金属有机框架/聚丙烯纤维基复合材料对化学战剂模拟物的快速降解

Metal-organic frameworks/polypropylene fiber-based composite for rapid degradation of chemical warfare agent simulants

为将金属有机框架(MOFs)均匀且稳固地固定在纤维材料表面,创造出柔软且具备自净化防护面料,采用单宁酸-3-氨丙基三乙氧基硅烷(TA-APTES)涂层改性的聚丙烯(PP)非织造布作为载体,通过原位生长法制备高MOFs负载量的纤维基复合材料。借助扫描电子显微镜、红外光谱仪、X-射线衍射仪、X-射线光电子能谱仪等手段对复合材料的表面形貌、组成和化学结构进行表征,并对复合材料的MOFs负载量和表面浸润性进行了分析。结果表明:TA-APTES涂层能够显著提高复合材料中MOFs的负载量,可达20.96%;并且有效提高复合材料的表面湿润性,从而提高其在水溶液中的催化降解效率,实现快速降解化学战剂模拟物4-硝基苯磷酸二甲酯(DMNP),在30 min左右即可实现100%的转化率,其降解半衰期短(4.8 min)。

Objective Metal-organic frameworks(MOFs)possess an exceptionally high active specific surface area and exhibit structural and functional diversity,among other characteristics.Studies have shown that MOFs have demonstrated effective degradation of chemical warfare agents.However,the crystal morphology of MOFs powders limits their practical application in catalytic degradation processes.To address this issue,the utilization of a coating modification technique becomes crucial.This technique leverages the adhesion and secondary reactivity of hydrophilic modified coatings to facilitate the in-situ growth of MOFs crystals on the modified polypropylene(PP)surface.This research aims to boost the MOFs loading on the substrate and improve the stability of the MOFs.Overall,this method is significant for developing textiles tailored for the rapid removal of chemical warfare agent simulants.Method PP nonwovens were immersed in a mixed solution of tannic acid(TA)and aminopropyltriethoxysilane(APTES)to prepare TA-APTES coating modified PP nonwovens.The modified PP with the TA-APTES coating was sequentially submerged in the solution of zirconium tetrachloride and 2-aminoterephthalic acid,enabling the in-situ growth of zirconia-based metal-organic frameworks(UiO-66-NH2)on the PP surface to prepare a PP/TA-APTES/UiO-66-NH2(PTAU)fiber-based composite.The surface morphology,composition,and structure of the composite were characterized by scanning electron microscopy,Fourier transform infrared,X-ray diffraction and X-ray photoelectron spectroscopy(XPS),respectively.The loading of MOFs in the composite was characterized by inductively coupled plasma optical emission spectrometry and the wettability of the composite was characterized by static water contact angle test.Moreover,the degradation performance of the composite on chemical warfare agent simulants was evaluated.Results Compared with the unmodified PP,the surface of PP composite modified by TA-APTES coating became rough which is conducive to the growth of MOFs on the surface of PP.The infrared spectrum showed the characteristic peaks of the modified TA-APTES and UiO-66-NH2.The XRD pattern of the PP after TA-APTES coating confirmed that the UiO-66-NH2 crystalline form remained unchanged in the composite.The XPS characterization revealed the elemental valence composition of the composite surface before and after the reaction.The thermogravimetric testing suggested that the final residual mass percentage of the original PP nonwovens was 1.3%,while the residual mass percentage of PTAU composite was 17.4%,indicating that the thermal stability performance of the treated PP was improved.These results showed that the MOFs was successfully modified on the surface of TA-APTES coating on PP.Additionally,TA-APTES coatings significantly changed the wettability of PP composites and enhanced the loading capacity of MOFs on the composite surface to 20.96%.The UV spectrum of dimethyl p-nitrophenyl phosphate(DMNP)degradation catalyzed by composite demonstrated that the characteristic peak of DMNP at 270 nm gradually decreases and the characteristic peak of the hydrolysis product p-nitrophenol at 400 nm gradually increases,and the degradation rate of the composite reached 100%after 30 min.The half-life of degradation of PTAU composite was 4.8 min.Conclusion TA-APTES coating was used to modify PP nonwoven to construct the active site of MOF nucleation,which promoted the uniform distribution and robust growth of UiO-66-NH2 on PP surface.The inductively coupled plasma optical emission spectrometry results showed that the loading of UiO-66-NH2 in composite was increased by TA-APTES coating,reaching up to 20.96%.The experimental results demonstrate that TA-APTES coating can effectively improve the surface wettability of PP composite material from hydrophobic to hydrophilic,and greatly improving its catalytic degradation efficiency in aqueous solution.The catalytic degradation experiment showed that the catalytic degradation efficiency of PTAU composite was further improved,the conversion rate reached 100%in approximately 30 minutes,and the degradation half-life was about 4.8 min.