Synthesis Of Bimetallic Catalyst From Biomass Pyrolysis And Mechanism Study Of Sulfur Transformation In Coal Pyrolysis

Biomass is a type of sustainable resource and pyrolysis is an important conversion method of biomass.The issue of functional material synthesis from biomass pyrolysis is of great significance and has focused intensive attention.In addition,pyrolysis is a clean ultilization method of coal,as well as a critical intermediate stage in various conversion processes of coal.Pollutant transformation in coal pyrolysis is closely related to its practical application.Here,we synthesized a bimetallic catalyst from biomass pyrolysis and investigated its environmental application.In addition,we investigated sulfur evolution in coal pyrolysis using online TG-FTIR-MS method.The main contents and conclusions are as follows:Functionalization of biochar produced from biomass pyrolysis is a win-win strategy to both sufficient ultilization of waste biomass and facile synthesis of functional material in a environmentally friendly way.This work presents a facile and green strategy to synthesize a carbon supported Ru-Cu bimetallic material(Ru-Cu/C)with well-dispersed nanoparticles by fast pyrolysis of Cu2+ preloaded waste biomass and subsequent galvanic replacement reaction.The as-synthesized Ru-Cu/C with trace of Ru showed better catalytic activity for Cr(VI)reduction with N2H4·H2O than the monometallic catalysts(Cu/C and Ru/C),achieving complete reduction of Cr(VI)in aqueous solution in 3 min and a total chromium removal rate of 94%without additional precipitation process.Various characterizations were conducted and the results revealed the relationship between the structure and the synergistic effect of the bimetallic material.For example,XPS showed that strong interaction was found to exist between Cu and Ru in Ru-Cu/C.Furthermore,we explored the possible mechanism of the catalytic system and the active hydrogen species were confirmed to be the main contributor for Cr(VI)reduction.Coal pyrolysis is an intermediate stage of various coal conversion processes including gasification,combustion and liquefaction,as well as an effective method of sulfur removal.Due to the complexity of sulfur forms in coal and the pyrolysis process,the pyrolysis behavior of sulfur in coal is still unclear.In order to develop and evaluate desulfurization method,it is essential to understand the sulfur transformation in coal pyrolysis.In this study,the evolution of sulfur during coal pyrolysis in the presence and absence of CaO is investigated employing an online analysis method,thermogravimetry coupled with Fourier transform infrared spectroscopy and interfaced with mass spectrometry(TG-FTIR-MS).We monitored ten types of sulfur-containing products,including H2S,SO2,thiols,and thiophene.Combining the TG-FTIR-MS and XRD and XPS results,we have proposed the migration and transformation pathways of sulfur during coal pyrolysis.