Design of Novel Equipment Capable to Quickly Produce Efficient Nanomaterials for Use in Environmental and Sanitary Emergencies

• Published in: Chemical engineering transactions 2019-04, Vol.73
• Main Authors: Stoller, Marco, Cheng, Khley, Traore, Mamadou, Marchetti, Angela, Kanaev, Andrei, Chiavola, Agostina
• Format: Article
• Language: English
• Subjects: Engineering Sciences
• ISSN: 1974-9791; 2283-9216
• DOI: 10.3303/CET1973032

In emergency, to produce safe water, that is "potable water free from harmful microorganisms and substances even if it may have colour, odour or taste problem due to dissolved minerals", applied methods should be immediately available to treat contaminated water, to reach at least a microbiological pollution in terms of bacteria concentration is maximum 10 8 UFC/mL and a maximum concentration of As and COD are 0.1 mg/L and 20 mg/L, respectively. In this work, the treatment of contaminated water to use in environmental and sanitary emergency is performed by the production and employment of proper nanomaterials produced locally. The development of a novel equipment capable to produce quickly and continuously these specific nanomaterials is necessary. Therefore, it was suggested to perform continuous production of the materials by means of process intensification techniques such as the spinning disk reactor (SDR) or the T-mixer reactor (TMR), respectively.Both equipment performed well in producing the required nanomaterials. Concerning the efficiency of the produced materials to lead to safe water in case of emergency, three main parameters were considered: organic matter degradation, heavy metal elimination and anti-bacterial properties. The final results showed that the produced materials are capable to guarantee the required treatment, and it is suggested to use an SDR to produce ferromagnetic core silica shell Al2O3 and Zr/TiO 2 coated nanoparticles; the first capable to remove 59.6% of the organic matter, 59.5% of heavy metals and more than 99% of bacteria after 24h. Finally, the nanomaterial can be removed with ease from the water by magnets at 99.1%. This appears to be very good in terms of ease of the emergency handling. Nowadays, the adopted procedure concerns only bacteria and coarse material removal, performed by addition of toxic chlorine. Since the bacteria content is not known, this requires time lasting "trial & error" procedures to adjust the right amount of added chlorine, since it should be sufficient to deactivate 99% of the bacteria but should not exceed specific residual concentration values due to high toxicity. The new approach suggested in this work permits the immediate use of nanomaterials for contaminated water treatment in emergency to a safe one.