Once dismissed as a ubiquitous urban nuisance, cigarette butts are now drawing scientific attention as a promising source for advanced energy materials.
A new review published in Advanced Powder Materials reveals their potential for use in green technologies — and highlights the growing environmental damage resulting from their improper disposal.
CBs, made primarily of cellulose acetate, are one of the most littered waste items globally. Their environmental persistence and toxicity are growing concerns.
According to the study, each CB can release over 100 microplastic particles per day and up to 300,000 tons of these pollutants are estimated to enter aquatic ecosystems annually.
“They degrade slowly and release hazardous microplastics and heavy metals that accumulate in living organisms, threatening both ecological and human health,” said Ye Chen, lead author of the study and researcher at Henan Normal University’s School of Materials Science and Engineering.
The study also found that under coastal weather conditions, CBs can emit as much as 147.5 kg of toxic heavy metals per year. “These substances — including lead, cadmium, and nickel — are non-degradable and accumulate through food chains,” Chen noted.
A Costly Waste Stream
Despite a global decline in smoking rates, cigarette consumption remains high, with an estimated 1.245 billion smokers in 2022.
According to WHO data and market sources, 2.74 trillion cigarettes were sold in 2023. Improper disposal remains rampant — up to 73.5 percent of smokers discard butts on the ground.
The global economic toll of CB pollution is estimated at $26 billion annually, with environmental cleanup and ecological damage accounting for most of the losses.
Recycling Programs Gain Ground
Several pilot recycling initiatives are underway, transforming CBs into building and infrastructure materials:
- Clay bricks made with 5 percent CB content demonstrated energy savings of 58.4 percent, though compressive strength decreased, limiting structural use.
- Asphalt pavement using encapsulated CBs in India showed enhanced thermal properties and reduced costs by $300 per km.
- Gypsum and sound-absorbing materials reinforced with CBs improved mechanical strength and acoustic properties.
“These recycling methods offer a sustainable route to reuse this non-biodegradable waste, but must be carefully managed to avoid releasing secondary pollutants,” Chen emphasized.
A Green Tech Breakthrough
Beyond construction, the study highlights CBs as a rich source of carbon-based low-dimensional materials, or CLDMs, such as graphene-like nanofibers, highly valued in energy storage and electronics. Through chemical treatment, CBs can be converted into materials with:
- Supercapacitors reaching 432.8 F/g specific capacitance
- Triboelectric nanogenerators with outputs up to 400V
- Flexible batteries with high cycle stability
- Photocatalytic membranes for degrading pollutants and capturing carbon dioxide
“CBs are an abundant and inexpensive source of nanostructured carbon,” said Chen. “Their hierarchical pore structures and doped active sites significantly enhance energy storage performance.”
In one example, modified CB-derived TENGs were able to simultaneously light 96 LEDs and maintain their performance over 12,000 cycles, illustrating their durability.
Outlook: From Litter to Resource
The review concludes that cigarette butts, long regarded as a mere public nuisance, may help address two significant global challenges: environmental waste and the pursuit of sustainable energy.
“If we can establish scalable recycling frameworks,” Chen said, “this waste could become a valuable raw material in the low-carbon economy. It’s an opportunity to turn pollution into power.”
The authors urge policymakers to support collection infrastructure, public awareness campaigns and innovation grants to realize the full potential of CB-derived materials.
“This review aims to provide new avenues for solving the intractable problem of CBs,” Chen wrote, “and to reduce the manufacturing costs of renewable energy materials.”
