Electrochemical study on adsorption behavior of surfactants at β-2CaO·SiO2/NaAlO2 interface

β-2CaO·SiO2 was obtained with analytical grade reagents. Polyethylene glycol (PEG), sodium polyacrylate (PAAS) and their mixture were used to inhibit the decomposition of β-2CaO·SiO2 in sodium aluminate solution. The potential of solid-liquid interface and the adsorption mechanism were studied by the methods of Zeta potential measurement and XPS. The results indicate that PEG and PAAS have synergistic effect on the inhibition of secondary reaction. The inhibitory effect is the best when the volume ratio of PAAS to PEG is 1:1 and the total concentration is 12.5 mg/L. PAAS adsorbs on the surface of β-2CaO·SiO2 by the formation of —COOCa coordinate bond, and the negative charge enters into Stern layer, which results in the decrease of particle potential and the obvious change of binding energy of Ca 2p, Si 2p and O 1s. PEG only physically adsorbs on the surface of β-2CaO·SiO2, and had little effect on particle potential and binding energy of Ca 2p, Si 2p and O 1s.