The effluents of the sugar and bio-ethanol industry, mainly vinasse as well as lignocellulosic waste, are produced in high volumes. Therefore, their treatment and valorization would reduce the environmental impact and make this industry more productive and competitive. The purpose of this study was to determine the potential use of press mud (lignocellulosic waste), vinasse powder, and vinasse sludge from an extraction process with ethanol, as raw materials for conventional pyrolysis evaluating the physicochemical characteristics that affect this thermochemical process, such as calorific power, density, ash content, volatile material, moisture and nitrogen, sulfur, carbon and hydrogen content, thermogravimetric profile, and quantification of lignin cellulose and hemicellulose. The batch pyrolysis experiments showed that all three wastes could be converted successfully into more valuable products. The powder vinasse led to the formation of the lowest content of bio-char (42.7%), the highest production of volatiles (61.6 wt.%), and the lowest ash content (20.5 wt.%). Besides, it showed the high heating value of 15.63 MJ/kg. Meanwhile, the extraction sludge presented the highest liquid yield (32%) with the lowest gas formation (18.2 wt.%) and the lowest heating value of 8.57 MJ/kg. Thus, the sludge could be a good feedstock for production of bio-oil and bio-char.

El índigo carmín es uno de los componentes más contaminantes encontrados en los efluentes de la industria textil. Se exploró el desempeño del magnesio de alta pureza y la aleación AZ31 como ánodos de sacrificio en la electrocoagulación de soluciones de índigo carmín para la disminución de color y carbono orgánico disuelto (COD). Los experimentos se llevaron a cabo empleando un diseño factorial fraccionado a dos niveles con los siguientes factores: velocidad de agitación (cero y 840 rpm), temperatura (28 y 50 °C), concentración de colorante (100 y 300 mg/L) y densidad de corriente (20 y 50 A/m2). Como electrolito se utilizó NaCl y la magnitud de la carga eléctrica específica se mantuvo constante en 5,000 coulomb/litro (C/L). Se alcanzaron disminuciones cercanas al 99% en color y 84% en COD. Se evidenció que ambos materiales son competitivos en relación con la remoción de color y de COD alcanzadas.

Globally, an estimated 7.4 billion tons of plastic have accumulated, with projections suggesting this could escalate to 40 billion metric tons by 2050. Unfortunately, only about 10% of this plastic is recycled, due to the lack of sustainable and economical solutions [1]. Alarmingly, over 70% of plastic waste ends up in landfills or oceans where it gradually decomposes into small particles (average diameter less than 5 mm), often referred to as microplastics (MPs). This widespread presence of microplastics poses a significant hazard to global ecosystems and human health. Microplastics can be ingested by organisms through various pathways including consumption of contaminated food, inhalation of polluted air, and dermal contact [2]. Polyethylene terephthalate (PET), is the second most abundant plastic produced worldwide due to its extensive use in consumer packaging. Conventional mechanical recycling of PET often leads to the loss of its desirable properties [3]. Therefore, there is significant interest in chemical recycling technologies capable of depolymerizing PET. Through chemical hydrolysis at high temperatures, PET can be broken down into its constituent monomers, terephthalic acid and ethylene glycol. Nonetheless, the subsequent chemical separation of these products, particularly ethylene glycol (EG), presents challenges due to its high boiling point, viscosity, and water solubility, necessitating energy-intensive distillation processes. In response to this challenge, electrochemical methods have gained popularity for oxidizing PET hydrolysates into valuable products such as formic acid and glycolate, thereby offering a more sustainable pathway for upcycling [4]. However, most studies on electrochemical upcycling of PET still utilize a two-stage process. Initially, PET is hydrolyzed in a potassium hydroxide KOH solution at temperatures exceeding 80°C. Subsequently hydrolysate is used as an electrolyte to produce formate at the anode while hydrogen is produced at the cathode. Botte's group is investigating electrochemical approaches to convert plastics into valuable chemicals [5]. An effective enhanced electrocatalytic hydrolysis process for recycling PET waste into value-added chemicals was developed. This novel approach integrates the hydrolysis of PET with the concurrent electrochemical oxidation of ethylene glycol employing transition metals as catalyst and using mid temperature conditions. The effect of different variables on the overall conversion and the product distribution were evaluated. Operating time, voltage and particle size were varied, and the end products were characterized by FTIR, SEM, NMR, and IC. Our studies indicate that the electrochemical approach enhanced PET hydrolysis in comparison to traditional chemical hydrolysis [6] along with the oxidation of ethylene glycol into formic acid/formate in a single process eliminating the need for separate hydrolysis. Optimization of this process could be a sustainable approach for upcycling of PET microplastic into valuable products. [1] Li, M. and S. Zhang, Tandem Chemical Depolymerization and Photoreforming of Waste PET Plastic to High-Value-Added Chemicals. ACS Catal. 2024. 14(5): p. 2949-2958,doi: 10.1021/acscatal.3c05535. [2] E. Bäckström, K. Odelius, and M. Hakkarainen, “Trash to Treasure: Microwave-Assisted Conversion of Polyethylene to Functional Chemicals,” Ind. Eng. Chem. Res., vol. 56, no. 50, pp. 14814–14821, Dec. 2017, doi: 10.1021/acs.iecr.7b04091. [3] R. K. Brizendine et al., “Particle Size Reduction of Poly(ethylene terephthalate) Increases the Rate of Enzymatic Depolymerization But Does Not Increase the Overall Conversion Extent,” ACS Sustain. Chem. Eng., vol. 10, no. 28, pp. 9131–9140, Jul. 2022, doi: 10.1021/acssuschemeng.2c01961. [4] Y. Li, L. Q. Lee, H. Zhao, Y. Zhao, P. Gao, and H. Li, “Alcohol–alkali hydrolysis for high-throughput PET waste electroreforming-assisted green hydrogen generation,” J. Mater. Chem. A, vol. 12, no. 4, pp. 2121–2128, Jan. 2024, doi: 10.1039/D3TA05522A. [5] G. G. Botte, “Processes for electrochemical up-cycling of plastics and systems thereof,” WO2021257972A1, Dec. 23, 2021 Accessed: Jul. 21, 2023. [Online]. Available: https://patents.google.com/patent/WO2021257972A1/en [6] F. Lu and G. G. Botte, “Understanding the Electrochemically Induced Conversion of Urea to Ammonia Using Nickel Based Catalysts,” Electrochimica Acta, vol. 246, pp. 564–571, Aug. 2017, doi: 10.1016/j.electacta.2017.06.055.

