Sargassum in the Caribbean region has affected the livelihood of several coastal communities due to the influx of large quantities of the seaweed in recent times. This article seeks to explore how waste Sargassum natans can be utilized to produce sodium alginate. The novelty in this research lies in the optimization process, whereby multistage extraction and precipitation were investigated over commonly used single stage processing, in an effort to maximize both yield and purity. The results showed that a maximum yield of 19% was observed after 1 stage, while the purity was 74% after 4 stages. In addition, optimization of the multistage precipitation process using the Global Optimization Toolbox in MATLAB R2017b provided a novel model which indicated that a compromise between the maximum purity and yield can be obtained at 3 stages; 71-74% and 12-16% respectively. Furthermore, characterization was done using FTIR and NMR, with results comparable to a commercial sodium alginate brand, giving absorption bands at 1610 cm-1 and 1395 cm-1 and an M/G ratio of 0.51 respectively.

For much of the Caribbean, plastic pollution and the great Atlantic Sargassum belt has led to significant regional loss. To elevate these problematic areas, we present a novel calcium alginate bioplastic process from the lens of techno-economic and life cycle assessments.

Supplementing the increasing global methanol demand has forced traditional methanol processing to evolve towards mega-methanol production (MM). With strong legislative change supporting greater adherence to environmental quality, global producers will need to consider a more sustainable process design. Therefore, the need exists to identify viable pathways for the transition of the global methanol industry towards greater sustainability, utilizing existing infrastructure. Here we present a critical assessment of viable MM routes using steam reforming (SMR), combined reforming (CMR) and auto-thermal reforming (ATR), through techno-economics with insight into environmental and global impacts. Our results highlight ATR and CMR as more energy efficient designs, promoting greater environmental benefits. Economically, ATR cases benefit from smaller reforming capacities, providing a cheaper alternative over CMR and SMR designs. Utilization of a Planetary Boundary Framework (PB-LCIA) showed MM technologies transgress PBs affiliated with climate change and ocean acidification. Furthermore, these impacts worsen with increased methanol production, illustrating energy efficiency as a key performance indicator (KPI) that should strongly be considered during process optimization. Additionally, results emphasize industrial symbiosis as a solution to lowering environmental burden. Ultimately, decarbonization coupled with CO₂ utilization provides a viable pathway to the absolute sustainability of the MM process across all sustainability domains- with ATR emerging as the best performing technology. Thus, these results highlight critical energy considerations and environmental benefits, underpinning the global MM industry decision on potential sustainable development strategies.