Marrying the mussel inspired chemistry and Kabachnik–Fields reaction for preparation of SiO2 polymer composites and enhancement removal of methylene blue

The removal of organic dyes using functionalization SiO 2 composites (denoted as SiO 2 -PDA-CSH) were prepared via a facile method that combined with mussel inspired chemistry and Kabachnik–Fields (KF) reaction. The size and surface morphology, chemical structure, thermal stability, surface charging property, and elemental composition were evaluated by means of transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), zeta potential, and X-ray photoelectron spectroscopy (XPS), respectively. The results demonstrated that the organic functional groups can be successfully introduced onto the surface of SiO 2 microspheres through the combination of mussel inspired chemistry and KF reaction. The removal of cationic dye methylene blue (MB) by the raw SiO 2 and SiO 2 -PDA-CSH composites was examined and compared using a series of batch adsorption experiments. The results suggested that SiO 2 -PDA-CSH composites had a 3-fold increase in the adsorption capacity towards MB than that of pure SiO 2 microspheres and the adsorption process was dependent on the solution pH. According to the adsorption kinetics, the adsorption of MB onto SiO 2 -PDA-CSH composites was well described by pseudo-second-order kinetic model. The equilibrium data were fitted with Langmuir and Freundlich isotherm models with R 2   =   0.9981 and R 2   =   0.9982, respectively. The maximum adsorption capacity from Langmuir isotherm was found to be 688.85   mg/g. The adsorption thermodynamics was also investigated in detailed. The parameters revealed that the adsorption process was spontaneous and endothermic in nature. The adsorption mechanism might be the synergistic action of physical adsorption of SiO 2 -PDA-CSH particles and electrostatic interaction between the MB and functional groups on the surface of SiO 2 -PDA-CSH composites, including sulfydryl, amino, aromatic moieties, and phosphate groups. Taken together, we developed a novel and facile strategy for the surface modification of SiO 2 to achieve high adsorption towards MB based on the mussel inspired chemistry and multicomponent KF reaction. More importantly, this strategy could be easily extended for fabrication of many other high efficient adsorbents due to the universality of mussel inspired chemistry and various multicomponent reactions based on amino groups. Therefore, this work will open a new avenue and direction for the environmental applications of mussel inspired chemistry.