldwide are grappling with the challenge of dust pollution. Recently, the application potential of enzymatically induced carbonate precipitation (EICP), a novel environmentally friendly method, for dust control has been convincingly demonstrated. However, the long-term durability of EICP treatment is consistently a significant concern, particularly in regions prone to recurrent erosion caused by rainfall. As a result, the erosion durability of the EICP-treated dust soils requires further investigation. To address this, Polyacrylic acid (PAA) was added to the cementation solution in this study as the combined PAA and EICP treatment for dust control. The results showed that the addition of PAA slightly affected urea degradation; however, the combined PAA and EICP treatment significantly improved surface strength from 300 kPa to 500 kPa, especially for the wind-erosion resistance compared with the EICP treatment alone. The surface strength of samples treated with the combined PAA and EICP still exhibited a decrease due to repeated rainfall erosion, along with a reduction in calcium carbonate (CaCO3) contents. Nevertheless, the decreasing slopes of surface strength (k = 13.434, 14.002, or 14.186) in response to repeated rainfall for EICP-PAA-treated slopes were much smaller than those for EICP-treated samples (k = 14.271), as well as the decreasing slopes of CaCO3 contents, which suggested the slopes with the combined treatment had significantly improved durability. By comparing the cementation effect and the influence of repeated rainfalls on treated dust samples, the EICP-PAA (50 g/L) treatment achieved better dust control effects. Overall, the combined treatment of EICP-PAA shows promising potential for effectively suppressing dust generation and enhancing erosion durability.