Preparation of tourmaline/diatomite-based interior wall bricks and kinetics of formaldehyde removal

Abstract

Diatomite was used as the main raw material, to which tourmaline powder and sintering additives were added, using an ultra-fine wet grinding process to prepare glaze slurry, and impregnating the surface and pore channel of diatomite-based porous ceramics, tourmaline/diatomite-based interior wall bricks were prepared by low-temperature calcination. The adsorption and degradation abilities of the materials were discussed by using formaldehyde gas as the target pollutant. Results indicate that the tourmaline/diatomite-based inner wall bricks, the original pore structure of diatomite, and the pores formed by particle accumulation constitute an organic whole. After 16% ultrafine tourmaline powder was added to the glaze layer, the average pore diameter and porosity decreased from 4243.8 nm and 45.5% to 2814.5 nm and 41.8% respectively, while the specific surface area increased from 6.14 m2/g to 8.62 m2/g. In a 1-m3 controlled-environment chamber, after 5 h of purification, the concentration of formaldehyde decreased from 0.303 mg/m3 to 0.0782 mg/m3. Based on the Langmuir-Hinshelwood model, the kinetic equation of formaldehyde adsorption in its gas phase was established. The reaction rate constants of formaldehyde gas phase adsorption degradation were obtained by linear regression as follows: κ = 0.483 mg/(m3·min), and the apparent rate constant K = 0.036 m3/mg.