Investigating the Effect of Coagulation and Flocculation - Adsorption Process on Boron Removal from Industrial Wastewater (Case Study: Ceramic Tile Industry)

Boron is widely found in raw materials and wastewater of the tile industry and its removal from aquatic environments is very complex. The aim of this study was to remove boron from wastewater of ceramic tile industry using coagulation and flocculation-adsorption process.

This was an experimental study. Initially, for the coagulation process, pH parameters between 5 to 11, concentrations of 150 to 450 mg/L of poly-aluminum chloride (PAC) and concentrations of 0.5 to 2.5 mg/L of anionic and cationic polymers were examined. Then, in the adsorption process, the effect of pH between 2 to 7 at contact times of 5 to 20 min was investigated. Finally, the data were analyzed using Pearson’s correlation test.

The results showed that the percentage of boron removal by poly-aluminum chloride at the optimum pH equal 8 and the concentration of 400 mg/L was 35.7% and in combination with 1.5 and 2.5 mg/L anionic and cationic polymer, removal efficiency of 54.2 % (from 35 to 16 mg/L) was observed. Then, in the adsorption process with an optimum pH equal 5 and contact time of 15 minutes, removal efficiency of 50% (from 16 to 8 mg/L) was obtained. Examination of isotherms in the adsorption process showed that boron adsorption follows the Freundlich isotherm and first-degree kinetics.

According to the results, the combined process of coagulation and flocculation with adsorption can be introduced as an effective process in boron removal.