Inorganic Chemicals Industry ›› 2025, Vol. 57 ›› Issue (11): 23-30.doi: 10.19964/j.issn.1006-4990.2024-0662

• Research & Development • Previous Articles     Next Articles

Study on removing metal ions from phosphoric acid by hydrogen-bonded organic framework nanofiltration membrane

WANG Jiandong(), GONG Jianping, CHEN Jianjun(), LI Jun, LIU Daijun   

  1. School of Chemical Engineering,Sichuan University,Ministry of Education Research Center for Comprehensive Utilization and Clean Processing Engineering of Phosphorus Resources,Chengdu 610065,China
  • Received:2024-12-10 Online:2025-11-10 Published:2025-05-27
  • Contact: CHEN Jianjun E-mail:2103471140@qq.com;chenjianjun@scu.edu.cn

Abstract:

Wet-process phosphoric acid offers greater economic advantages over its thermal-process counterpart.However,it introduces substantial quantities of metal ions during production,which requires economical and environmentally sustainable removal strategies.Nanofiltration membranes,which efficiently separate ions and molecules with minimal environmental impact,have demonstrated considerable potential in the purification of phosphoric acid.However,the extremely low pH and high viscosity of crude phosphoric acid significantly hinder the applicability of conventional nanofiltration membranes,often leading to membrane degradation and reduced permeability.For this reason,a highly permeable,acid-resistant nanofiltration membrane(HOF-HDI) was synthesized for phosphoric acid purification by interfacial polymerization,employing C3H8N6SO4(HOF) as the aqueous-phase monomer and hexamethylene diisocyanate(HDI) as the organic-phase monomer.The successful fabrication of the membrane was confirmed through FT-IR and XPS.By optimizing the monomer concentration and thermal curing temperature,the optimal preparation conditions were established.The experimental results revealed that the HOF-HDI membrane achieved a permeation rate of 0.85 L/(h·m²·bar) in phosphoric acid solution(20% mass fraction in terms of P2O5).The rejection rates for Al3+,Mg2+,and Fe3+ ions decreased in the following order:Al3+(51.00%),Mg2+ (47.99%),Fe3+(46.33%).Static and dynamic acid resistance tests demonstrated the superior acid stability of the modified membrane.Investigating the influence of monomer type on membrane structure revealed that cavity-containing monomers enhance membrane permeability.Collectively,these findings underscored the great promise of the HOF-HDI nanofiltration membrane for effective phosphoric acid purification.

Key words: nanofiltration membrane, acid-resistant, high permeability, hydrogen-bonded organic framework, phosphoric acid

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