Facile and Green Production of Cu from CuO Using Cellulose under Hydrothermal Conditions

Potential application of carbohydrate biomass in hydrometallurgy: one-pot reduction of metal oxides/salts under mild hydrothermal conditions

Carbohydrate biomass can be employed as a reductant for metallic material preparation due to it possessing diverse reducing functional groups. The reported studies focused on reduction of metal ions in acidic solution with the aid of biomass. However, we found alkali hydrothermal conditions are favorable to metal compound reduction, even direct conversion of metal oxides to metals. Based on our previous research on direct reduction of CuO and NiO into the corresponding metals, herein, conversion of other metal oxides (Fe2O3, MnO2, Co3O4, PbO2) with glucose was investigated to illustrate the universal applicability of direct reduction of metal oxides with carbohydrates under alkali hydrothermal conditions. Furthermore, metal salt reduction by carbohydrates was studied and the reduction performance of glucose and cellulose with and without alkali was compared. The results showed an alkaline hydrothermal environment is more conducive to metal reduction. Unlike the complete reduction of CuO and NiO, oxides of Fe(iii), Mn(iv), Co(iii) and Pb(iv) can only be partially reduced under the experimental conditions. Not only carbohydrates but also decomposed intermediates can reduce metal oxides or salts. In addition, due to the formation of stable complexes between the anions of salts and the decomposition products of carbohydrates, the reduction effects of various copper salts are significantly different. This study may provide an alternative approach to metal preparation in hydrometallurgy.

In situ microwave heating fabrication of copper nanoparticles inside cotton fiber using pressurization in immiscible liquids with raw material solutions

We developed a method for in situ fabrication of copper nanoparticles inside cotton fibers. Copper nanoparticles can be fabricated mainly in the central part of the fiber by absorbing a raw material solution and by applying microwave heating in a state where the raw material solution is pressed with immiscible liquids. Surface SEM images and cross-sectional EDS mapping for the fabricated fibers clarified that copper nanoparticles fabricated on the cotton surface were suppressed considerably more by the hydrophobic raw material solution than by the hydrophilic raw material solution. These cotton fibers containing copper nanoparticles were found to have antiviral properties against the influenza A virus.

Cellulose nanocrystal (CNC)–inorganic hybrid systems: synthesis, properties and applications

Cellulose nanocrystal (CNC), a class of sustainable nanomaterial derived from forest and agro-biomass can serve as nature's storage for carbon dioxide.

Hydrothermal synthesis of bacterial cellulose-copper oxide nanocomposites and evaluation of their antimicrobial activity

In this work, for the first time bacterial cellulose (BC) hydrogel membranes were used for the fabrication of antimicrobial cellulosic nanocomposites by hydrothermal deposition of Cu derivative nanoparticles (i.e.Cu(0) and CuxOy species). BC-Cu nanocomposites were characterized by FTIR, SEM, AFM, XRD and TGA, to study the effect of hydrothermal processing time on the final physicochemical properties of final products. XRD result show that depending on heating time (3-48h), different CuxOy phases were achieved. SEM and AFM analyses unveil the presence of the Cu(0) and copper CuxOy nanoparticles over BC fibrils while the surface of 3D network became more compact and smother for longer heating times. Furthermore, the increase of heating time placed deleterious effect on the structure of BC network leading to decrease of BC crystallinity as well as of the on-set degradation temperature. Notwithstanding, BC-Cu nanocomposites showed excellent antimicrobial activity against E. coli, S. aureus and Salmonella bacteria suggesting potential applications as bactericidal films.