Lignin nanoparticles enable recyclable paper to rival plastic packaging

A Pickering emulsion strategy unites water resistance, oil repellency, biodegradability, and recyclability in paper-based materials

Journal of Bioresources and Bioproducts

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A Pickering emulsion strategy unites water resistance, oil repellency, biodegradability, and recyclability in paper-based materials

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Credit: Key Laboratory of Bio-based Material Science and Technology (Ministry of Education), College of Materials Science and Engineering, Northeast Forestry University, Harbin 150040, China

The global push to reduce plastic waste has intensified interest in paper as a sustainable packaging material. Derived from renewable plant fibers, paper is biodegradable, recyclable, and widely available. However, its intrinsic porosity and hydrophilicity result in poor resistance to water and oil, severely limiting its use in food and consumer packaging. Conventional solutions, such as fluorinated coatings or polyethylene laminates, improve barrier properties but undermine recyclability and introduce environmental concerns.
In a study now available in Journal of Bioresources and Bioproducts, researchers present a new coating strategy that addresses these long-standing challenges by integrating biodegradable components into a lignin nanoparticle–stabilized Pickering emulsion. The approach leverages the amphiphilic nature of lignin nanoparticles to stabilize an oil-in-water emulsion composed of polyvinyl alcohol (PVA) and stearic acid (SA), forming a multifunctional coating that enhances paper performance without sacrificing environmental compatibility.
In the reported system, PVA serves as a hydrophilic, film-forming polymer in the aqueous phase, providing mechanical reinforcement and oil resistance through a dense hydrogen-bonded network. Stearic acid, a naturally derived fatty acid, acts as the hydrophobic oil phase, imparting water repellency. Lignin nanoparticles, prepared through a solvent-exchange self-assembly process, irreversibly adsorb at the oil–water interface, stabilizing the emulsion without synthetic surfactants. This Pickering emulsion design enables the uniform dispersion of hydrophobic components within a water-based coating system.
When applied to paper substrates, the emulsion forms a continuous and compact coating layer that seals surface pores and creates a synergistic barrier against both water and oil. The coated paper exhibits a water contact angle exceeding 110°, a Cobb 60 value below 18 g/m², and a Kit oil resistance rating above 9/12—levels comparable to those of commercially used plastic-coated papers. At the same time, tensile strength and wet strength are significantly improved, allowing the paper to maintain structural integrity even after prolonged water exposure.
Beyond barrier and mechanical performance, the study places strong emphasis on end-of-life considerations. Unlike conventional plastic-coated papers, the reported coating can be removed through a simple hot-water repulping process. During recycling, PVA dissolves, stearic acid melts and disperses, and lignin nanoparticles are released, enabling clean recovery of cellulose fibers without degrading recycled paper quality. Soil burial tests further demonstrate that the coated paper fully degrades within approximately 120 days, while polyethylene films show no observable degradation under identical conditions.
The coated paper also demonstrates functional advantages in food preservation. Packaging tests using fruits such as bayberries, grapes, and cherry tomatoes show that the coating effectively reduces moisture loss by lowering water vapor transmission, extending freshness compared with uncoated paper. These results suggest potential applications in fresh produce and food packaging, where moisture control is critical.
By combining biomass-derived materials with Pickering emulsion technology, the reported strategy provides a scalable and environmentally benign route to high-performance paper packaging. While further optimization is needed—particularly in simplifying lignin nanoparticle production and improving gas barrier properties—the work illustrates how renewable nanomaterials can help bridge the performance gap between paper and plastics. As regulatory pressure and consumer demand continue to drive the transition toward sustainable packaging, such multifunctional, recyclable coatings may play a key role in enabling paper to replace plastics in demanding applications.

