Analysis of the technical and economic viability of upcycling sustainable fish waste for bioproduct production

The valorization of fish waste presents a promising avenue for sustainable resource utilization and economic value creation. In this regard, this paper conducted a comprehensive technoeconomic investigation into alternative technologies for the valorization of fish waste. Various technologies, including subcritical water hydrolysis, enzymatic hydrolysis, and anaerobic digestion, were considered in the analysis. Through economic modelling and sensitivity analyses using ASPEN Plus software, the feasibility and economic viability of different valorization strategies, designated as scenarios (a), (b), and (c) for the production of protein hydrolysate, electricity, protein hydrolysate, fatty acids, and electricity only, respectively, were assessed. The results revealed that utilizing subcritical water technology in scenario (b) yields the most economically viable strategy, with its positive Net Present Value (NPVs) of US$31.67 million indicating economic feasibility. Conversely, the NPVs of scenarios (a) and (c) of -US$24.95 million and of -US$12.09 million respectively demonstrated economic infeasibility. Further investigations into the economic viability demonstrated the important role of processing capacities and operating costs on economic feasibility. Despite challenges and uncertainties, the study underscores the potential for sustainable and economically viable utilization of fish waste, offering valuable insights for decision-makers in the seafood industry

A study of plasma-porous carbon-CO2interactions: Ammonia plasma treatment and CO2capture

Owing to its high porosity and tunable surface chemistry activated carbon (AC) is considered a promising material for CO2 adsorption. Functionalising porous materials by plasma is challenging but if successful, it could enhance the CO2 uptake capacity of AC via chemisorption. This work presents an in-depth analysis of the interactions between ammonia plasmas and the porous surface of AC monolithic samples. The treatment involved an ammonia based atmospheric-pressure dielectric barrier discharge and a low-pressure radio frequency plasma. Unique plasma reactor designs for treating 3-dimensional, electrically conducting and non-conducting monolithic structures at atmospheric pressure with versatile applications are presented. The plasma-surface interactions were analysed using emission spectroscopy and X-ray photoelectron spectroscopy. High surface N containing AC samples were then used to assess the treatment effect on the subsurface. A much lower although a still significant amount of N was found at depths of ∼30 μm. A simple fit of the results showed that the ratio of plasma species reaching the surface with higher to lower sticking probability was 4:1. A slight decrease in the microporosity of the plasma treated samples was found and attributed to pore blocking by the grafted N species. Plasma treated AC with high N showed an improved CO2 adsorption capacity of up to 14 % and selectivity against CH4 and N2 adsorption showed that the treatment was selective primarily towards CO2.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Understanding the role of sodium during adsorption. A force field for alkanes in sodium exchanged faujasites

We have developed a united atom force field able to accurately describe the adsorption properties of linear alkanes in the sodium form of FAU-type zeolites. This force field successfully reproduces experimental adsorption properties of n-alkanes over a wide range of sodium cation densities, temperatures, and pressures. The force field reproduces the sodium positions in dehydrated FAU-type zeolites known from crystallography, and it predicts how the sodium cations redistribute when n-alkanes adsorb. The cations in the sodalite cages are significantly more sensitive to the n-alkane loading than those in the supercages. We provide a simple expression that adequately describes the n-alkane Henry coefficient and adsorption enthalpy as a function of sodium density and temperature at low coverage. This expression affords an adequate substitute for complex configurational-bias Monte Carlo simulations. The applicability of the force field is by no means limited to low pressure and pure adsorbates, for it also successfully reproduces the adsorption from binary mixtures at high pressure

Improving the selectivity to 4-tert-butylresorcinol by adjusting the surface chemistry of heteropolyacid-based alkylation catalysts

Keggin tungstophosphoric acid (H3PW12O40, HPW) was immobilized onto Santa Barbara Amorphous (SBA-15) type silica to obtain selective catalysts for the resorcinol tert-butylation with methyl-tert-butyl ether. The challenge was to enhance the reaction selectivity to the mono-alkylated product i.e. 4-tert-butylresorcinol at the expenses of other more thermodynamically favored products as the 4,6-di-tert-butylresorcinol. Using HPW@SBA15 catalysts, remarkable selectivity to 4-tert-butylresorcinol was obtained, up to 42% (at 20% of resorcinol conversion). Our finding is that the change in the product distribution was dependent on the catalyst surface chemistry: 4TBR selectivity can be increased adjusting the fraction of Brønsted acid sites versus Lewis ones at the catalyst surface