金属盐协同预处理对木质素微波辅助解聚产物的影响OA

Lignin(Fe-Lignin and W-Lignin)was pre-impregnated with inexpensive metal salts(ferrous sulfate and ammonium metatungstate),and microwave-assisted depolymerization of lignin was conducted via a microwave-assisted dynamic gas-phase flow reaction system to investigate the generation characteristics of the liquid and solid products from depolymerization.Electromagnetic properties showed that the dielectric loss tangent(tan δ)of lignin after pre-impregnation was higher than that of untreated lignin,especially ferrous sulfate-ammonium metatungsate pre-impregnation(W-Fe-Lignin),which increased the tan δ(2.45 GHz)of lignin from 0.039 to 0.072.Microwave-assisted depolymerization showed that W-Fe-Lignin raised the lignin conversion rate from 44.76%for untreated lignin to48.77%,while the yield of phenolic monomers represented by guaiacol and vanillin increased from 91.00 mg/g to 167.35 mg/g;W-Fe-Lignin also increased the tan δ(2.45 GHz)of lignin-based biochar to 0.197.Analysis of depolymerization products and multiphysics coupling indicated that W-Fe-Lignin,with high microwave absorption characteristics,could achieve rapid heating under microwave irradiation and convert to metal oxides,raising the temperature field from 570.5℃to 640.8℃,thereby promoting efficient lignin conversion and directional selectivity.