Enhancing protein-based foam stability by xanthan gum and alkyl glycosides for the reduction of odor emissions from polluted soils

Odorous contamination would occur in the polluted soils' remediation of the abandoned industry factory. To suppress odorous substances' emissions, a novel foam was prepared with plant protein, xanthan gum, and alkyl glycosides. Since xanthan gum and alkyl glycosides have the characteristics of prolonged foam half-life and enhanced foaming ability, the optimal ratio of xanthan gum to alkyl glycosides is crucial during foam formulation determination. When xanthan gum concentration increased from 0.00% to 0.30%, the viscosity of the foaming solution increased from 12 to 223 mPa∙s, while the surface tension declined by 12.3%. As a result, the foam half-life increased from 0.3 to 56 h, and the foaming volume decreased by 25.5%. On contrary, with the addition of alkyl glycosides, the surface tension decreased significantly, and the foaming volume increased by 36.5% under the xanthan gum concentration of 0.30%. Therefore, the optimal content of xanthan was 0.30% in the presence of 100 mM alkyl glycoside. Then, this novel foam could prevent 67% of p-xylene from escaping within 24 h. In actual sites, novel foams showed a barrier rate of over 75% on different odorous substances most of the time.