Removal of dyes from water using Citrullus lanatus seed powder in continuous and discontinuous systems.

The objective of this study is to develop a low-cost biosorbent using residual seeds of the Citrullus lanatus fruit for the removal of cationic dyes. Physicochemical parameters such as pH, adsorbent mass, contact time, and temperature were evaluated for their effects on dye removal. The biosorbent is composed of lignin and cellulose, exhibiting a highly heterogeneous surface with randomly distributed cavities and bulges. The adsorption of both dyes was most effective at natural pH with a dosage of 0.8 g L-1. Equilibrium was reached within 120 min, regardless of concentration, indicating rapid kinetics. The Elovich model and pseudo-second-order kinetics were observed for crystal violet and basic fuchsin dye, respectively. The Langmuir model fitted well with the equilibrium data of both dyes. However, the increased temperature had a negative impact on dye adsorption. The biosorbent also demonstrated satisfactory performance (R = 43%) against a synthetic mixture of dyes and inorganic salts, with a small mass transfer zone. The adsorption capacities for crystal violet and basic fuchsin dye were 48.13 mg g-1 and 44.26 mg g-1, respectively. Thermodynamic studies confirmed an exothermic nature of adsorption. Overall, this low-cost biosorbent showed potential for the removal of dyes from aqueous solutions.

In this work, a novel biosorbent was developed using residual Citrullus lanatus fruit seeds that can efficiently remove cationic dyes from aqueous solutions. The biosorbent's composition includes lignin and cellulose, and its surface structure is highly heterogeneous, consisting of randomly distributed cavities and bulges. The biosorbent demonstrated a rapid and efficient adsorption capacity for both crystal violet and basic fuchsin, regardless of dye concentration. Moreover, the biosorbent was successfully employed in the treatment of a synthetic mixture containing several dyes and inorganic salts. Finally, the application of the biosorbent in continuous adsorption showed a low zone of mass transfer and high breakthrough time, indicating it to be an excellent material for fixed-bed operation. Overall, this study provides a low-cost and efficient alternative for the removal of dyes from aqueous solutions, with promising practical applications.

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.

Augmented degradation of dyed organic pollutant using Fe2O3 supported on char formed from poultry slaughterhouse waste.

In this work, a novel support for an iron-based catalyst was prepared and employed for Ponceau 4R degradation by photo-Fenton reaction. To this, poultry waste was used for producing char, which was subsequently used to prepare the Fe2O3/Char composite. Process parameters, including catalyst dosage, pH, and hydrogen peroxide concentration, were investigated. The characterization analysis indicated that the textural properties of the composite were improved after impregnation with Fe2O3. The composite exhibited excellent catalytic activity, achieving a decolorization efficiency of 97% at 45 min and 81.06% organic carbon removal at 300 min. In addition, the material showed acceptable performance after four consecutive cycles. Furthermore, a scavenger test was performed to investigate the major reactive species involved in the Ponceau 4R oxidation, and a plausible mechanism for the respective reaction was projected. Therefore, the results of this research demonstrate that this material can be used as a potential catalyst for the abatement of dyed molecules from wastewater.

Preparation of carbonaceous materials from flotation-sludge of the poultry industry and its application in the methylene blue adsorption.

In this work, different carbonaceous materials based on floated sludge from a poultry industry wastewater treatment plant (PI-WTP) were synthesized. These materials were characterized and investigated in methylene blue dye (MB) adsorption. The influences of the initial pH solution, adsorbent dosage, kinetics, equilibrium, and thermodynamics were evaluated in the adsorption experiments. A simulation of a real textile effluent was also carried out to evaluate the adsorbent. The results of the adsorbents' characterization demonstrated that adding ZnCl2 + lime, followed by pyrolysis and acid leaching, significantly improved the material's properties, leading to abundant porosity and high surface area. The adsorption experiments indicated that the natural pH of the solution (8.0) and the AC-II dosage of 0.75 g L-1 are optimal for MB removal. Elovich and Sips' models (with a maximum adsorption capacity of 221.02 mg g-1 at 328 K) best fitted the experimental kinetic and equilibrium data, respectively. The adsorption process is spontaneous and endothermic according to thermodynamic parameters. The discoloration efficiency of the simulated effluent was 67.8%. In conclusion, the floated sludge, a residue produced on a large scale that needs to be disposed of correctly, can be converted into a value-added material (carbonaceous adsorbent) and applied to treat colored effluents.

Submerged cultivation of Nigrospora sp. in batch and fed-batch modes for microbial oil production.

