DOPA-MELANIN/H2TCPPspm4 FILM AS REUSABLE POROUS MATERIAL IN WATER REMEDIATION

The 3,4-dihydroxy-L-phenylalanine (L-DOPA) can polymerize to form a melanin-like material which is at the base of the attachment ability of mussels on surfaces. The bio-material is characterized by a various number of chemical functional groups capable to interact via secondary bonds with molecules. The proposed work involved the study of the quality of L-DOPA-melanin films introducing the H2TCPPspm4 porphyrin. The entire process of synthesis and deposition was performed in green conditions: at room temperature, in one pot process design, and with no use of harmful reactants and solvents. The obtained hybrid film was employed as a functional supported device in the remediation of water, with an easy absorbent recovery and negligible absorbent leakage. The hybrid material was deposited on glass in a water environment by varying the buffer solution and the deposition time. The quality of the deposited film was analyzed by UV-Vis and FT-IR spectroscopies, AFM, and SEM techniques. Absorption experiments were executed using the methylene blue (MB) molecule as a pollutant model. The best results in terms of surface porosity were obtained according to a L-DOPA concentration of 0.5 mM, in PBS buffer solution (pH=7.4), 14 days of deposition, and the introduction of the H2TCPPspm4 porphyrin as a porous inducer. The interaction between the DOPA/melanin matrix and the porphyrins was confirmed due to porphyrin’s 30% hypochromicity. The introduction of porphyrin led to a notable increase in the development of the surface area. Thermodynamics and kinetics features of the absorption process were evaluated by using consolidated physical models. It was discovered an interesting 20% absorption capacity increment of the DOPA-melanin/ H2TCPPspm4 film (170 mg/g) concerning the only DOPA-melanin system. The hybrid film was used in reusability experiments. The samples were cleaned by dipping them in a SDS solution at 0.5% w/V. The film exhibited high reusability properties since it was observed a small 3-4% decrease in dye absorption per cycle. Its high pollutants absorbance capacity and remarkable reusability make the hybrid DOPA-melanin/ H2TCPPspm4 a good candidate as a green device for water remediation to possible further scaling-up experiments.