Concerns relating to the potential environmental and land-use impacts associated with terrestrial energy crops have sparked an interest in the alternative use of marine feedstocks, such as seaweed (macroalgae). In contrast to terrestrial crops farming seaweed does not require the input of freshwater or chemical fertiliser and does not compete for land required by food crops. Seaweed remains a largely untapped source of valuable polysaccharides, proteins, fatty acids, and pigments which can be purified, or used as feedstock in the production of platform chemicals. Recently, Life cycle assessment (LCA) has been used to evaluate the potential environmental impacts arising from the use of seaweed feedstocks, predominately in the production of bioenergy. There are a range of different methods which can be used to cultivate and harvest seaweed for further downstream processing. These include land- and tank-based methods, nearshore and offshore cultivation, as well as integrated multitrophic aquaculture. As interest in seaweed cultivation in Europe grows, it is important to understand the associated environmental impacts. To date, a number of LCAs have assessed these different cultivation methods, either in isolation or as part of a wider seaweed biorefining product system. This work aims to bring these studies together—identifying where specific environmental hotspots lie within the cultivation and harvesting processes, and to understand the role of different design aspects. Overall, this review identifies challenges relating to future cultivation system design and LCA methodology.

The increasing demand for sustainable energy systems (SES) has driven significant advancements in the fields of techno-economic analysis (TEA) and life cycle assessment (LCA). This comprehensive review explores the integration of machine learning (ML) techniques into these assessments to address inherent data limitations and uncertainties. TEA and LCA methods are enhanced through ML's predictive modeling, optimization algorithms, and data analysis capabilities, providing more precise and efficient evaluations of SES. The review's scope includes recent TEA and LCA of SES to understand gaps in current practices, and ML SES studies that address these practices. Our literature search identified only three papers integrating TEA, LCA, and ML. Many studies investigate combinations of TEA or LCA with ML. However, there are unique challenges and opportunities for considering all three aspects of SES. Thus, we propose near- and long-term opportunities to further integrate ML with TEA and LCA. Key case studies demonstrate the transformative potential of ML in improving economic viability and environmental sustainability, highlighting its role in predicting system performance, optimizing configurations, and reducing costs and impacts. The review identifies critical areas for future research, including improving data quality, advancing ML techniques, interdisciplinary training, real-world applications, and policy considerations. This integration represents a significant advancement in the field, offering new opportunities for innovation and optimization in sustainable energy technology assessments.

Solid-state proton conduction has gained considerable attention owing to its importance in various fields, including the proton exchange membrane fuel cell (PEMFC), which serves as an efficient renewable energy resource. Recently, graphene materials have been explored as proton-conducting membranes/solids, which are the fundamental element of PEMFCs. Due to its structural diversity and tunable properties, it provides multiple channels for the mobility of protons. This perspective offers the design strategies that have been employed in order to enhance the proton conductivity of graphene-based materials. It also provides further scope for fabricating better proton-conducting materials for real-world applications.

Advancement of new materials for hydrogen generation and storage under mild conditions has very high desirability in both application and fundamental aspects. One of the main reasons to attain large scale hydrogen production is the accessibility of highly stable and active electrocatalysts. Alloy strategies can embrace the hardships of enhancing electrocatalysts activity and optimizing their costs. In this review, recent developments on alloy based electrocatalysts for hydrogen evolution and storage have been thoroughly discussed. Firstly, the advancements in the synthesis of alloy based electrocatalysts have been reviewed, afterwards the recent reports on binary and ternary alloy electrocatalysts for hydrogen evolution reaction and storage have been summarized. However, for their adoption at an industrial scale, it is important to ensure that these electrocatalysts demonstrate long-term stability and sustainability. While this work highlights the exceptional properties of alloy-based electrocatalysts, it also addresses the remaining challenges, such as scalability, durability, and cost-effectiveness that must be overcome to fully realize their potential in practical applications.

Membrane technology has numerous applications in potable water generation, wastewater (WW) reuse, desalination, and many others. However, the manufacture of membranes generates solvent-contaminated WW, especially via the non-solvent-induced phase separation method. Here, we tested the suitability of different microalgae to clean up membrane manufacturing WW and reuse it for subsequent membrane fabrication. Specifically, we determined the toxicity of six organic solvents to four different microalgae (Tetradesmus, Scenedesmus, Chlamydomonas, and Galdieria) and observed that all were able to tolerate solvent contaminant concentrations common to membrane manufacture with varying growth rates. Removal of triethyl phosphate varied greatly between strains, with >50% removal by cultures of Chlamydomonas and Galdieria, whereas PolarClean was almost entirely removed by Chlamydomonas, Tetradesmus and Scenedesmus. The four algae mentioned above, and two others, Monoraphidium and Chlorella were additionally grown in contaminated membrane manufacture WW, where the Tetradesmus, Scenedesmus and Chlorella removed PolarClean entirely, regardless of CO₂ supplementation. The reuse of Scenedesmus-treated WW in a subsequent membrane fabrication did not affect the physicochemical properties of produced membranes, and the morphology of these membranes was comparable to control conditions. We observed that using photosynthetic microbes to clean membrane manufacture WW enables the generation of their valuable biomasses and the reuse of treated water for further membrane fabrication. Our results indicate that coupling biodegradable solvents and algal cultivation can enable circularity and reduce solvent emissions from membrane manufacturing processes.