Microbial lipids are a valuable source of potential biofuels and essential polyunsaturated fatty acids. The optimization of the fermentation conditions is a strategy that affects the total lipid concentration. The genus Nigrospora sp. has been the target of investigations based on its potential bioherbicidal action. Therefore, this study developed a strategy to maximize the biomass concentration and lipid accumulation by Nigrospora sp. in submerged fermentation. Different media compositions and process variables were investigated in shaken flasks and bioreactor in batch and fed-batch modes. Maximum biomass concentration and lipid accumulations were 40.17 g/L and 21.32 wt% in the bioreactor, which was 2.1 and 5.4 times higher than the same condition in shaken flasks, respectively. This study presents relevant information to the production of fungal lipids since few investigations are exploring the fed-batch strategy to increase the yield of fungi lipids, as well as few studies investigating Nigrospora sp. to produce lipids.

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.

Effective adsorptive removal of textile pollutant using coal bottom ash with high surface area obtained by alkaline fusion route.

In this work, coal bottom ash was modified by alkaline fusion route in order to improve its pore properties and make it a potential adsorbent to remove crystal violet dye from aqueous medium. The solids were characterized and posteriorly subjected to kinetic, isotherm, and thermodynamic studies, as well as regenerated and reused for five adsorption tests. The alkaline fusion step resulted in the amorphization of material and generation of high surface area (102 m 2 g -1) and pore volume (0.180 cm 3 g-1), resulting in superior performance compared to the raw material. Kinetic and equilibrium studies showed that the adsorption process was better adjusted by the pseudo-second order and Langmuir models, respectively. The maximum adsorption capacity at equilibrium was 177. 37 mg g-1, with the adsorptive step occurring spontaneously and endothermically. The adsorbent maintained notable levels of dye removal after five consecutive cycles of thermal regeneration and reuse. Besides, the adsorbent was able to remove 64% of the colour of simulated industrial wastewater. Therefore, the alkaline fusion step proved to be a route capable of transforming the coal bottom ash into an adsorbent with improved textural and adsorptive properties.

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.

Solid wastes from the enzyme production as a potential biosorbent to treat colored effluents containing crystal violet dye.

Sugarcane bagasse, a largely available waste worldwide, was submitted to solid-state fermentation (SSF) using the fungus Metarhizium anisopliae, aiming to produce enzymes. The solid waste generated from SSF was tested as an alternative biosorbent to treat colored effluents containing crystal violet (CV) dye. The biosorbent, here named BW (bagasse waste), was characterized, and experimental tests were performed to verify the influence of pH and dosage on the CV biosorption. Isotherms and biosorption kinetics were performed, and the biosorption thermodynamic parameters were determined. The potential of BW was also evaluated for the treatment of a simulated textile effluent. The maximum biosorption capacity was 131.2 mg g-1 at 328 K, and the Liu was the most appropriate model to represent equilibrium data. The biosorption was spontaneous and endothermic. The use of BW in the simulated effluent showed that it is an efficient material, reaching color removal values of 85%. Therefore, the sugarcane bagasse generated from SSF can be considered a potential biosorbent to remove CV from textile effluents. This finding is relevant from the total environment viewpoint, since, at the same time, SSF generates enzymes and a solid waste, which in turn can be used as biosorbent to treat colored effluents.

Application of Beauveria bassiana spore waste as adsorbent to uptake acid red 97 dye from aqueous medium.

The adsorption of acid red 97 dye (RED 97) by the waste of the filamentous fungus Beauveria bassiana was analyzed. The adsorbent was obtained as a waste of a fermentative process, and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffractometry (XRD), and specific surface area (BET). After the characterization, adsorption tests were carried out to determine the ideal conditions of pH, adsorbent mass, and contact time for the process. Adsorption isotherms, thermodynamic studies, and the treatment of textile effluent were also investigated. The adsorbent characterization allowed the visualization of its amorphous structure, with irregular and heterogeneous particles. The pore diameter was 51.9 nm and the surface area was 0.247 m2 g-1. 1.2 g L-1 of the adsorbent and pH of 2.0 were the ideal conditions for RED 97 adsorption. The pseudo-second-order kinetic model was the most appropriate to represent the experimental data, being the equilibrium reached in about 110 min. The Langmuir model was the most suitable to represent the equilibrium data, with maximum adsorption capacity of 194.1 mg g-1 at 45 °C. The adsorption processes was thermodynamically spontaneous, favorable, and exothermic. In the treatment of a real textile effluent, 5 g L-1 of the spores was capable to decolorize 70% of the solution. Therefore, spore wastes of Beauveria bassiana were promising for RED 97 adsorption.

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.

Potential of Cedrella fissilis bark as an adsorbent for the removal of red 97 dye from aqueous effluents.

