Method for synthesizing mesoporous nano-sized ultra-stable y zeolite

A method for synthesizing a mesoporous nano-sized ultra-stable Y zeolite, the method comprising:

• mixing sodium hydroxide and water to form an aqueous NaOH solution;
• adding sodium aluminate and colloidal silica to the aqueous NaOH solution and mixing to form a hydrogel, where the hydrogel has a molar ratio composition of 5 to 15 Na2O:Al2O3:7 to 20 SiO2:200 to 400 H2O;
• transferring the hydrogel to an autoclave operated at 50° C. to 70° C. for 10 to 20 hours;
• further operating the autoclave at 80° C. to 120° C. for 10 to 20 hours to form a zeolite precursor;
• filtering and washing the zeolite precursor with water until the pH reaches 8 to 9 to form a nano-sized Y zeolite;
• combining the nano-sized Y zeolite with 30 to 1,000 milliliters water per gram of the nano-sized Y zeolite on a dry basis to form a nano-sized Y zeolite slurry mixture and heating the nano-sized Y zeolite slurry mixture to 70° C. to 100° C.;
• adding a 0.1 to 2.0 M aqueous solution of ammonium hexafluorosilicate over 1 to 2 hours to the nano-sized Y zeolite slurry mixture to form a dealuminated solution;
• holding the dealuminated solution at 70° C. to 100° C. for 1 to 8 hours;
• filtering and washing the dealuminated solution with water to form an ultra-stable Y zeolite precursor;
• drying the ultra-stable Y zeolite precursor at 80° C. to 150° C. for 6 to 24 hours to form a dried zeolite precursor;
• and
• calcining the dried zeolite precursor at 250° C. to 600° C. for 1 to 8 hours to form the nano-sized ultra-stable Y zeolite.