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 nanoscale 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 originalCMCmolecules (41,000 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 theCMC 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 still present and new functional groupswerenot produced after shearing.The intensity of themain functional group β-1-4-glycosidic bond (wavenumber 1062 cm?1) was observed to markedly decrease after shearing.These results indicatedthat the long-chainCMCwas cleaved into short-chainCMC.A degradation mechanism was proposed whereby the cutting force generated by the rapid motion of the nano-knivesmay be responsible for the breakage ofβ-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 fromaqueous solution without the need of chemical or biological reagents.