Renewable Carbon Research Articles

Ultra-efficient removal of aqueous hexavalent chromium by activated biochar nanoparticles derived from squid ink

Biochar have been recognized as efficient and renewable carbon sorbents, which attracted much attention on Cr contamination remediation in wastewater. In this study, we propose a cost-effective one-step strategy to synthesize activated biochar nanoparticles derived from squid ink (AS-BC) for aqueous Cr(VI) removal. The results demonstrated that AS-BC achieved a removal rate of 24.29 h-1 at 700 °C (400-times higher than the unmodified one). This was also a state-of-the-art removal performance for aqueous Cr(VI) compared to other reported materials. AS-BC possessed an enormous specific surface (2408 m2/g at 700 °C) with abundant O- and N-containing groups, condensed aromatic structures, and high electron transfer capacity (3.64 and 2.13 mmol e-/g for EAC and EDC at 700 °C), contributing to the ultra-efficient removal of Cr(VI) by synergistic adsorption and reduction. AS-BC absorbed Cr(VI) in the form of HCrO4- by electrostatic attraction with protonated amine-N and hydroxy (-NH3+ and -OH2+) groups and Cr(III) in the form of Cr3+ by complexation with amine-N and hydroxy groups. With a hydroxy-quinone and conjugated π-electron system, AS-BC served as mediator and shuttle to accelerate electron transfer in Cr(VI) reduction with an electron donor. Therefore, our findings highlight the immense potential of AS-BC biochar nanoparticles represent a potential alternative for high-performance Cr(VI) remediation in wastewater.

Examining the nexus between carbon dioxide emissions, economic growth, fossil fuel energy use, urbanization and renewable energy towards achieving environmental sustainability in India

Purpose Global urbanization has accelerated due to the persistent trend of rural-to-urban migration in search of better prospects and livelihoods, which has had serious negative effects on the environment, especially in rapidly developing economies. Hence, the purpose of the study is to analyse the relationship between urbanization, economic growth, consumption of renewable energy and carbon emissions with careful examination, particularly in the context of India, where urban population growth has skyrocketed. Design/methodology/approach This study uses econometric methods like Granger causality analysis and the ARDL bound tests, to analyse the intricate relationships between the selected time series variables for India from 1970 to 2022. Findings This research highlights the difficult task of striking a balance between economic development and environmental preservation by emphasizing the crucial role that urbanization and economic expansion play in causing carbon emissions. India’s urbanization trajectory presents a significant policy problem that calls for a move towards renewable energy sources to successfully decrease carbon emissions. Moreover, this research indicates a two-way causal relationship between economic growth, urbanization and carbon emissions, pointing to the intricate interactions between these variables during the developmental stage. Research limitations/implications Despite India’s per capita emissions remaining below the global average, this study highlights the mounting policy challenge of balancing economic development with environmental sustainability as urbanization persists. The paper emphasizes the need for India to invest in renewable energy capacity to replace non-renewable sources and mitigate the carbon footprint of its growing energy demands. Collaborative efforts between India and the developed world to facilitate access to clean energy technologies are crucial for India to achieve sustainable growth in the long run. Originality/value To the best of the authors’ knowledge, existing literature predominantly focuses on investigating the relationship between renewable energy and economic growth, with only a limited number of studies exploring the impact on sustainable development to attain carbon neutrality. Furthermore, these studies have not considered the role of urbanization and non-renewable energy in addressing the challenge of sustainability issues in an emerging country like India. Hence, this study is a comprehensive study that addresses the research gap in these directions.

