RESUMO
A simple and derivative spectrophotometric method has been developed for the determination of mercury (II) using Diacetylmonoxime benzoylhydrazone (DMBH). Mercury (II) forms an orange coloured water soluble complex with the reagent in basic medium (pH 10.5).The molar absorptivity and Sandell’s sensitivity of coloured species are 2.01 x 104 L.mol-1 cm-1 and 0.0099 mg/cm2 respectively. Beer’s law is obeyed in the range 1.0029 – 12.0354 mg/ml of Hg (II) at lmax 361 nm. The developed derivative spectrophotometric method was employed for the determination of mercury (II). This method has been satisfactorily applied for the determination of mercury (II) in different environmental water samples and biological samples.
RESUMO
Removal of toxic Cr(VI) in aqueous medium was investigated using activated carbon adsorbents prepared from Simarouba glauca seed shells. The pH effect, Cr(VI) concentration, adsorbent dosage and contact time period were studied in batch experiment. The removal of Cr(VI) was in general most effective at pH range 2.0-4.0 and high Cr(VI) concentrations. Activated carbons are prepared at 80050 degrees C temperature. One is non-impregnated and the remaining three are impregnated with zinc chloride in 1:1,1:2,1:3 ratio. Important characteristics of activated carbons are also investigated. The data for all the adsorbents fit well to the Freundlich adsorption isotherm. The removal of Cr(VI) is around 97% was observed with 1:2 impregnated activated carbon at pH 3.0 where as other adsorbents showed much lower activities.