RESUMEN
Biomass can be used as an energy source to thermochemical conversion processes to biocrude production. However, the supply and dependence on only one biomass for biocrude production can be an obstacle due to its seasonality, availability, and logistics costs. In this way, biomass waste and agroindustrial residues can be mixture and used as feedstock to the hydrothermal co-liquefaction (co-HTL) process as an alternative to obtaining biocrude. In this sense, the present paper analyzed the biocrude yield influence of the co-HTL from a quaternary unprecedented blend of different biomasses, such as sugarcane bagasse, brewer's spent grain (BSG), sludge from a paper recycling mill (PRM), and microalgae (Chlorella vulgaris). In this way, a simplex lattice design was employed and co-HTL experiments were carried out in a 2000 mL high-pressure stirred autoclave reactor under 275 °C for 60 min, considering 15% of feedstock/water ratio. Significant effects in each feedstock and their blends were analyzed aiming to increase biocrude and biochar yield. It was found that the addition of microalgae is only significant when considered more than 50% into the blend with BSG and PRM sludge to increase biocrude yield.
Asunto(s)
Carbón Orgánico , Chlorella vulgaris , Microalgas , Saccharum , Aguas del Alcantarillado , Celulosa , Temperatura , Microalgas/química , Biomasa , Agua/química , Biocombustibles/análisisRESUMEN
The numerous oxidation states of the element boron bring great challenges in containing its contamination in receptor bodies. This scenario increases significantly due to the widespread use of boron compounds in various industries in recent years. For this reason, the removal of this contaminant is receiving worldwide attention. Although adsorption is a promising method in boron removal, finding suitable adsorbents, that is, those with high efficiency, and feasible remains a constant challenge. Hence, this review presents the boron removal methods in comparison to costs of adsorbents, reaction mechanisms, economic viability, continuous bed application, and regeneration capacity. In addition, the approach of multivariate algorithms in the solution of multiobjective problems can enable the optimized conditions of dosage of adsorbents and coagulants, pH, and initial concentration of boron. Therefore, this review sought to comprehensively and critically demonstrate strategic issues that may guide the choice of method and adsorbent or coagulant material in future research for bench and industrial scale boron removal.
Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Purificación del Agua/métodos , Boro/química , Adsorción , Contaminantes Químicos del Agua/análisis , Agua/químicaRESUMEN
The present work presents the results obtained in the production of vanillin-doped alginate biopolymeric film using green chemistry methodology. Alginate dressings are already a therapeutic reality, but they act only by maintaining the appropriate environment for healing. In order to improve their properties, the incorporation of vanillin was proposed due to its antioxidant and antimicrobial potential. Different biopolymeric films were produced employing the experiment planning through response surface analysis, which allowed determining the best region for a medium value of solubility and high degree of swelling. This region refers to values above 0.07 g of CaCl2 and concentrations above 0.024 g of vanillin, triggering solubility between 25 and 30% and a degree of swelling above 100% and with fixed values of alginate (0.85 g). Such data are related to experiments (A), (B), and (C) listed in Table 1. Regarding the optimization of the process, the normal boundary intersection (NBI) method allowed the analysis of concave regions, predicting the optimal points and generating the Pareto chart with equidistant limits. The antimicrobial test allowed observing the antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa microorganisms from the biopolymeric films, as well as a solution of vanillin with calcium chloride and glycerol obtaining a halo of inhibition only in the presence of vanillin, and there was no significant difference between the results obtained in the experiments (A) and (B). The thermal analyses showed that the material has thermal stability in the ideal temperature range (~ 25 °C) for application as a biocurative. We preliminarily concluded that the alginate biopolymeric film doped with vanillin prepared using green chemical methodology presents antimicrobial properties and thermal stability that indicate its potential use as biocurative.
