Danlin Zeng

A nano-sized solid acid synthesized from rice hull ash for biodiesel production

A nano-sized solid acid was synthesized from rice hull ash by acid activation. The solid acid was characterized by XRD, FT-IR, TEM and solid-state NMR spectroscopy. The characterization results show that the solid acid is amorphous silica with –OH and –SO3H functional acid groups. The TEM images show that the particle size range of the solid acid catalyst is 50–100 nm. In addition, the catalytic results indicate that the solid acid exhibits excellent activity and recyclability for the transesterification reaction of soybean oil with methanol, suggesting promising industrial applications in biodiesel production.

Ultra-deep oxidative desulfurization of fuel with H2O2 catalyzed by phosphomolybdic acid supported on silica

A highly active catalyst of phosphomolybdic acid (HPMo) was prepared and applied in the catalytic oxidative desulfurization (CODS) system. The catalyst was characterized by FT-IR, XRD, XPS and superconducting NMR. The influences of m (catalyst)/ m (oil), V (H 2 O 2 )/ V (oil), reaction temperature and reaction time on the fractional conversion of benzothiophene (BT) and dibenzothiophene (DBT) were investigated. GC-MS and micro-coulometric methods were employed to investigate the reaction. The catalyst has high desulfurization activity in the removal of BT and DBT under mild conditions. The recycling experiments indicated that DBT and BT removal could still reach 95.2% and 95.7% after 10 cycles.

Effect of oxidised mesoporous carbon containing silver nanoparticle on selectivity of adsorption desulphurisation

Abstract This paper presents the experimental investigation of the effects of nitric acid oxidation and silver loaded modification of coal tar pitch based mesoporous carbons (MCs) on adsorption capacity of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The structural and textural properties of the samples were characterised by means of X-ray diffraction, scanning electron microscopy, Boehm titration and nitrogen adsorption–desorption techniques. The results show that after oxidative modification, the average pore sizes of MCs were not changed. It is also found that the specific surface area decreased, while the mesopore ratio, the density of the surface oxygen containing groups increased remarkably. Furthermore, silver loaded modification improved the mesopore ratio obviously. The oxidative modification considerably enhanced the adsorption capacity and silver loaded modification improved the selectivity against benzene. After three regeneration cycles, the regenerated adsorption afforded 96 and 93% of the initial adsorption capacities of DBT and 4,6-DMDBT respectively. The results suggest excellent reuse ability of the MCs.

Ultra-deep oxidative desulfurization of fuel with H2O2 catalyzed by molybdenum oxide supported on alumina modified by Ca2+

A highly active catalyst of molybdenum oxide supported on mesoporous alumina modified by Ca2+ was synthesized by an in situ method and applied in the catalytic oxidative desulfurization (CODS) system. This catalyst was characterized by FT-IR, XRD, BET and XPS. The influences of m(catalyst)/m(model oil), V(H2O2)/V(model oil), reaction temperature and reaction time on oxidative desulfurization of 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzothiophene (DBT) and benzothiophene (BT) were investigated. This catalyst has high desulfurization activity in the removal of organic sulfides under mild conditions. The catalytic oxidation reactivity of sulfur-containing compounds is in the order of DBT > 4,6-DMDBT > BT. The kinetic studies reveal that the oxidative desulfurization of the organic sulfides can present a pseudo first-order kinetic process, and the apparent activation energies of 4,6-DMDBT, DBT and BT are 34.67 kJ mol−1, 33.01 kJ mol−1 and 40.16 kJ mol−1, respectively. The recycling experiments indicate that 4,6-DMDBT, DBT and BT removal can still reach 90.0%, 89.9% and 87.3% after eight cycles.

Photocatalysis of sulfones for the utilization of the oxidized sulfur compounds by oxidative desulfurization of fuel oil

Photocatalysis of dibenzothiophene (DBT) sulfone and benzothiophene (BT) sulfone for the utilization of the oxidized sulfur compounds by oxidative desulfurization of fuel oil have been investigated. Results show that DBT sulfone, when dissolved in 2-propanol and photoirradiated with high-pressure mercury lamp, can be converted completely into biphenyl in 5 h. However, the photoconversion of BT sulfone can be up to 100 % only in 10 min. The reaction conditions, such as the time of N2 gas bubbled through the solution, distance between the high-pressure mercury lamp and the tube, photoirradiation time and the concentration of sulfones, are all impacted on the photoconversion of DBT sulfone and BT sulfone.