Zwitterionic Copolymer-Modified Mesoporous Silica Material: A Promising Adsorbent for Both Anionic and Cationic Dye Removal and an Efficient Stationary Phase for Liquid Chromatography

Abstract The creation of innovative single materials with a variety of applications is a major need for materials in the future. The decolorization of both anionic and cationic dye-contaminated water with high adsorption capacities is one of the most challenging problems for the existing adsorbents. At the same time, separating highly polar compounds with high selectivity is also challenging with the existing stationary phases in liquid chromatography. The new material was designed with two important monomers such as methyl acrylate (MA) containing a carbonyl group and sulfobetaine methacrylate (SBMA) containing zwitterions (anionic and cationic sites) to interact with both anions and cations in dye-contaminated wastewater as well as for electrostatic interactions with polar analytes for their separation. 3-Mercaptopropyltrimethoxysilane (MPS) end-functionalized copolymer (telomer) of MA and SBMA was synthesized, characterized (by 1H NMR), and then immobilized onto silica by the “grafting to” method to obtain Sil-(MA10-co-SBMA10). After immobilization onto silica, the novel material was characterized by elemental analysis, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Cationic methylene blue (MB) was effectively adsorbed onto Sil-(MA10-co-SBMA10), with the highest adsorption capacity of 2000.00 mg/g at varying pH. Similarly, anionic Congo Red (CR) showed an adsorption capacity of 1666.67 mg/g under different pH conditions. The Sil-(MA10-co-SBMA10) material showed the highest adsorption capacities among the reported silica-based adsorbents. The material’s zeta potential was evaluated to identify the adsorption technique’s interaction mechanism. For hydrophilic interaction chromatography (HILIC), the same material was simultaneously packed onto a 150 × 2.1 mm HPLC column and assessed with Tanaka test probes. Remarkably, when contrasting it with the most popular commercial HILIC columns, the best segregation was achieved using the Sil-(MA10-co-SBMA10). Therefore, it will create a new way of thinking to design materials for more than one application.