Minglei Su, Rong Zhang*, Jingpeng Li, Xiaobei Jin, Xiaofeng Zhang, Daochun Qin*

Cellulose, 2021,28:11713-11727

Bamboo, as a fast-grown forest resource, can be functionalized by metal–organic frameworks (MOFs) with various potential applications. However, the stability of MOFs immobilized on bamboo surface remains to be improved. In this work, MOF199, as known as HKUST-1, was in situ anchoring on moso bamboo via regulating pretreatment of bamboo and a green two-step synthesis route.

Fig. 1 Illustration of the two-step in situ growth of MOF199 on pretreated bamboo with antibacterial properties.

Fig. 2 The number of E. coli colonies formed in the antibacterial test of the negative control (NC), natural bamboo, MOF199/B, MOF199/DB, MOF199/CB, and MOF199/DCB and the antibacterial ratio of these samples.

To improve the attachment of MOFs on bamboo surface, pretreatment with carboxymethylation and delignification was carried out collaboratively (Fig.1). Notably, the two-step preparation process could be used industrially and is environmentally sustainable, particularly as both the copper nitrate solution and BTC solution can be reused. With the collaboration of delignification and carboxymethylation pretreatment of bamboo, a dense and well-dispersed MOF coating was successfully synthesized (Fig.2), the adhesion between MOF199 and bamboo surface was also improved.

Besides, the quantity and size of MOF199 on bamboo can be tailored by tunning the carboxyl groups of pretreated bamboo and the concentration of copper nitrate solution. More importantly, results show that the formation of carboxyl-copper (II) complex served as nucleation sites for the growth of MOF199 crystals, which was essential to prepare uniform MOF layers. The growth of MOF199 endowed bamboo with good antibacterial activity against E. coli (Fig.3). This method provides a facile and practical strategy for designing MOF coated woody materials.