Valorization of a poultry industry floated sludge as a raw material to produce char and activated carbon for pharmaceutical compounds adsorption.

This study was intended to valorize a floated sludge of a poultry slaughterhouse using it as a precursor to producing char and activated carbon, which were tested as adsorbents in removing ketoprofen and diclofenac sodium from the water. The addition of zinc chloride or calcium hydroxide was determinant for forming a porous carbonaceous structure with a high surface area in AC-FSP (656.54 m2 g-1), differently from that exhibited by the CHAR-FSP (8.11 m2 g-1). Kinetic and equilibrium studies indicated that the pseudo-second-order and the Sips models were suitable. The AC- FSP maximum adsorption capacity for ketoprofen and diclofenac sodium was 124.98 mg g-1 and 138.32 mg g-1, respectively. The adsorption was a spontaneous and endothermic process. It was concluded that AC-FSP is a more efficient and promising adsorbent than CHAR-FSP for the adsorption of drugs in contaminated wastewater. In addition, AC-FSP can be reused, maintaining good adsorption levels for about 5 cycles. Therefore, this study is aligned with the 2030 Agenda for global sustainability since converting waste (valueless) into an adsorbent is also directly linked to the circular economy and neutral carbon.

Conversion of foliar residues of Sansevieria trifasciata into adsorbents: dye adsorption in continuous and discontinuous systems.

The study analyzed the potential of leaf powder prepared from the residual leaves of the species Sansevieria trifasciata, as a potential adsorbent for methylene blue (MB) removal. The equilibrium was reached fast for almost all concentrations after 60 min, obtaining the maximum capacity of 139.98 mg g-1 for 200 mg L-1. The increase in temperature disfavored the dye adsorption, with the maximum adsorption capacity of 225.8 mg g-1, observed for 298 K. The thermodynamic parameters confirmed that the adsorption process is spontaneous and exothermic. A direct sloping curve was established for the fixed bed, with breakthrough time (tb), column stoichiometric capacities (qeq), and the mass transfer zone lengths (Zm) were 1430, 1130, and 525 min; 60.48, 187.01, and 322.65 mg g-1; and 8.81, 11.28, and 10.71 cm, for 100, 200, and 500 mg L-1, respectively. Furthermore, in a mixture of several dyes, the adsorbent obtained the removal of 51% of the color.

Application of Cordia trichotoma sawdust as an effective biosorbent for removal of crystal violet from aqueous solution in batch system and fixed-bed column.

In this work, for the first time, Cordia trichotoma sawdust, a residue derived from noble wood processing, was applied as an alternative biosorbent for the removal of crystal violet by discontinuous and continuous biosorption processes. The optimum conditions for biosorption of crystal violet were 7.5 pH and a biosorbent dosage of 0.8 g L-1. The biosorption kinetics showed that the equilibrium was reached at 120 min, achieving a maximum biosorption capacity of 107 mg g-1 for initial dye concentration of 200 mg L-1. The Elovich model was the proper model for representing the biosorption kinetics. The isotherm assays showed that the rise of temperature causes an increase in the biosorption capacity of the crystal violet, with a maximum biosorption capacity of 129.77 mg g-1 at 328 K. The Langmuir model was the most proper model for describing the behavior. The sign of ΔG0 indicates that the process was spontaneous and favorable, whereas the ΔH0 indicates an endothermic process. The treatment of the colored simulated effluent composed by dyes and salts resulted in 80% of color removal. The application of biosorbent in the fixed-bed system achieved a breakthrough time of 505 min, resulting in 83.35% of color removal. The Thomas and Yoon-Nelson models were able to describe the fixed-bed biosorption behavior. This collection of experimental evidence shows that the Cordia trichotoma sawdust can be applied for the removal of crystal violet and a mixture of other dyes that contain them.

Macro-fungal (Agaricus bisporus) wastes as an adsorbent in the removal of the acid red 97 and crystal violet dyes from ideal colored effluents.

The wastes from the macro-fungus Agaricus bisporus were used as an eco-friendly and low-cost adsorbent for the treatment of colored effluents containing the recalcitrant dyes, acid red 97 (AR97) and crystal violet (CV). The macro-fungal waste presented an amorphous structure, composed of particles with different sizes and shapes. Also, it presents typical functional chemical groups of proteins and carbohydrates with a point of zero charge of 4.6. The optimum conditions for the dosage were found to be as follows: 0.5 g L-1 with an initial pH at 2.0 for the AR97 and 8.0 for the CV. From the kinetic test, it was found that it took 210 min and an adsorption capacity of 165 mg g-1 for the AR97. Concerning the CV kinetics, it took 120 min to reach the equilibrium and it achieved an adsorption capacity of 165.9 mg g-1. The Elovich model was the most proper model for describing the experimental data, achieving an R2 ≥ 0.997 and MSE ≤ 36.98 (mg g-1)2. The isotherm curves were best represented by the Langmuir model, predicting maximum adsorption capacity of 372.69 and 228.74 mg g-1 for the AR97 and CV, respectively. The process was spontaneous and favorable for both dyes. The ∆H0 values were 9.53 and 10.69 kJ mol-1 for AR97 and CV, respectively, indicating physical and endothermic adsorption. Overall, the wastes from Agaricus bisporus have the potential to adsorb cationic and anionic dyes, thus solving environmental problems related to water quality and residue disposal.

