Zeology

Zeolite structure / Source: Nera Tanning

AsiaEuropeHeat ResistantLeatherNorth AmericaStrongTextilesUV-ResistantZeology

WHAT WE SAY:

After the ethical hurdle, the main accusation aimed at leather is that this theoretically circular, natural material is anything but, especially when it is bathed in toxic chemicals during tanning.

Which is why Zeology, a chrome-free, aldehyde-free and heavy metal-free tanning agent is worth diving deeper into, especially given its eye-opening claims about its radically improved biodegradability metrics. Can this new offering make leather the truly sustainable, circular product it was always supposed to be?

Zeology

WHAT IS ZEOLOGY?

Zeology is a zeolite-based, chrome-free, aldehyde-free and heavy metal-free tanning agent for Leather.
Tanning with Zeology reduces the discharge of hazardous chemicals in waste and wastewater, and improves biodegradability of the finished leather product.
Zeology is the only leather tanning agent to achieve the Platinum level C2C-Certified Material Health Certificate, in addition to earning the top level ZDHC MRSL (Manufactured Restricted Substance List) Conformance and ToxFMD Screened Chemistry certification.
Zeology-tanned leather, called Zeo White, is a chrome-free, lightfast and heat-resistant material, with high grain tightness. It has a naturally white colour, which facilitates the manufacture of white and other bright-coloured leathers.
British designer and Greenpeace ambassador Anya Hindmarch has launched the Zeology-based Return To Nature handbag collection, while German sports brand Puma has developed an experimental biodegradable pilot of its classic Suede sneaker, dubbed the Re:Suede, manufactured using Zeology-tanned suede.

KEY PROPERTIES:

Heat Resistant
Strong
UV-Resistant

INDUSTRY:

Textiles

AVAILABILITY:

Commercially Available

DIVE DEEPER:

Mass industrial leather tanning uses chrome, which can end up in the local environment, and cause cancer, respiratory issues and other health problems.
Most chromium-free leather on the market is pre-tanned with glutaraldehyde, itself a harmful chemical that was placed on the European Union’s Substance of Very High Concern Candidate List in 2021.
Zeology is a chrome-free, aldehyde-free and heavy metal-free tanning agent, made with aluminosilicates called zeolites – a type of mineral made out of Aluminium, silicon and oxygen – sourced as sand and bauxite naturally occurring in the Earth’s crust. It is used by tanners during pickling and diffusion, after a sequence of soaking, liming and deliming animal hides.
Nera sources its zeolites from another Dutch company that is a EcoVadis Supplier Sustainability Participant, with RC 14001, ISO 14001, ISO 9001 certifications. That company, in turn, sources its sand from Belgium and the Netherlands, and bauxite mined globally from countries like Australia, Brazil, Guinea, China and India.
Nera Tanning’s parent company Smit & Zoon claims to be the only entity allowed to develop any type of strategic or commercial relationships for products based on its patented modified zeolite, which has been developed for optimal leather.
Nera Tanning claims that its bright, white-coloured, chrome-free, lightfast and heat-resistant leather intermediate, Zeo White, rapidly bio-disintegrates, and has almost complete compostability and aqueous biodegradation – though this may be compromised depending on how the leather is ultimately finished by the tannery and designer.
Zeology-tanned leather can be integrated with other materials for a compostable finished product. Puma’s experimental Re:Suede sneaker combines Zeology-tanned suede with biodegradable TPE and hemp fibres, and is currently being trialed in the No Time For Waste initiative. Anya Hindmarch’s Return To Nature handbags marry Zeology-tanned leather with Activated Silk Technology, from Evolved By Nature, for a truly compostable bag that degrades only 10% slower than untanned animal skin.

Leather tanning process / Source: Nera Tanning

Various sheets of tanned leather / Source: Nera Tanning

KEY FACTS:

10%

Anya Hindmarch’s Return To Nature handbags, using Zeology-tanned leather, degrade only 10% slower than untanned animal skin.

75%

Zeo White biodegrades impressively in its ‘raw’ state – up to 75% after 20 days.

Key Questions to Ask:

Will your customers pay the Zeology premium?

As with many promising new technologies, there is a green premium for Zeology-tanned leather, meaning it will not be suitable for all mass brands and products. Though, Nera Tanning offers to put designers in contact with a suitable Zeology leather supplier and mass market brand Puma’s experimentation with the material, points to a future of greater scalability.

What ultimate finish are you looking for and how will this impact the product's sustainability credentials?

While Zeo White biodegrades impressively in its ‘raw’ state – up to 75% after 20 days – Nera Tanning notes that this may be compromised by finishing from tanneries or designers, such as waterproofing with polyurethane.

What other design changes will the pursuit of end-to-end circularity demand?

Inspired by creating a biodegradable bag made from Zeology-tanned leather, Anya Hindmarch removed all metallic fastenings and used the Activated Silk Technology from Evolved By Nature, rather than a polyurethane coating, ensuring that her Return to Nature bag lived up to its name.

Could Zeology form part of leather's clean future?

Many brands won't touch animal leather no matter how clean the tanning process is, due to concerns around animal welfare and land use. However, imagine Zeology's tanning process being applied to VitroLab's cell-cultured, lab-grown, cow-free leather. That could fundamentally transform the debate around the ethics and impact of using leather.