Claims:We Claim: 1. A method for synthesis of a 13X zeolite, wherein, the method comprising steps of: preparing a seed material, wherein, the seed material is prepared by mixing sodium aluminate, sodium silicate, NaOH into water to get a seed mixture, stirring the seed mixture for 1-1.5 hour and aging at 30-45 °C for 18-26 hours; and preparing the 13X zeolite by mixing sodium aluminate, sodium silicate, NaOH into water, followed by addition of the seed material to obtain a gel mixture, stirring the gel mixture for 50-70 minutes and crystallization of the gel mixture at 95-100 °C for 8-12 hours, a filtration step and a washing step with hot demineralized water is performed to obtain a 13X zeolite cake. 2. The method as claimed in claim 1, wherein the amount of seed material added in the gel mixture is 0-5 wt.% of the gel mixture. 3. The method as claimed in claim 2, wherein the amount of seed material added in the gel mixture is 0-2 wt.% of gel mixture. 4. The method as claimed in claim 1, wherein, the seed material is prepared by mixing sodium aluminate, sodium silicate, NaOH, and water to get the seed mixture having a molar composition of 10-20SiO2:Al2O3:10-20Na2O:200-300H2O. 5. The method as claimed in claim 4, wherein, the seed material is prepared by mixing sodium aluminate, sodium silicate, NaOH, and water to get the seed mixture having a molar composition of 12-15SiO2:Al2O3:13-16Na2O:250-300H2O. 6. The method as claimed in claim 1, wherein, the 13X zeolite is prepared by mixing sodium aluminate, sodium silicate, NaOH, and water to get the gel mixture having a molar composition of 2-7SiO2:Al2O3:2-7Na2O:200-300H2O. 7. The method as claimed in claim 6, wherein, the 13X zeolite is prepared by mixing sodium aluminate, sodium silicate, NaOH, and water to get the gel mixture having a molar composition of 2-4SiO2:Al2O3:3-5Na2O:250-300H2O. 8. The method as claimed in claim 1-7, wherein, the 13X zeolite cake is dried at 120 °C for 24 hours, then crushed and grinded to obtain a 13X zeolite powder. 9. A method for preparing a 13X zeolite adsorbent by binding the 13X zeolite powder as claimed in claim 8 with a binder, preparing extrudes or beads of the 13X zeolite adsorbent, and then drying the said extrudes or beads at 120 °C. 10. The method as claimed in claim 9, wherein, the binder is selected from a clay, an organic polymer. 11. The method as claimed in claim 10, wherein, the organic polymer is a polyvinyl alcohol. 12. The method as claimed in claim 9, wherein, the 13X zeolite powder is 95-98 weight % and the binder is 2-5 weight %. 13. The 13X zeolite adsorbent as claimed in claim 9-12, wherein, the said 13X zeolite adsorbent has crystallinity in the range of 110 – 120%. 14. The 13X zeolite adsorbent as claimed in claim 9-12, wherein, the said 13X zeolite adsorbent has surface area in the range of 750-810 m2/g. 15. The 13X zeolite adsorbent as claimed in claim 9-12, wherein, the said 13X zeolite adsorbent has nitrogen adsorption capacity 30.6 cc/gm at 4.8 bar and high crushing strength. , Description:FIELD OF THE INVENTION: The present invention relates to a 13X zeolite, synthesis method and use thereof. Specifically, the present invention relates to a 13X zeolite adsorbent used for improving nitrogen adsorption capacity during oxygen production process from air. BACKGROUND OF THE INVENTION: Oxygen is a colorless gas found in the air and is a most important chemical element. Further, oxygen is required by all animals and is one of the life-sustaining elements on earth. Oxygen is also used in many industrial, commercial, medical and scientific applications. Recently, during the COVID-19 outbreak many countries faced shortage of oxygen supply in their critical care units. Due to many applications, there is always huge demand for pure oxygen and separation of oxygen from air is the best known industrial process for economically producing pure Oxygen. However, production of oxygen from air requires removal of other components like nitrogen, helium, argon and the like. The most common method for production of oxygen from air is pressure swing adsorption/vacuum pressure swing adsorption. For adsorption of nitrogen and other contaminants, an adsorbent based on 13X zeolite and LSX zeolite are used. Some of these prior known zeolites and their use in producing oxygen from air is explained hereinbelow. WO1996002462A1 discloses a method for producing crystalline synthetic faujasite of the zeolite 'X' type. The method comprises (a) separately preparing a sodium silicate solution and a sodium aluminate solution, (b) admixing the sodium silicate solution and the sodium aluminate solution at high shear until a mixture results having a ratio of sodium oxide to silica of 0.4:1 to 1:1, silica to alumina of 25:1 to 1.5:1, and water to sodium oxide of 20:1 to 50:1, (c) heating said mixture to a temperature of about 80 to 120 °C in the absence of any further mixing for a period of time sufficient to produce the desired crystalline faujasite of the zeolite 'X' type, and (d) recovering said zeolite 'X'. US10850988B2 discloses a process for synthesizing zeolite X crystals comprising at least one step of adding seeding agent(s) into a synthesis gel and at least one step of forming zeolite X crystals at a temperature strictly greater than 120° C, preferably equal to or greater than 130° C. US10888837B2 discloses the use, for gas separation, of at least one zeolite adsorbent material comprising at least one FAU zeolite, said adsorbent having an external surface area greater than 20 m2·g−1, a non-zeolite phase (PNZ) content such that 0