Fabrication of ZnO/nanobentonite as a new efficient adsorbent for rapid elimination of xylenol orange dye

Abstract

A novel ZnO-nanobentonite (ZnO/NB) nanocomposite was successfully prepared using hexadecyltrimethylammonium bromide (HDTMA) as a surfactant and used as an efficient adsorbent to remove the xylenol orange (XO) from aqueous solutions. The fabricated nanocomposite was fully characterized by FTIR, FESEM, XRD, EDX, and BET measurements. The ZnO33%/NB sample with a high SBET and low total pore volume compared with the nanobentonite clay, based on BET results, indicated an increase in SBET due to the incorporation of ZnO nanoparticles into the layer of nanobentonite. For achieving the optimum condition, the effect of ZnO33%/NB sorbent dosage, initial pH, reaction time, and primary dye concentration, on XO dye elimination was investigated. The result show that the 97% elimination of XO dye occurred at optimum condition (40 mgl/l of dye concentration, pH 2, 15 mg of ZnO33%/NB adsorbent at 30 minutes), and the adsorption capacity and residual XO after treatment at this conditions is 48.5 and 1.2 ppm, respectively. Langmuir models and Freundlich model were used to studying the adsorption isotherms of the elimination process and results authenticated that XO dye adsorption followed the Langmuir model. Also, the recycling experiments showed that ZnO33%/NB adsorbent had more stability and recoverability. High adsorption capacity, simple fabrication method, short reaction time, and supreme reusability of ZnO33%/NB nanocomposite make it an effective sorbent for the elimination of XO dye from wastewaters.