The Passive Carbon-Capture and Mineralizing Planter

The Passive Carbon-Capture and Mineralizing Planter

An urban structure powered by rain, snowmelt, and sunlight — beginning with the physics of French fries

Public Technical Disclosure Zero-Power Operation Take-Home Planter
While looking into how water and heat move inside a French fry, I imagined a bead that captures atmospheric CO₂ when dry and releases it when wet. Place such beads in natural airflow, let rain and snowmelt carry the released carbon down into a planter's wollastonite mineralization layer, and atmospheric CO₂ becomes solid carbonate inside the city — without anyone using electricity. In summer, a separated rainwater reservoir wets a porous outer skin and cools the surroundings; in winter, a black solar-absorbing contact surface briefly warms a passerby's hand. The finished planter is taken home freely and planted in. This paper publicly discloses the device configuration, operating sequence, and variations.

A Bead Born from the Physics of French Fries

Watching how starch swells with water while a crisp layer forms as moisture leaves, I imagined a bead that captures carbon when dry and releases it when wet. Not the whole device moving — only the beads inside, breathing.

Moisture-Swing — Capture When Dry, Release When Wet

Anion-exchange resin beads adsorb CO₂ from dry air and release it when contacted by water (Wang, Lackner, Wright 2011). Moisture changes alone drive the capture-and-release cycle — no heat, no vacuum.

Rain and Snowmelt Transport the Carbon

Natural airflow passes air through the beads; rain and snowmelt carry the released carbon into a planter cartridge; gravity drains the residue. A complete-drainage structure prevents winter freeze damage. Flory et al. (2025) demonstrated the same moisture-driven transport in an outdoor pilot.

The Wollastonite Layer Solidifies the Carbon

Calcium silicate (wollastonite) reacts with CO₂ and water to form solid calcium carbonate (CaSiO₃ + CO₂ + H₂O → CaCO₃ + SiO₂·H₂O). Di Lorenzo 2018's model reaction and Wu 2026's ambient-temperature waste-brine mineralization provide the basis for the planter cartridge.

Summer Rain Cooling, Winter Sun Hand-Warming

A rainwater reservoir separated from the carbon route wets a porous ceramic skin for passive evaporative cooling (He, Hoyano 2010). In winter, a sunlight-absorbing black PDMS surface warms a handle so a passerby can briefly warm their hand (Jung 2025).

A Planter Anyone Can Take Home

After mineralization, completed planter cartridges are separated from the reaction section and placed on a free shelf, a rotating display, or a gravity-fed dispensing bin. Anyone can take one home, add soil, and plant in it. Carbon once dispersed in the air becomes the place where a plant grows in one person's home.