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The redox performances of 1–10 wt% Na-modified Fe 2 O 3 /Al 2 O 3 oxygen carrier from seawater were investigated using syngas/air as reactive gases in the thermogravimetric analyzer (TGA) and lab-scaled semi-fluidized bed reactor (semi-FzBR). NaNO 3(aq) as the source of sodium dopants to prepare Na-contained solution was implemented by an air atmospheric pressure plasma jet (Air-APPJ) process, which can increase the feasibility of seawater. For the prepared samples, the materials properties, including crystalline phases, surface morphologies, surface areas, and attrition loss performances were well correlated with the Na contents. The results indicated that the poor reduction kinetics and attrition resistance were obtained with the Na adjunction over 5 wt%, attributing to the sintering issue on excessive phases of Na 2 (Al, Fe) 12 O 19 and Na(Al, Fe)O 2 solid solution in the samples. Therefore, the slight incorporation of Na content in the Fe 2 O 3 /Al 2 O 3 samples which improved the reduction rate was proved as the candidate oxygen carriers. Particularly, the Na content with 1 wt% in Fe 2 O 3 /Al 2 O 3 sample (Na1FA32) can significantly promote the reduction behavior, thermal stability, and attrition resistance as compared to the raw Fe 2 O 3 /Al 2 O 3 oxygen carrier. It is environmentally beneficial to use the Na1FA32 as oxygen carrier in a practical chemical looping combustion process. [ABSTRACT FROM AUTHOR]

The use of seawater as catalytic agents for hematite (Fe 2 O 3 ) as oxygen carrier in chemical looping combustion process is attractive, because of its abundance and low cost. Unfortunately, seawater itself with major NaCl compound under reactive species accompanying the volatilization of chlorine-containing gases probably lead to the corrosion on reactors during the combustion process. In this study, the feasibility evaluation of sodium dopants extracted from seawater as an effective catalytic agent via an air atmospheric pressure plasma jet (Air-APPJ) is performed, and as such it is combined with Fe 2 O 3 /Al 2 O 3 to assess any possible enhancement on the reduction kinetics. The sodium-contained solutions, NaNO 3(aq) and NaCl (aq) , as precursors are used to prepare the sodium dopants due to the evaporation-decomposition of water and dissolved salts via plasma discharge reaction. The sodium-modified Fe 2 O 3 /Al 2 O 3 oxygen carrier can significantly promote the efficiency of the carbon capture efficiency and CO 2 yield. Especially for the NaCl (aq) as precursor in an Air-APPJ system, the high carbon capture efficiency, CO 2 molar fraction and CO 2 yield around 0.96, 0.95 and 0.91 after fifty redox cycle for the sodium-modified Fe 2 O 3 /Al 2 O 3 oxygen carrier are achieved. It can be anticipated that the sodium-modified Fe 2 O 3 /Al 2 O 3 from seawater by an Air-APPJ system as an oxygen carrier candidate in a reversible CLC process would be notably attractive. [ABSTRACT FROM AUTHOR]