Production of activated carbon from agave residues and its synergistic application in a hybrid adsorption-AOPs system for effective removal of sulfamethazine from aqueous solutions.

Tequila production in Mexico generates large quantities of agave bagasse (AB), a waste that could be used more efficiently. AB has a high cellulose, hemicellulose, and lignin content, which allows its use as a precursor for synthesizing carbonaceous materials. In the present work, the synthesis of activated carbon impregnated with Fe2+ (AG-Fe-II) and Fe3+ (AG-Fe-III) was carried out and evaluated in a hybrid adsorption-AOP (advanced oxidation process) methodology for sulfamethazine removal (SMT). The materials were characterized before and after the process to determine their morphological, textural, and physicochemical properties. Subsequently, the effect of the main operational variables (pH, initial SMT concentration, mass, and activator dosage) on the hybrid adsorption-degradation process was studied. The Fenton-like reaction was selected as the AOP for the degradation step, and potassium persulfate (K2S2O8) was used as an activating agent. The main iron crystallographic phases in AG-Fe-II were FeS, with a uniform distribution of iron particles over the material's surface. The main crystallographic phase for AG-Fe-III was Fe3O4. The hybrid process achieved 61% and 78% removal efficiency using AG-Fe-II and AG-Fe-III samples, respectively. The pH and initial SMT concentration were the most critical factors for removing SMT from an aqueous phase. Finally, the material was successfully tested in repeated adsorption-degradation cycles.

Application of artificial intelligence for the optimization of advanced oxidation processes to improve the water quality polluted with pharmaceutical compounds.

Sulfamethoxazole and metronidazole are emerging pollutants commonly found in surface water and wastewater. These compounds have a significant environmental impact, being necessary in the design of technologies for their removal. Recently, the advanced oxidation process has been proven successful in the elimination of this kind of compounds. In this sense, the present work discusses the application of UV/H2O2 and ozonation for the degradation of both molecules in single and binary systems. Experimental kinetic data from O3 and UV/H2O2 process were adequately described by a first and second kinetic model, respectively. From the ANOVA analysis, it was determined that the most statistically significant variables were the initial concentration of the drugs (0.03 mmol L-1) and the pH = 8 for UV/H2O2 system, and only the pH (optimal value of 6) was significant for degradation with O3. Results showed that both molecules were eliminated with high degradation efficiencies (88-94% for UV/H2O2 and 79-98% for O3) in short reaction times (around 30-90 min). The modeling was performed using a quadratic regression model through response surface methodology representing adequately 90 % of the experimental data. On the other hand, an artificial neural network was used to evaluate a non-linear multi-variable system, a 98% of fit between the model and experimental data was obtained. The identification of degradation byproducts was performed by high-performance liquid chromatography coupled to a time mass detector. After each process, at least four to five stable byproducts were found in the treated water, reducing the mineralization percentage to 20% for both molecules.

A systematic review on the current situation of emerging pollutants in Mexico: A perspective on policies, regulation, detection, and elimination in water and wastewater.

Emerging pollutants (EPs) emerged as a group of new compounds whose presence in the environment has been widely detected in Mexico. In this country, different concentrations of pharmaceutical compounds, pesticides, dyes, and microplastics have been reported, which vary depending on the region and the analyzed matrix (i.e., wastewater, surface water, groundwater). The evidence of the EPs' presence focuses on the detection of them, but there is a gap in information regarding is biomonitoring and their effects in health in Mexico. The presence of these pollutants in the country associated with lack of proper regulations in the discharge and disposal of EPs. Therefore, this review aims to provide a comprehensive view of the current environmental status, policies, and frameworks regarding Mexico's situation. The review also highlights the lack of information about biomonitoring since EPs are present in water even after their treatment, leading to a critical situation, which is high exposure to humans and animals. Although, technologies to efficiently eliminate EPs are available, their application has been reported only at a laboratory scale thus far. Here, an overview of health and environmental impacts and a summary of the research works reported in Mexico from 2014 to 2023 were presented. This review concludes with a concrete point of view and perspective on the status of the EPs' research in Mexico as an alert for government entities about the necessity of measures to control the EPs disposal and treatment.

Advances in the development of tailor-made color alcoholic beverages based on an accelerated maturation process.

