Treated diatomite for toluidine blue removal from wastewater. Is it worth it?

Abstract

The adsorption of Toluidine Blue (TB) cationic dye was performed using raw and treated (thermal, chemical, thermo-chemical, ultrasonic) diatomite. Solid samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (EDX), and Fourier Transformed Infrared Spectroscopy (FTIR). Adsorption experiments were performed in batch conditions (20 ± 2°C, 100 mg TB/L, 100 mL, 0.1 g adsorbent). The best sample proved to be the one thermally treated at 250°C for 2 h with an adsorption capacity of 7.97 mg/L and 77% removal efficiency. The regeneration process of the used diatomite was also performed (calcination, HCl, water), the most efficient was the one using water. Kinetic models (pseudo-first-, pseudo-second-order, liquid film, and intra-particle diffusion) were considered to describe the experimental data. The calculated data showed that liquid film diffusion might be rate-determining step in this case.

Advance Aerobic Granular Sludge Development for the Treatment of Low Strength Wastewater

“…The result was comparable with Van Leeuwe et al [31], claiming that the microbes clearly dominated the pennate diatomite but less abundant in centric diatomite. According to Măicăneanu et al [32], the pennate diatomite has superior technical properties, that elevates the adsorption ability. In the SEM analysis, the pennate diatomite was discovered to have open-pores dispersed in clay matrix.…”