Kinetic and ecotoxicological evaluation of the direct orange 26 dye degradation by Fenton and solar photo-Fenton processes

Abstract

The presence of color in textile effluents has been studied because of the need for more effective treatments. Therefore, advanced oxidative processes (AOP) have been used in the degradation of dyes, as well as in the conversion of organic matter. This study evaluated the degradation of the direct orange 26 textile dye by Fenton and photo-Fenton processes (with natural solar radiation). A statistical analysis, based on factorial 23 indicated the best working conditions, being: [H2O2] = 100 mg·L-1 and pH 3-4, for both AOP in that the [Fe] = 1 e 5 mg·L-1, for photo-Fenton and Fenton, respectively. The results of the kinetic studies demonstrated a good fit to the nonlinear kinetic model proposed by Chan and Chu, with values of R2 > 0,996 (photo-fenton) and R2 > 0,939 (Fenton). The tests performed to evaluate the chemical oxygen demand indicated conversions of 62.05% (Fenton) and 66.41% (photo-Fenton). Finally, the ecotoxicity study indicated that the post-treatment samples were non-toxic to the bacteria Escherichia coli and Proteus mirabilis but showed growth inhibition for Lactuca sativa (Fenton and photo-Fenton) seeds and for Brassica juncea and Portulaca grandiflora (Fenton).

Kinetic Evaluation of Dye Decolorization by Fenton Processes in the Presence of 3-Hydroxyanthranilic Acid

“…By considering parameter 1/ b obtained by the BMG model, it is possible to observe that the maximum oxidation capacity of Fe 2+ -containing reactions ( R 2 > 0.9) increased in the presence of 3-HAA, e.g., the oxidation capacity of safranin T was almost three times greater in the presence of 3-HAA. Santana et al [42,43] showed the same upward trend in 1/ b on the decolorization kinetics of different dyes by Fenton systems using dihydroxybenzenes and gallic acid as redox mediators. Regarding parameter 1/ m , there were no significant changes in the initial degradation rates of dyes in the presence of 3-HAA.…”

“…Therefore, the BMG model was more suitable to represent the Fe 2+ /H 2 O 2 system kinetics. In previous studies, the fitting of experimental kinetic data on two-stage decolorization of several dyes by classical Fenton reaction was better with the BMG model [34,39,40,41,42,43].…”

Synthesis, characterization and application of Clinoptilolite-based catalysts for the degradation of Reactive Blue dye via photo-Fenton process

“…Nesse contexto, aponta-se o uso de processos oxidativos avançados (POA's) como uma solução para a contaminação de corpos hídricos pela presença de corantes advindos de efluentes têxteis. Partindo disso, tem-se que para o corante Reactive Blue, um dos mais utilizados na indústria têxtil, uma classe de POA's que vem apresentando resultados satisfatórios de degradação é a da fotocatálise, em especial o processo foto-Fenton (Santana, Nascimento & Napoleão et. al., 2017;Araujo, 2002).…”