Synthesis and Application of Silica Aerogel-MWCNT Nanocomposites for Adsorption of Organic Pollutants

Abstract

Silica aerogel-multi wall carbon nanotube composites were synthesized successfully with a waterglass precursor and an ambient pressure drying method. Pure silica aerogels are so fragile that they cannot be used easily. Carbon nanotubes (MWCNT) were used as reinforcements to strengthen the mechanical properties of pure silica aerogels. Results show that inserting small amounts of MWCNT causes silica aerogels to monolith. By addition of MWCNT, monolith nanocomposites were produced with 800 m2/g surface area and a 140 contact angle. Results show that the silica aerogels and reinforced composites have an excellent adsorption property for the removal of organic pollutants from water. The average adsorption capacity was about 5 times the composite weight for benzene, toluene, n-Hexane, kerosene, gasoline and petroleum. The adsorption isotherm was type IV for pure silica aerogels and nanocomposites, which is ideal for excellent adsorbency. Addition of MWCNTs will not decrease the pollutant adsorption capacity of the aerogels. TEM, SEM, FTIR, contact angle, BET, BJH and the porosity of pure silica aerogels and nanocomposites are measured and reported. Adsorption isotherms show that synthesized adsorbents obey the Freundlich isotherm equation.