No abstract

This study aimed to evaluate the implementation of an advanced oxidation system based on UV radiation and UV/H 2 O 2 for degradation of TCS and IBU in synthetic effluent. The assays occurred in a 2-L reactor, protected from external light and equipped with a UV lamp ( λ = 254 nm). The effect of contaminant concentration, fractions of chemical species present, and mineralization were evaluated. In the UV/ H 2 O 2 system, different concentrations of H 2 O 2 were studied for oxidation of the contaminants. The kinetic experiments took place between 75 and 270 min of UV irradiation. The results showed > 99% oxidation of TCS in the direct photolysis system at pH 9.4 after 12 min. The degradation of IBU in the UV/H 2 O 2 system, when 10 mg L −1 of H 2 O 2 was used, was 97.39% oxidation. We obtained k′ values of 0.189 min −1 for TCS when its highest oxidation occurred and k′ values of 0.0219 min −1 for IBU. The system was not able to completely mineralize the contaminants, presenting high values of TOC and COD after treatment, thus suggesting the occurrence of phototransformation. Supplementary Information The online version contains supplementary material available at 10.1007/s11270-022-05583-z.

The Indigo Blue dye is widely used in the textile industry, specifically in jeans dyeing, the effluents of which, rich in organic pollutants with recalcitrant characteristics, end up causing several environmental impacts, requiring efficient treatments. Several pieces of research have been conducted in search of effective treatment methods, among which is electrocoagulation. This treatment consists of an electrochemical process that generates its own coagulant by applying electric current on metallic electrodes, bypassing the use of other chemical products. The objective of this work was to evaluate the potential use of iron slag in the electrocoagulation of a synthetic effluent containing commercial dye Indigo Blue and the effluent from a textile factory. The quantified parameters were color, turbidity, pH, electrical conductivity, sludge generation, phenol removal, chemical oxygen demand (COD), and total organic carbon (TOC). The electrocoagulation treatment presented a good efficiency in removing the analyzed parameters, obtaining average removal in the synthetic effluent of 85 % of color and 100 % of phenol after 25 min of electrolysis. For the effluent from the textile factory, average reductions of 80 % of color, 91 % of turbidity, 100 % of phenol, 55 % of COD, and 73 % of TOC were measured after 60 min of electrolysis. The results obtained demonstrate the potential of using iron slag as an electrode in the electrocoagulation process in order to reuse industrial waste and reduce costs in the treatment and disposal of solid waste.

This study aimed to evaluate the implementation of an advanced oxidation system based on UV radiation and UV/H2O2 for degradation of TCS and IBU in synthetic effluent. The assays occurred in a 2L reactor, protected from external light and equipped with a UV lamp (λ = 254nm). The effect of contaminant concentration, fractions of chemical species present, and mineralization were evaluated. In the UV/ H2O2 system, different concentrations of H2O2 were studied for oxidation of the contaminants. The kinetic experiments took place between 75 - 270 min of UV irradiation. The results showed > 99% oxidation of TCS in the direct photolysis system at pH 9.4 after 12 min. The degradation of IBU in the UV/H2O2 system, when 10mg L-1 of H2O2 was used, obtained 97.39% oxidation. We obtained k' values of 0.189 min-1 for TCS when its highest oxidation occurred, and k' values of 0.0219 min-1 for IBU. The system was not able to completely mineralize the contaminants, presenting high values of TOC and COD after treatment, thus suggesting the occurrence of phototransformation.

Concerning water resources, several ordinances and legislation determine standards and conditions for the discharge of effluents into water bodies. However, several contaminants are not covered by these guidelines because they are found in low concentrations and due to little knowledge of their long-term effects. These contaminants are called emergents, and this category includes drugs, such as anti-inflammatory drugs. The electrocoagulation process associated with advanced oxidation comes up as an alternative to conventional effluent treatment processes, and the objective of this work was to evaluate this process using scrap iron as sacrificial electrodes in the treatment of synthetic effluents containing Ibuprofen. High performance liquid chromatography (HPLC) was used to quantify the drug in synthetic effluents. The CCRD 24 was used in an experimental design, having as independent variables evaluated the concentration of contaminants, applied current, the concentration of the primary oxidizing agent H2O2 and the reaction time. The optimized conditions determined by statistical analysis were drug concentration of 5 mg.L-1, H2O2 concentration of 200 mg.L-1, current of 5 A and 150 min. The removals obtained under these conditions were higher than 92% in the aqueous phase, showing that ECP technique has the potential to treat contaminants such as drugs present in effluents and waters.