Wood-derived adsorbents for the removal of pharmaceutical contamination from wastewater: a review

Worldwide pollution of ecosystems by pharmaceuticals is a major health issue requiring the development of advanced, carbon neutral remediation methods. Here we review the use of wood-derived adsorbents, with emphasis on synthesis of wood-derived adsorbents, and their use to remove pharmaceuticals. Adsorbents include sponges, biochar, activated carbon, functionalised wood and wood composites. We detail applications to the removal of antibiotics and non-steroidal anti-inflammatories. Engineered wood sponges achieved adsorption of up to 863.8 mg tetracycline per g, and diclofenac up to 321.3 mg/g, displaying water contact angles of up to 151° due to their higher surface area and improved hydrophobicity. Wood-derived biochar removed up to 397.2 mg/g sulfamethoxazole. Activated carbon removed up to 714.2 mg/g amoxicillin. The higher number of adsorptive sites on functionalised wood enhanced adsorption, showing tetracycline removal up to 305.9 mg/g, and diclofenac removal up 350.0 mg/g. Wood composites have enhanced properties such as a tensile strength of 68.1 megapascals and electrical conductivity of 1858 Siemens/metre for MXene/wood composites. Wood composites showed uptake capacities of up to 106.4 mg/g for diclofenac, and 310.7 mg/g for oxytetracycline hydrochloride.