Removal of Chlorine Ions from Desulfurization Wastewater by Modified Fly Ash Hydrotalcite

[Image: see text] The effective removal of chlorine ion from the desulfurization slurry is of great significance to the stable operation of the desulfurization system. Modified fly ash hydrotalcites were prepared by alkali/acid-combined roasting and microwaving and used as an adsorbent for chlorine ion in desulfurized wastewater. The specific surface area and porosity of different adsorbents were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impacts of pH, temperature, adsorbent dosage, and adsorption shaking time on adsorption performance were investigated. Results showed the alkali-combined roasting-modified fly ash hydrotalcite has the optimum removal effect on Cl(–). The optimal adsorption performance was achieved when the pH was 8, the adsorption temperature was 60 °C, the mass concentration of adsorbent was 10 g/L, the adsorption shaking time was 180 min, and the removal percentage of Cl(–) was 68.1%. The adsorption isotherm was consistent with the Langmuir isotherm model, and the adsorption saturation was 694.4 mg/g, which belonged to monolayer adsorption.