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Contributions of ultrasonic wave, metal ions, and oxidation on the depolymerization of cellulose and its kinetics

Author:
Li, Hengxiang, Zhang, Kang, Zhang, Xiaohua, Cao, Qing, Jin, Li'e
Source:
Renewable energy 2018 v.126 pp. 699-707
ISSN:
0960-1481
Subject:
Fourier transform infrared spectroscopy, X-ray diffraction, activation energy, cellulose, cobalt, copper, depolymerization, equations, hydrogen peroxide, hydrolysis, iron, manganese, metal ions, nickel, oxidants, oxidation, polymerization, renewable energy sources, scanning electron microscopy, ultrasonics
Abstract:
Contributions of ultrasonic wave, metal ions and oxidation on the degree of polymerization (DP) of microcrystalline cellulose (MCC) were evaluated. Five transition metal ions, namely, Ni2+, Cu2+, Co2+, Mn2+, and Fe2+, were selected. H2O2, as an oxidizing agent, was also investigated. Changes in the structure of MCC induced by the ions were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, and field-emission scanning electron microscopy. Results indicated that DP decreased by 16.6%, 32.8%, 47.9% using U-MCC, Ni2+/U-MCC, and ONi2+/U-MCC, respectively. DP of MCC was reduced from 195 to 101.5 under ONi2+/U-MCC due to the destruction of interchain-hydrogen bond. Kinetic of depolymerization process for MCC obeyed the equation: DP = 102.2 + 93.8e−0.000798t, with activation energy of 17.33 kJ/mol. The result suggests that depolymerization of MCC was mainly a physical process at these conditions, and the interchain-hydrogen bond were disrupted. This study is beneficial for the deep hydrolysis and its utilization of MCC.
Agid:
6015424