Naiwang Liu

A novel preparation method of sulfonic functionalized silica: CH 3 SO 3 H as the sulfonic source and Al as the bridge

A novel approach is designed to optimize the synthesis of sulfonic-functionalized silica material. Results from 29Si and 27Al NMR suggest that the Al acts as the bridging atom connecting the methanesulfonate and silica matrix. Further pyridine-FTIR spectra followed by catalytic activity tests demonstrate that compared with previous methods, our new approach results in higher Lewis acid site concentration, higher thermal stability and superior catalytic activity. Moreover, the whole catalysis preparation procedure is environmentally friendly. Specifically, the silica matrix is synthesized through hydrolysis of tetraethylorthosilicate employing formic acid as hydro-catalyst, in which no surfactant species or precursors were involved.

A novel method to anchor methanesulfonic acid in silica matrix

Methanesulfonic acid (MSA) was successfully immobilized in silica, leading to a novel and environmentally friendly solid acid catalyst SMSA. The most important feature of SMSA is that anhydrous formic acid is used to hydrolysis of tetraethylorthosilicate (TEOS). No water was added in the whole preparation. Therefore, MSA could be anchored in silica matrix more effectively instead of being dissolved in water. This new organic/inorganic hybrid catalyst was characterized by powder X-ray diffraction (XRD), energy dispersive spectrum (EDS), N2 adsorption-desorption analyzer, thermogravimetric analysis (TGA-DSC) and pyridine-FTIR. The catalytic activity was tested by alkylation of olefins and aromatics. High concentration acid sites, both Lewis and Brønsted, abundant porosity and large surface area enabled the highest activity for SMSA, among MCM-22, ZSM-5 and industrial acidity clay.

From waste to best: excellent desulfurization performance of spent FCC catalyst

ABSTRACT Fluidized catalytic cracking (FCC) is an important link in heavy oil processing. Industrial FCC catalyst which mainly consists of molecular sieves, substrates and adhesives is used in large quantities every year. Spent FCC catalyst is one kind of hazardous solid waste that is hard to handle. In this paper, we used a spent FCC catalyst as a desulfurization adsorbent, and show that it displays advanced desulfurization property. Furthermore, regeneration experiment showed that calcination was an effective method to remove the sulfides adsorbed in spent FCC catalyst, after four cycles it still owned a high sulfur adsorption ability. The results of metal impregnation indicated that the high ability to remove sulfur in LPG was due to those metals deposited on WC. The sulfur removal further increased by calcination of the spent catalyst since carbon deposition on the catalyst surface which blocked the active sites was minimized by calcination, thus leading an increase in the number of active sites available. GRAPHICAL ABSTRACT

Excellent adsorption performance of dibenzothiophene on functionalized low-cost activated carbons with different oxidation methods

ABSTRACT Low-cost activated carbon (KAC) was functionalized by HNO3, (NH4)2S2O8 and air oxidation, respectively, to remove dibenzothiophene (DBT) from model fuel. The changes in physical and chemical properties of these activated carbons were characterized by thermal analysis, elemental analysis, nitrogen adsorption apparatus, Raman spectra, scanning electron microscope and Boehm’s titration method. HNO3 and (NH4)2S2O8 oxidation result in a significant decrease in pore structure, while air oxidation only causes slight pore reduction due to the re-activation by O2. The oxygen-containing functional groups (OFGs) increase markedly after oxidative modification, in which (NH4)2S2O8 oxidation is considered as the most efficient method with respect to the introduction of OFGs. HNO3 and (NH4)2S2O8 oxidation are more selective to generate carboxyls and lactones, whereas air oxidation creates more phenols, carbonyls and ethers. The DBT adsorption capacity follows the order: NAC (HNO3-oxidized KAC) > OAC (air-oxidized KAC) > KAC > SAC ((NH4)2S2O8-oxidized KAC), implying the introduction of OFGs is beneficial for the DBT adsorption process, especially for selectivity, but excessive OFGs have a negative effect on the removal of DBT. Thus, to achieve high DBT adsorption performance, there should be a trade-off between the micropore volume and the OFGs amount. GRAPHICAL ABSTRACT