Bulgarian Chemical Communications 

About: Bulgarian Chemical Communications is an academic journal. The journal publishes majorly in the area(s): Catalysis & Adsorption. It has an ISSN identifier of 0861-9808. Over the lifetime, 377 publications have been published receiving 1010 citations.

Peanut shells and talc powder for removal of hexavalent chromium from aqueous solutions

Abstract: In this work, talc powder and peanut shells were investigated as potential adsorbents for the removal of hexavalent chromium from aqueous solutions. The effect of important parameters, such as contact time, solution pH and adsorbent dosage were also evaluated for the adsorption process of chromium (IV). The experimental data showed that a contact time of 30 min for peanut shells and 70 min for talc powder and pH of 4 were optimum for the adsorption to reach equilibrium. Furthermore, FT-IR, SEM and BET measurements were made in order to assess the physicochemical properties of the substrates. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were used to fit the equilibrium data, heat and energy of adsorption of both adsorbents. Determinations of the rate of adsorption using kinetic models follow pseudo-first order for peanut shells and talc powder with intraparticle diffusion.

Prediction of the color of dyes by using time-dependent density functional theory (TD-DFT)

Abstract: Time-dependent density functional theory calculations (6-31+G* basis set) at four functional levels of theory (B3LYP, B97XD, M06-2X, and PBE0) have been performed in order to estimate their applicability to predict the visible spectra of organic colorants. The absorption wavelength calculations give the following order of performance: M06-2X>B97XD>PBE0>B3LYP when set of ionic and neutral dyes is used. In the case of neutral dyes only, the performance at all time-dependent PBE0, B97XD and M06-2X methods is statistically comparable. The importance of the specific interactions on the max prediction in the case of anionic phenylhydrazone dyes is shown. The comparison between experimental and calculated oscillator strengths was possible only in the case of anthraquinone dyes and has shown that all four methods predict reasonably well the trend of change of the oscillator strength as function of the substituents.