As a first step, we developed and/or adapted green and low-cost materials to be exploited in pollutants removal.
Adsorbent materials were successfully produced from exhausted biomass and low-cost supplies. Lignocellulosic polymers, coming from different residues as agricultural or pulp, have been modified through oxidation and chemical functionalization to produce derivatives with carboxyl, hydroxyl, organic nitrogen, and sulphur groups, functionalized with acrylated and methacrylated groups and exploited for Potentially Toxic Elements (PTEs) removal.
Soybean hulls have been used for extracting peroxidase enzyme to be coupled with adsorbent or photoactive materials; furthermore, the residual cellulosic structure has been successfully used to produce functionalized materials capable of adsorbing pollutants.
Several photocatalysts with enhanced absorption on the visible region and enhanced capability to produce hydrogen peroxide have been developed. They allow, on one side, the exploitation of sunlight to achieve abiotic transformation of Contaminants of Emerging Concern (CECs) and PTEs and, on the other side, the employment of the so-produced hydrogen peroxide for the activation of peroxidase enzyme. Up to now, these materials have been successfully dispersed in hydrogels to create a self-standing and self-maintaining enzymatic system, capable to act in synergy with the oxidative action of radical species induced by the presence of the photocatalyst. We are now exploring other forms of supporting materials.
Lastly, enhanced nanofiltration membranes, i.e. sol-gel derived ceramics and graphene oxide (GO), for the retention of target pollutants have been developed and integrated with advanced oxidation steps.
As a second step, we applied the developed methodologies to some case studies. The performance of the materials developed was evaluated on selected key pollutants (PTEs, CECs), by analysing waters before and after treatment with the materials, and on the removal of taste and odour components; the obtained results are promising.
In parallel, the monitoring of water quality in Wastewater Treatment Plants (WWTP), and in several aquaculture sites located in Italy, Denmark and Thailand have been performed by using a target and untarget approach. It has been accomplished by using inductively coupled plasma-mass spectrometry (ICP-MS), gas and liquid chromatography coupled to mass spectrometry (GC-MS and LC-MS) and by employing new methods based on green analytical approaches, such as the development of portable instrumentation for on-site analysis. Electrochemical methods using portable device have been developed for the on-site detection of PTEs and CECs and the performance of voltammetry and its applicability for determination of inorganic and organic contaminants in water has been assessed. A portable procedure for the determination of mercury and methylmercury has been developed, and a procedure for the determination of organic UV filters has been performed for their determination in water samples.