Exploring Recent Advances in Lignocellulosic Biomass Waste Delignification Through the Combined Use of Eutectic Solvents and Intensification Techniques

Growing awareness of resource sustainability and waste management has driven the search for circular-economy solutions. Lignocellulosic biomass waste, the most abundant renewable carbon resource, offers green potential as an alternative to declining non-renewable fuels. However, due to its recalcitrant nature, it requires pre-processing to convert it into valuable products like energy and chemicals. Biorefineries play a key role in this process by promoting the integral use of biomass, by finding ways to utilize lignin, previously treated as waste. Common pretreatment methods are unsustainable, prompting research into eco-friendly solvents and advanced techniques like ultrasound- and microwave-assisted methods. Recent approaches have also explored the use of eutectic solvents, which, when combined with these intensification techniques, offer promising results. These green technologies improve delignification efficiency, which in turn improves the saccharification process, reduces solvent use, and minimizes environmental impact. Despite progress, challenges remain in making these methods economically viable and adaptable to diverse biomass types. This review article highlights recent advances in sustainable treatment technologies, including the combined use of eutectic solvents and process-intensification techniques, and the potential of the obtained lignin in various industrial applications. It also discusses future prospects for more environmentally friendly processes in biomass utilization.

Fungal Chitin Nanofibrils Improve Mechanical Performance and UV-Light Resistance in Carboxymethylcellulose and Polyvinylpyrrolidone Films.

Materials from renewable carbon feedstock can limit our dependence on fossil carbon and facilitate the transition from linear carbon-intensive economies to sustainable, circular economies. Chitin nanofibrils (ChNFs) isolated from white mushrooms offer remarkable environmental benefits over conventional crustacean-derived nanochitin. Herein, ChNFs are utilized to reinforce polymers of natural and fossil origin, carboxymethyl cellulose (CMC) and polyvinylpyrrolidone (PVP), respectively. Incorporation of 5 wt % ChNFs increases the Young's modulus from 1217 ± 11 to 1509 ± 22 MPa for PVP and from 1979 ± 48 to 2216 ± 102 MPa for CMC. ChNFs increase surface hydrophobicity and retard the scission of the C-H bond as a result of UV-light irradiation in both polymers under investigation. The yellowing from chain scission is reduced, while long-lasting retention of ductility is ensured. Given these results, we propose the utilization of ChNFs in sustainable polymeric materials from renewable carbon with competitive performance against fossil-based benchmark plastics.

Evaluation of the Highly Ordered Structure, Ligature, and Enzymatic Degradation of Poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] Elastic Porous Fibers.

We prepared biocompatible elastic fibers with high porosity and high tensile strength from poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate], which is a microbial polyester that can be produced from renewable carbon resources by isothermal crystallization. It was possible to control the pore size by adjusting the isothermal crystallization time. Most of the pores were approximately less than 10 μm in diameter, did not penetrate, and were distributed discontinuously throughout the fibers. The elasticity of the fibers was apparently attributable to the generation of tie molecules with planar zigzag conformations between lamellar crystals and to the deformation of the pores. The ligature area occupied by the porous fibers in surgical knots was reduced by 75% compared with that of nonporous fibers. This is expected to make the ligature more difficult to untie and reduce the feeling of foreign matter. X-ray tomography revealed that the porous fibers had a relatively small fiber diameter owing to the collapse of the porous area. The rate of enzymatic degradation of the porous fibers was more than four times that of nonporous fibers. These results suggest that this elastic porous fiber will have many applications, including in the medical and marine material fields.

Green synthesis of renewable biomass-derived porous carbon hosts for superior aqueous zinc-iodine batteries

Green synthesis of renewable biomass-derived porous carbon hosts for superior aqueous zinc-iodine batteries

Data analytics driving net zero tracker for renewable energy

This research aims to assess the impact of renewable energy policies, investments, and emissions reductions toward achieving net-zero targets by 2050. We analysed key metrics using the Net Zero Tracker (NZT), including renewable energy capacity, policy strength, financial investment, and carbon emissions across multiple regions and industries. Our methodology involved data collection from 2020 to 2050, utilising predictive modeling to project trends in renewable energy adoption and emissions reduction. Key findings show that renewable energy capacity is expected to surpass 1000 GW by 2050, with an exponential increase around 2045. Policy Strength Index (PSI) will grow by 20 %, from 50 in 2020 to 60 in 2050, while investments in renewable energy will rise from $10 billion to $25 billion over the same period. Emissions are projected to steadily decrease to zero by 2050, which aligns with net-zero goals. The margin of error in the projections is ±5 %, considering potential policy implementation and technology development variations. These results underscore the critical role of enhanced policies, sustained investments, and international cooperation in accelerating the global transition to renewable energy. The research offers valuable insights for policymakers and stakeholders to guide future strategies for achieving a sustainable energy future.

