Near infrared and mid infrared investigations of adsorbed phenol on HDTMAB organoclays

X-ray diffraction patterns (XRD), infrared Spectroscopy (IR) and near infrared spectroscopy (NIR) have been used to measure the adsorption of phenol on untreated montmorillonite and on hexadecyltrimethylammonium bromide (HDTMAB) modified montmorillonite. The mid infrared spectra indicate that both the surfactant molecule and phenol enter the interlayer of organoclays, replacing the interlayer cations. The higher concentration surfactant leads to a decrease in wavenumber of the bands of organoclays and to increase in intensity. The near infrared spectra (9000–4000 cm−1) show a prominent band 8260 cm−1, assigned to the combination result of the CH stretching vibrations of high concentration surfactant and absorbed phenol. The main band observed at 7090 cm−1 is assigned to the first fundamental overtone of the OH stretching vibrations at 3415 cm−1 for organoclay. The organoclays are characterised by prominent bands situated between 5900 and 5700 cm−1. Both the higher concentration of organic molecules and adsorbed phenol causing the near infrared spectra of organic clays to be more complex for spectra in the region from 4700 to 5500 cm−1. The main band of 4535 cm−1 for montmorillonite shifts towards the lower wavenumber sites for higher concentration organoclay. The intensity of near infrared spectra generally rises with the value of surfactant concentration increasing, showing certain regularity. It is concluded that phenol is adsorbed to significantly greater amounts on the higher concentration organoclays.