Asunto(s)
Antiinfecciosos , Materiales Biocompatibles , Alginatos/química , Antiinfecciosos/farmacología , BenzaldehídosRESUMEN
The use of dispersed catalysts in aqueous medium inside reactors in advanced oxidative processes is common among researchers. However, due to the difficult separation of these species after treatment, in many cases, the treatment process is unfeasible. In this context, the main target of the work was the evaluation of degradation of the phenolic solution by ozonation titanium dioxide (TiO2/P25), supported on zeolite spheres. The process was investigated through the response surface methodology (RSM) and optimized by the generalized reduced gradient (GRG) algorithm. The effects of various operating parameters including pH, power ozone (O3) generation, flow rate, and treatment time were investigated, using as a response to removal of chemical oxygen demand (COD). It was made in optimum conditions the ratio of biochemical oxygen demand (BOD)/chemical oxygen demand to check the increasing biodegradability, aiming ozonation as preliminary treatment, with the possibility of subsequent biological treatments. There was an increase in this ratio from 0.17 to 0.50 in 48 min, which would facilitate the use of the subsequent biological process. The proposed model showed good fit to the experimental data with R2 and R2adj correlation coefficients of 0.9964 and 0.9932, respectively.
Asunto(s)
Fenol/análisis , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/análisis , Biodegradación Ambiental , Análisis de la Demanda Biológica de Oxígeno , Catálisis , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Ozono , Fenol/química , Fenoles , Titanio/química , Aguas Residuales/química , Contaminantes Químicos del Agua/química , ZeolitasRESUMEN
Ozone and a Fe2+/TiO2-based catalyst were examined in the degradation of a synthetic solution of benzene toluene and xylene (BTX) in an advanced oxidation process (AOP). The catalyst beads were made from the slurry waste of aluminum production process, by inserting the TiO2 content and subsequent calcination. The reduction of the BTX concentration load was monitored by the reduction of chemical oxygen demand (COD) and BTX concentration. Different levels were used on factors: pH, time of treatment, initial concentration of BTX, and percentage of TiO2. The process was conducted in a bubble column reactor with the insertion of catalyst beads. A response surface methodology technique (CCD) was used to build a model based on COD reduction results. The model was optimized using the normal-boundary intersection (NBI) algorithm to maximize COD reduction and minimize the variance attributed to the process. Optimization led to COD reductions of 80% in 2 h of experiment. Correlation analysis of coefficient models from experimental data R2adj was 0.9966, showing a good fit of model data. In the optimized conditions, the possible increase of the biodegradability ratio of the BTX solution, through the biochemical oxygen demand (BOD) and COD, was also analyzed. Under pre-treatment conditions, the BOD/COD ratio was 0.13. After the treatment, it increased to 0.56. Graphical abstract á .
Asunto(s)
Benceno/química , Sedimentos Geológicos/química , Ozono/química , Titanio/química , Tolueno/química , Eliminación de Residuos Líquidos/métodos , Xilenos/química , Algoritmos , Aluminio , Biodegradación Ambiental , Análisis de la Demanda Biológica de Oxígeno , Catálisis , Monitoreo del Ambiente , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Industria Manufacturera , Oxidación-Reducción , SolucionesRESUMEN
Amoxicillin is a useful antibiotic to combat bacterial infections. However, this drug can cause serious problems when discarded in waterways due to its great bioaccumulation potential. This compound can be treated via advanced oxidation processes (AOPs), which are capable of converting amoxicillin into carbon dioxide and water. In this context, the use of ozone as an oxidizer has excelled in amoxicillin degradation. This paper aims at treating a synthetic solution of amoxicillin (0.1 g L-1) in a reactor with ozone bubbling. A Design of Experiment (DoE) with a response surface known as Central Composite Design (CCD) was used to optimize the treatment process. In addition, a Normal Boundary Intersection (NBI) method was used in the construction of a Pareto boundary chart. Results after 1-h treatment showed a reduction of 53% of the initial organic matter from a designed model using factors, such as pH, ozone generator power, and O3 flow. A model was built from the CCD with score of 0.9929. Thus, the model was able to represent the real scenario with confidence.