Synthesis Of New-type Adsorbent Via Deep Eutectic Solvents For Adsorption Desulfurization

As human attention to environmental problems,all the developed countries and developing countries formulate the strict product quality standard for fuel.In order to synchronize with euro V emission standard,the state council executive meeting clearly formulated the V standard in 2013,in which the sulfur content must reduce to 10 ppm and this standard must be crossed the country in 2018.Adsorption desulfurization,using the adsorption principle,is a kind of the emerging technologies of desulfurization.Comparing with hydrodesulfurization in industry,it has more advantages,thus it is worthy of excavation and research.First of all,this work first time used theoretical calculation to discuss the results of experiment and phenomenon,respectively for three typical deep eutectic solvents(ChCl/Gly,ChCl/AcOH and ChCl/Urea).The FT-IR,Raman,structure and formation mechanism were further discussed.Eventually,it is found that all the assignments of vibrational modes byprevious experimental works are reasonable.The calculated spectra agree well with the experimental results.Nearly all the experimental characteristic peaks of IR and Raman have been assigned according to the calculated results.Secondly,Considering the current discussion of the existing mechanisms of adsorptive desulfurization,?-complexation is the main mechanism in the system that metal complexes adsorbs sulfide.This work introduced a series of metal into the h-BN to enhance the adsorption property.The deep eutectic solvents(ZnCl2/urea,SnCl2/urea)were used as a medium of metal-doping.The metal Zn and Sn were doped into h-BN respectively.Results found that in the h-BN precursor preparation process,this kind of deep eutectic solvents will combine with boric acid to form metal compounds(Zn(CN2),SnO2)with h-BN,forming composite material similar to the heterojunction.it is found that this new type of adsorbents synthesized by this method show 17.93 mg/g adsorption performance.Finally,this work guessed from the adsorption mechanism of hard and soft acid-base theory model,by means of introducing the carbon atoms in the h-BN network to reduce the chemical hardness of adsorbent,so that raising the adsorption capacity.This work firstly employed conceptual density functional theory to analyze the frontier orbital of BN_xC and the chemical hardness.The results found that the chemical hardness of BN_xC is reduced as the increasing of carbon content.Thus,a series of different carbon content of BCN-x were synthesized.The adsorption capacities of BCN-x are increased as the increasing of carbon content(the adsorption capacity of BCN-50 is 27.43 mg/g).It is proved that structure-activity relationship between hardness and its adsorption performance,and reasonably explained the mechanism of adsorption.By calculation of adsorption energy,it can be also confirmed that with the increasing of carbon content,the adsorption performance of BCN will improve accordingly.