Dynamic impacts of globalization and environmental performance on renewable energy

This study investigates the dynamic relationships between renewable energy consumption, globalization, trade openness, carbon emissions, and arable land in Somalia from 1990 to 2020 using annual time series data from various sources. Employing econometric models such as the ARDL, FMOLS, and DOLS, the analysis reveals significant long-run relationships. A 1% increase in globalization (LnGI) and trade openness (LnTO) boosts renewable energy consumption (LnRE) by 0.123% and 0.020%, respectively, while a 1% rise in carbon emissions (LnCO2) decreases LnRE by 0.088%. Short-run dynamics show similar trends. These findings, validated by FMOLS and DOLS techniques, emphasize the impact of globalization, trade openness, and carbon emissions on renewable energy adoption. Policymakers should promote global integration and trade openness while enforcing strict carbon reduction measures to support renewable energy use and achieve sustainable development goals.

Investigation of Bottleneck Enzyme Through Flux Balance Analysis to Improve Glycolic Acid Production in Escherichia coli.

Amid rising environmental concerns, attempts have been made to produce glycolic acid (GA) using microbial processes with renewable carbon resources instead of using chemicals. The Dahms pathway for GA production uses xylose as a substrate and consists of relatively simple enzymatic steps. However, employing it leads to a decrease in cell growth and GA productivity. Systematically identifying and addressing metabolic bottlenecks in the Dahms pathway are essential for efficient glycolic acid (GA) production have not yet been performed. Through metabolic flux balance analysis, we found that insufficient aldehyde dehydrogenase (AldA) activity lowers GA production and negatively affects cell growth due to reduced energy production. Thus, we discovered a novel AldA isolated from Buttiauxella agrestis (BaAldA) demonstrated a 1.69-fold lower KM and a 1.49-fold higher turnover rate (kcat/KM) than AldA from Escherichia coli (EcAldA). GA production in E. coli harboring BaAldA was 1.59 times higher than in the original strain. Fed-batch fermentation of E. coli harboring BaAldA produced 22.70g/L GA with a yield of 0.497g/gxylose (98.2% of the theoretical maximum yield in the Dahms pathway), showing a higher final yield for GA than previously reported in E. coli. Our novel BaAldA enzyme shows great potential for the production of GA using microorganisms or enzymes. Furthermore, our approach to identifying metabolic bottlenecks using flux balance analysis could be utilized to enhance the microbial production of various desirable products in future studies.

Regional variations in energy efficiency: Modifying China's industrial approaches to meet sustainability goals

China has devoted much attention to the “carbon peaking” and “carbon neutrality” objectives, the related research focuses on renewable energy, carbon removal, electrification, and hydrogen technologies. Yet, energy efficiency, especially in resource-based and older industrial cities continue to be a research gap in this regard. This study fills this research gap by assessing the role of China's national Industrial Transformation and Upgrade Demonstration Zones (ITUDZ) in energy conservation from 2010 to 2021. In this paper, applying the time-varying Difference-in-Differences (DID) method, we confirm that ITUDZ effectively decreases the energy utilization of these cities. These tests are reliable based on the results obtained above. Mechanism assessments show that the ITUDZ does so through enhancing green innovation and adjusting industrial patterns and that marketization enhances the energy-saving impacts. Geographical heteroscedasticity tests also show that the effects are significant for multi-urban areas and eastern China but weaker for central-western and single-urban city areas. Therefore, this study serves to add to the existing knowledge regarding place-based industrial policies and their contribution towards the realization of China's sustainable development agenda.