Electrocoagulation consists of the in-situ generation of the coagulant by the electro dissolution of sacrificial electrodes (Mg and Al). This technique, besides being normally used for water treatment, can be used to synthesize Layered Double Hydroxides (LDH) or Hydrotalcites (HT) such as green rust, MgAlCl/LDH, and other oxides as Magnetite. The HT has a high tendency for water in the interlayer to be replaced by anions, these exchange characteristics generate a high interest in the fields of drug administration, photodegradation, catalyst supports, supercapacitors, and water oxidation. There are several routes of synthesis for these compounds such as co-precipitation, hydrolysis of urea, hydrothermal treatment and a novel route by electrocoagulation (EC). This work discloses the data of the energy consumption at laboratory-scale production in the synthesis of hydrotalcite (HT) or Layered Double Hydroxides (LDH) by electrocoagulation, the values obtained through these experiments are intended to provide support due to the lack of information on the energy consumption of this novel production method. Aluminum and AZ31 electrodes were used as a cations source during two- and four-hours operation, at 50 °C with 5 mA cm^-2 of current density, and 5 minutes of polarity change for Aluminum and 8 minutes for AZ31 (Magnesium alloy).

Formed from the fossilized remains of ancient plants, coal is a combustible sedimentary rock classified as a nonrenewable resource due to its extremely slow formation process. The chemical structure of coal contains diverse types of carbon, including aliphatic carbons, aromatic carbons, and carbonyl carbons [1], [2]. Coal is considered the most economical source of energy; however, its potential as a repository for valuable chemical compounds remains underutilized. Although solvent extraction offers a way to extract specific components from coal, it comes with limited extraction efficiencies and significant environmental, and economic drawbacks. Coal electrolysis is a process that utilizes electricity to break down and oxidize carbon structures in diverse ways, yielding liquid-phase products [3]. One key application of coal electrolysis is the production of hydrogen gas. Traditional methods, such as Indirect coal liquefaction (ICL) and Direct coal liquefaction (DCL), rely on high-temperature and high Pressure (ranging from 200-1450°C, 100-200 atm) respectively. In contrast, the technology known as the “Continuous Coal Electrolytic Cell (CEC)” facilitates the direct conversion of coal into valuable chemicals and liquid fuels at mild temperatures (25-180°C) and low pressures (1-2 atm) [4]. Therefore, this process could potentially be more efficient and less energy-intensive than conventional methods. In the CEC, electric power is applied to a coal-slurry to directly convert the coal into pure clean hydrogen, and organic compounds (liquid form), with minimum CO₂ emissions. During the CEC process, the surface of the coal particles (electrolyzed coal char) gets oxidized into lower molecular weight hydrocarbons than coal. Subsequently the electrolyzed coal char undergoes extraction to separate the liquid fuels and/or valuable chemicals. This technology has already proven that temperature and applied current are the most influential factors in maximizing hydrogen production. However, the conditions for obtaining various liquid-phase products have not yet been optimized. In this study, the effect of coal particle size during electrolysis and the subsequent extraction process was explored more in-depth specifically to determine the characteristic of the liquid extracted. Three coal particle size were electrolyzed using Pt-Ir catalyst, followed by extraction using two different solvents. The changes in the main functional groups of coal particles were studied by FTIR, while proximate analysis and carbon structure were analyzed by TGA/DSC and CHNS, SEM and XRD, respectively. Our findings reveal the distribution of sulfur and nitrogen after electrolysis and the benefits of solvent selection since it is known that the solvent influences the interaction between organic and mineral matter. By demonstrating that coal electrolysis, combined with extraction, can remove valuable chemicals, new market opportunities emerge for coal across various applications. [1] D. Jing, X. Meng, S. Ge, T. Zhang, M. Ma, and G. Wang, “Structural Model Construction and Optimal Characterization of High-Volatile Bituminous Coal Molecules,” ACS Omega, vol. 7, no. 22, pp. 18350–18360, May 2022, doi: 10.1021/acsomega.2c00505. [2] X. Gong, M. Wang, Y. Liu, Z. Wang, and Z. Guo, “Variation with time of cell voltage for coal slurry electrolysis in sulfuric acid,” Energy, vol. 65, pp. 233–239, Feb. 2014, doi: 10.1016/j.energy.2013.11.083. [3] S. Chen, W. Zhou, Y. Ding, G. Zhao, and J. Gao, “Coal-Assisted Water Electrolysis for Hydrogen Production: Evolution of Carbon Structure in Different-Rank Coal,” Energy Fuels, vol. 35, no. 4, pp. 3512–3520, Feb. 2021, doi: 10.1021/acs.energyfuels.0c04122. [4] X. Jin and G. G. Botte, “Feasibility of hydrogen production from coal electrolysis at intermediate temperatures,” J. Power Sources, vol. 171, no. 2, pp. 826–834, Sep. 2007, doi: 10.1016/j.jpowsour.2007.06.209.