Catalytic effects of ammonium dihydrogen phosphate on the pyrolysis of lignocellulosic biomass: Selective production of furfural and levoglucosenone

The catalytic effects of ammonium dihydrogen phosphate (ADP) on the biomass pyrolysis and its mechanism for the selective production of furfural (FF) and levoglucosenone (LGO) were investigated in this study. Samples were prepared with rice husk and ADP solutions with gradient-concentration and pyrolyzed via TG-FTIR and PyGC/MS. Results showed that ADP made the decomposition of cellulose occur at a lower temperature and greatly enhanced the release of C=O groups and carbohydrates below 300 degrees C, indicating the breakage of glycosidic bond and dehydration reaction during pyrolysis were promoted by ADP. In the pyrolysis volatiles, the production of anhydrosugars and furans was promoted significantly. Due to the rearrangement of the methoxy group, the production of methoxy phenols and CH4 was decreased simultaneously. ADP showed good selectivity for both FF and LGO. With the increased ADP dose, the yield and relative content of FF and LGO increased firstly and then kept stable. 400 degrees C was found the optimal temperature for the production of FF and LGO, where the sum of the relative peak area of LGO and FF could reach 52.23%. Finally, a possible formation pathway of LGO and FF under the catalysis of ADP was speculated.