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Li, et al.

performance improved with increasing Ru/NH 4 within both the supercages and the internal channels of
+
molar ratio, suggesting that sulfur removal is strongly the Y-zeolite. However, only the RuOx clusters located in
dependent on the RuOx clusters present in the RuY-X the supercages contribute significantly to TP selectivity,
sample. However, further increases in Ru loading whereas those migrating into the inner channels show
beyond this ratio slightly reduced sulfur removal, negligible adsorption capability . Furthermore, the
18
likely due to the formation of bulk RuO₂ nanocrystals, H₂-TPR reduction peak area correlates with the amount
which may block the micropores of the Y-zeolite. The of RuOx clusters, and RuY-1/2 showed a slightly higher
RuY-1/2(N₂) sample containing Ru3+ species showed reduction peak area than RuY-1.
a sulfur removal of only 3%, much lower than that of
RuY-1/2 (44%), indicating that Ru⁴⁺ is more effective 3.3. Adsorption isotherm
for thiophene adsorption. The adsorption isotherms were investigated through
batch adsorption experiments. Two models were used
3.2.3. Effects of adsorbent acidity on TP adsorption to describe the equilibrium data: (1) The Langmuir
NH -TPD analysis showed that the RuY-1 sample model explains properties such as physisorption
3
exhibits the highest concentration of strong acid sites with homogeneous monolayer adsorption, in which
among the MY-1 series, despite showing the lowest all the active sites are equivalent and independent;
Lewis acidity on the external surface area as observed (2) The Freundlich model is an empirical model that
in the Py-IR study. Meanwhile, the BET study showed describes adsorption on heterogeneous surfaces and
that the RuY-1 sample had the largest internal surface multilayer adsorption. The Langmuir equation and the
area of 665 m /g. Based on these findings, it is proposed Freundlich equation are described in Equations V and
2
that the acidity of RuY-1 is predominantly contributed VI, respectively. 50,51
by RuOx clusters located within the internal surface C C
area (micropores) of the Y-zeolite. These RuOx clusters, e 1 e (V)
particularly those containing Ru⁴⁺, serve as active sites q e q K L q m
m
and significantly enhance thiophene removal. q = K C 1/n (VI)
The distribution of RuOx clusters in the RuY-X e F e
series was further studied using H₂-TPR. The results
confirmed that the RuOx clusters are highly dispersed

Figure 11. Adsorption isotherm for TP using
RuY-1/2 adsorbent. Experimental conditions:
Figure 10. Effect of Ru loading amount in RuY-X Initial TP concentration = 20 ppm; model gasoline
on sulfur removal. Adsorption conditions: initial volume = 10 mL; adsorbent weight = 0.1 g;
sulfur concentration = 20 ppm; model gasoline temperature = 80°C; contact time = 2 h.
volume = 10 mL; adsorbent weight = 0.1 g; Abbreviations: C : Remaining concentration of TP
e
temperature = 80°C; contact time = 2 h. at equilibrium (mg/L), q Amount of TP adsorbed
e:
Abbreviations: Ru: Ruthenium; RuY: Ruthenium- at equilibrium (mg/g); RuY: Ruthenium-modified
modified Y-zeolite. Y-zeolite; TP: Thiophene.

Volume 22 Issue 6 (2025) 98 doi: 10.36922/AJWEP025250204