Decomposition of carboxymethyl cellulose based on nano-knife principle

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Zhou, Q., Hong, L., Di Bonito, M. ORCID: 0000-0001-8590-0267 and Pan, G. ORCID: 0000-0003-0920-3018, 2018. Decomposition of carboxymethyl cellulose based on nano-knife principle. Journal of Environmental Sciences. ISSN 1001-0742

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Official URL: http://doi.org/10.1016/j.jes.2018.10.007

Abstract

The traditional degradation of organic pollutants is based on the sacrifice of chemical or biological reagents. In this study, a purely physical technique was developed to break the chemical bonds and consequently decompose macromolecules in aqueous solution. Assisted with a high-speed mechanical blade, refined quartz sand grains with particularly sharp nano-scale edges can act as ‘nano-knives’, which are able to cut the long chain of carboxymethyl cellulose (CMC, as a model molecule). High performance size exclusion chromatography measurements evidenced that the original CMC molecules (41000 Da) were decomposed into a series of smaller molecules (460, 1000, 2200, 21,000, 27,000 and 31,000 Da). Consequently, the initial viscosity of the CMC solution (2 g/L) rapidly decreased by approximately 50% after 3 min treatment by the nano-knife materials along with the mechanical blade. Fourier transform infrared (FTIR) spectra indicated that the original functional groups were 1 still present and new functional groups were not produced after shearing. The intensity of the main functional group β-1-4-glycosidic bond (wavenumber 1062 cm-1) was observed to markedly decrease after shearing. These results indicated that the long-chain CMC was cleaved into short-chain CMC. A degradation mechanism was proposed whereby the cutting force generated by the rapid motion of the nano-knives may be responsible for the breakage of β-1-4-glycosidic bonds in the macromolecular cellulose backbone. These results provide support for a potentially more affordable and environment-friendly strategy for physical-based decomposition of recalcitrant organic pollutants from aqueous solution without the need of chemical or biological reagents.

Item Type:

Journal article

Publication Title:

Journal of Environmental Sciences

Creators:

Zhou, Q., Hong, L., Di Bonito, M. and Pan, G.

Publisher:

Elsevier

Date:

30 October 2018

ISSN:

1001-0742