Silver nanoparticles incorporated in dicarboxylic/TEPA modified halloysite nanotubes for the degradation of organic contaminants

Abstract

Silver supported on organo-modified halloysite nanotubes (Ag-HNTX/T) were fabricated through three steps of modifications; (i) functionalization of pristine halloysite nanotubes (HNT) with dicarboxylic acids, namely succinic acid (SA), oxalic acid (OX), or sebacic acid (SB), (ii) addition of tetraethylenepentamine (TEPA), and finally (iii) incorporation of silver particles (Ag). The modification with dicarboxylic acid and TEPA on HNT was proven by the presence of COOH and NH functional groups in the FTIR spectra. Upon introduction of Ag particles on the organo-modified HNT, the Ag-HNTSA/T sample exhibits UV-DRS absorption at 460 nm, corresponding to the presence of Ag particles with the average size of 12.1 ± 6.5 nm. The HRTEM result reveals that Ag particles are deposited on the surface and inside the lumen of HNT, which is in-line with slight decrease in SBET attributed to some pore blocking in Ag-HNTSA/T. The catalytic activity of the fabricated Ag-HNTX/T (X = SA, OX or SB) was evaluated through the borohydride-assisted degradation of organic contaminants, i.e. methyl orange (MO), methylene blue (MB), p-nitrophenol (p-NP), and bromocresol green (BG). The Ag-HNTX/T catalyst exhibited excellent catalytic activity and the process follows the pseudo-first order kinetics. The Ag-HNTX/T possesses sustainable catalytic performance up to 15 recycled applications.