@misc{10481/112724,
year = {2026},
month = {4},
url = {https://hdl.handle.net/10481/112724},
abstract = {The catalytic upgrading of vacuum residue (VR) is constrained by the high cost, diffu
sional limitations, and rapid deactivation of conventional zeolite-based catalysts due to 
severe coking. Addressing this, we developed novel, low-cost, and coke-resistant catalysts 
utilizing naturally abundant Iraqi kaolin. A composite support comprising 80 wt.% Iraqi 
red kaolin and 20 wt.% white kaolin was synthesized via thermal activation at 800 °C and 
acid leaching. This support was subsequently impregnated with transition and rare-earth 
metals (Ni, Co, Ce) at 3–40 wt.% loadings, and comprehensively characterized using XRD, 
BET, SEM-EDX, and XPS. Catalytic performance was evaluated during VR upgrading in 
a fixed-bed batch reactor at 450 °C. Among the formulations, the 20 wt.% Ce-loaded cata
lyst (MKRW-800A@Ce20%) exhibited superior efficiency, achieving 80.15% VR conver
sion, 61.04% liquid yield, and minimal coke formation (3.81 g) compared to Ni and Co 
counterparts. This enhanced activity is attributed to synergistic effects of improved sur
face acidity, textural accessibility, and the Ce3+/Ce4+ redox couple, which promotes selec
tive cracking while suppressing coke precursors. These findings provide new insights into 
the rational design of natural clay-based catalysts, establishing Ce-modified metakaolin 
as a viable, sustainable alternative to zeolites for industrial heavy-oil processing.},
organization = {Consejería de Universidad, Investigación e Innovación and the ERDF Andalusia Program 2021–2027 - (C-EXP-247-UGR23) (PLSQ_2023_00183)},
organization = {MICIU/AEI/10.13039/501100011033, the “European Union NextGenerationEU/PRTR” program - (PID2021-127803OB-I00)},
organization = {“ERDF A way of making Europe” under Projects - (CNS2023-144680)},
publisher = {MDPI},
keywords = {Kaolin},
keywords = {Catalytic cracking},
keywords = {Vacuum residue},
title = {Catalytic Upgrading of Vacuum Residue Over Metal-Loaded   Iraqi Kaolin Using a Fixed-Bed Reactor},
doi = {10.3390/app16073597},
author = {Basil Al-Ameri, Osamah and Elmouwahidi, Abdelhakim and Alzuhairi, Mohammed and Bailón García, Esther and Amaro-Gahete, Juan and Carrasco Marín, Francisco},
}