Concatenating Microbial, Enzymatic, and Organometallic Catalysis for Integrated Conversion of Renewable Carbon Sources

Concatenating Microbial, Enzymatic, and Organometallic Catalysis for Integrated Conversion of Renewable Carbon Sources

Interactions among the primary causes of carbon dioxide emissions in selected south Asian countries: Does renewable energy mitigate carbon dioxide emissions?

The primary aim of this study is to examine the relationship between economic growth (EG), financial development, renewable energy consumption and environmental pollution in South Asian countries (SAC). The “Autoregressive Distributed Lag (ARDL) model” applies panel data analysis from 1990 to 2021 in selected SAC. This study reveals that a 1 percent increase in financial development (FD) tends to increase 0.3356 percent of CO2 emissions. Renewable energy consumption (RE) essentially diminishes ecological contamination: a 1 percent expansion in RE will reduce 0.5878 percent of CO2. Expanded reception sources are related to a significant decrease in CO2 highlighting the capability of clean energy to advance manageable turns of events. The blunder rectification term remains at - 0.3741 with measurably critical outcomes which suggests that the speed of equilibrium is 37% to arrive at a drawn-out balance in SAC. We urge policymakers to find some kind of harmony between financial development and natural maintainability by advancing sustainable power projects and implementing stricter ecological guidelines. This study contributes to the literature by presenting empirical evidence on the environmental impact of economic and financial dynamics in a region experiencing rapid growth and development challenges.

Conversion of Carbon Dioxide into Molecular-based Porous Frameworks.

ConspectusThe conversion of carbon dioxide (CO2) to value-added functional materials is a major challenge in realizing a carbon-neutral society. Although CO2 is an attractive renewable carbon resource with high natural abundance, its chemical inertness has made the conversion of CO2 into materials with the desired structures and functionality difficult. Molecular-based porous materials, such as metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs), are designable porous solids constructed from molecular-based building units. While MOF/COFs attract wide attention as functional porous materials, the synthetic methods to convert CO2 into MOF/COFs have been unexplored due to the lack of synthetic guidelines for converting CO2 into molecular-based building units.In this Account, we describe state-of-the-art studies on the conversion of CO2 into MOF/COFs. First, we outline the key design principles of CO2-derived molecular building units for the construction of porous structures. The appropriate design of reactivity and the positioning of bridging sites in CO2-derived molecular building units is essential for constructing CO2-derived MOF/COFs with desired structures and properties. The synthesis of CO2-derived MOF/COFs involves both the transformation of CO2 into building units and the formation of extended structures of the MOF/COFs. We categorized the synthetic methods into three types as follows: a one-step synthesis (Type-I); a one-pot synthesis without workup (Type-II); and a multistep synthesis which needs workup (Type-III).We demonstrate that borohydride can convert CO2 into formate and formylhydroborate that serve as a bridging linker for MOFs in the Type-I and Type-II synthesis, representing the first examples of CO2-derived MOFs. The electronegativity of coexisting metal ions determines the selective conversion of CO2 into formate and formylhydroborate. Formylhydroborate-based MOFs exhibit flexible pore sizes controlled by the pressure of CO2 during synthesis. In pursuit of highly porous structures, we present the Type-I synthesis of MOFs from CO2 via the in situ transformation of CO2 into carbamate linkers by amines. The direct conversion of diluted CO2 (400 ppm) in air into carbamate-based MOFs is also feasible. Coordination interactions stabilize the intrinsically labile carbamate in the MOF lattice. A recent study demonstrates that the Type-III synthesis using alkynylsilane precursors enables the synthesis of highly porous and stable carboxylate-based MOFs from CO2, which exhibit catalytic activity in CO2 conversion. We also extended the synthesis of MOFs from CO2 to COFs. The Type-III synthesis using a formamide monomer affords stable CO2-derived COFs showing proton conduction properties. The precise design of CO2-derived building units enables expansion of the structures and functionalities of CO2-derived MOF/COFs. Finally, we propose future challenges in this field: (i) expanding structural diversity through synthesis using external fields and (ii) exploring unique functionalities of CO2-derived MOF/COFs, such as carriers for CO2 capture and precursors for CO2 transformation. We anticipate that this Account will lay the foundation for exploring new chemistry of the conversion of CO2 into porous materials.

