O interesse em utilizar a biomassa para produção de energia tem crescido consideravelmente. Além do reaproveitamento de resíduos de indústrias agrícolas e alimentícias a energia da biomassa evita o aumento de dióxido de carbono na atmosfera. A biomassa residual pode ser utilizada de diversas maneiras com o objetivo de gerar energia. Uma delas, e talvez a mais eficiente, é a produção de hidrogênio. O estudo da produção de hidrogênio por fontes alternativas cresceu nos últimos anos em função da necessidade da utilização de fontes renováveis e do desenvolvimento tecnológico de células a combustível. Dentre várias alternativas, a gaseificação em água supercrítica tem a vantagem de não ser específica para determinado resíduo (agrícolas ou de efluentes de processos diversos). Durante a gaseificação em água supercrítica, ou seja, em temperaturas e pressões maiores ou iguais a 374 °C e 22.1 MPa, respectivamente, são produzidos em grande parte hidrogênio (H2) e dióxido de carbono (CO2). No entanto, por atingir temperaturas e pressões elevadas, os materiais para construção e manutenção da planta de produção merecem atenção especial e o alto custo operacional torna-se o maior obstáculo para o desenvolvimento desta tecnologia. Contudo, verifica-se que, além de grande eficiência energética, a utilização de hidrogênio em células a combustível gera apenas água como subproduto, tornando, portanto, a substituição de processos que utilizam combustíveis fósseis por processos que utilizem fontes alternativas, conveniente e oportuna. A tecnologia de geração de hidrogênio em água supercrítica atende a esse anseio e novos estudos vêm sendo realizados para torná-la mais viável.

We investigated antifungal properties of two kraft-pulping liquors as potential environmentally friendly wood preservatives targeting in deterioration by white rot (WRF) and brown rot fungi (BRF). The in vitro antifungal activity of crude black liquor (BL) and the product from a hydrothermal gasification (BLW_Supc) process were investigated. Both products showed high bioactivity, with BL completely inhibiting the activity of WRF and BRF; 80% was entirely suppressed at low BL concentrations (5–10% vol/vol). Using the BLW_Supc at 2.55% wt/wt, we achieved the same inhibitory effect as BL (15% vol/vol) for the two fungi. These antifungal effects can be explained by the composition of liquors that act as antioxidants, promoting enzymatic inactivation and inhibiting the growth of WRF and BRF. BLW_Supc exhibited radical quenching activity against DPPH of 43.9%, and the BL, a phenolic content about 20 times higher (23.635 mg/L) than BLW_Supc (2.093 mg/L), suggesting that antifungal activity of BL and BLW is related to their chemical composition. An opportunity demonstrated by this study is the reuse of BLW_Supc as a protective treatment within a sustainable chain.

The recycling of spent lithium-ion batteries and selected complex electronic waste fractions is commonly evaluated using isolated metrics such as leaching yield, metal removal efficiency, and reagent consumption. However, this approach fails to address the central challenge of sustainable valorization: integrating upstream conversion with downstream selective recovery without shifting environmental and separation burdens. This review focuses specifically on spent LIBs as the primary model system, while also drawing insights from related e-waste streams (e.g., printed circuit boards and polymer-containing residues) where the interface-driven framework applies. It examines how key interfaces—solid–fluid, polymer–metal–fluid, membrane–solution, electrode–electrolyte, and crystal–solution—govern metal mobilization, selectivity, effluent quality, product purity, and scalability. Emphasis is placed on hydrothermal and supercritical water processing, PVC/CPVC (Polyvinyl Chloride/Chlorinated Polyvinyl Chloride)-assisted metal mobilization and membrane-based recovery techniques, including nanofiltration, membrane distillation, membrane distillation crystallization, ion exchange, and electrochemical methods. Supercritical water and membrane processes are complementary only when upstream chemistry is designed to facilitate downstream separation. PVC-rich waste is reconsidered as a reactive chlorine source, provided that corrosion, HCl formation, and salt precipitation are controlled. Critical gaps include incomplete mass balances, limited multicomponent studies, weak integration between process stages, and scarce techno-economic and life-cycle analyses. A roadmap is proposed for scalable, integrated hydrothermal–membrane systems enabling efficient resource recovery and water reuse.

Thermodynamic equilibrium modeling is a useful approach for predicting gas production during supercritical water gasification (SCWG) of wet biomass; however, Gibbs energy minimization can be computationally demanding for repeated process simulations. This study developed an artificial neural network (ANN) surrogate model to predict the equilibrium yields of H₂, CO, CO₂, and CH₄ during SCWG of açaí residual biomass from Maranhão, Brazil. Four biomass samples collected under different geographical and seasonal conditions were characterized by ultimate analysis and used to generate a thermodynamic database with 1,000 simulations per sample using the TeS-Thermo PyPI Python library. The ANN comprised 10 input variables, two hidden layers with 12 and 6 neurons, and 4 output neurons, and was trained using the Levenberg–Marquardt algo-rithm. The selected ANN achieved R² values of 0.99989, 0.99553, 0.99957, and 0.99963 for H₂, CO, CO₂, and CH₄, respectively. External validation using an independent biomass composition provided evidence of the ANN's generalization capability within the in-vestigated compositional domain, with R² values above 0.98 for all four species. Sensi-tivity analyses further demonstrated that the ANN reproduced the effects of temperature (700–1100 K), water-to-biomass molar ratio (3–6 mol mol⁻¹), and pressure (230–260 bar), with low deviations from TeS-Thermo predictions. These results demonstrate that the ANN provides an accurate and computationally efficient surrogate model for rapid thermo-dynamic screening, sensitivity analysis and process optimization of SCWG biomass processes.