Clean Technologies

The objective of this study was to valorise eggshell waste (ESW) by investigating its biosorption properties and evaluating its efficiency as a sustainable biosorbent for the removal of the synthetic dye Congo Red (CR) from model CR solutions and synthetic wastewater with the addition of CR. Batch biosorption experiments were conducted to investigate the influence of several factors on the biosorption process, including ESW concentration (1–15 g L⁻¹), contact time (1–360 min), temperature (15, 25, 35, 45 °C) and initial CR concentration (10–100 mg L⁻¹). Desorption experiments were performed using ultrapure water, 0.1 M NaCl, 50% ethanol, 0.1 M HCl, or 0.1 M NaOH as solvents. A higher ESW concentration improved CR removal, but the amount of CR adsorbed on ESW decreased. The dye uptake by ESW was increased with prolonged contact time and temperature increase. When the effect of CR initial concentration was investigated, the results indicated that the process is concentration-dependent and that overall, CR uptake by ESW was higher in synthetic wastewater than in the model dye solution. The biosorption process was better described by the Langmuir isotherm model than by the Freundlich model, indicating monolayer adsorption. Kinetic analysis showed that the pseudo-second-order model provided a better fit than the pseudo-first-order model. Desorption of CR from ESW under the applied experimental conditions was generally low (0.67–27.13%).

A system dynamics approach is described to explore the path of Carbon Capture diffusion. The proposed model, in principle, follows the Bass diffusion of innovation theory and includes all major influencing factors. The primary contribution of this paper is the modification of Bass’s model to reflect parameters affecting the adoption of Carbon capture and storage technology. Consequently, it differs from other extensions to Bass’s model. The underpinning of this work is the system dynamics (SD) approach, which can open a pathway for further research into CCS acceptance. The proposed model’s behaviour is illustrated for various transition pathways of the technology, for different regimes. By modifying the proposed model, the paper also allows consideration of various capturing technologies on their merit. The proposed framework enables the examination of the impact of intervention policies on the adoption of CCS by individual investors. The purpose is to identify the parameters of these policies to support the under-resourced CCS technology and reduce the need for government participation. It is worth noting that the SD is primarily a descriptive method used for scenario analysis to illustrate what the future would look like.

The Arctic is warming three to four times faster than the global average. This is transforming global maritime routes, thereby increasing shipping and resource extraction in Alaska. This surge requires sustainable energy solutions as policy trends towards stricter emissions standards. This article assesses the potential of Geothermal-to-X (GtX) technologies in establishing clean refueling infrastructure across Alaska, using its untapped geothermal resources. GtX uses electrolysis to split water into hydrogen and oxygen, a process powered by geothermal energy. Hydrogen and its X products, such as green methane or green ammonia, can be stored as fuels and are largely recognized as the key to a carbon-free future to address the growing energy demand. This study assesses the technical, economic, strategic, and geological feasibility of GtX refueling hubs in Alaska. Five locations were denoted as potential candidates and beckon future research. This study concludes that Unalaska is the most viable initial GtX hub given the highest Multi Criteria Decision Analysis (MCDA) score from its combination of a high-quality geothermal resource, an existing and accessible deepwater port, and a sizable local energy demand. The goal of this study is to provide an accessible and comprehensive resource for stakeholders and policymakers, outlining an energy future with sustainable maritime development, powered by affordable and secure energy.