Properties of surfactants on high salt-affected sandy land in enhanced sand fixation: salt tolerance, adsorption isotherms and ecological effect
In the present paper surfactant, for the first time, was used to improve the sand fixing ability of emulsion in high salt-affected sandy land. This study started from the analysis of the main components of sand particles from Golmud sandy land, Qinghai province, China, by X-ray diffraction (XRD). Then, two surfactants, sodium dodecyl sulfate (SDS, an anionic surfactant) and Pluronic L35 (L35, a nonionic surfactant), were selected and used to conduct a salt tolerance test before their reaction with sand from a salty desert. The water solubilization method and Fourier transform infrared (FTIR) spectroscopy have been adopted to investigate the salt tolerance of surfactants and their reaction with sand particles, respectively. The adsorption and adsorption characteristics of two surfactants at varied salinities by sand particles have been considered because of its significance for the interaction. In addition, the influence of SDS and L35 on the growth of Escherichia coli (E. coli) and sand microbes were evaluated to understand their ecological effect. The experimental results showed that SDS and L35 can visibly enhance the sand-fixing ability of the emulsion in high salt-affected sandy land. The related mechanism is that, first, SDS and L35 could improve the stability of the emulsion against the salt if the preparation of emulsion uses SDS and L35 as the emulsifying agents; second, SDS and L35 could change the morphology of salt in sand (this experimental result we will report in another paper). The investigation into the influence of SDS and L35 on the growth of E. coli and sand microbes also showed a dependable ecological effect.