The scale-up of CrioPurA via a more sustainable strategy

The present work is aimed at the scale up of CrioPurA, a chelating material that is used in water treatment for the removal of toxic metals such as chromium, boron, and arsenic, with higher efficiencies than current competitors. The advancement of the TRL (Technology Readiness Level) of the proof-of-concept material to levels 5-6 concerns the study of environmental sustainability in relation to the economy of production, and the possible alternative methods of use. The scaling up was carried out on the synthesis of 4-vinyl-benzyl chloride with N-methyl-D-glucamine, a reaction that leads to the formation of the monomer 4-vinyl-benzyl-N-methyl-D-glucamine (VbNMDG). The synthesis of the monomer, used for the cryo-polymerization of the filtering material, has been modified to allow greater environmental sustainability and cost-effectiveness of the process. Specifically, methanol, used as a solvent for monomer synthesis, was recycled with a 10% loss. Furthermore, on a laboratory scale1,2, the purification of the monomer takes place by crystallization from CHCl3. During the scale-up, this step was advantageously eliminated. The subsequent polymerization process was therefore reviewed in terms of stoichiometric ratios of the reactants, to achieve reaction yields and chemical-physical properties like those tested for the proof of concept 1, 2. The scale-up process was carried out gradually, going through three intermediate steps, up to 1 kg of production, obtaining an 80% yield. Finally, CrioPurA was tested in a demonstrator purposely made to allow flow tests up to a flow rate of 300 liters/hour by varying the load of polluted water. The product obtained by applying the new protocol was also analyzed at different pH values, comparing the data obtained with those of the main competitors on the market. The advancement of the TRL of the CrioPurA material has allowed the design of alternative and more sustainable synthetic roads both in economic and environmental terms. The material has been successfully tested both in batch and flow, at different pH values and using polluting loads of organic nature.