The influence of periodic surfactant drip irrigation on the fate of petroleum pollutants in soil in arid regions

Taking conventional sprinkler irrigation (SPI) as a control, this study explored the effect of drip irrigation (DRI) on the phytoremediation efficiency of petroleum-contaminated soil in arid areas. It investigated the migration and distribution of petroleum pollutants and water in the soil, plant physiological indicators, as well as the petroleum removal effect under the DRI. The results showed that compared with SPI, DRI could weaken the migration of petroleum to deep soil, enhance the absorption of petroleum pollutants by plant roots, and increase the biomass of ryegrass by 13.793%. In addition, applying surfactants through periodic DRI could improve the utilization efficiency of surfactants in soil and promote the absorption and degradation of petroleum by plants. Under DRI, when the mass ratios of sodium dodecyl benzene sulfonate (SDBS) to Tween 80 were 9:1 and 1:1, the phytoremediation efficiencies were 1.66 times and 1.44 times higher than those in the group without surfactants, respectively. Meanwhile, the phytoremediation efficiency of petroleum was much lower than the degradation efficiency of surfactants, which reduced the secondary pollution caused by surfactants. In conclusion, combining mixed surfactants with DRI technology is an excellent choice to improve the phytoremediation effect of petroleum pollutants in soil.