Sviluppo di nanocatalizzatori innovativi a tre componenti recuperabili magneticamente per il trattamento dell'acqua reflua

Responsabili di progetto

Cristina Dellapina, Mohamed Mohamed Ayad

Accordo

EGITTO - ASRT - Academy of Scientific Research and Technology

Bando

CNR-ASRT 2016-2017

Dipartimento

Scienze chimiche e tecnologie dei materiali

Area tematica

Scienze chimiche e tecnologie dei materiali

Stato del progetto

Nuovo

Proposta di ricerca

The progressive growth of world population and industrialization have produced a number of emerging problems, e.g., environmental pollution, which threaten human health and life quality.
Large amounts of dyes are annually produced and applied in many industrial fields, such as textile, paper mill, leather, pharmaceutical, food and so on. The dye annual production has been estimated to be over 700 000 tons, fifteen percent of which is lost during the dyeing processes. Dyes and pigments are typical wastewater pollutants which may present eco-toxic hazards and potential bioaccumulation dangers, hence their removal has become an important objective. Various techniques, such as precipitation, membrane filtration, coagulation, electrochemical, ion exchange, chemical oxidation and adsorption, are employed for the removal of dyes from wastewater. However these techniques are not efficient since they only transfer the non- biodegradable matter into sludge, giving rise to a new type of pollution, which needs further treatment. Moreover, the cleaning up of hazardous waste sites costs hundreds billions dollars. Therefore, a growing interest has recently been focused on the development of innovative systems based on the use of heterogeneous nanocatalysts for wastewater treatment by oxidation and reduction reactions. The possibility to have materials characterized by good stability, solvent compatibility, catalytic activity and possibility to be magnetically removed has become a focus of people's attention. The present proposal deals with the preparation of three-component nanocatalysts (MRTCNs) by new environmentally friendly approaches to promote a sustainable development, and testing them in dyes degradation from wastewater by optimizing their catalytic performances. The experimental plan is articulated in workpackages (WP) and tasks to be carried out in 2 years, as shown below ("Pianificazione del lavoro"). More in detail, WP1 collects the whole synthetic activity. In Task 1.1 we will focus on the preparation of magnetic nanoparticles, typically ferrites, with controlled size and shape. Many methods will be tested and, if necessary, developed to reach this aim. In Task 1.2 intrinsically conducting polymers (polyaniline and polypyrrole) will be produced by means of "green" catalytic approaches developed by our group. Many efforts will be addressed to prepare materials characterized by high conductivity and stability. In the successive steps the obtained materials will be used as pristine or blended with insulating polymer, i.e. chitosan or polymethyl metacrylate, in order to improve their mechanical properties (PM). MNPs prepared in Task 1.1 will be embedded in the PMs by dispersion in proper solvents in order to achieve MNPs/PMs with magnetic and electrical properties (Task 1.3).
However, other approaches will be developed to prepare MNPs/PMs composites by one or two-step synthetic routes. In this context, we will exploit the MNPs catalytic activity for the synthesis of conducting polymers but also in situ surface polymerization and ultrasound-assisted polymerization will be investigated (Task 1.4). Finally, in Task 1.5 MNPs/PMs composites will be decorated with metal nanoparticles (Au, Ag, Pd). This step will be realized following different methods. At first, metal nanoparticles will be produced by traditional chemical reduction and then immobilized on MNPs/PMs via electrostatic attractions. Afterwards, metal nanoparticles will be synthesized by in situ reduction of metal precursors in aqueous solution on the surface of conducting polymers.
WP2 collects any characterization activity, including SEM and TEM microscopy for MNPs (Task 2.1), PMs (Task 2.2), MNPs/PMs composites (Task 2.3) and three-component nanomaterials (Task 2.4), spectroscopic analysis (FT-IR and UV-vis) for PMs (Task 2.2), MNPs/PMs composites (Task 2.3) and three-component nanomaterials (Task 2.4), thermal behavior by TG analyses for PMs (Task 2.2), MNPs/PMs composites (Task 2.3) and three-component nanomaterials (Task 2.4), as well as electromagnetic investigations for MNPs (Task 2.1), PMs (Task 2.2), MNPs/PMs composites (Task 2.3) and three-component nanomaterials (Task 2.4). Further materials properties will be evaluated, such as metal leaching and passivation, nanomaterials stability and recoverability in acidic/alkaline media in the absence and in the presence of high electrolytes amounts.
WP3 collects any activity directly related to the evaluation of the three-component nanomaterials performance as catalysts in the dyes wastewater treatment and optimization.
Catalytic tests will be carried out on wastewater samples prepared in laboratory, using dyes as model molecules, including Congo Red, Rhodamine B, Reactive Black 5, Orange II and p-nitrophenol (Task 3.1). The catalytic tests will be realized by reduction and oxidation processes. In particular, hydrogen (H2) and NaBH4 will be employed as the reducing agents, whereas molecular oxygen (O2) and H2O2 will be investigated as the oxidizing agents. All the catalytic tests will be performed in aqueous solution and different reaction temperatures will be explored.
Finally, Task 3.2 will be devoted to the materials preparation and dyes degradation optimization. In particular, the effect of metal type and size on the catalytic performances will be examined, as well as the effect and role of the conducting matrix.
Reaction parameters (temperature, catalyst and oxidizing/reducing agent concentration, reaction rate, etc.) will be optimized aiming at the total degradation of dyes in short times.

Obiettivi della ricerca

The present project aims at preparing innovative magnetically recoverable three-component materials by environmentally friendly synthetic approaches and testing them as nanocatalysts for dyes degradation from wastewater by reduction and oxidation reactions. The nanocatalysts consist of iron oxide nanoparticles as a magnetic core embedded in an electrically conducting matrix (namely, polyaniline and polypyrrole) decorated with noble metal nanoparticles (namely, Au, Ag, Pd). The noble metal nanoparticles act as real catalytic component. The catalytic properties of these materials for some dyes taken as probes, such as Congo Red, Rhodamine B, Reactive Black 5, Orange II and p-nitrophenol, will be tested in water. Afterwards, all the materials will be evaluated as catalysts in the dye degradation from wastewater and their catalytic performance will be optimized. In summary:
1) Development of innovative eco-friendly syntheses of the three-component materials and their characterization
2) Evaluation of the catalytic activity in dyes degradation via oxidation/reduction reactions
3) Optimization of both the synthetic protocols of the materials and their performance in dyes degradation

Ultimo aggiornamento: 01/07/2025