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A.Kareem, University of Notre Dame, USA
J. Turmo, UPC Barcelona Tech, Spain
G. G. Deierlein, Stanford University, USA
H. A. Mang, Vienna University of Technology, Austria
Hyun-Moo Koh, Seoul National University, South Korea
Jielian Zheng, Guangxi University, China
Jingquan Wang, PLA University of Science and Technology, China
Paul Gauvreau, University of Toronto, Canada
S. Kitipornchai, University of Queensland, Australia
Wenzhong Deng, T.Y. Lin International, USA
Yozo Fujino, Yokohama National University, Japan
Yuanpei Lin, Shanghai Municipal Engineering Design Institute, China.
Zhengqing Chen, Hunan University, China
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REVIEW ARTICLENMR investigation of degradation processes of ancient and modern paper at different hydration levelsFrontiers of Physics, 2018, 13(1): 138202. https://doi.org/10.1007/s11467-017-0686-6
The degradation process of cellulose-made materials was investigated by means of nuclear magnetic resonance (NMR) spectroscopy, with particular emphasis on the role of water and on the hydration mechanism of cellulose fibrils. To accomplish this, the structure and dynamics of water within ancient and modern samples with different aging histories were investigated. The results mainly indicated that hydrolytic and oxidative reactions provoked the formation of acidic by-products. Furthermore, degradation processes were enhanced by higher amounts of water giving a progressive consumption of the amorphous regions of the cellulose. We propose NMR experiments as a benchmark for characterization of the degradation state of paper, as well as for investigating the effectiveness of restoration treatments.
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RESEARCH ARTICLEFrontiers of Physics, 2018, 13(1): 138201. https://doi.org/10.1007/s11467-017-0685-7
Herein we study the different microscopic interactions occurring in water/methanol solutions at different methanol molar fractions, using NMR spctroscopy. Temperature was found to determine which interaction dominates. It was found that the mixing between water and methanol is non-ideal because of the presence of interactions like hydrophobicity and hydrophilicity. These results indicate that the competition between hydrophilic and hydrophobic interactions is different in different thermal regions, and that the physical properties of the solution are determined by the character of the solution itself, which in turn depends on the mole fraction of methanol and on the temperature.
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RESEARCH ARTICLEFrontiers of Environmental Science & Engineering, 2018, 12(1): 2. https://doi.org/10.1007/s11783-017-0971-1
Tunisian clay has been successfully pillared with Al and Fe by microwave irradiation.
Microwave method reduces considerably the synthesis time and the water consumption.
AlFe-pillared clays are highly stable in the severe operating conditions of CWAO.
Oxidation takes place through a heterogeneous mechanism.
Microwave pillared-clays are good candidate for CWAO industrial water treatment.
Microwave irradiation has been used to prepare Al, Fe-pillared clays from a natural Tunisian smectite from the El Hicha deposit (province of Gabes). Chemical analysis, XRD spectra and surface properties evidenced the success of pillaring process. The obtained solids present higher surface area and pore volume than conventionally prepared Al-Fe pillared clays. The main advantages of the microwave methodology are the considerable reduction of the synthesis time and the consumption of water. The microwave-derived Al-Fe pillared clays have been tested for catalytic wet air oxidation (CWAO) of phenol in a stirred tank at 160°C and 20 bar of pure oxygen pressure. These materials are efficient for CWAO of phenol and are highly stable despite the severe operating conditions (acidic media, high pressure, high temperature). The catalyst deactivation was also significantly hindered when compared to conventionally prepared clays. Al-Fe pillared clays prepared by microwave methodology are promising as catalysts for CWAO industrial water treatment.
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