Lignin-based hierarchical porous carbon with high specific surface area and preparation method and application thereof

A preparation method for a lignin-based hierarchical porous carbon with a specific surface area of 2200-3000 m2/g, comprising the following steps:

• (1) stirring and mixing aqueous solutions of triethanolamine and glutaraldehyde at 50 to 80° C., and reacting for 1 to 6 h, to obtain a solution of triethanolamine-glutaraldehyde condensate;
• (2) formulating a lignin into an aqueous solution having a mass concentration of 50 to 300 g/L, then adding maleic anhydride, acrylic acid and hypophosphorous acid thereinto, stirring evenly at 60 to 80° C., then dropwise adding an initiator solution having a predetermined mass concentration, reacting for 2 to 4 h, then adding the solution of condensate of the step (1) thereinto, and continuing to react for 1 to 6 h, to obtain a solution of lignin graft-copolymerized by phosphino carboxylic acid copolymer;
• (3) adding an aqueous solution of a soluble calcium salt into the solution of lignin graft-copolymerized by phosphino carboxylic acid copolymer obtained in the step (2) at a predetermined volumetric flowrate, continuing to stir and mix for 30 min to 2 h after a completion of the adding, then adding an aqueous solution of a soluble carbonate thereinto at a predetermined volumetric flowrate, continuing to stir and mix for 1 to 3 h after completion of the adding, standing still and aging for 3 to 6 h, filtering and separating out a precipitate, and drying the precipitate, to obtain a lignin/nano CaCO3 complex;
• and
• (4) carbonizing the lignin/nano CaCO3 complex obtained in the step (3) in an inert atmosphere, then washing with an acid, washing with water, filtering, and drying, to obtain a lignin-based hierarchical porous carbon;
• in terms of parts by weight, a formula for quantities of respective reactants is as follows:
• lignin
• 100
• parts,
• triethanolamine
• 5 to 20
• parts,
• glutaraldehyde
• 5 to 20
• parts,
• maleic anhydride
• 2 to 20
• parts,
• acrylic acid
• 2 to 20
• parts,
• hypophosphorous acid
• 1 to 10
• parts,
• initiator
• 2 to 20
• parts,
• soluble calcium salt
• 50 to 100
• parts, and
• soluble carbonate
• 50 to 100
• parts,
• the lignin in the step (2) is at least one selected from the group consisting of sodium lignosulfonate in a red liquor from acid pulping, calcium lignosulphonate in the red liquor from acid pulping, magnesium lignosulfonate in the red liquor from acid pulping, a sulfonated product of alkali lignin in a black liquor from alkaline pulping or a sulfonated product of enzymatic lignin from a biorefinery process.