Optimising Portugal’s 2050 energy system: Electric vehicles and hydrogen integration using Grey Wolf Optimiser and EnergyPLAN

The global shift to sustainable energy, driven by climate concerns and energy security, is backed by worldwide governmental commitments to reduce greenhouse gas emissions and enhance renewable energy sources in the energy systems. In 2016, the Portuguese Government pledged to carbon neutrality by 2050 as part of this global effort. This article proposes technical solutions for reducing carbon dioxide emissions and increasing renewable energy in the Portuguese mainland energy system by 2050, considering the targets set by the government. An energy system modelling approach based on the Grey Wolf Optimiser and the EnergyPLAN software was introduced. Seven scenarios for 2050 assess the impacts of transport electrification and hydrogen grid integration while minimising costs and/or carbon dioxide emissions. The results show that achieving a nearly 100% renewable electricity system and carbon neutrality is possible, considering a carbon capture ranging from 2.65Mt to 5.87Mt. The 2050 energy system requires a minimum battery storage of 5.1GWh and a minimum natural gas storage of 2,063GWh. Transport electrification requires an increase in the total installed capacity by at least 1.83GW, while hydrogen integration increases it by a minimum of 8.25GW. Developing interconnection capacity beyond 15% of the total installed capacity is crucial for grid stability and reducing fossil fuel dependence.

Renewable and hydrophilic carbon quantum dots derived from human hair as the filler in Nafion composite membrane for vanadium redox flow battery application

Renewable and environmentally benign hydrophilic carbon quantum dots (CQDs) were synthesized using a hydrothermal method. Subsequently, composite membranes of Nafion/CQDs, demonstrating outstanding performance metrics for vanadium redox flow batteries (VRFBs), were developed. Employing a straightforward solution-casting technique, these membranes exhibited superior proton conductivity and reduced vanadium ion permeability. Tested at an elevated current density of 120 mA/cm2, the single cell VRFB integrated with the optimized Nafion/CQDs composite membrane outperformed its commercial counterparts, achieving a high coulombic efficiency of approximately 96.13 % and an energy efficiency of nearly 85.46 %. Moreover, it demonstrated significant cycle life, retaining about 17.1 % of its capacity after 100 cycles, compared to 27.2 % capacity retention for the N-recast membrane over the same period. These results position the Nafion/CQDs composite membrane as a formidable contender in the VRFB domain, emphasizing its potential for broader commercial applications.

Industrial symbiosis as enabler and barrier for defossilization: The case of Höchst Industrial Park

Höchst Industrial Park (IPH) was founded in 1863. Over the years, a network of symbiotic relationships has developed between the companies in the park, the park, and the Rhine-Main region, resulting in the efficient use of resources. However, while this industrial symbiosis reduces greenhouse gas (GHG) emissions, a shift towards more sustainable energy and raw material supplies is required to meet climate goals. Options include renewable electricity, heat electrification, green hydrogen, carbon capture and utilisation, biomass, and recycling. Such a transformation is challenging because it requires the application of highly innovative technologies on a large scale, the cooperation of many public and private actors, a fast pace to achieve GHG reduction targets, and a high degree of structural complexity due to the need to adapt the infrastructure. This need must be managed amid considerable regulatory uncertainty, a lack of infrastructure for producing and transporting green hydrogen and electricity and increasing international competition between production sites. We analyse how established symbiotic relationships affect the transformation of an existing industrial park using the case of IPH and focus on the manufacturing companies at this site. In addition, we show how a defossilised energy supply in IPH could look and which new symbiotic relationships could develop. We also discuss the role of stakeholder management in achieving coordinated action.

