Effect of Chitosan on the Performance of NiMoP-Supported Catalysts for the Hydrodesulfurization of Dibenzothiophene

Abstract

Chitosan-added NiMoP catalysts supported on alumina and alumina-titania were studied in the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The preparation of catalysts containing Mo (12 wt%), Ni (3 wt%), P (1.6 wt%), and chitosan/nickel = 2 (mol ratio) was accomplished by sequential pore-filling impregnation varying the order of chitosan integration. Materials were characterized by DRIFTS, TPR, TG-DTA, and XPS techniques. The TG-DTA study showed that the nature of the support influences the degradation of chitosan onto the catalytic materials and also influences the HDS of DBT and the product distribution as well. The series of catalysts supported on alumina presented the most remarkable effect of chitosan, in which the OH and NH groups of the organic molecule interact with acid sites of the support weakening the interaction between alumina and deposited metal phases. In all cases, DBT was converted mainly through direct sulfur removal. The catalysts ChP3/A (alumina support impregnated with chitosan in phosphoric acid solution, prior to NiMoP deposition) and ChP4/AT (alumina-titania support impregnated with NiMoP solution, prior to contacting with a solution comprising chitosan and phosphorus) exhibited the best performance in HDS reactions and also showed the highest selectivity in biphenyl formation. Presence of carbonaceous residua on the catalyst’s surface, as shown by XPS, could enhance the HDS activity over the ChP4/AT sample.

Synthesis and characterization of a novel slow-release nanourea/chitosan nanocomposite and its effect on Vigna radiata L.

“…Chitosan, which has been used herein as the coating material, exhibits good thermal stability up to 270 °C, followed by ∼35% weight loss between 270 and 320 °C, 48 owing to rupture of polysaccharide chains specifically including deamination, deacetylation, dehydration, etc. 49 The increase in the thermal behavior of the composite observed in this study indicates that chitosan coating effectively increases the resistance of nanourea against high temperature. FESEM.…”

Efficient CoMoS Catalysts Supported on Bio‐Inspired Polymer Coated Alumina for Hydrotreating Reactions

“…As a result, more Co atoms are available to promote the MoS 2 crystallites formed during sulfidation. Coating the surface of alumina with carbon is another suitable option . Weakening the interaction with the support avoids the formation of catalytically inactive refractory species like CoAl 2 O 4 and Al(OH) 6 Mo 6 O 18 , but may also decrease the dispersion of the active phase.…”

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications

“…Hydrogenolysis ReactionsLikewise, a slurry containing chitosan with PdCl 2 adsorbed in ethanolic solution was reduced with NaBH 4 at room temperature, being active in the transformation of 2-phenyloxirane to 2-phenyl-ethanol, which is used in the fragrance industry[260]. On the other hand, Santes et al synthesized a multicomponent (Mo, Ni and P) chitosan-based catalyst by pore-filling impregnation, being tested in the hydrodesulfurization of dibenzothiophene to obtain high proportion of biphenyl[261].…”