Arachis hypogaea derived activated carbon/Pt catalyst: reduction of organic dyes

Activated carbon from agro waste groundnut (Arachis hypogaea) shell was prepared by chemical activation and used as support for dispersion of 5% platinum nanoparticles. The Pt nanoparticles were obtained by the reduction in hydrogen gas medium. The synthesized groundnut activated carbon/platinum catalyst was characterized by various techniques such as X-ray powder diffraction, electron microscopies and X-ray photoelectron spectroscopy. The catalytic behaviour of the synthesized catalyst was investigated by exploring it as catalyst for the reduction of various classes of dyes; namely, triphenylmethane dyes such as Malachite green, phenol red and bromophenol blue, xanthene dyes: rose bengal, rhodamine 6G, rhodamine B, thiazine dye: methyelene blue, azo dye: congo red and 4-nitrophenol by sodium borohydride in aqueous medium. Under suitable reaction conditions, for all tested dyes, cationic dyes were reduced at a faster rate than anionic dyes. The rate of reduction on the structure of dye and nature of catalyst was employed

Chromogenic polyaniline picrate- A novel sorbent for selectivity of anions in potassium and sodium salts

104-113<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">A novel chromogenic, polymeric sorbent material Polyaniline picrate (PANIPI) has been synthesized by chemical oxidative polymerization and characterized using various spectral techniques. Cyclic voltammetry and four probe conductivity measurements have revealed that the polymer is highly electroactive. Surface morphology is analyzed using SEM and TEM micrographs. Potassium halides, potassium sulphate and potassium thiocyanate are used as sorbate materials for ion exchange on PANIPI. Five types of sorption isotherms namely Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Redlich-Peterson are applied to the sorption process. Among these isotherms Langmuir, Freundlich and Temkin models fitted well for the sorption of potassium salts on PANIPI. The maximum adsorption capacity (qm) follows the size order of anions. The intensity of FT-IR stretching vibration for SCN- at 2066 cm-1 varies linearly with concentration, making PANIPI an effective sensor material for the quantitative determination of SCN-. The potassium to sodium selectivity of 2:1 is observed at both low and high sorbate concentrations.</span