Preparation of diatomite-based porous ceramics and their adsorption properties for Cu2+

Diatomite-based porous ceramics were prepared by wet grinding and high temperature calcination with diatomite as the main raw material. The structure and properties of the ceramics were characterized by SEM, XRD, and FI-TR detection techniques. The results show that the diatomite-based porous ceramics are mainly quartz crystal phase and contain a large amount of Si-OH. Their pore size distribution is 500 similar to 3500 nm, the specific surface area is 6.14 m(2)/g, and the porosity is 47.8 %. The static adsorption process of Cu2+ in water by ceramic particles conforms to the quasi-second-order kinetic model, and the adsorption equilibrium is reached after 6 h with the maximum adsorption capacity of 4.5 mg/g. The Thomas model can be applied to represent the dynamic adsorption of Cu2+ in water. In the adsorption of Cu2+, pH exerts a strong influence. In solution, Cu2+ forms a ligand with hydroxyl surface functional groups on the surface of ceramics and pores through electrostatic interaction, and the hydrogen on the hydroxyl group exchanges with Cu2+, so that Cu2+ can be removed.