Production of formalin, which is among the highest production volume chemicals, is highly energy-intensive; thus, reduction of energy use is very important in reducing cost and emissions. The aim of this and its larger overall research is to systemically analyze how to improve sustainability of processes producing formalin as an intermediate or final product. In this part of the work, energy consumption requirements are analyzed for the conventional formalin production process via methane steam reforming, where opportunities for energy consumption reduction are identified. This work will serve as a base case for further investigation of alternative formalin production pathways. To achieve energy savings, heat integration technology by combined pinch analysis and mathematical programming is applied. The formalin production process is simulated using Aspen HYSYS, and heat integration of the production process was performed based on simulated design using GAMS software. Economic and environmental footprint analyses were performed for both non-integrated and integrated designs. Results show that heat integration reduces heat consumption by around 39%, leading to a saving of 11% in capital cost and turning annual operating cost into positive revenue. Heat integration also improves the environmental aspect, where a 7–22% reduction in selected environmental footprints is achieved.

Microplastics (MPs) that are ubiquitous in aquatic environments and industrial wastewater streams have been identified as key hotspots of MP contamination. It is significantly more effective to remove MPs at these points before they enter municipal wastewater streams. This study is an environmental assessment of a novel pilot plant for the removal of MPs and the chemical oxygen demand (COD) from wastewater with a high MP contamination from a plastics manufacturer in Germany. MP removal is based on physical–chemical agglomeration–fixation by organosilanes. Formed agglomerates are separated using a belt filter. The COD is removed by an adsorption process. The resulting MP removal was 98.0 ± 1.1% by mass and 99.9987 ± 0.0007% by particle count, while the COD was reduced by 96 ± 2.7%. The system’s sustainability is evaluated using the Life Cycle Assessment methodology, evaluating system construction, operation, and end-of-life considerations. The current pilot plant is also compared to an optimized circular and sustainable upgrade, where drivers of environmental burdens are eliminated and collected MPs are reused. Significant reductions in environmental impact categories are achieved and the global warming potential is reduced by 96%. This study provides a sustainability assessment of a novel technology and circular solution to remove MPs from highly polluted industrial wastewater.

Chitosan, one of the significant marine polysaccharides, has attracted widespread attention due to its excellent biocompatibility and broad application prospects. This study proposes a novel green extraction method based on Brønsted acid-base deep eutectic solvents (DESs) for the efficient production of chitosan from the exoskeleton of blue crabs, achieving a green alternative to traditional inorganic acid-base chemical processes. Unlike conventional processes, this study innovatively replaces inorganic acids with acidic DESs and sodium hydroxide with alkaline DES, establishing an environmentally friendly deacetylation route. The effects of four different acidic DESs on chitosan purity were systematically compared. The produced chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and nuclear magnetic resonance (¹H NMR). Characteristic NMR peaks at 4.6 and 4.8 ppm confirm the formation of glucosamine structures, indicating that the purity of the resulting chitosan is comparable to that of commercial one. Furthermore, this study established a process technology roadmap and life cycle assessment (LCA) model to identify environmental impact hotspots during the extraction process. The results showed that electricity consumption during the manufacturing phase was the primary source of environmental burden, providing clear guidance for subsequent energy optimization and industrial scale-up.