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Journal

Journal of Bioresources and Bioproducts

DOI

10.1016/j.jobab.2026.100230 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Lignin Nanoparticle Stabilized Pickering Emulsion Coating for Fabricating Water- and Oil-Proof, Biodegradable, and Recyclable Paper

Article Publication Date

27-Jan-2026

Phytic acid–driven structural engineering unlocks high-performance lignin-based carbon aerogel supercapacitors

Spherical architecture and dual phosphorus–sulfur doping synergistically elevate biomass-derived energy storage materials

Journal of Bioresources and Bioproducts

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Spherical architecture and dual phosphorus–sulfur doping synergistically elevate biomass-derived energy storage materials

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Credit: School of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian 116034, China

The global transition toward renewable energy systems such as wind and solar power has intensified the need for advanced energy storage technologies capable of balancing intermittency while maintaining long operational lifetimes. Among various candidates, supercapacitors have attracted sustained attention due to their high power density, rapid charge–discharge capability, and exceptional cycling stability. However, their broader deployment remains constrained by the performance limitations and environmental costs associated with conventional electrode materials.
In this context, biomass-derived carbon aerogels have emerged as a promising alternative, offering renewable sourcing, tunable microstructures, and compatibility with green manufacturing pathways. Lignin, one of the most abundant aromatic biopolymers on Earth and a major byproduct of the pulp and paper industry, represents an especially attractive carbon precursor. Yet transforming lignin into high-performance supercapacitor electrodes requires precise control over both pore architecture and surface chemistry.
The newly reported work addresses this challenge by developing a synergistic structure–doping regulation strategy for lignin-based carbon aerogels. Magnesium lignosulfonate, which inherently contains sulfur, was employed as the primary carbon source, while sodium alginate served as a natural gel-forming agent. Phytic acid played a dual role: acting simultaneously as a phosphorus dopant and as an acidity regulator that directs gelation behavior and structural evolution.
During freeze-drying and subsequent carbonization, phytic acid promoted the formation of uniform spherical hierarchical structures within the aerogel matrix. These spheres, enriched with phosphorus and oxygen species, effectively confined heteroatoms while increasing interlayer spacing and accessible surface area. High-temperature treatment further interconnected the pore network, yielding a mesopore-dominated architecture favorable for fast electrolyte ion transport.
Electrochemical evaluation revealed that the optimized carbon aerogel, prepared at a specific precursor ratio and carbonized at 700 °C, achieved a high specific capacitance of 362 F g⁻¹ at 0.5 A g⁻¹. When assembled into a symmetric supercapacitor device, it delivered an energy density of 40.1 W h kg⁻¹ at a power density of 700 W kg⁻¹, while retaining 82.5% of its capacitance after 20,000 charge–discharge cycles. These metrics compare favorably with many previously reported lignin-derived carbon materials.
Mechanistic analysis attributes this performance to the cooperative effects of structural hierarchy and dual heteroatom functionality. The spherical mesoporous framework facilitates efficient electric double-layer formation and rapid ion diffusion, while phosphorus- and sulfur-containing functional groups introduce additional pseudocapacitive contributions through reversible surface redox reactions. Together, these features overcome the traditional trade-offs between power capability, energy density, and cycling stability that often limit carbon-based supercapacitors.
Beyond performance metrics, the study highlights a sustainable materials design philosophy. By exploiting the intrinsic sulfur content of magnesium lignosulfonate for in situ self-doping and using phytic acid as a multifunctional additive, the approach minimizes chemical inputs and simplifies processing. This strategy not only advances the practical utilization of industrial lignin waste but also provides a generalizable framework for designing high-performance biomass-derived energy storage materials.

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Journal

Journal of Bioresources and Bioproducts

DOI

10.1016/j.jobab.2026.100234 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Synergistic Enhancement of Electrochemical Performance in Lignin-Based Carbon Aerogel Supercapacitors through Phytic Acid-Induced Spherical Structure Formation and Dual P/S Heteroatom Doping

Article Publication Date

27-Jan-2026

 

From litter to power: Turning cigarette butts into high-performance supercapacitors

Maximum Academic Press

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By converting this hazardous waste into advanced nanoporous carbon electrodes, the researchers demonstrate that cigarette butts can serve as an unexpected yet highly effective resource for supercapacitors. The resulting devices exhibit high energy and power densities alongside exceptional long-term stability, highlighting a rare combination of environmental remediation and technological value.

