Recovery and recycling of Zr(OH)4 with a ZrCl4 coagulant from waste of the zirconium pentahydroxide [Zr(OH)5−] displacement technique

Ion exchange technology is the most effective and economical to remove heat stable salts (HSS) in CO2 absorption processes. However, the disadvantage of high waste generation remains an unsolved problem. This study attempted to reduce the amount of waste generated during the Zr(OH)5− regeneration process through resource recovery by using ZrCl4 coagulant, then recycling the recovered Zr(OH)4 precipitate to produce Zr(OH)5− regenerant. The experimental results showed a waste coagulant efficiency of about 75%. The coagulation mechanism was suggested based on the conductivity and zeta potential analysis. The recovered Zr(OH)4 had no differences in terms of chemical composition and regeneration efficiency, when compared with virgin material. These results indicate that the recovery and recycling of Zr(OH)4 from the waste stream using ZrCl4 as a coagulant reduced a large amount of the waste generated from the ion exchange process.