Mild-acid-assisted thermal or hydrothermal dealumination of zeolite beta, its regulation to Al distribution and catalytic cracking performance to hydrocarbons

•Dilute HCl combined with steaming or calcination removed ∼70% Al of zeolite β.•Combined dealumination was more versatile than single treatment.•Acid steaming removed Al on T2, T5, T6, and T7 sites and drove poly-EFAL to external surface.•Acid calcination resulted in a more homogeneous Al distribution in zeolite β structure.•Acid calcination caused stronger B acidity and higher B acid density than acid steaming.