The study of the evolution of color of alcoholic beverages subjected to accelerate maturation process using heat-treated French oak wood fragments is presented. The results show that it is possible to obtain tonalities like aged beverages in 4 weeks. In this sense, the fragments conditioned at 150 °C (light toasted) proportionated colors like white wine, pale straw, and pale gold. On the other hand, the fragments that received a heat treatment at 200 °C (medium toasted) present yellow tones such as old gold, amber, and deep gold. Finally, the fragments treated at 250 °C (heavily toasted) are those with the most intense yellow tones, classified as sweet chestnut, sherry, russet, muscat, and tawny. The studies of kinetic maturation concluded that the mathematical model of parabolic diffusion could correctly describe the process. Based on this, it is concluded that the heat treatment increases the cavities of the most exposed surface of the wood, increasing the maximum humidity of the materials by 20 %; in such a way that during the first two weeks, there is a diffusion of the solution to the active sites. Wood bioactive compounds on the outer surface achieve a rapid extraction, such as flavonoids, which oxidize rapidly within the solution, generating an increase in yellow color. The previous results were corroborated in a real case analysis using Tequila which can be concluded that the proposed process can give the beverage similar colors to an aged, extra-aged, and ultra-aged class in less than 4 weeks.

A Current Review of Water Pollutants in American Continent: Trends and Perspectives in Detection, Health Risks, and Treatment Technologies.

Currently, water pollution represents a serious environmental threat, causing an impact not only to fauna and flora but also to human health. Among these pollutants, inorganic and organic pollutants are predominantly important representing high toxicity and persistence and being difficult to treat using current methodologies. For this reason, several research groups are searching for strategies to detect and remedy contaminated water bodies and effluents. Due to the above, a current review of the state of the situation has been carried out. The results obtained show that in the American continent a high diversity of contaminants is present in the water bodies affecting several aspects, in which in some cases, there exists alternatives to realize the remediation of contaminated water. It is concluded that the actual challenge is to establish sanitation measures at the local level based on the specific needs of the geographical area of interest. Therefore, water treatment plants must be designed according to the contaminants present in the water of the region and tailored to the needs of the population of interest.

Development of a Predictive Model for Agave Prices Employing Environmental, Economic, and Social Factors: Towards a Planned Supply Chain for Agave-Tequila Industry.

The interest of consumers to acquire Tequila has caused an increase in its sales. As demand increases, the Tequila industry must obtain its raw material at a constant rate and agave farmers must be prepared to satisfy this supply chain. Because of this, modernization of the strategies used to ensure a planned, scheduled, timely, and predictable production will allow farmers to maintain the current demand for Tequila. This has been evidenced in official historical records from 1999 to 2020 where there is a fluctuation in the price of agave due to supply and demand. Given this scenario, this research shows the development of a multivariable predictive mathematical model that will permit the agave−Tequila production chain to work based on a smart implementation of planned actions to guarantee the agave supply to the Tequila industry. The proposed model has a goodness of fit (R = 0.8676; R¯2 = 0.8609; F(1,20) = 131.01 > F0.01 (1,20) = 8.10) and demonstrates the impact on agave prices is due to several factors: Tequila exports (α = 0.50) > agave plants harvested "jima" (α = 0.44) > dollar exchange (α = 0.43) > Tequila production (α = 0.06) > annual accumulated precipitation (α = 0.05). Nevertheless, the price forecast can be influenced by climate change or economic crises that affect the supply chain. In conclusion, a prediction of agave price stabilization for five years is shown where authorized producers can evaluate future scenarios so that the agave supply chain can be guaranteed for Tequila production, facilitating the decision making regarding its raw material.

Elucidation of adsorption mechanisms and mass transfer controlling resistances during single and binary adsorption of caffeic and chlorogenic acids.

In this work, the potential of activated carbon to remove caffeic and chlorogenic acids in aqueous solution was investigated. The study focused on evaluating the single and binary adsorption equilibrium, as well as investigating the mass transfer resistances present during the process by applying diffusional models for a future scale-up of the process. For both compounds, the single adsorption equilibrium was studied at pH values of 3, 5, and 7. The experimental adsorption isotherms were interpreted using the Langmuir and Freundlich models, obtaining maximum adsorption capacities of 1.33 and 1.62 mmol/g for caffeic and chlorogenic acid, respectively. It was found that the adsorption mechanisms for both compounds were derived from π-π, electrostatic, and H-bonding interactions. Also, the binary adsorption equilibrium was performed, and the experimental data were interpreted using the extended multicomponent Langmuir model. The results evidenced that the binary adsorption of caffeic acid and chlorogenic acid is antagonistic in nature. Finally, the experimental adsorption rate data were interpreted by an external mass transport model and a diffusional model, finding that the overall adsorption rate is governed by intraparticle diffusion. Moreover, the surface and pore volume diffusion mechanisms were meaningful.

Evaluation of the Environmental Performance of Adsorbent Materials Prepared from Agave Bagasse for Water Remediation: Solid Waste Management Proposal of the Tequila Industry.