CO2 Conversion by Oxygen-Enriched Gasification of Wood Chips

With increasing efforts to lower CO2 emissions globally, the demand for carbon-based resources in industries remains on a high level, leading to new technologies being able to provide those essential carbon sources. To the best of our knowledge, we were able to show for the first time the adaption of a readily available gasifier for the gasification of wood chips using only O2 (18.4–23.1 Vol.-%) and CO2 as gasification agents, creating a nitrogen-free product gas. It was found that the setup used was able to convert up to 27.2% of the CO2 from the gasification agent to CO, creating a promising route for the production of renewable carbon sources for future carbon-based applications. Furthermore, no decrease in gasification performance was observed as the cold gas efficiency was at 83.5–95.5% with only minor formation of tar.

Visible Light Mediated CO2 Fixation Reactions to Produce Carbamates and Carbonates: A Comprehensive Review

ABSTRACTCO2 is a significant greenhouse gas, and is considered as a copious renewable carbon reagent. From a synthetic perspective, it can be used as a sustainable and substitute C1 building block because of its nontoxic, nonflammable, and abundant nature. The transformation of a wide range of organic molecules with CO2 into numerous efficient commodities is a defining feature of recent success in this sector. Because of its numerous applications, photocatalysts and visible light‐mediated synthesis of carbamates and cyclic carbonates using CO2 have drawn a lot of interest from researchers. This mini review mainly focusses on the different one‐pot reactions that are proven to be efficacious for chemical fixation of CO2 in producing industry‐based compounds of carbamates and carbonates with the creation of CO, CH, CC, and CN bonds.

Dynamic correlation among renewable energy, technology, and carbon markets: Evidence from a novel nonparametric time-frequency approach

In addressing the challenges of energy security and climate change, ongoing efforts involve the development of innovative technologies to support the shift from conventional to clean energy sources. Concurrently, the establishment of carbon markets aims to facilitate a decrease in carbon emissions by enabling the trade of carbon credits. This study adds to the energy-climate discussion by examining the evolving dynamics of returns on investments in renewable energy, technology, and carbon markets. Specifically, the time-varying correlation among renewable energy, technology, and carbon markets in the European Union is examined from September 18, 2017 to December 14, 2022. The techniques employed for empirical analyses are the nonparametric time-frequency, Benjamini-Hochberg, and Benjamini-Yekutieli correlation techniques, as well as the time-varying Granger causality. Highlights from the results are as follows. Renewable energy, technology, and carbon markets exhibit time and frequency variations in their relationships, with significant correlations notably present during periods marked by major shifts in energy policy. Secondly, renewable energy and carbon markets exhibit very weak or even absent correlation, indicating their suitability for portfolio diversification. Furthermore, investors could benefit significantly by including both technology and carbon markets in their portfolios to reduce overall risk. Several additional recommendations are also provided in this study.

A high-performance all-day vertical thermoelectric generator based on a double-sided reflective structure

Harvesting environmental energy sources is crucial for achieving renewable energy generation and net-zero emissions. However, ensuring uninterrupted electricity generation from environmental energy sources remains challenging. In this study, we present a simple, compact, and expandable all-day vertical passive thermoelectric generator (V-TEG) with a double-sided reflective structure that simultaneously harnesses solar and space cold energy. Outdoor experimental measurements, combined with finite element simulation analysis, revealed that the optimal angles of the solar reflector relative to the TEG range from 30° to 50°. Additionally, the TEG placed in the north–south orientation was found to enhance its daytime performance. The use of low-cost black paint combined with the solar reflector achieved equivalent spectral selectivity, effectively minimizing the infrared heat loss of the hot end of the TEG. During a 48-h outdoor test, the V-TEG achieved an average daytime power of 112.00 mW/m2 and a peak of 363.42 mW/m2. Comparative experiments demonstrated that the V-TEG outperformed horizontally placed TEG during the daytime. Furthermore, scaling the system by connecting three TEGs in series significantly increased the daily power output. This compact V- TEG system offers a promising solution for long-term power generation in low-power sensors and off-grid communities, supporting renewable energy and carbon neutrality goals.