纳米纤维素光热吸油气凝胶的构建及性能

Fabrication and properties of nanocellulose-based photothermal aerogel as oil absorbents

采用物理吸收法清理石油及石油产品在海上的泄漏是油水分离最具潜力的方法之一。以可降解麦秆基LCNFs(木质纳米纤维素纤丝)为原料,以PVA(聚乙烯醇)为增强相、PDA(聚多巴胺)为光热成分,通过冷冻干燥及MTMS(甲基三甲氧基硅烷)化学沉积法制备具有光热性能的M-LPPA(疏水性LCNFs/PVA/PDA气凝胶)。对M-LPPA的微观结构、接触角、光热转化性能进行表征,并对不同质量分数PVA的M-LPPA的吸油性能进行初步研究。结果表明:M-LPPA为深灰色弹性气凝胶,具有大、小孔互穿的三维网络结构。M-LPPA疏水角均>130°,且随着PVA质量分数的增加而增加。M-LPPA-0.25对不同有机溶剂及轻质油的吸附容量可达43—168 g/g(以每g气凝胶计),其中对二氯甲烷的吸附量高达168 g/g。在一个太阳光下,M-LPPA-0.25气凝胶在5 min内温度可上升至57.7℃,表明其具有良好的光热性能,可以降低高黏度原油的黏度,提高其吸附性能。

Physical absorption method is one of the most promising methods for oil and water separation to clean up leakage of petroleum and petroleum products at sea.The M-LPPA(hydrophobic aerogel LCNFs/PVA/PDA)with photothermal properties was prepared by freeze-drying and MTMS(Methyltrimethoxysilane)chemical deposition using wheat straw LCNFs(lignin cellulose nanofibrils)as raw material,PVA(polyvinyl alcohol)as reinforcing agent and PDA(polydopamine)as photothermal component.The microstructure,contact angle and photothermal properties of M-LPPA were characterized,and the absorption properties of M-LPPA with different PVA mass fraction were studied as well.The results show that M-LPPA is a dark gray elastic aerogel and exhibites 3-dimensional interpenetrating network structure with large and small pores.The water contact angles of M-LPPA aerogel are all greater than 130°and increases with the increase of PVA mass fraction.The adsorption capacity of M-LPPA-0.25 for different organic solvents and light oils can reach 43-168 g/g(measured per gram of aerogel).The maximal absorption capacity of dichloromethane can reach 168 g/g.The temperature of M-LPPA-0.25 aerogel rises to 57.7℃within 5 min under a single sunlight,which indicates that it has good photothermal properties and can reduce the viscosity of high-viscosity crude oil and improve its adsorption performance.