A review on Adsorption of Textile Dyes Onto an Unconventional Biosorbent: Marine Waste of Posidonia Oceanica

Synthetic dye removal from textile wastewater is still a major occupation for water treatment specialists due to the high pollutant load and poor biodegradability of these materials. Among several wastewater treatment methods, adsorption has been shown to be an effective technique that can lead to complete colour removal from dyeing effluents. However, the relatively excessive cost of conventional adsorbents, particularly activated carbon, the complexity of its manufacture and the high emissions of CO 2 , syngas and pyrolytic oils during pyrolysis, impose considerable limitations on its use, especially in the current context of climate change. Therefore, a new generation of adsorbents has been developed based on the use of natural, renewable, local, abundant, and low-cost materials. In this context, Posidonia oceanica , an aquatic plant from the Mediterranean basin that is abundant as marine waste on beach shores, appeared to be an efficient biosorbent for dye removal. Several scientific publications dealing with Posidonia oceanica have studied its use as an adsorbent support in different forms: as a raw fibre or powder, chemically or physically treated adsorbent, cellulose nanofiber or nanocrystal and precursor to activated carbon. Related studies have shown that all forms of Posidonia oceanica significantly adsorb various pollutants, particularly heavy metals, and textile dyes even when compared to other biosorbents. In this review, the physical and chemical characteristics of different forms of Posidonia oceanica as well as their use as biosorbents for textile dye elimination in batch or dynamic column mode were described, as reported in related scientific papers.