This study presents a sustainable approach for the valorization of spent coffee grounds(CG)by converting them into carboxylated cellulose nanofibrils(CG-TCNF)via formic acid/hydrogen peroxide pretreatment followed by ...This study presents a sustainable approach for the valorization of spent coffee grounds(CG)by converting them into carboxylated cellulose nanofibrils(CG-TCNF)via formic acid/hydrogen peroxide pretreatment followed by TEMPO/NaClO/NaClO_(2)-mediated oxidation.The pretreatment efficiently removed lignin,hemicellulose,and other non-cellulosic components,yielding purified cellulose(CG-C)with high crystallinity(CrI=84%).Subsequent regioselective oxidation introduced carboxyl groups at the C6 position of cellulose chains,achieving a high carboxylate content of 1.4 mmol/g.The resulting CG-TCNF exhibited a well-dispersed nanofibrillar morphology with an average width of 3.57 nm and a high specific surface area of 265 m^(2)/g.Comprehensive characterization confirmed the successful oxidation and nanofibrillation:Fourier TransformInfaraed(FT-IR)Spectroscopy revealed the characteristic carboxylate absorption bands,X-ray Diffraction(XRD)showed preserved cellulose I structurewith a slight reduction in crystallinity(CrI=79.2%),and zeta potential measurements indicated good colloidal stability(-45.23 mV)in aqueous suspension.Thermal analysis demonstrated that the introduced carboxyl groups reduced the thermal stability of the nanofibrils compared to the precursor cellulose.This work establishes a novel route for directly transforming coffee grounds into functional nanocellulose,highlighting its potential as a sustainable feedstock for high-value nanomaterials.展开更多
基金funded by the training Program for College Students’Innovation and Entrepreneurship of Jiamusi University in Jiamusi City,Heilongjiang Province(grant number S202410222123).
文摘This study presents a sustainable approach for the valorization of spent coffee grounds(CG)by converting them into carboxylated cellulose nanofibrils(CG-TCNF)via formic acid/hydrogen peroxide pretreatment followed by TEMPO/NaClO/NaClO_(2)-mediated oxidation.The pretreatment efficiently removed lignin,hemicellulose,and other non-cellulosic components,yielding purified cellulose(CG-C)with high crystallinity(CrI=84%).Subsequent regioselective oxidation introduced carboxyl groups at the C6 position of cellulose chains,achieving a high carboxylate content of 1.4 mmol/g.The resulting CG-TCNF exhibited a well-dispersed nanofibrillar morphology with an average width of 3.57 nm and a high specific surface area of 265 m^(2)/g.Comprehensive characterization confirmed the successful oxidation and nanofibrillation:Fourier TransformInfaraed(FT-IR)Spectroscopy revealed the characteristic carboxylate absorption bands,X-ray Diffraction(XRD)showed preserved cellulose I structurewith a slight reduction in crystallinity(CrI=79.2%),and zeta potential measurements indicated good colloidal stability(-45.23 mV)in aqueous suspension.Thermal analysis demonstrated that the introduced carboxyl groups reduced the thermal stability of the nanofibrils compared to the precursor cellulose.This work establishes a novel route for directly transforming coffee grounds into functional nanocellulose,highlighting its potential as a sustainable feedstock for high-value nanomaterials.
