Inorganic Chemicals Industry ›› 2026, Vol. 58 ›› Issue (2): 92-99.doi: 10.19964/j.issn.1006-4990.2025-0025

• Environment·Health·Safety • Previous Articles     Next Articles

Study on removal of chloride ions from wastewater produced in production of monopotassium phosphate using extraction method

CHEN Taizun(), LI Jun(), JIN Yang   

  1. School of Chemical Engineering,Sichuan University,Chengdu 610065,China
  • Received:2025-01-15 Online:2026-02-10 Published:2026-03-12
  • Contact: LI Jun E-mail:leshanctz@163.com;lijun@scu.edu.cn

Abstract:

In response to the challenging issue of treating high-concentration chloride-containing wastewater generated during the production of monopotassium phosphate(MKP),a method for removing chloride ions from wastewater using trioctylamine(TOA) as an extractant was proposed.The effects of factors such as extractant formulation,extraction phase ratio,temperature and time on chloride ion removal rate were investigated,and the conditions for countercurrent extraction stages and stripping were explored.The results showed that under the conditions of an extractant formulation with a volume ratio of TOA,isooctyl alcohol,and kerosene at 2∶1∶7,with a phase ratio of 1∶1,an extraction temperature of 25 ℃,and an extraction time of 10 minutes,chloride ion concentration in the wastewater was decreased from 7500 mg/L to 294 mg/L after three stages of countercurrent extraction,achieving a chloride removal rate of 96.08%.Using 5 mol/L ammonia solution for three stages of countercurrent stripping with a phase ratio of 6∶1,the stripping rate reached 95.43%.The extraction mechanism was analyzed using the slope method and infrared spectroscopy,revealing that the extraction process followed an ion association-ion exchange mechanism,with a chloride-to-TOA molar ratio of 1∶1 in the extracted complex.This study presented an effective method for removing chloride ions from MKP production wastewater,preventing corrosion of equipment during subsequent treatment stages and providing a new approach for the treatment of chloride-containing wastewater in MKP production.

Key words: monopotassium phosphate, wastewater treatment, extraction method, chloride removal

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