The conventional blast furnace (BF) ironmaking and coal-to-methanol (CTM) process both suffer from high energy consumption and significant carbon emissions. In this work, a novel coal gasification, flash ironmaking, and methanol synthesis coupled process (CG-FI-MS) was proposed and designed to simultaneously obtain high-quality iron metal and methanol. The new process contains eight units: air separation, CG-FI, smelting reduction, water gas shift, acid gas removal, CO₂ compression, Claus unit, MS and purification unit. The impact of critical operating parameters on the CG-FI unit was investigated including iron ore/coal, oxygen/coal, and steam/coal ratios. The thermodynamic properties and techno-economic analysis of the proposed process were examined. The analysis demonstrated that the optimum operating conditions for a flash ironmaking furnace were using iron ore/coal = 1.43, oxygen/coal = 0.79, and steam/coal = 0.01. 1 million tonnes of iron and 0.7 million tonnes of methanol as a basis for techno-economic analysis, the CO₂ emissions of the CG-FI-MS process decreased considerably by 74%, compared to conventional CTM and BF processes with the same methanol and iron yields. The energy and exergy efficiencies were 74.69% and 70.60%, respectively. The total capital investment and total production cost of the CG-FI-MS process are 1058 million and 494 million, respectively. The internal rate of return, payback period, net present value, and return on investment are estimated as 26%, 1018 million, 22.65%, and 3.20 years based on current prices, respectively. Meanwhile, the influences of coal and iron ore prices and iron and methanol prices on economic performance are explored.

In this study, a circular solution to enhance the food and water nexus by using a zero-waste process to produce carboxylated nanocellulose adsorbents from a model lignocellulose feedstock (jute) for ammonium (NH₄⁺) nutrient recovery and reuse was demonstrated. The study represents a new pathway to close the nitrogen loop that will be suitable for some agricultural practices. In specific, anionic nanocellulose containing COO⁻ groups, produced by the nitro-oxidization process, are efficient for removing NH₄⁺ from contaminated water, where the spent adsorbent can be repurposed as an effective plant fertilizer. The nitro-oxidized cellulose nanofiber (NO-CNF) scaffold prepared from raw jute exhibited a maximum adsorption capacity of 22.7 mg g⁻¹ for NH₄⁺ removal, which is significantly higher than any natural sorptive materials reported thus far, including biochar and activated carbons. The effect of pH (from 2 to 10) on the ammonium adsorption efficiency and the corresponding zeta potential of NO-CNF was investigated, where the optimal adsorption capacity was near neutral pH conditions. The zeta potential of ammonium-loaded NO-CNF was found to covert from a negative value (−50 mV) to a positive value (100 mV) with the increasing ammonium content at a critical NH₄⁺:COO⁻ molar ratio around 0.85). The NH₄⁺-loaded NO-CNF was repurposed as a fertilizer for soybean growth with efficacy similar to a typical urea fertilizer. This study illustrates an exemplary advance in the development of zero-waste process to upcycle natural waste feedstocks into valued products that can simultaneously reduce nitrogen pollution problems and close the nitrogen loop for food production.

Surface hydroxyl on semiconductors strongly affects their photocatalytic performance by changing the generation of reactive oxygen species (ROSs). However, the intrinsic relationships are still unknown, especially on the aspect of surface atomic configurations of photocatalysts. In this study, we demonstrate that surface hydroxyl manipulation of BiOCl nanosheets can control the surface steric hindrance and the formation energy of oxygen vacancies (V_O). Hydroxyl-poor BiOCl ultrathin nanosheets of lower steric hindrance, in contrast to their hydroxyl-rich counterparts, possess the weakened surface Bi–O bond to promote the V_O formation, and also switch the ROSs from superoxide radicals (‧O₂^‒) to peroxyl anion (O₂²⁻) during the photocatalytic O₂ activation. The O₂²⁻ facilitates the complete oxidation of NO into bidentate nitrate and effectively prevents the formation of more hazardous NO₂ and the back reduction of generated nitrate to NO. This study deepens our understanding of surface structure-activity of photocatalysts for selective generation of ROSs and sustainable development.

