Abstract
Solvent extraction experiments of Ca2+ with D2EHPA and 15% saponified D2EHPA from cation-exchange resin regeneration wastewater have been performed. Compared with the extraction efficiency (E) of Ca2+ with D2EHPA, the use of 15% saponified D2EHPA significantly increases the extraction efficiency (E) of Ca2+. In this work, a systematic study on the extraction of Ca2+ from cation-exchange resin regeneration wastewater using saponified D2EHPA has been carried out. To study the extraction efficiency and advantages of the method in the removal of Ca2+, various parameters such as saponification ratio of D2EHPA, D2EHPA mass fraction, reaction temperature, phase mass ratio, initial pH of wastewater, transfer-speed, and transfer-time are studied and optimized. The results show that Ca2+ in wastewater can be effectively removed by saponified D2EHPA. An extraction efficiency of more than 99.9% is attained at the optimized parameters and the cation-exchange resin regeneration waste-water can be discharged directly by two levels of extraction, and it meets the Chinese National Emission Standards.
Acknowledgement
The authors gratefully acknowledge the financial support of this work by the New Century Excellent Talents of Ministry of Education (NCET-07-0577), the People’s Republic of China.