The rising demand for fast, reliable, and sustainable energy storage is challenging conventional technologies such as lithium-ion batteries. Supercapacitors offer a compelling alternative because they store energy through electrostatic charge accumulation, enabling rapid charging, high power output, and long cycle life. Their performance, however, strongly depends on electrode materials, particularly surface area, pore structure, and electrical conductivity. Biomass-derived porous carbons have attracted growing interest as sustainable and tunable electrode materials. Among them, cigarette butts—mainly composed of cellulose and cellulose acetate—represent an underutilized biomass resource whose polymeric structure makes them promising precursors for advanced porous carbons when properly processed.

A study (DOI:10.48130/een-0025-0016) published in Energy & Environment Nexus on 13 January 2026 by Leichang Cao’s team, Henan University, only addresses the urgent challenge of managing millions of tons of cigarette butt waste generated each year, but also points to a scalable pathway for producing sustainable, low-cost electrode materials for next-generation energy storage systems.

The study first employed a hydrothermal carbonization–pyrolysis activation strategy to convert waste cigarette butts into N,O co-doped hierarchical nanoporous biochars (CNPBs), followed by systematic structural, chemical, and electrochemical characterization to elucidate structure–performance relationships. Cigarette butts were hydrothermally carbonized to form nitrogen-containing hydrochar with stacked spherical morphologies, and subsequently activated using potassium hydroxide (KOH) at different ratios and temperatures to tune pore architecture. Scanning electron microscopy revealed that the initially dense, smooth carbon spheres evolved into three-dimensional scaffold-like porous structures after KOH activation, with increasing KOH ratios transforming spheres into looser, honeycomb-like mesoporous networks that favor rapid ion and electron transport. Nitrogen adsorption–desorption analyses showed that all activated CNPBs exhibited highly developed micro–mesoporous structures, with the optimal sample (CNPB-700-4) achieving an ultra-high specific surface area of 2,133.5 m² g⁻¹ and a balanced pore size distribution (1–3 nm), enabling efficient charge storage and electrolyte diffusion. X-ray diffraction and Raman spectroscopy further demonstrated that moderate activation temperature (700 °C) preserved favorable graphitization while limiting excessive defect formation, whereas higher temperatures induced structural disorder. Elemental analysis and XPS confirmed uniform incorporation of nitrogen and oxygen functional groups, including pyridinic and pyrrolic nitrogen species, which contribute additional pseudo-capacitance and enhanced conductivity. Corresponding electrochemical tests in a three-electrode system revealed that CNPB-700-4 delivered the highest specific capacitance of 344.91 F g⁻¹ at 1 A g⁻¹, excellent rate capability, and low internal resistance, with 95.44% capacitance retention after 10,000 cycles. When assembled into a symmetric two-electrode supercapacitor, the material achieved a high energy density of 24.33 Wh kg⁻¹ and a power density of 373.71 W kg⁻¹, outperforming many biomass-derived and commercial activated carbons. Together, these results demonstrate that the controlled hydrothermal–activation method directly governs pore structure, surface chemistry, and graphitization, which synergistically underpin the outstanding electrochemical performance of cigarette butt–derived CNPBs.

The results show that cigarette butts, traditionally viewed as hazardous waste, can be transformed into high-value energy storage materials. The resulting supercapacitors are well suited for fast-charging, long-life applications such as grid stabilization, regenerative braking, and portable electronics. Importantly, this work presents a scalable and eco-friendly waste-to-resource strategy that aligns with circular economy principles, simultaneously reducing environmental pollution and supporting sustainable energy technologies.

