Hydrophobic nanocellulose aerogels with high loading of metal-organic framework particles as floating and reusable oil absorbents

In this paper,we employed a facile approach to prepare flexible and porous metal-organic frameworks(MOFs)containing cellulose nanofiber(CNF)aerogels(MNCAs)through freeze-drying MOF-containing cellulose nanofiber suspensions.After coating with methyltrimethoxysilane(MTMS)by chemical vapor deposition,recycled and hydrophobic MTMS-coated MNCAs(MMNCAs)were obtained.Due to the low density(0.009 g/cm^(3)),high porosity(97%)and good mechanical properties of the aerogel,the adsorption capacity of MMNCAs reached up to 210 g/g,which was nearly 3–5 times that of pure CNF aerogels.These prepared aerogels showed excellent oil/water selectivity and high capacity to adsorb oil and organic solvents.This kind of cellulose-based aerogel may be applicable in the field of environmental protection.

Spectroscopic/Microscopic Elucid

The Arundo donax is a typical fast-growing species from the family Gramineae,which is widely cultivated in China.With a huge yield of A.donax in China,this plant offers great potential for biofuels production.The different types of organization of cell and the tissue in the A.donax could influence the efficiency of enzymatic hydrolysis.In this study,A.donax was subjected to 0.5%(w/w)sulfuric acid(H2SO4)for pretreatment at 140℃for 10 min,20 min,40 min,and 60 min,respectively.The changes in microstructure,chemical composition,topochemical properties were comprehensively analyzed.Using a series of spectroscopic and microscopic techniques including Fourier transform infrared spectroscopy(FT-IR),X-Ray diffraction(XRD),polarized light microscopy(PLM),and confocal Raman microscopy(CRM)to obtain the correlative structural and chemical information.Analysis results of chemical composition,FT-IR spectra and XRD indicated that with increasing reaction time,more hemicellulose and lignin would be removed.Correspondingly,there was an obvious increase of the cellulose relative crystallinity via extending reaction time.Results of the PLM observations showed that the birefringence gradually dimmed due to the diminishing of the cellulose component.Furthermore,the CRM mapping images showed the lignin component in compound middle lamellar(CML)was difficult to remove relatively as compared with that in secondary walls.These results indicated that the combination of spectroscopic and microscopic elucidation could give an insightful understanding of chemical changes in cellular level during pretreatment.