Simultaneous removal of Congo red and Cr(VI) using amino-modified GO/MS composite materials

Mesoporous silica (MS) and graphene oxide (GO) are good absorbents. Combining them not only prevents GO agglomeration but increases the number of MS active sites. In addition, their composites can preferentially adsorb specific pollutants after modification. In this work, amino-modified GO/MS materials were prepared by post-grafting to remove Congo red (CR) and Cr(VI) in solution. Characterization methods, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Zeta potential, and N 2 adsorption/desorption, were adopted. The prepared GO/MS@HBP has a porous structure with a specific surface area of 49.32 m 2 ·g −1 . The effect of initial concentration, pH, adsorption time, temperature and other ions was determined on the adsorption amount. Relying on this, the GO/MS@HBP maximum capacity for Cr(VI) and CR adsorption are 93.73±2.3% and 257.69+1.5% mg·g −1 , respectively. Pseudo-second-order kinetic and Langmuir isotherms are more suitable to describe the adsorption process, indicating that chemical adsorption plays a major role in the entire adsorption process. Thermodynamics showed that the enthalpy (H) of materials adsorbing two pollutants was positive and that the Gibbs free energy (G) was negative, suggesting that Cr(VI) and CR adsorption on GO/MS@HBP was spontaneously endothermic. GO/MS@HBP could simultaneously remove CR and Cr(VI) in solution, and be an effective adsorbent for removing harmful substances.