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References

DOI

10.48130/een-0025-0016

Original Source URL

https://doi.org/10.48130/een-0025-0016

Funding information

The authors are thankful for the support from the China Postdoctoral Science Foundation (Grant No. 2023M731169), the Ministry of Human Resources and Social Security's Research and Selected Funding Project For Overseas Returnees (J24018Y), the Key Scientific Research Projects of Universities in Henan Province (Grant No. 23A610006), the Key Science and Technology Department Project of Henan Province (Grant No. 222102320252), and the Yellow River Scholar Program of Henan University.

About Energy & Environment Nexus

Energy & Environment Nexus is a multidisciplinary journal for communicating advances in the science, technology and engineering of energy, environment and their Nexus.

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DOI

10.48130/een-0025-0016 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

N,O co-doped hierarchical nanoporous biochar derived from waste cigarette butts for high-performance energy-storage application

 

A global strategy is needed to reduce ozone levels

Research Institute for Sustainability (RIFS) – Helmholtz Centre Potsdam

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In North America and Europe, emissions of ozone precursors such as nitrogen oxides (NOx) and volatile organic compounds (VOCs) declined by half between 2000 and 2018. However, the ozone content of the air – and thus the risk to human health – has not decreased proportionally. Until now, theories about the causes have been largely based on statistical conjecture. Scientists from the Research Institute for Sustainability (RIFS) at GFZ and collaborators have now provided more clarity. Their study, published in Atmospheric Chemistry and Physics, shows that the weaker-than-expected decline of ozone is mainly driven by increased transport of ozone produced abroad.

On the one hand, Europe and North America have been successful with their measures to improve local air quality: by implementing strict air quality guidelines and regulations, they have significantly reduced emissions of ozone precursors. These measures included setting stricter emission standards for vehicles and industrial processes, promoting clean technologies and utilising technological advances. As a result, ozone levels fall over the summer months. However, winter and spring levels have risen, so that the annual ozone exposure for the population did not change significantly.

"The observed seasonal and annual changes have been discussed in studies since the early 2000s. These refer to a variety of possible causes, for example increased intrusion of ozone from the stratosphere due to climate change and higher ozone imports from regions with rapidly rising emissions, particularly in East Asia. In addition, there is a reduced removal of ozone in winter due to decreases in local NOx emissions. It is important to understand that the same NOx which produces ozone in the presence of sunlight also removes it in the absence of sunlight. However, these explanations have largely remained within the realm of statistical conjecture," explains first author Tabish Ansari.

Simulations performed using an atmospheric chemistry transport model with a novel emissions tagging system developed at RIFS enabled the research team to model global ozone distributions and assign them to original emissions from various regions and sectors. The results demonstrate a clear offsetting of the gains from local emission controls by an increasing share of foreign-produced ozone. As a result, previous statistical assumptions about the role of increasing foreign contribution can now be considered a certainty. “The increase in NOx emissions from regions such as East Asia, especially China, and the increasing contribution of international shipping contribute significantly to the hemispheric and intercontinental transport of ozone," says Ansari.

Air pollutants from Asia reach Europe and America

According to the study, the increased influence of natural NOx emissions, for example from vegetation, forest fires and lightning, on ozone formation is also noteworthy. Natural NOx emissions have not increased significantly, but are currently producing more ozone. This is because the competition from NOx emissions from anthropogenic sources such as industry or vehicles has decreased. As less anthropogenic NOx is available to form ozone in North American and European air, natural NOx has become more active. This type of competition between molecules is a well-known phenomenon in atmospheric chemistry.

The authors emphasise that effective ozone mitigation requires international engagement and cooperation. The development of a trusting dialogue, based on reliable estimates of ozone transport between regions, is crucial for the implementation of effective measures. Regional measures alone are not sufficient to control pollutants such as ozone, which persist in the atmosphere long enough to travel intercontinentally.

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Journal

Atmospheric Chemistry and Physics

DOI

10.5194/acp-25-16833-2025 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Explaining trends and changing seasonal cycles of surface ozone in North America and Europe over the 2000–2018 period: a global modelling study with NOx and VOC tagging

Article Publication Date

26-Nov-2025

COI Statement

At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.