Recovery of Sodium Bicarbonate from Textile Dye Bath Effluent Using Carbon Dioxide Gas

Abstract

Water pollution from textile industries is caused by the disposal of brackish dye bath effluent, containing a high concentration of sodium chloride. The targeted removal of Na+ from the effluent using carbon dioxide would provide environmental benefits, both in reducing the environmental impact of disposal and in the production of valuable bicarbonate product. This paper describes a method based on the Solvay process for converting Na+ in the saline effluent to a useful product. The production of sodium bicarbonate from the effluent using carbon dioxide has been elucidated in a batch mode. The influence of various operating conditions including concentration of ammonium hydroxide, reaction temperature, carbonation time, and the flow rate of carbon dioxide gas on the bicarbonate yield was analyzed. Moreover, the efficiency of struvite precipitation in the removal of NH4+ from the resulting solution of the modified Solvay process was evaluated. The highest Na+ removal of 38% of the saline effluent and the b...