Cedar bark (Cedrella fissilis), a waste from wood processing, was evaluated as an adsorbent for the removal of red 97 dye from effluents. The material exhibited an amorphous structure, irregular surface, and was mainly composed of lignin and holocellulose. The adsorption was favored at pH 2.0. The general order model was most suitable for describing the experimental kinetic data, being the equilibrium reached in around 30 min. The isotherm experiments were better described by the Langmuir model. The maximum adsorption capacity was 422.87 mg g-1 at 328 K. The values of standard Gibbs free energy change (ΔG0) were from - 21 to - 26 kJ mol-1, indicating a spontaneous and favorable process. The enthalpy change (ΔH0) was 18.98 kJ mol-1, indicating an endothermic process. From the fixed bed adsorption experiment, an inclined breakthrough curve was found, with a mass transfer zone of 5.36 cm and a breakthrough time of 329 min. Cedar bark was able to treat a simulated effluent attaining color removal of 86.6%. These findings indicated that cedar bark has the potential to be applied as a low-cost adsorbent for the treatment of colored effluents in batch and continuous adsorption systems.

Biosorption of crystal violet dye using inactive biomass of the fungus Diaporthe schini.

An inactive biomass of a new fungus recently discovered, Diaporthe schini, was evaluated for the biosorption of crystal violet (CV) in simulated textile effluents. The characterization assays were performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and N2 adsorption/desorption isotherms. The influences of pH and biosorbent dosage on the biosorption capacity were evaluated. Kinetics, equilibrium and thermodynamic studies were also carried out. Characterization techniques showed an amorphous biosorbent, with a rough surface containing irregular particles and surface area of 6.5 m2 g-1. The most adequate values of pH and biosorbent dosage were 7.5 and 0.4 g L-1, respectively. The Elovich kinetic model and the Sips equilibrium model were suitable to fit the experimental data. The biosorption capacity increased with temperature, reaching a maximum biosorption capacity of 642.3 mg g-1 at 328 K. The biosorption was a spontaneous and endothermic process. Diaporthe schini inactive biomass was an interesting biosorbent to treat colored effluents, presenting efficiency of 87% in the decolorization of a simulated dye house effluent.

Potential of Araucaria angustifolia bark as adsorbent to remove Gentian Violet dye from aqueous effluents.

Araucaria angustifolia bark (AA-bark), a waste generated in wood processing, was evaluated as a potential adsorbent to remove Gentian Violet (GV) dye from aqueous solutions. The AA-bark presented an amorphous structure with irregular surface and was composed mainly of lignin and holocellulose. These characteristics indicated that the adsorbent contains available sites to accommodate the dye molecules. The GV adsorption on AA-bark was favored at pH 8.0 with adsorbent dosage of 0.80 g L-1. Pseudo-nth order model was adequate to represent the adsorption kinetics of GV on AA-bark. A fast adsorption rate was verified, with the equilibrium being attained within 30 min. Equilibrium data were well represented by the Langmuir model. The maximum adsorption capacity was 305.3 mg g-1. Adsorption was spontaneous, favorable and endothermic. AA-bark was able to treat a simulated dye house effluent, reaching color removal values of 80%. An excellent performance was found in fixed bed experiments, where the length of the mass transfer zone was only 5.38 cm and the breakthrough time was 138.5 h. AA-bark can be regenerated two times using HNO3 0.5 mol L-1. AA-bark can be used as a low-cost material to treat colored effluents in batch and fixed bed adsorption systems.

Prematuros hacia el 2000: Un desafío / Prematures towards year 2000: a challenge

Se realizó el seguimiento, por equipo multidisciplinario, de recién nacidos con peso al nacer igual o menor a 2000gr. y edad gestacional igual o menor a 37 semanas. Se indicó en Setiembre 1994, realizandose un corte en febrero 1999. Las variables estudiadas fueron: edad gestacional, peso al nacer, Apgar, episodios de apnea, requerimientos de asistencia ventiladoria mecánica, días de internación, curvas de crecimiento, patología pulmonar, secuelas neurológicas, alteraciones visuales, conductas de apego y medio socioeconómico. De los 69 niños estudiados, un alto porcentaje tuvieron crecimiento y desarrollo dentro de límites normales, la mayoría de éstos tuvieron peso al nacer superior a 1500grs. Se destaca un elevado número de niños con secuelas neurológicas, patología pulmonar crónica y trastornos del vínculo madre-hijo. Su diagnóstico precoz permite efectuar un abordaje terapéutico coordinado, destacandose el valor de la intervención temprana de la fisioterapia y del apoyo psicológico con el fin de lograr que las secuelas sean lo menos invalidantes posibles