Boron adsorption mechanism of a hybrid gel derived from tetraethoxysilane and bis(trimethoxysilylpropyl)amine

An organic/inorganic hybrid gel was prepared with tetraethoxysilane (TEOS) and bis(trimethoxysilylpropyl)amine (TSPA) as precursors. The adsorption of boron on the hybrid gel in aqueous solutions was investigated comprehensively by varying the initial boron concentration, pH, ionic strength, and temperature. The equilibrium adsorption amount of boron increases with the increase in initial boron concentration and ionic strength, but decreases with the increase in temperature. The adsorption amount exhibits a maximum at initial pH of 4–10. Boron appears to be adsorbed in both H3BO3 and B(OH)4− forms through the hydrogen bonding, electrostatic and hydrophobic attractions.