Organically Modified Saponites: SAXS Study of Swelling and Application in Caffeine Removal

ACS Appl Mater Interfaces. 2015 May 27;7(20):10853-62. doi: 10.1021/acsami.5b01894. Epub 2015 May 13.

Abstract

This study aimed to assess the capacity of saponite modified with n-hexadecyltrimethylammonium bromide (CTAB) and/or 3-aminopropyltriethoxysilane (APTS) to adsorb and remove caffeine from aqueous solutions. Powder X-ray diffraction (PXRD) revealed increased basal spacing in the modified saponites. Small-angle X-ray scattering (SAXS) confirmed the PXRD results; it also showed how the different clay layers were stacked and provided information on the swelling of natural saponite and of the saponites functionalized with CTAB and/or APTS. Thermal analyses, infrared spectroscopy, scanning electron microscopy, element chemical analysis, and textural analyses confirmed functionalization of the natural saponite. The maximum adsorption capacity at equilibrium was 80.54 mg/g, indicating that the saponite modified with 3-aminopropyltriethoxysilane constitutes an efficient and suitable caffeine adsorbent.

Keywords: caffeine adsorption; emerging contaminants; organoclay; saponite; wastewater.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Aluminum Silicates / chemistry*
  • Caffeine / chemistry
  • Caffeine / isolation & purification*
  • Nanoparticles / chemistry
  • Nanoparticles / ultrastructure
  • Organic Chemicals / chemistry*
  • Particle Size
  • Scattering, Small Angle
  • Water Pollutants, Chemical / isolation & purification
  • Water Purification / methods*
  • X-Ray Diffraction / methods*

Substances

  • Aluminum Silicates
  • Organic Chemicals
  • Water Pollutants, Chemical
  • Caffeine
  • saponite