Camila Velloso

Abstract Effluents stemming from the textile industry are concerning from the environmental viewpoint, given that large volumes are generated and they present a high concentration of organic matter and toxicity. Dyes stand out among the substances present in such effluents because part of them does not fix on the fiber during the dyeing process, leaving the effluent with a strongly colored aspect and difficult to be treated. Due to the limitations and low efficiency of conventional processes, alternative forms for the treatment of textile effluents have been evaluated. Among them, the Fenton oxidation processes stand out, which are based on the use of iron as a catalyst in the conversion of H2O2 into highly reactive free radicals. The catalyst may be solubilized or used in the insoluble form (heterogeneous catalysis). Fenton reaction can be enhanced by combining UV, visible (photo-Fenton, solar photo-Fenton), or ultrasound radiation (sono-Fenton), and electrical current (Electro-Fenton). In this review, a brief mention of textile effluent characteristics is presented, and the fundamentals, advantages, limitations, and recent progress of the Fenton processes are addressed as alternatives to the treatment of textile effluents. A survey on the efficiency of such processes regarding the reduction of important characterization parameters (organic matter concentration, color, turbidity) for real textile effluents also is presented. From the real effluent data, it was noted that these processes are efficient in the reduction of organic pollutants and color. Among the Fenton processes, photo-Fenton showed better efficiencies and less variability for the different effluents treated (reducing on average 82% of COD and 95% of color). It has also been observed that such processes can be also efficient when combined with other processes (e.g. coagulation-flocculation or biological processes). Treated effluents present less toxicity and have been reused in the dyeing stage, although such an approach is still poorly evaluated. The costs for the treatment of real effluents calculated by different authors ranged from 1.1 to 28.9 USD per Kg of COD removed, where the processes that presented the lowest costs were classical Fenton and technologies that use solar energy, such Photo-Fenton and Photo-electro-Fenton.

ADVANCES IN THE PRODUCTION AND FORMULATION OF MICROBIAL INOCULANTS FOR A MORE SUSTAINABLE AGRICULTURE. The wide application of beneficial microorganisms in agriculture as inoculants to combat pests and diseases and/or to improve soil fertility and the nutrients availability for plants has been considered as an effective and more sustainable alternative than chemical fertilizers and agricultural defensives. However, it is necessary to examine all processing steps of these bio-based products under a more integrated view including the type of microorganisms and the whole production process in order to reduce dependence on synthetic chemical inputs. Here, recent developments on the production and formulation technologies of microbial inoculants and the main types of inoculants currently applied in agriculture are addressed. The different types of microbial formulations are compared with emphasis on the encapsulation technology. Moreover, the application of biofertilizers in seed coating...

The present work evaluated the influence of phenolic mediators (five dihydroxybenzenes and gallic acid) on the decolorization kinetics of phenol red, chromotrope 2R, and methylene blue by Fenton systems. The reactions were performed with H2O2, iron salts as catalysts, and the absence or presence of phenolic mediators. Based on the decolorization data from previous study of our group, the 1st and 2nd order kinetic models were analyzed, as well as the alternative BMG model. It was found that the mediators accelerated the reactions, based in 1st and 2nd order kinetic models. Reactions containing Fe2+ fitted better to the BMG model, while reactions containing Fe3+ fitted better to the 2nd order kinetic model, independent of mediators. Based on the three evaluated kinetic models, pro-oxidant properties were observed for the mediators in Fenton systems.

Abstract Effluents stemming from the textile industry are concerning from the environmental viewpoint, given that large volumes are generated and they present a high concentration of organic matter and toxicity. Dyes stand out among the substances present in such effluents because part of them does not fix on the fiber during the dyeing process, leaving the effluent with a strongly colored aspect and difficult to be treated. Due to the limitations and low efficiency of conventional processes, alternative forms for the treatment of textile effluents have been evaluated. Among them, the Fenton oxidation processes stand out, which are based on the use of iron as a catalyst in the conversion of H2O2 into highly reactive free radicals. The catalyst may be solubilized or used in the insoluble form (heterogeneous catalysis). Fenton reaction can be enhanced by combining UV, visible (photo-Fenton, solar photo-Fenton), or ultrasound radiation (sono-Fenton), and electrical current (Electro-Fenton). In this review, a brief mention of textile effluent characteristics is presented, and the fundamentals, advantages, limitations, and recent progress of the Fenton processes are addressed as alternatives to the treatment of textile effluents. A survey on the efficiency of such processes regarding the reduction of important characterization parameters (organic matter concentration, color, turbidity) for real textile effluents also is presented. From the real effluent data, it was noted that these processes are efficient in the reduction of organic pollutants and color. Among the Fenton processes, photo-Fenton showed better efficiencies and less variability for the different effluents treated (reducing on average 82% of COD and 95% of color). It has also been observed that such processes can be also efficient when combined with other processes (e.g. coagulation-flocculation or biological processes). Treated effluents present less toxicity and have been reused in the dyeing stage, although such an approach is still poorly evaluated. The costs for the treatment of real effluents calculated by different authors ranged from 1.1 to 28.9 USD per Kg of COD removed, where the processes that presented the lowest costs were classical Fenton and technologies that use solar energy, such Photo-Fenton and Photo-electro-Fenton.

The fungal metabolite 3-hydroxyanthranilic acid (3-HAA) was used as a redox mediator with the aim of increasing dye degradation by Fenton oxidative processes (Fe2+/H2O2, Fe3+/H2O2). Its Fe3+-reducing activity can enhance the generation of reactive oxygen species as HO● radicals. Initially, the influence of 3-HAA on decolorization kinetics of five dyes (methylene blue, chromotrope 2R, methyl orange, phenol red, and safranin T) was investigated using decolorization data from a previous work conducted by the present research group. Fe3+-containing reaction data were well fitted with first-order and mainly second-order kinetic models, whereas the BMG (Behnajady, Modirshahla and Ghanbary) model obtained optimal fit to Fe2+. Improvements in kinetic parameters (i.e., apparent rate constants and maximum oxidation capacity) were observed with the addition of 3-HAA. In another set of experiments, a decrease in apparent activation energy was observed due to introducing 3-HAA into reactions con...

Plant growth promoting bacteria (PGPB) are an efficient and sustainable alternative to mitigate biotic and abiotic stresses in maize. This work aimed to sequence the genome of two Bacillus strains (B116 and B119) and to evaluate their plant growth-promoting (PGP) potential in vitro and their capacity to trigger specific responses in different maize genotypes. Analysis of the genomic sequences revealed the presence of genes related to PGP activities. Both strains were able to produce biofilm and exopolysaccharides, and solubilize phosphate. The strain B119 produced higher amounts of IAA-like molecules and phytase, whereas B116 was capable to produce more acid phosphatase. Maize seedlings inoculated with either strains were submitted to polyethylene glycol-induced osmotic stress and showed an increase of thicker roots, which resulted in a higher root dry weight. The inoculation also increased the total dry weight and modified the root morphology of 16 out of 21 maize genotypes, indica...