Innovative adsorbent materials for reactive capping of contaminated marine sediments

The development of anthropogenic coastal activities has led to the contamination of marine sediments with hazardous substances, posing serious risks to the health and well-being of humans and the environment. It is of paramount importance to develop sustainable technologies for the simultaneous treatment of different contaminants, providing a permanent solution to reduce the hazardousness of sediments in aquatic environments. Recently, nanomaterials are gaining ground in the remediation sector, so the need arises to develop ever-new ones concerning sustainability. Materials that have natural substances or waste as precursors are ideal candidates. This study aimed to develop sustainable materials for the remediation of contaminated marine sediments. The synthesis of the materials involves oxidation of the precursors (cellulose) with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), acidification and branching with branched polyethyleneimine (bPEI), and freezing overnight. The better method to obtain this material was individuated between freeze-drying, Soxhlet extractor or a combination of both. A Soxhlet extractor with ethanol as solvent was the best way in terms of time and yield and it was used to obtain the chitin-based material. After being chemically and microstructurally characterized, the materials obtained was subjected to adsorption tests with three organic tracers: Methylene Blue, 4-Nitrobenzaldehyde and 4-Nitrophenol, and two heavy metals: Chromium and Cadmium. All the experiments were implemented with LCA analysis to evaluate the environmental impact.