Potentiality of the Phoma sp. inactive fungal biomass, a waste from the bioherbicide production, for the treatment of colored effluents.

The potentiality of Phoma sp. inactive fungal biomass, waste from the bioherbicide production, was evaluated for the treatment of colored effluents containing Acid Red 18 (AR 18) dye. The batch experiments were performed to evaluate the following parameters: pH of the solution (2-10), dye concentration (50-200 mg L-1), adsorbent dose (0.5-2.5 g L-1), contact time (0-180 min) and temperature (298-328 K). The batch experiments using a synthetic dye solution revealed that Phoma sp. was efficient at pH of 2.0, 298 K and using a dosage of 1.25 g L-1. The process was fast, being the equilibrium reached within 180 min. The maximum value of biosorption capacity was 63.58 mg g-1, being the process favorable and exothermic. From the fixed bed assays, breakthrough curves were obtained, presenting a mass transfer zone of 7.08 cm and breakthrough time of 443 min. Phoma sp. was efficient to decolorize a simulated effluent, removing more than 90% of the color. From the obtained results, it can be concluded that Phoma sp. inactive biomass is a low-cost option to treat colored effluents in continuous and discontinuous biosorption modes. These indicate that Phoma sp. of inactive biomass is an option for the treatment of colored effluents.

Antifungal and antibacterial activity of extracts produced from Diaporthe schini.

The aim of this work was the production of bioactive metabolites by submerged fermentation from the fungus Diaporthe schini, followed by their extraction, separation and characterization. Different solvents (methanol, dichloromethane and hexane) were used for the extraction of metabolites from the fermentation broth and the extracts obtained were evaluated by in vitro antibacterial and antifungal activity. The separation and characterization of the extract from the hexane extraction was performed by column chromatography and GC-MS, respectively. The extracts had a great inhibitory action on the Gram-positive bacteria Staphylococcus epidermidis and Staphylococcus aureus, on the Gram-negative bacteria Enterobacter aerogenes and Klebsiella pneumoniae and on the fungus Candida krusei. The main metabolites produced were: 13-docosenamide, (Z)-; 2-hexadecene, 3,7,11,15-tetramethyl; 9-octadecenamide and 11-octadecenoic acid. Studies related to the antibacterial and antifungal activities of metabolites extracted from microorganisms are found in the literature. However, works about the identification of metabolites produced by submerged fermentation from Diaporthe schini were not found until the present moment. This work is an initial study where the conditions of the process can be optimized by looking for the production of a specific compound and can be a promising source for obtaining new drugs.

Production of cellulolytic enzymes and application of crude enzymatic extract for saccharification of lignocellulosic biomass.

In this study, the optimal conditions for production of cellulolytic enzymes by Trichoderma reesei NRRL-6156 using the solid-state fermentation were assessed in conical flasks and validated in a packed-bed bioreactor. Afterwards, the crude enzymatic extract obtained in the optimized condition was used for hydrolysis of sugarcane bagasse in water and ultrasound baths. The enzyme activities determined in this work were filter paper, exocellulase, endocellulase, and xylanase. The optimized condition for production was moisture content 68.6 wt% and soybean bran concentration 0.9 wt%. The crude enzymatic extract was applied for hydrolysis of sugarcane bagasse, being obtained 224.0 and 229 g kg(-1) at temperature of 43.4 °C and concentration of enzymatic extract of 18.6 % in water and ultrasound baths, respectively. The yields obtained are comparable to commercial enzymes.

Effects of Solvent Diols on the Synthesis of ZnFe2O4 Particles and Their Use as Heterogeneous Photo-Fenton Catalysts.

A solvothermal method was used to prepare zinc ferrite spinel oxide (ZnFe2O4) using ethylene glycol and 1,4 butanediol as solvent diols, and the influence of diols on the physical properties of ZnFe2O4 particles was investigated. The produced particles were characterized by X-ray powder diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption isotherms, and the catalytic activity for the organic pollutant decomposition by heterogeneous photo-Fenton reaction was investigated. Both solvents produced particles with cubic spinel structure. Microporous and mesoporous structures were obtained when ethylene glycol and 1,4 butanediol were used as diols, respectively. A higher pore volume and surface area, as well as a higher catalytic activity for the pollutant degradation were found when 1,4 butanediol was used as solvent.

Degradation of Direct Black 38 dye under visible light and sunlight irradiation by N-doped anatase TIO2 as photocatalyst.

The N-doped TiO(2) photocatalyst was prepared by calcination of a hydrolysis product composed of titanium (IV) isopropoxide with ammonia as the precipitator. X-ray diffraction, surface area, XPS and UV-vis spectra analyses showed a nanosized anatase structure and the appearance of a new absorption band in the visible region caused by nitrogen doping. The degradation of Direct Black 38 dye on the nitrogen-doped TiO(2) photocatalyst was investigated under visible light and sunlight irradiation. The N-doped anatase TiO(2) demonstrated excellent photocatalytic activity under visible light. Under sunlight irradiation, the N-doped sample showed slightly higher activity than that of the non-doped sample.