A binary sampling flow analysis system equipped with gas diffusion cell was developed for NH4+ and/or NH2Cl determination in wastewater and disinfection products samples based on the Berthelot reaction of the NH2Cl diffused through the semi-permeable PTFE membrane. The effect of the analytical conditions related to the reaction and flow parameters were evaluated and N-NH4+ and N-NH2Cl were determined in concentration ranges from 0.17 to 5 mg L-1 and from 0.5 to 14.5 mg L-1, respectively. Limits of detection (3σ) of 50 and 140 µg L-1 for N-NH4+ and N-NH2Cl were calculated, respectively, and RSD of 5 and 2% were calculated for 10 consecutive determinations of N-NH4+ (1 and 3 mg L-1) and N-NH2Cl (3 and 9 mg L-1), respectively with 30 determinations h-1.

In this work the CCl4 degradation in aqueous solution by sonication with 40 kHz commercial ultrasonic bath was investigated. Sonochemical degradation of CCl4 occur by the cleavage of C-Cl bond into the cavitation bubbles. Oxidation reactions and the pH decreasing in the bulk solution during sonication were attributed to chlorine radicals produced by CCl4 sonolysis, leading to increase the chloride concentration. The formation of oxidizing agents was evaluated employing I- and Fe2+ ion solutions, converted to I2 and HIO, and Fe3+, respectively. The amount of chloride and hydronium ions produced after 3 min of irradiation was 11.52 and 12.19 mmol, respectively, suggesting that the same reaction was involved to produce these ions. Fe2+ oxidation and the pH variation were monitored to estimate chlorine radical formation rate in the presence (0.107 mumol s-1) and absence (0.092 mumol s-1) of metallic ion during the first minute of sonication.