Marine materials as innovative metal sorbents suitable for applications in wastewater treatments

The growing interest for urban mining strategies has pushed the research towards innovative strategies for metal recovery from electronic waste. Nevertheless, the treatment of the resulting metal-rich wastewater is still an issue. In this context, the present paper shows a method to use the capacity of Ulva algae to adsorb metals for the treatment of a synthetic solutions which simulates that resulting from a printed circuit board recycling process. The experiments considered a copper-zinc-iron system, showing a copper adsorption capacity of biomaterial up to 65 mg/g, at pH 5, favoured by iron presence. The process needs a short time (around 15 min) and it is suitable to be performed in a fixed-bed column able to treat more than 30 L of copper-contaminated wastewater, decreasing the energetic costs for mixing (compared to the typical slurry-reactor configuration) with an almost completed metal removal. The sustainability of the process is further improved by the selection of a macroalga which often accumulates on beaches (becoming a waste to remove) complying with the circular economy pillars.