Researches on the application of calcium carbide residues in carbon fixation is mainly conducted at a macroscopic level

with limited studies exploring the carbon fixation mechanism of calcium carbide residues from a microscopic perspective. It

remains unclear whether the various impurities present in calcium carbide residues adversely affect the CO

2

adsorption activity of this material. To solve this problem

the phase compositions of calcium carbide residues before and after calcination were analyzed using X-ray diffraction

and density functional theory was employed to construct the most stable low-index crystal planes such as CaO-CaO(0 0 1)

CaO-Fe_2O

3

(0 0 1)

CaO-Al_2O

3

(1 1 1)

CaO-MgO(1 0 0) and CaO-SiO

2

(0 0 1). Moreover

the adsorption properties of CaO clusters on various impurity-supported surfaces and doped surfaces were simulated

along with the capabilities of these surfaces to support the adsorption of CO

2

molecules. The adsorption energy

charge transfer

density of states

and differential charge density of each adsorption system were analyzed. The results indicate that SiO

2

does not significantly influence the adsorption process. The four different supported surfaces enhance the anti-sintering performance of calcium carbide residues

with the strength of the effects ranked as follows: Al_2O

3

Fe_2O

3

MgO CaO. The adsorption energy on the Al_2O

3

supported surface is –8.82 eV

which is 1.24

2.45

and 3.69 times greater than that on the Fe_2O

3

MgO

and CaO supported surfaces

respectively. The capacities of the various surfaces to support CaO in the adsorption of CO

2

are similar

with the electron transfer quantities for the CaO clusters adsorbing CO

2

on the CaO

Fe_2O

3

Al_2O

3

and MgO supported surfaces being 0.67

0.68

0.71 and 0.66 e

respectively. The presence of impurities can effectively improve the anti-sintering performance of calcium carbide residue as a CaObased material

but can not significantly enhance the CO

2

adsorption effect. Compared with the pure CaO supported surfaces

the doped surfaces exhibit a stronger capability for CaO to adsorb CO

2

with ad

sorption energy and electron transfer quantities being –4.92 eV and 0.71 e

respectively.