INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY, cilt.13, ss.1277-1288, 2016 (SCI İndekslerine Giren Dergi)
This study presents the results of chromate adsorption upon organically modified clinoptilolite obtained by the treatment of Bigadic clinoptilolite with surfactants in primary amine structure, namely 1-dodecylamine, 1-hexadecylamine and oleylamine. Natural and organo-clinoptilolites were characterized by X-ray diffraction, thermal gravimetry and Fourier transform infrared spectrometry which proved the integration of amine groups followed by the order oleylamine > 1-hexadecylamine > 1-dodecylamine. Organo-clinoptilolites were tested for their efficacy in chromate removal under base case conditions which implied 100 ppm initial concentration, pH 4.0, 10 g l(-1) adsorbent dose and at 298 K. Results showed that amine loading induced chromate removal reaching up to 90 % for oleylamine-modified clinoptilolite. Experimentation was continued to determine the effects of pH, adsorbent dosage and initial concentration on chromate adsorption. Accordingly, maximum removal of 94.0 % was attained with 14 g l(-1) of oleylamine-modified clinoptilolite, from Cr(VI) solution of 100 ppm initially at pH 3.0. Langmuir isotherm described the adsorption of chromate on oleylamine-modified clinoptilolite with 96.4 % consistency. Maximum theoretical uptake capacity was calculated as 6.72 mg g(-1). Kinetic data were consistent with pseudo-second-order model with the controlling steps being film and pore diffusions.