ISI BILIMI VE TEKNIGI DERGISI-JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY, cilt.41, sa.1, ss.1-9, 2021 (SCI-Expanded)
In this paper, the dehydrogenation reaction of NaBH4 was performed in the presence of Co-ion loaded hydrogel catalyst. The reactions took place within 27, 18 and 9 hours at 25, 35 and 45 degrees C, respectively. In addition, the relation between the initial concentration of NaBH4 and released hydrogen was investigated at 45 degrees C. A linear relationship between initial borohydride concentration and produced H-2 was determined. Also, differential method was used to determine reaction rate constants and rate order. Hence, first-order-kinetics was proved by using experimental data. After that, the activation energy was found as 58.26 kJ/mol by means of the slope of the graph of lnk versus 1/T for the dehydrogenation reaction. This value is nearly equal to 50kJ/mol, which was expected in literature for the studies of the catalytic dehydrogenation. As the hydrophilic and macroporous structure of the prepared poly(acrylamide-co-acrylic acid) (p(AAm-co-AAc)-Co) hydrogel catalyst allowed inlet of NaBH4 solution up to its interior and release of produced H-2, effect of pore diffusion limitation was neglected. Dehydrogenation index of NaBH4 was calculated as 2526.31 mL H-2/g NaBH4 according to the amount of NaBH4 in the aqueous solution.