聚乳酸/羟基磷灰石复合纤维膜制备及其对水中氟离子的吸附

Fabrication of Poly Lactic Acid/Hydroxyapatite Composites Fibrous Mat and Its Property for Defluorination

以聚乳酸(polylactic acisd,PLLA)/羟基磷灰石(hydroxyapatite,HAP)/四氢呋喃(tetrahydrofuran,THF)为淬火溶液,无其他添加剂条件下,通过-20℃低温淬火、萃取、洗涤和干燥得到直径为400~700 nm PLLA/HAP复合纤维膜。研究了PLLA/HAP比例、聚合物浓度等条件对纤维形貌影响。实验结果表明,纯PLLA为"哑铃状"捆束结构,结晶度、比表面积和孔隙率分别为40. 71%、11. 23 m^2/g和95. 12%。加入无机物HAP后,PLLA/HAP(5/5)复合纤维膜的结晶度、比表面积和孔隙率分别降低到24. 12%、8. 01 m^2/g和82. 12%。主要因为HAP加入阻碍了PLLA分子链的有序规整堆积,影响PLLA的结晶。研究PLLA/HAP复合纤维膜对氟离子的吸附性能。实验结果表明,拟二级动力学和Langmuir模型更适合该吸附体系。纤维膜对氟离子的最大吸附容量为6. 06 mg/g,纤维膜对氟离子的吸附更趋于单层吸附且化学吸附占主导地位。纤维膜重复使用5次后,吸附效率仍然保持在87. 67%。

Poly lactic acid/Hydroxyapatite/tetrahydrofuran(PLLA/HAP/THF)composites fibrous mat with diameter of 400~700 nm were fabricated by-20℃low-temperature quenching,extraction,washing and drying from its tetrahydrofuran solution without the assistance of other additives.The effect of the ratio of PLLA/HAP and concentration etc on the morphology of fibrous mat were investigated.The results show that PLLA was“dumbbell shape”sheaves,and the crystallinity,specific surface areas and porosity were 40.71%,11.23 m 2/g and 95.12%.The crystallinity,specific surface areas and porosity of PLLA/HAP(5/5)composites fibrous mat decreased to 24.12%,8.01 m 2/g and 82.12%.It was contributed that HAP hindered ordered folding of PLLA chain and effected the crystallization of PLLA.The results showed that pseudo-second-order and Langmuir model were superior to other model.The adsorption of fluoride ion by PLLA/HAP composites fibrous mat were studied.The max adsorption of fibrous mat for fluoride iron was 6.06 mg/g,the adsorption of fluoride iron on fibrous mat are more agreeable with monolayer adsorption mode via mainly chemical interaction.After five regeneration and reuse cycles,fibrous mat kept high regeneration efficiency to 87.67%.