Micro-emulsion has unique advantages in repairing diesel oil contaminated sand due to its low interfacial tension and strong solubility. By Winsor phase diagram

it was found that with the increase of salinity

the phase of microemulsion transformed from Winsor I to Winsor III to Winsor II. Under cryogenic electron microscope

it was observed that Winsor I was O/W type

Winsor II was W/O type

and Winsor III type was bi-continuous type. The effect of inorganic salts

alcohol and temperature on the oil removal rate of diesel oil contaminated sand was investigated by static recovery of micro-emulsion precursor. The results showed that for the anionic microemulsion system

with the increase of salinity and alcohols

the oil yield of the upper phase increased first and then decreased

and the two components had a certain compensation effect. For non-ionic micro-emulsion system

with the increase of temperature

the oil yield in the upper phase rose first and then decreased. At the same time

the influence of leaching conditions on oil removal rate was investigated by one-dimensional sand column leaching experiment. It was found that for diesel oil contaminated sand with 15% oil content

when the formulation

was 2.00 wt% SDBS

4.05 wt%

n

-butanol and 0.40 wt% sodium chloride

the optimum leaching conditions were leaching rate of 4 ml·min

-1

and leaching amount of 400 ml. Under such conditions

the oil removal rate was up to 82.84%

that is

the oil content of the sand was reduced to 2.57%. Moreover

the micro-emulsion has good cyclicity

and it can still achieve high oil yield after six cycles.