Efficient adsorptive removal of dibenzothiophene from model fuels by encapsulated of Cu+ and phosphotungstic acid (PTA) in Co-MOF

Abstract

Co-containing materials have raised much concern in adsorption desulfurization due to its unsaturated metal sites. Herein, we introduced Cu+ and phosphotungstic acid (PTA) to Co-MOF to prepare Co-MOF-Cu+/PTA through post-modification method under mild condition, and then Co-MOF-Cu+/PTA were used for adsorption and removal dibenzothiophene (DBT) from model fuels. The physico-chemical property of adsorbents was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), NH3-temperature programmed desorption (NH3-TPD), and inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS and EDX characterization results showed that Cu+ had been uniformly dispersed on the Co-MOF-Cu+/PTA. The NH3-TPD demonstrated that the PTA could enhance surface acidity of the Co-MOF-Cu+/PTA. Due to the introduction of Cu+ and PTA, the adsorption capacity of the Co-MOF-Cu+/PTA for DBT was much greater than Co-MOF. The Cu+ ions served as active sites for π-π interaction and sulfur-metal (S-M) adsorption, meanwhile the Co2+ and PTA adsorbed DBT through acid-base interaction. The adsorption capacity of Co-MOF-Cu+/PTA for DBT could reach 188.7 ​mg/g. The adsorption behavior was spontaneous and endothermic, and be well fitted by Langmuir isotherm and pseudo-second-order kinetic. The Co-MOF-Cu+/PTA had excellent selectivity and regeneration performance.