Method of storing hydrogen in an underground geological formation

1 . A method of storing hydrogen in an underground geological formation, comprising:

injecting a liquid activated carbon into the underground geological formation,

wherein the underground geological formation is at least one subterranean rock selected from the group consisting of sandstone, limestone and eagle ford shale;

absorbing the liquid activated carbon in the underground geological formation to form a treated underground geological formation; and

injecting a gaseous mixture comprising mainly hydrogen into the treated underground geological formation, thereby absorbing the hydrogen gas into the treated underground geological formation,

wherein the liquid activated carbon and the gaseous mixture is injected through different boreholes into the same underground geological formation.

2 . The method of claim 1 , wherein the subterranean rock is sandstone comprising:

quartz, at a weight percentage of 90 to 98 wt. %;

dolomite, at a weight percentage of 0.5 to 1.0 wt. %; and

microcline, at a weight percentage of 3 to 5 wt. %,

based on the total weight of the subterranean rock.

3 . The method of claim 1 , wherein the subterranean rock is limestone comprising calcite.

4 . The method of claim 1 , wherein the subterranean rock is eagle ford shale comprising:

quartz, at a weight percentage of 11 to 15 wt. %; and

calcite, at a weight percentage of 80 to 90 wt. %,

based on the total weight of the subterranean rock.

5 . The method of claim 1 , wherein the subterranean rock comprises quartz comprising:

elemental silicon, at a weight percentage of 85 to 90 wt. %;

elemental sulfur, at a weight percentage of 0.01 to 0.05 wt. %;

elemental potassium, at a weight percentage of 1 to 5 wt. %;

elemental calcium, at a weight percentage of 1 to 5 wt. %;

elemental titanium, at a weight percentage of 0.1 to 1 wt. %;

elemental chromium, at a weight percentage of 0.1 to 1 wt. %;

elemental manganese, at a weight percentage of 0.1 to 1 wt. %;

elemental iron, at a weight percentage of 5 to 10 wt. %;

elemental zinc, at a weight percentage of 0.01 to 0.05 wt. %; and

elemental zirconium, at a weight percentage of 0.1 to 0.5 wt. %,

based on the total weight of the quartz.

6 . The method of claim 1 , wherein the subterranean rock comprises calcite comprising:

elemental silicon, at a weight percentage of 0.1 to 0.5 wt. %;

elemental sulfur, at a weight percentage of 0.1 to 0.5 wt. %;

elemental calcium, at a weight percentage of 95 to 99.5 wt. %;

elemental manganese, at a weight percentage of 0.01 to 0.05 wt. %;

elemental iron, at a weight percentage of 0.1 to 0.5 wt. %;

elemental zinc, at a weight percentage of 0.01 to 0.05 wt. %; and

elemental zirconium, at a weight percentage of 0.01 to 0.05 wt. %,

based on the total weight of the calcite.

7 . The method of claim 1 , wherein the subterranean rock is eagle ford shale comprising:

elemental silicon, at a weight percentage of 15 to 25 wt. %;

elemental sulfur, at a weight percentage of 1 to 5 wt. %;

elemental potassium, at a weight percentage of 0.1 to 0.5 wt. %;

elemental calcium, at a weight percentage of 70 to 80 wt. %;

elemental manganese, at a weight percentage of 0.1 to 1 wt. %;

elemental iron, at a weight percentage of 0.5 to 1 wt. %;

elemental aluminum, at a weight percentage of 1 to 5 wt. %; and

elemental phosphorus, at a weight percentage of 0.1 to 0.5 wt. %,

based on the total weight of the eagle ford shale.

8 . The method of claim 1 , wherein the subterranean rock comprises a plurality of particles having a particle size of 1 to 100 microns (μm), and the liquid activated carbon is absorbed at a volume percentage of 100 to 200 mL per 10 to 20 grams of the subterranean rock.

9 . The method of claim 1 , wherein the liquid activated carbon is absorbed in the underground geological formation at an ambient temperature for at least 24 hours.

10 . The method of claim 1 , wherein the gaseous mixture comprises hydrogen at a volume percentage of 95 to 100 vol. %.

11 . The method of claim 1 , wherein hydrogen is injected at a pressure of 0.5 to 10 MPa under an ambient temperature.

12 . The method of claim 1 , wherein 0.4 to 0.8 mmol of H 2 per 1 gram of the subterranean rock is adsorbed by the treated underground geological formation.

13 . The method of claim 1 , wherein 8 to 50% more H 2 by mole per 1 gram of the subterranean rock is absorbed by the treated underground geological formation than an untreated underground geological formation.

14 . The method of claim 1 , wherein hydrogen is injected at a pressure of 6 to 7 MPa, and the subterranean rock comprises quartz, and

wherein 0.4 to 0.5 mmol of H 2 per 1 gram of the quartz is absorbed by the treated underground geological formation.

15 . The method of claim 14 , wherein 8 to 10% more H 2 by mole per 1 gram of the subterranean rock is absorbed by the treated underground geological formation than an untreated underground geological formation.

16 . The method of claim 1 , wherein hydrogen is injected at a pressure of 6 to 7 MPa, and the subterranean rock comprises calcite, and

wherein 0.7 to 0.8 mmol of H 2 per 1 gram of the calcite is absorbed by the treated underground geological formation.

17 . The method of claim 16 , wherein 20 to 30% more H 2 by mole per 1 gram of the subterranean rock is absorbed by the treated underground geological formation than an untreated underground geological formation.

18 . The method of claim 1 , wherein the hydrogen is injected at a pressure of 6 to 7 MPa, and the subterranean rock is eagle ford shale, and

wherein 0.6 to 0.7 mmol of H 2 per 1 gram of the eagle ford shale is absorbed by the treated underground geological formation.

19 . The method of claim 18 , wherein 40 to 50% more H 2 by mole per 1 gram of the subterranean rock is absorbed by the treated underground geological formation than an untreated underground geological formation.