Effect of xanthan gum on mechanical strength and microstructure of Cu (II)-contaminated soil subjected to freeze–thaw cycles

Soil pollution, particularly heavy metal contamination, has emerged as a critical global environmental issue. This study investigates the impact of Xanthan Gum (XG) on the mechanical properties of Cu (II)-Contaminated Soil, especially under freeze–thaw cycles conditions. Heavy metals, such as Cu 2 ⁺, affect over 50% of contaminated sites worldwide, posing significant risks to ecosystems and human health through the food chain. In this research, the effects of curing time, XG content, and the number of freeze–thaw cycles on the stress–strain behavior and microstructural evolution of Cu (II)-Contaminated Soil were examined using unconfined compressive strength tests and scanning electron microscopy (SEM). The results indicate that XG effectively enhances the strength of contaminated soils, with the strength initially increasing and subsequently stabilizing under repeated freeze–thaw cycles. SEM analysis further reveals that XG improves soil microstructure by filling interparticle pores and strengthening particle bonding, thereby enhancing the macroscopic mechanical performance. This study introduces Xanthan Gum as a promising eco-friendly material for the remediation of heavy metal-contaminated soils.