Organo-Silicate Nanocomposites for the Removal of Chlorinated Phenols from Aqueous Media: Kinetics and Environmental Stability

Abstract

Organosilicate nanocomposite hexagonal mesostructure (NHMS) was synthesized from dodecylamine and tetraethyl orthosilicate (TEOS). The nanocomposite (NMCM) of numbers 41, 48, and 50 were synthesized from cetyltrimethylammonium bromide (CTABr) and (TEOS). The rates, affinity, and stability of these synthetic nanocomposite materials to remove and retain chlorinated phenols from aqueous solution were investigated; all materials have the ability for sorption and retention of 2,4-dichlophenol (2,4-DCP). Batch absorption kinetics indicates that NHMS, NMCM-41, NMCM-48, and NMCM-50 are 1st order reactions, with rate constants of 0.412, 0.296, 0.112, and 0.0161 hr⁻¹, respectively. Average percent 2,4-DCP removal for NHMS, NMCM-41, NMCM-48, and NMCM-50 was 92, 98, 90, and 52%, respectively. Isothermic measurements fit Freundlich and Langmuir models. NHMS and NMCM-41 best fit Langmuir model. Stability of the adsorbents in 0.10 M CaCl₂ for 56 days was in the order: NMCM-41 > NHMS > NMCM-50 > NMCM-48.

Keywords:

• Chlorinated phenols
• Remediation
• Nanocomposite
• Mesostructure
• Adsorption