The use of active nitrogen emitted from social activities, pyridine derivatives were synthesized from ammonium carbonate and ethanol in a single reactor system. Ammonium carbonates, a promising nitrogen source recoverable from sewage water, was employed in this study. Using nickel supported on hydrotalcite (Ni/HT) as the catalyst, a 2.1% yield of pyridines and 88% selectivity for methylpyridine were achieved. Time-course analysis of reaction products revealed that nickel catalyzes the oxidation of ethanol in the initial reaction stage, followed by hydrotalcite-catalyzed ring formation. Additionally, pyridine derivatives were synthesized from other nitrogen sources, including ammonium bicarbonate, ammonium carbamate, and urea. Pyridine derivatives were also successfully synthesized from recovered ammonium bicarbonate from ammonia solution.

Organo-mineral fertilizers (OMFs) combine organic and mineral components to enhance soil fertility, nutrient availability, and crop productivity while reducing environmental harm. They address key agricultural challenges, contributing to sustainable agriculture and global food security. OMFs utilize bio-based materials like biochar and compost to reduce nutrient leaching by up to 40%, improve water retention, and mitigate erosion. Improved soil aggregation, porosity, and microbial activity promote efficient nutrient cycling and resilience to environmental stress. Slow-release mechanisms optimize nutrient delivery, minimizing runoff and volatilization. OMFs increase soil organic carbon, support beneficial microbial communities, and enable sustainable intensification in nutrient-poor soils. They reduce greenhouse gas emissions, aligning with climate action goals and the United Nations Sustainable Development Goals. Precise nutrient management reduces input costs, improves yields, and reduces chemical residues in crops. OMFs contribute to the circular bioeconomy by transforming agricultural residues into nutrient-rich fertilizers, reducing waste by 20% and sequestering carbon to mitigate environmental degradation. Adoption challenges include optimizing formulations for diverse soils and efficiently scaling production. OMFs enhance sustainable agriculture by increasing crop yields, reducing greenhouse gas emissions by up to 30%, and mitigating nutrient leaching, supporting global goals for food security and climate change adaptation. Collaboration among researchers, policymakers, and agricultural stakeholders is essential for refining technologies and ensuring broader adoption.

Advancement of new materials for hydrogen generation and storage under mild conditions has very high desirability in both application and fundamental aspects. One of the main reasons to attain large scale hydrogen production is the accessibility of highly stable and active electrocatalysts. Alloy strategies can embrace the hardships of enhancing electrocatalysts activity and optimizing their costs. In this review, recent developments on alloy based electrocatalysts for hydrogen evolution and storage have been thoroughly discussed. Firstly, the advancements in the synthesis of alloy based electrocatalysts have been reviewed, afterwards the recent reports on binary and ternary alloy electrocatalysts for hydrogen evolution reaction and storage have been summarized. However, for their adoption at an industrial scale, it is important to ensure that these electrocatalysts demonstrate long-term stability and sustainability. While this work highlights the exceptional properties of alloy-based electrocatalysts, it also addresses the remaining challenges, such as scalability, durability, and cost-effectiveness that must be overcome to fully realize their potential in practical applications.

The increasing demand for sustainable energy systems (SES) has driven significant advancements in the fields of techno-economic analysis (TEA) and life cycle assessment (LCA). This comprehensive review explores the integration of machine learning (ML) techniques into these assessments to address inherent data limitations and uncertainties. TEA and LCA methods are enhanced through ML's predictive modeling, optimization algorithms, and data analysis capabilities, providing more precise and efficient evaluations of SES. The review's scope includes recent TEA and LCA of SES to understand gaps in current practices, and ML SES studies that address these practices. Our literature search identified only three papers integrating TEA, LCA, and ML. Many studies investigate combinations of TEA or LCA with ML. However, there are unique challenges and opportunities for considering all three aspects of SES. Thus, we propose near- and long-term opportunities to further integrate ML with TEA and LCA. Key case studies demonstrate the transformative potential of ML in improving economic viability and environmental sustainability, highlighting its role in predicting system performance, optimizing configurations, and reducing costs and impacts. The review identifies critical areas for future research, including improving data quality, advancing ML techniques, interdisciplinary training, real-world applications, and policy considerations. This integration represents a significant advancement in the field, offering new opportunities for innovation and optimization in sustainable energy technology assessments.

