Study On The Adsorption Of Organic Sulfur In The Oils

This work mainly involved the investigation of the adsorption ofmercaptan, thioether and dimethyl disulfide on activated bentonite and Na-Y zeolite. And the adsorbents were modified through the method of kneading and liquid ion-exchange. Effects of metal cations, optimal loading and preparation conditions on the removal efficiency have been accessed by performing the dynamic and static tests.The results indicated thatthe modified bentonite, with a Cu(Ⅱ) loading of15wt%and the optimum calcination temperature was150℃, showed excellent adsorption performance of propylmercaptan and dimethyl sulfide. And the sulfur adsorption capacity can reach235mg-S/g of adsorbent. The characteristic of the Cu-S and C-S stretching vibrations were found in the Raman spectrum of the complex, which indicated that the S-M (σ) bond was formed through the complexing adsorption of dimethyl sulfide and copper ions. Removal of dimethyl disulfide from its solution has been investigated by using adsorption on the Ag-bentonites and ion-exchanged Y zeolites. When the loading of Ag+was6wt%and calcination temperature was150C, the modified bentonite showed the best desulfurization performance. On the basis of complex adsorption reaction and hybrid orbital theory, the adsorption of dimethyl disulfide on modified bentonite occurred via multilayer intermolecular forces and S-M (σ) bonds. The modified Y zeolites were prepared by the liquid ion-exchange method and the breakthrough adsorption capacity for DMDS was in "Cu(Ⅰ)-Y> Ni-Y> Co-Y> Cu(Ⅱ)-Y> Na-Y> Ce-Y"order. Thermal desorption of DMDS absorbed on modified Y zeolite was carried through two different kinetic processes:the one desorption process is the breakage of S-M (σ) bond between DMDS and metal ions, the other one is the decomposition of DMDS into dimethyl sulfide, methyl mercaptanand hydrogen sulfide with existence of Lewis acid on the zeolite surfaces at a higher temperature.The desorption activated energy, EA,of DMDS on the modified zeolite has been obtained and was in "Cu(Ⅰ)-Y> Ni-Y> Co-Y> Na-Y" order.