The preparation of novel mineral-based mesoporous microsphere by microencapsulation technology and its application in the adsorption of dye contaminants.

Abstract

Microencapsulation technology was adopted to prepare the novel mineral-based mesoporous microsphere (MBMM) for the removal of dye contaminants from water. Field emission scanning electron microscopy, energy dispersive spectrometry, Brunauer-Emmett-Teller zeta potential analysis, and Fourier transform infrared spectrometry were used to investigate the microstructure characteristics of MBMM and its changes in the functional groups before and after adsorption. Batch experiments were carried out to investigate the effect of calcination temperature, initial concentration, pH, contact temperature, and time on the adsorption behavior of rhodamine B and methylene blue onto MBMM. The results indicated that the prepared MBMM had a hollow structure and mesoporous surface, which was beneficial to improving its adsorption capacity. The maximum adsorption capacities of rhodamine B and methylene blue onto MBMM prepared at calcination temperature 500 °C were 57.79 mg g-1 and 55.94 mg g-1 under the conditions of initial concentration 300 mg L-1, dosage 0.1 g, pH 7.0, adsorption temperature 55 °C, and adsorption time 7 h. The results showed that the calcining treatment was beneficial to the formation of mesoporous microspheres, improving their adsorption capacities. The adsorption process was endothermic reaction, and electrostatic attraction and hydrogen bonding were the driving forces of the reaction.