Modified natural zeolite using ammonium quaternary based material for Acid red 18 removal from aqueous solution

The aims of this study were to modify local clinoptilolite zeolite (CZ) to surfactant modified form and investigate its potential for acid red 18 (AR18) removal from aqueous solution. Hexadecyltrimethylammonium chloride (HDTMA-CL) was applied to promote the adsorption capacity of CZ. X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM) were utilized to determine physical, chemical, and morphological properties of raw and modified CZ. Batch experiments were carried out to investigate the isotherms and kinetic models of AR18 adsorption on surfactant modified clinoptilolite zeolite (SMCZ). Besides, the effect of contact time and initial dye concentration on removal efficiency were examined. Nonlinear isotherms and kinetic models was obtained using Goodness of fit (GooF) method. Also, removal mechanism was discussed. Higher removal efficiencies were observed as the detention time was increased and the process reached to the equilibrium during 150 min. GooF results showed that the best isotherm for a description of adsorption equilibrium data was Langmuir model. The maximum adsorption capacity of 11 mg/g was obtained according to Langmuir equation. Also, kinetic studies showed that adsorption followed an Elovich model. The initial sorption rate of 5.8 mg/g min was obtained for selected kinetic. Electrostatic adsorption was determined as possible removal mechanism. The SMCZ can be used as an efficient adsorbent for AR18 removal from aqueous solution because of its low cost, and high availability in nature.