Selective Adsorption and Removal of Congo Red Based on Ethylenediamine Functionalized Mesoporous Silica

Abstract Five types of mesoporous silica‐based adsorbents were prepared by rationally implementing five diverse amine‐containing functional units into the mesoporous SBA‐15 structures. The prepared materials were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorption−desorption isotherms and thermogravimetric analysis. Among the five adsorbents, the ethylenediamine functionalized SBA‐15, namely, AAPTMS‐SBA‐15, achieved the complete adsorption of Congo red (CR) at pH 6.0, with the maximum adsorption capacity of 4608 mg/g. The AAPTMS‐SBA‐15 material was used effectively for CR adsorption from the individual and binary dye aqueous solutions, indicating that AAPTMS‐SBA‐15 can selectively remove and separate CR from wastewater. The hydrogen bonding interactions between AAPTMS‐SBA‐15 and CR were beneficial to the high selectivity and excellent adsorption capacity of AAPTMS‐SBA‐15 toward CR. Moreover, the selective adsorption and efficient separation of CR realized the recovery and reusability of AAPTMS‐SBA‐15 and CR, which can not only avoid secondary environmental pollution, but also save economic costs.