Concerns relating to the potential environmental and land-use impacts associated with terrestrial energy crops have sparked an interest in the alternative use of marine feedstocks, such as seaweed (macroalgae). In contrast to terrestrial crops farming seaweed does not require the input of freshwater or chemical fertiliser and does not compete for land required by food crops. Seaweed remains a largely untapped source of valuable polysaccharides, proteins, fatty acids, and pigments which can be purified, or used as feedstock in the production of platform chemicals. Recently, Life cycle assessment (LCA) has been used to evaluate the potential environmental impacts arising from the use of seaweed feedstocks, predominately in the production of bioenergy. There are a range of different methods which can be used to cultivate and harvest seaweed for further downstream processing. These include land- and tank-based methods, nearshore and offshore cultivation, as well as integrated multitrophic aquaculture. As interest in seaweed cultivation in Europe grows, it is important to understand the associated environmental impacts. To date, a number of LCAs have assessed these different cultivation methods, either in isolation or as part of a wider seaweed biorefining product system. This work aims to bring these studies together—identifying where specific environmental hotspots lie within the cultivation and harvesting processes, and to understand the role of different design aspects. Overall, this review identifies challenges relating to future cultivation system design and LCA methodology.

A sustainable alternating copolymer was synthesized using chain copolymerization of acrylic monomer derived from high oleic soybean oil (the hydrophobic portion, HOSBM) and maleic anhydride (the hydrophilic portion, MA). Using surface tension measurements and fluorescence spectroscopy, surface activity of the resulted macromolecules is demonstrated to confirm HOSBM-MA micellization (CMC = 1.9 mg/L based on solubilization of pyrene probe molecules). The biorenewable carbon index (BCI) of HOSBM-MA was determined as 66.7%, confirming its predominantly sustainable nature. The micelles from the synthesized HOSBM-MA readily solubilize highly hydrophobic molecules (as exemplified by Nile Red dye). 
Furthermore, the obtained results demonstrate that HOSBM-MA can be considered as an alternative for various surfactant/emulsifier applications. In this study, experimental results on HOSBM-MA mixtures with widely used as a surfactant sodium lauryl sulfate (SLS) confirm interactions between biobased macromolecules and SLS. The resulting highly surface-active mixtures were successfully applied as emulsifiers in latex (emulsion polymer) synthesis, further underscoring the potential of HOSBM-MA as a sustainable alternative to conventional surfactants. Synthesized latexes synthesized (monomer conversion >90%, particle sizes 40 - 60 nm) exhibit high colloidal stability, indicating the effectiveness of HOSBM-MA as polymeric surfactant/emulsifier. 

Continental brines, with total dissolved solids ranging from 170-350 g L^-1, are the most abundant lithium resources, although lithium is one of the minor brine components, at concentrations around 1%. Amongst several requirements, for an efficient lithium recovery, it is imperative to improve the Li⁺ to Na⁺ concentration ratio. Here we report a membrane electrolysis process for Na⁺ abatement from brines avoiding solid incrustations inside the reactor and minimizing lithium losses. Sodium is precipitated by CO₂ absorption and conversion to bicarbonate anions under basic conditions. Variables such as CO₂ flow rate and applied current densities were modified under different experimental designs. Three different arrangements were tested, with the best results found for an uncoupled CO2 conversion and the recovery of the effluent from solid washing. Following this strategy, a reduction in the Na⁺ content of approximately 70% was achieved with a decrease of more than 3-fold in the Na⁺/Li⁺ ratio of concentrations. Lithium recoveries of up to 66.6% in the catholyte were obtained with a mass balance close to 100% for both lithium and sodium. The proposed methodology has the potential to capture about 146.4 g of CO₂ per liter of electrolyzed brine, permanently storing CO₂ as mineral carbonates.

Millions of people worldwide rely on disposable sanitary pads, but the high concentration of fossil-based polymers in their composition has negative effects on the environment. This includes the impact of extracting raw materials and the disposal of used products. While sustainable alternatives to traditional pads exist, they are not widely adopted due to their low level of commoditization. This makes them less attractive to companies who prioritize elevated levels of consumption. One promising alternative is the use of biopolymer-based disposable absorbents, particularly polylactic acid, that can be derived from corn starch and is biodegradable. This study used the Life Cycle Assessment and found that using sanitary pads made with polyethylene for one year generates impacts about seventeen times higher compared to using absorbents made with polylactic acid. However, PLA production contributes to higher land use and agricultural emissions. Despite these challenges, PLA remains a promising alternative due to its renewable sourcing and lower environmental footprint in key impact categories. The findings align with UN Sustainable Development Goals (SDGs) 3 (Good Health and Well-being), 12 (Responsible Consumption and Production), and 13 (Climate Action), promoting sustainable hygiene products while mitigating environmental impacts.