Chemistry Journal of Moldova

DOI: dx.doi.org/10.19261/cjm.2015.10(1).11

Graphical Abstract:  The surface chemistry of the commercial active carbon AG-5 has been modified by oxidation with concentrated nitric acid. The structural changes caused by oxidative treatment were estimated on the basis of nitrogen adsorption-desorption isotherms and thermal analysis. Boehm titration method and infrared spectral analysis have been used in order to evaluate surface chemistry characteristics of active carbon samples.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).12

Graphical Abstract:  57Fe Mӧssbauer spectra were recorded for 1'-terpyridine ferrocenecarboxylic acid and [bis(1'-terpyridine ferrocenecarboxylic acid) Fe(II)]2+ in the temperature range 7 – 293 K. The temperature dependence of the Quadrupole Splitting, Isomer Shift and Debye-Waller factor are discussed. The Debye temperature, θ_D, for the iron nuclei in the investigated compounds was determined.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).13

Graphical Abstract:  The preferred mechanism of the reaction of dihydroxyfumaric acid and its dimethyl ether with the free stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH*) was revealed by means of Density Functional Theory (DFT) calculations. The proposed mechanism has an ionic character and includes the formation of charge-transfer complexes as the main stage. It is also shown that the lower antioxidant activity of dimethyl ether of dihydroxyfumaric acid is caused by both its lower acidity (as compared with its precursor acid) and formation of more stable intermediates during its reaction with DPPH*. Our results allow one to rationalize the available experimental data.

DOI: dx.doi.org/10.19261/cjm.2015.10(1).14

Graphical Abstract: This paper reports on the preparation of activated carbon from walnut shell. Orthogonal array experimental design method was used to optimize the preparation of activated carbon with phosphoric acid by using microwave treatment. The optimization parameters were: microwave power, activation time, phosphoric acid concentration and particle sizes of nut shells. Thermal analysis of the intact and impregnated with phosphoric acid walnut shells was used for the simulation of activation process. Activated carbon with the optimal parameters was obtained, being characterized by gas adsorption method and scanning electron microscopy.

 

DOI: dx.doi.org/10.19261/cjm.2014.09(2).11

Graphical Abstract: We present experimental results on copolymer-based nanocomposite made of styrene with butyl methacrylate (1:1) and inorganic semiconductor CdS. Thin film composite samples have been characterized by UV-Vis absorption and photoluminescent spectroscopy, as well as by transmission electron microscopy.