纳米纤维素气凝胶构建及其过滤聚苯乙烯微塑料性能研究

Construction of Nanocellulose Aerogel and Its Filtration Properties for Polystyrene Microplastics

以漂白桉木浆为原料,分别通过2,2,6,6-四甲基哌啶氧化物(TEMPO)和2,3-环氧丙基三甲基氯化铵(EPTMAC)对其化学改性,并借助高压均质处理得到改性纤维素纳米纤丝(CNF),最后采用冷冻干燥法制备得到改性CNF气凝胶。研究了聚苯乙烯微塑料(PSMPs)种类和浓度对改性CNF气凝胶过滤性能的影响。结果表明,EPTMAC改性气凝胶(QCNF)对羧基化聚苯乙烯(PS-COOH)的过滤效率为99%;TEMPO氧化改性气凝胶(TCNF)对氨基化聚苯乙烯(PS-NH_(2))的过滤效率为75%。改性CNF气凝胶对PSMPs的过滤性能得益于材料本身的超亲水性、独特的三维多孔结构和表面丰富的活性结合位点。此外,QCNF气凝胶经过8次循环过滤后,QCNF气凝胶对PS-COOH的过滤效率始终保持在99%以上,过滤通量稳定且超过20.2L/(m^(2)·h),具有良好的稳定性和可重复利用性。

Bleached eucalyptus pulp was chemically modified by 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)and 2,3-epoxypropyltrimethylammonium chloride(EPTMAC),respectively,to produce modified cellulose nanofibrils(CNF)by high pressure homogenization.Then,modified CNF aerogels were prepared by freeze-drying process.The effects of types and concentrations of polystyrene microplastics(PSMPs)on the filtration properties of modified CNF aerogels were studied.Results showed that the filtration efficiency of EPTMAC modified aerogel(QCNF)for carboxylated polystyrene(PS-COOH)was 99%,while the filtration efficiency of TEMPO-oxidized CNF aerogel(TCNF)for aminated polystyrene(PS-NH_(2))was 75%.The excellent filtration performance of modified aerogels mainly relied on the super hydrophilicity,unique three-dimensional porous structure and abundant surface active binding sites of the material.In addition,the filtration efficiency and flux of the modified CNF aerogels were over 99% and 20.2 L/(m^(2)·h)after 8 cycles of filtration,showing good stability and reusability.