A quartz boat was filled with ca. 0.1 g of the zeolite 13X synthesized using the bottom ash precipitate, positioned into the middle of the horizontal tubular reactor, and the furnace temperature was increased to 700 ◦C and maintained for 30 min in a flowing gas mixture of Ar:H2:C2H2 = 14:5:1. The flow rate of argon was kept constant at 100 ml/min. To purify the obtained products, oxidation in air at 470 ◦C was carried out for 20 min at a fast heating rate (10 ◦C/min), followed by acid etching using 45 wt% HF for 24 h and a 10 wt% HCl solution to remove the zeolite support.