Selective adsorption and separation of toxic cationic dyes using hierarchically porous SDBS modified vaterite microspheres (Hr-SMV)

Abstract The application of hierarchically porous sodium dodecylbenzene sulfonate (SDBS) modified vaterite microspheres (Hr-SMV) for the selective adsorption of toxic cationic dyes has been explored in this work. Hr-SMV has been synthesized using a facile and low-cost precipitation method. X-Ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA) and N2 adsorption-desorption isotherms have been used to understand the crystal structure, surface area, morphology and surface functionalities of Hr-SMV. As prepared Hr-SMV possesses a surface area of 31.15 m2 g−1 and a hierarchical porous structure. Influence of adsorption parameters on the adsorption of two cationic dyes, Crystal violet (CV) and Methylene blue (MB) has been studied in detail using batch adsorption studies. Maximum adsorption capacities of 68.8 and 316.8 mg g−1 were exhibited by Hr-SMV for MB and CV, respectively. Further, Hr-SMV shows efficient adsorptive removal of other cationic dyes, including Basic fuchsine (BF) and Auramine O (AO). In binary mixtures of cationic dyes, Hr-SMV efficiently removes both cationic dyes, thus highlighting its prospect for practical applications. In binary mixtures of cationic and anionic dyes, Hr-SMV is found to selectively adsorb cationic dyes with high separation factors. Thus, Hr-SMV has been found to be a promising low-cost adsorbent for the efficient adsorption and separation of cationic dyes from effluents.