▎ 摘　　要

NOVELTY - Preparation of solid acid catalyst comprises reacting graphene oxide suspension dissolved with aluminum salt by liquid phase deposition to obtain alumina modified graphene oxide; and reacting the alumina modified graphene oxide with concentrated sulfuric acid to obtain the product. USE - The solid acid catalyst is used for catalyzing esterification and/or transesterification reaction of kitchen waste oil and formic acid (claimed). ADVANTAGE - The method has simple operation, and mild condition. The solid acid catalyst has good catalytic effect, can realize fatty acid methyl ester yield higher than 90%, is easy to separate from the product, can be recycled by simple treatment, has no pollution, and reduces the production cost of kitchen waste oil to prepare bio-diesel. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a solid acid catalyst.