Synthesis of zeolites by hydrothermal reaction of zeolite P1
AssigneeCalifornia Institute of Technology
InventorsMark E. Davis, Shervin Khodabandeh
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Abstract
New synthetic zeolites incorporating alkaline earth elements and routes for preparing those zeolites by hydrothermal alteration of zeolite P1 are disclosed. New methods for producing P1 zeolites are also identified. Synthetic heulandite, brewsterite, epistilbite and harmotome, among other zeolites can be prepared.
Claims57
A method of making a zeolite, comprising the steps of forming a mixture of a P1 zeolite in aqueous solution, said solution comprising at least one alkaline earth cation;
- and heating said mixture to produce a zeolite that is different from P1 but includes said alkaline earth cation.
A method of making a zeolite having a heulandite topology, comprising the steps of forming an aqueous mixture of an alkaline earth cation and adding a P1 zeolite thereto;
- and heating said mixture for a period of time to produce said zeolite having a heulandite topology and a molar composition in terms of mole ratios expressed by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3 :6-8 SiO.sub.2 :zH.sub.2 O, wherein X is at least one alkaline earth cation selected from the group consisting of Ca and Sr, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m, n+m is approximately 1, and z.gtoreq.0.
A method of making a zeolite having a brewsterite topology, comprising the steps of:
- forming an aqueous mixture of an alkaline earth cation, a P1 zeolite and seeds to form a mixture, wherein said seeds include a zeolite having a brewsterite topology;
- and heating said mixture for a period of time to produce said zeolite having a brewsterite topology and a molar composition expressed in terms of mole ratios by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3 :5.5-6.5 SiO.sub.2 :zH.sub.2 O, wherein X is at least one alkaline earth cation selected from the group consisting of Sr and Ca, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m, n+m is approximately 1, z.gtoreq.0 and wherein the amount of Ca.gtoreq.0 and the amount of Sr is greater than the amount of Ca.
A method of making a zeolite having a phillipsite topology, comprising the steps of forming an aqueous mixture of barium and a P1 zeolite;
- and heating said mixture for a period of time to form said zeolite having a phillipsite topology and a molar composition expressed in terms of mole ratios by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3 :4-6 SiO.sub.2 :zH.sub.2 O, wherein X is at least one alkaline earth cation selected from the group consisting of Ba and Ca, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m, n+m is approximately 1, z.gtoreq.0 and wherein Ca.gtoreq.0 and the amount of Ba is greater than the amount of Ca.
A method of making a zeolite having an epistilbite topology, comprising the steps of forming an aqueous mixture of a P1 zeolite, Ca.sup.2+ and an alkali metal cation;
- and heating said mixture for a period of time to form said zeolite and a molar composition expressed in terms of mole ratios by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3 :5-7 SiO.sub.2 :zH.sub.2 O, wherein X is Ca, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m and n+m is approximately 1 and z.gtoreq.0.
A method of making P1 zeolite, comprising the steps of forming a sodium aluminosilicate gel from an aqueous mixture including silica and alumina at a basic pH;
- drying said gel to form a dried solid, said dried solid having a composition expressed by the formula in terms of molar ratios of 1-4 Na.sub.2 O:Al.sub.2 O.sub.3 :9-10 SiO.sub.2 ;
- and mixing said dried solid with an aqueous solution of Na.sub.2 CO.sub.3 to form said P1 zeolite having a silicon to aluminum ratio of about 3 or greater.
A method for making P1 zeolite, comprising:
- heating an aqueous mixture containing perlite and an alkali metal cation in a basic environment to form said P1 zeolite having a silicon to aluminum ratio of 3 or greater.
A method of making P1 zeolite, comprising the steps of forming an aqueous mixture of Al(OH).sub.3 and NaOH;
- adding colloidal silica to said aqueous mixture to form a gel precursor;
- stirring said gel precursor to form a gel;
- heating said gel at about 110.degree. C.-175.degree. C. to produce said P1 zeolite, wherein said gel precursor has a composition such that said P1 zeolite has a silicon to aluminum ratio of about 3 or greater.
A method of making a zeolite, comprising the steps of:
- forming a mixture of a P1 zeolite in aqueous mixture, said mixture comprising at least one alkali metal cation;
- and heating said mixture to produce a zeolite that is different from P1 but includes said alkali metal cation.
Dependencies are inferred from the claim text.