Wood-based adsorbents remove pharmaceuticals from wastewater, review finds

Researchers at the University of Oulu, Finland, have identified wood-derived adsorbents as a promising solution for removing pharmaceutical contaminants from wastewater. The study, published in Environmental Chemistry Letters by Chirag Batukbhai Godiya and Tiina Leiviskä, explores the potential of materials such as delignified wood sponges, biochar, activated carbon, and functionalized wood composites. These materials, derived from timber and forestry waste, offer a sustainable and effective approach to capturing pharmaceuticals like antibiotics and anti-inflammatories.

Wood's natural composition—comprising cellulose, hemicellulose, and lignin—provides reactive sites for chemical modifications that enhance adsorption capabilities. The review highlights that wood-derived materials can achieve high adsorption rates, with engineered wood sponges capturing up to 863.8 mg of tetracycline per gram and wood-derived activated carbon removing up to 714.2 mg of amoxicillin per gram. These figures demonstrate the potential of wood-based adsorbents to outperform conventional activated carbons.

The production processes for these materials vary. Delignification removes lignin to create a porous cellulose structure, while biochar is produced through pyrolysis, leaving a carbon-rich solid. Activated carbon involves an additional activation step to refine the pore network. These processes enhance the materials' surface area and porosity, key factors in effective pharmaceutical adsorption.

Composite strategies further expand the functionality of wood-derived adsorbents. For instance, wood surfaces can be modified with zeolitic imidazolate frameworks to create magnetic, mesoporous composites. Other innovations include MXene/wood composites and molecularly imprinted membranes, which offer targeted adsorption capabilities.

Despite the promising laboratory results, the researchers caution that real-world applications face challenges. The concentrations tested in studies are higher than those typically found in wastewater, and issues such as fouling and microbial growth need addressing. The review calls for sustainable approaches, including the use of demolition wood waste and green chemistry, to ensure the viability of wood-derived adsorbents in industrial settings.

Overall, the study positions wood-derived adsorbents as a scalable, carbon-neutral option for water treatment, aligning with global sustainability initiatives. By transforming forestry waste into high-performance adsorbents, these materials offer a viable solution for mitigating pharmaceutical pollution in water bodies.