Zeolite nanoparticle as a superior adsorbent with high capacity: Synthesis, surface modification and pollutant adsorption ability from wastewater

Herein, sodalite zeolite nanoparticle (SZN) was synthesized and modified by different amounts of (3-aminopropyl) triethoxy silane and denoted as SZN(0.5), SZN(1) and SZN(1.5). They were characterized by FTIR, XRD, SEM and zeta potential. The surface modified zeolite nanoparticles were used for adsorbing Direct Red 23 (DR23) and Direct Red 80 (DR80) from wastewater. Effect of main parameters on adsorption capacity of adsorbents was studied. The maximum uptake of DR23 and DR80 was carried out by SZN(0.5) at pH 2.1. The data followed to the Langmuir isotherm and pseudo-second order kinetic. Adsorption capacity of SZN(0.5) was 2415 and 4842 mg/g for DR80 and DR23, respectively. The removal of DR23 and DR80 was a physical adsorption process, exothermic and spontaneous reaction. The Gibes free energy 298, 313, 323 and 333 K were −12.53, −14.68, −16.12, and −17.55 kJ/mol for DR23 and −9.27, −11.73, −13.37, and −15.01 kJ/mol for DR80, respectively.