Electrochemical polymerization of aniline was carried on platinum (Pt) wire electrode in sulfuric acid (H2SO4) solution by cyclic voltammetry using a conventional three-electrode cell at room temperature (20°C). The effects on the electrodeposition of the monomer concentration, anodic potential and potential scan rate are discussed. The conductive layer of emeraldine base polyaniline (Pani) was prepared in this work by repeating potential cycling between -0.24 and 0.9 V/SCE at 50 mV/s in 1 M H2SO4 solution containing 0.1 M aniline monomer.

This study focused mainly on the color removal of textile azo dye Reactive Orange 16 (RO16) by electrochemical oxidation. The effect of supporting electrolyte (H2SO4 and NaOH), RO16 concentration (from 0.5 to 10 mM) and potential scan rate (between 20 and 500 mV/s) was performed with cyclic voltammetry using platinum (Pt) wire as working electrode. The anodic peak current density was linear to RO16 concentrations. This allows the lowest concentrations to be determined voltammetrically in the two electrolytic media, acid (H2SO4 1 M) and alkaline (NaOH 0.1 M). Linearity between the current density and the square root of the potential scan rate was observed in both electrolytes. This means that the electrochemical reaction at the electrode-electrolyte interface is controlled by the diffusion process. The slope of the logarithm of peak current density versus the logarithm of potential scan rate was found to be 0.43 for RO16 in H2SO4 and 0.48 in NaOH these values of slop are close to the thеoretical value of 0.5 which confirms the diffusion process. The removal efficiency of the dye in acid electrolyte reached 40%, while it is 18% in the basic media after 4 hours of electrolysis by chronoamperometry.

The present study was conducted in order to investigate the adsorption and desorption behavior of Mefenpyr-diethyl (MFD) using the batch equilibration technique in four soils, with different ranges of organic matter content, from different regions of Morocco orders of Benimellal (Soil 1), Settat (Soil 2), Sidi Bettach (Soil 3) and EL Hajeb (Soil 4). The adsorption isotherm models Langmuir, linear and Freundlich were used to compare the adsorption capacity of the soils. The results indicated that the Freundlich equation provided the best fit for all adsorption data. The values of KF and Kd ranged from 4.45 to 15.9 and 4.30 to 18.30 L.kg-1 , respectively. The calculated total percentage of desorption values from the Soil 1, Soil 2, Soil 3 and Soil 4 after the four desorption process were 59 %; 55,6 %; 37,5 % and 52,5%, respectively. Highest adsorption and desorption were observed in soil 1, and the lowest was in soil 3. According to the adsorption and desorption results, organic matter and clay seemed to be the most important factors influencing the adsorption capacity of MFD.