Dechlorination and oxidative degradation of 4-chlorophenol with nanostructured iron-silver alginate beads

Catalytic Effect of Hydrogen Peroxide in the Electrochemical Treatment of Phenolic Pollutants using a BDD Anode

“…This analysis also showed that the reaction followed a first order kinetic model (R 2 = 0.95943) and a value for the rate constant of k = 0.0089 min À 1 (insert Figure SI-7). An equivalent behavior also was observed for NP 10 EO with a first order kinetic model (R 2 = 0.937) and a value for the rate constant of k = 0.0079 min À 1 (insert Figure 3).…”

“…The spectra obtained in the coupled process shows a decrease in the absorption of 4-CP as a single response, indicating that other aromatic intermediaries are rapidly eliminated and low chain carboxylic acids which have almost no absorbance, should be formed. In Figure 5, the absorption spectra also shows the decrease of the absorption of peaks of NP 10 EO, indicating that no other aromatic intermediaries are formed. Degradation mechanism by advanced oxidation processes using * OH radical (S 2 O 8 2À /UV) has been previously described, [55] where the first steps involve phenol formation and the release of the polyethoxylate chain; this electron rich phenol should be easier to eliminate than the starting compound, generating rapidly short chain carboxylic acids.…”

“…Hydrogen peroxide is considered as a non-selective oxidizer and reacts with the majority of organic compounds, through the homolitic cleavage of this molecule. [47,48,49] In order to see only the effect of hydrogen peroxide in the system without electrical current density and under pH value 2.3 � 0.5, temperature (20°C � 5), treatment time (200 min) previously applied for 4-CP and NP 10 EO, different amounts of hydrogen peroxide 30 % w/v (250 μL, 440 μL and 1 mL) were tested with both phenolic pollutants, the results showed a degradation percentage for 4-CP and NP 10 This behavior observed for both phenolic compounds can be explained by the fact that this oxidant has a very poor redox reactivity vs these compounds, and it requires a metallic ion (Fe 2 + or Cu 2 + ) (Fenton reaction) or UV radiation (Photo Fenton) to catalyze the hydroxyl radical generation.…”

“…[3,4,5] Thereupon, several investigations have been carried out in order to eliminate 4-chlorophenol (4-CP) applying different electrochemical methods as Electro-Fenton, Photoelectro-Fenton and Peroxi-Coagulation process, [6] in addition to coupled treatments such as Electrochemical reductionoxidation, [7] Fenton Oxidation, [8] Catalytic Oxidation, [9] Nanoparticles. [10] In these studies, the oxidation of chlorophenols achieves the mineralization of organic compounds obtaining a percentage removal in the range of 60-85 %. Nevertheless, in some of these treatments, residues such as sludge are generated, increasing the cost associated in the process.…”

“…Likewise, the nonylphenol ethoxylate, with 10 ethoxy group linked to the aromatic ring (NP 10 EOs o denoted NPE 10 ) is one of the most common nonionic surfactants. This way, the NPnEOs have been used for more 40 years as detergents, emulsifiers, wetting agents, and dispersing agents.…”