by Keyword: Co2 fixation

Arnau, Marc, Sans, Jordi, Gallego, Eva, Peraales, Jose Francisco, Turon, Pau, Aleman, Carlos, (2024). Polarized hydroxyapatite, a ceramic nanocatalyst to convert automotive carbon emissions into ethanol Journal Of Environmental Chemical Engineering 12, 112255

This paper is aimed to develop ultrananoporous polarized hydroxyapatite (HAp) catalyst and evaluate its per-formance in transforming CO2 into useable ethanol considering three different scenarios: 1) a batch reaction using a mixture of CO2 and CH4 as feeding gas; 2) a batch reaction using as reactant exhaust gases captured from the fumes of diesel vehicles; and 3) a continuous flow reaction using pure CO2 as feeding gas. Ultrananoporous HAp scaffolds were prepared using a four-step process: 1) as prepared HAp powder was mixed with 60% wt. of a commercial hydrogel at low-temperature; 2) the resulting paste was shaped at low temperature to reduce the adhesion between the metallic tools and the mixture, enhancing the homogeneity of the sample; 3) the shaped paste was calcined in air by applying 1000 oC during 2 h to eliminate the hydrogel; and 4) an external DC electric field of 3 kV/cm was imposed at 1000 oC during 1 h to the calcined scaffold. The resulting polarized scaffolds both ultrananoporosity and catalytic activation. Thus, the mass: volume ratio of the ultrananoporous catalyst was much lower than that of conventional HAp catalyst (718 vs 5093 g/L. Furthermore, the ethanol yield was much higher (up to a factor of x21.4) for the ultrananoporous catalyst than for the compact one, allowing us to conclude that ultrananoporous polarized HAp catalyst is a promising technology for transforming CO2 into valuable chemical products from highly polluted gases, especially those coming from road, sea and air transport.

JTD Keywords: A: ceramics, Air pollution, Automotives, Batch reactions, Calcination, Carbon, Carbon dioxide, Co2 fixation, Co2 reduction, Desig, Electric fields, Environmental process, Ethanol, Exhaust gases, Feeding gas, Fumes, Hydrogels, Hydroxyapatite, Lows-temperatures, Nano-catalyst, Nanocatalysts, Polarized catalys, Polarized catalyst, Scaffolds, Temperature, ]+ catalyst