膜萃取和CaO-MgO乳状液反萃取法由醋酸废水生产醋酸钙镁盐

Preparation of Calcium Magnesium Acetate from Acetic Acid Wastewater via Membrane Extraction and CaO-MgO Emulsion Reextraction

采用磺化聚醚砜中空纤维膜萃取醋酸废水,再用CaO-MgO乳状液反萃取制备醋酸钙镁盐。考察了膜萃取和反萃取的最佳实验条件。单级膜萃取醋酸废水(醋酸质量分数2%)的最佳条件为:水相走管程有机相走壳程(水外油内)逆流、有机相流量与水相流量比1.3、水相流量0.23 mL/min,在此条件下萃取率可达74%;采用二级萃取,总萃取率可达95%。反萃取的最佳条件为:采用质量浓度100g/L的CaO-MgO乳状液作反萃取剂,CaO-MgO与醋酸摩尔比1.0:2.0,投料钙与镁摩尔比2.9:7.0,反萃取时间30 min,室温,在此条件下反萃取率高于97%。

Calcium magnesium acetate was prepared from acetic acid wastewater via extraction using sulfonated polyethersulfone hollow-fiber membrane and reextraction using CaO-MgO emulsion. The optimum conditions for extraction and reextraction were studied. The optimum conditions for extraction are as follows： The mass fraction of wastewater acetic acid is 2%, the water flow in tube and the organic flow in shell of tube are countercurrent, the flow ratio of organic phase to water phase is 1.3, the water flow is 0.23 mL/min. The single stage extraction efficiency can reach 74%, and the twostage extraction efficiency can reach 95%. The optimum conditions for reextraction are as follows： CaO-MgO emulsion mass concentration 100 g/L, mol ratio of CaO-MgO to acetic acid 1.0 ： 2.0, mol ratio of Ca to Mg 2. 9 ： 7. 0, reextraction time 30 rain and room temperature. The reextraction efficiency can reach over 97 %.