In the present research work, the use of agro-industrial waste such as agave bagasse from the tequila industry was carried out. The agave bagasse was treated to obtain biosorbent and hydrochar materials. Direct Blue 86 was used as an adsorbate model to evaluate the performance of both materials. The adsorption studies showed an adsorption capacity of 6.49 mg g−1 in static and 17.7 mg g−1 in dynamic, associated with a physisorption process between functional groups of the material and the dye. The characterization of the biosorbent showed that the material was mainly composed of macroporous fibers with a surface area <5.0 m2 g−1. Elemental analysis showed a majority composition of C (57.19 wt%) and O (37.49 wt%). FTIR and XPS analyses showed that the material had C-O, C=O, -OH, O-C=O, and -NH2 surface groups. RAMAN and TGA were used to evaluate the composition, being cellulose (40.94%), lignin (20.15%), and hemicellulose (3.35%). Finally, the life-cycle assessment at a laboratory scale showed that the proposed biosorbent presents a 17% reduction in several environmental aspects compared to hydrochar, showing promise as an eco-friendly and highly efficient method for the remediation of water contaminated with dye, as well as being a promising alternative for the responsible management of solid waste generated by the tequila industry.

Effect of Age of Agave tequilana Weber Blue Variety on Quality and Authenticity Parameters for the Tequila 100% Agave Silver Class: Evaluation at the Industrial Scale Level.

Due to the oversupply and scarcity cycles of the Agave tequilana Weber blue variety, the effect of agave age (harvested in 4, 5, and 6 years) as raw material for the tequila 100% agave silver class was studied for each stage in a full-scale (industrial) process. Harvested plants showed differences in their morphological characteristics that affected the amount of juice; this had an impact in the fermentation stage since must composition was modified in the nitrogen content and juice/exudate ratio. This was noticed due to an increase in the production of higher alcohols attributed to the odd-chain fatty of the exudate, which affects n-propanol production. The characterization of the final product showed the feasibility to use agaves (less than 7 years) to produce the Tequila 100% agave silver class and to comply with the quality criteria. Furthermore, the final product was analyzed with the gas chromatography-isotope ratio mass-spectrometry technique to determine its authenticity. The δ13CVPDB isotopic parameter (-13.40‱ in average) values show the type of plant used as a raw material for ethanol production, while the δ18OVSMOW (20.52‱ in average) isotopic parameter can be helpful in corroborating and ensuring the traceability of the product and the geographical location of the beverage production.

Influence of Surface Chemistry on the Electrochemical Performance of Biomass-Derived Carbon Electrodes for its Use as Supercapacitors.

Activated carbons prepared by chemical activation from three different types of waste woods were treated with four agents: melamine, ammonium carbamate, nitric acid, and ammonium persulfate, for the introduction of nitrogen and oxygen groups on the surface of materials. The results indicate that the presence of the heteroatoms enhances the capacitance, energy density, and power density of all samples. The samples treated with ammonium persulfate show the maximum of capacitance of 290 F g-1 while for the melamine, ammonium carbamate, and nitric acid treatments, the samples reached the maximum capacitances values of 283, 280, and 455 F g-1 respectively. This remarkable electro-chemical performance, as the high specific capacitances can be due to several reasons: i) The excellent and adequate textural characteristics makes possible a large adsorption interface for electrolyte to form the electrical double layer, leading to a great electrochemical double layer capacitance. ii) The doping with hetero-atoms enhances the surface interaction of these materials with the aqueous electrolyte, increasing the accessibility of electrolyte ions. iii) The hetero-atoms groups can also provide considerable pseudo-capacitance improving the overall capacitance.

Towards understanding of heterogeneous Fenton reaction using carbon-Fe catalysts coupled to in-situ H2O2 electro-generation as clean technology for wastewater treatment.

Iron-supported catalyst on granular activated carbon was prepared for its use in heterogeneous Fenton reaction coupled to an in situ H2O2 electro-generation. For this process, an electrolysis cell was employed, using carbon felt as cathode and graphite as anode. A solution of H2O2 (electrogenerated at a rate of 30 mg L-1 h-1) was obtained using a current intensity of 12 mA. In order to promote the decomposition of H2O2 to OH, a Carbon-Fe catalyst was used. This catalyst was prepared by incipient wet impregnation using FeSO4 as precursor salt to obtain samples with 9% wt of iron. Samples were characterized by EDX, FTIR and XPS spectroscopy before and after wastewater treatment using phenol as model molecule. Two iron oxidation states on the samples were found, Fe2+ and Fe3+. The ratio between Fe2+/Fe3+ was 1.29 which was later reduced to 0.92 after Fenton process; this might be associated with the metal oxidation (Fe2+ to Fe+3) occurring during Fenton-reaction, thus indicating that H2O2 decomposition was carried out by Fe2+ on carbon surface. Detection and quantification of hydroxyl radical were carried out by fluorescence spectroscopy, obtaining a radical concentration of 3.5 µM in solution. Iron in solution were determined, showing a concentration of 0.1 mg L-1, making evident that the supported metal is stable and the reaction is carried out in a heterogeneous phase. Results showed an environmentally friendly process that can generate reagents in situ, with high efficiencies in the degradation of pollutants and minimizing the formation of toxic byproducts, which are common in conventional treatments.