COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, vol.630, 2021 (SCI-Expanded)
This study was performed to evaluate the removal from wastewater of reactive orange 16 (RO16) with magnetically separable zeolitic imidazole frameworks coated magnetic bentonite nanocomposites (ZIF(8)@Fe3O4@BNT). Various microscopic and spectroscopic analyses were carried out to reveal the surface characteristics of the nanocomposite. Point of zero charging (pHPZC) of ZIF-8@Fe3O4@BNT was obtained as 8.84. The dependence of RO16 removal yield on initial pH, initial dye concentration (Co), adsorbent dose and contact time was investigated using the central composite design (CCD) included in response surface methodology (RSM). With the obtained quadratic model equation from CCD, the optimum values were determined as initial pH of 3.9, initial concentration (Co) of 19.76 mg/L, adsorbent amount of 12 mg (480 mg/L), and contact time of 150 min. The maximum removal efficiency of 98.5% and the maximum adsorption capacity of 40.5 mg/g were reached at these optimal points. Adsorption kinetic analysis and equilibrium experiments showed that the best fit was reached with the pseudo-second-order and Langmuir isotherm models, respectively. Also, thermodynamic parameter changes for RO16 removal were calculated, and the results showed that the adsorption was favorable, spontaneous, and exothermic. With all of these, the fact that ZIF-8@Fe3O4@BNT has high recovery efficiency for RO16 removal, fast kinetics and can be separated easily and quickly with the help of a magnet before and after treatment provide significant advantages for wastewater treatment.