here below a method to obtain SiO2-coated desert sand particles in a quite simple way.
The fine raw sand was obtained from Kubuqi desert and was cleaned with deionized water only. To obtain the SiO2-coated sand, the sand first needed to be positively charged; therefore, 5 g sand in 100 mL ethanol was added to 50 mL 0.14 M cetyl-trimethyl ammonium bromide (C19H42BrN) aqueous solution and the mixture was stirred for 1 h. After that, the pH value of the solution was adjusted to 12 using ammonium hydroxide. Next, 10 mL tetraethoxysilane (TEOS) was added drop-wise to the above solution. Under continuous and vigorous stirring for 10 h, the hydrolysis of TEOS directly resulted in the formation of sand@SiO2 composite particles. The resulting product was achieved after fully rinsing with deionized water and drying at 60°C.
For more details, please see the source:
-Superhydrophobic sand: a hope for desert waterstorage and transportation projects
Liwei Chen, Yifan Si, Zhiguang Guo and Weimin Liu
J. Mater. Chem. A,5,6416 (2017)
Available at: https://www.researchgate.net/profile/Liwei_Chen19/publication/313871566_Superhydrophobic_SandA_Hope_for_Desert_Water_Storage_and_Transportation_Projects/links/5ebfa2bca6fdcc90d67a3ccb/Superhydrophobic-SandA-Hope-for-Desert-Water-Storage-and-Transportation-Projects.pdf