Volta metric behavior of mesotrione using silver/amalgam electrode

Volta metric behavior of mesotrione using silver/amalgam electrode we examined in this paper. Mesotrione belongs to the triketone group of herbicides. It is used against weeds in corn and operates by inhibition of 4-hydroxyphenyl piruvate in plants. There is little information about mesotrione as its presence in the market is short. For its wider application in the future, it is important to know details of its chemical characteristics and redox processes, including biogeochemical transformation and migration after application to agricultural land, which could contribute to its more efficient and safe application. The technique of cyclic voltammeter with conventional three-electrode cell and electrochemical workstation was used for the investigation of electrochemical behavior of mesotrione. Cyclic voltamograms of mesotrione were recorded at pH values 6, 8, 10 and 12. Several peaks were obtained at certain values of the potential and they were attributed to the reduction of two carbonyl groups [in position 1 and 3 of cyclohexane ring], the third carbonyl group and nitro group. The maximum current value was at pH 12

As[III] and As[V] Sorption on MnO[2] synthesized by mechano-chemical reaction from aqueous phase

Nanoparticles of manganese-dioxide synthesized by mechano-chemical reaction were used for As[III] and As[V] sorption from water environment. The influence of a milling time of manganese-dioxide on sorption was examined with batch procedure. Sorption as a function of contact time was investigated. Kinetic of sorption, for both As[III] and As[V], was fast. The equilibrium condition for milled sorbents was achieved after one hour of mixing. Experimental data were fitted to Freundlich and Langmuir adsorption models. Both models represent experimental data well with slightly better regression coefficient for Freundlich isotherm model. With the increase of the milling time manganese-dioxide adsorption capacity for As[III] and As[V] increased. The decrease of average particle size with milling could be responsible for increase of sorption capacity. The influence of pH on sorption was also investigated. The sorption of both, As[III] and As[V], in investigated pH range [6.0-9.0] was not significantly disturbed and showed similar behaviour, what could indirectly imply oxidation of As[III] to As[V] before sorption