While the C

4

F

7

N is an environmental-friendly insulation gas with a strong potential to replace SF

6

in the insulation devices

its decomposed species

especially C

2

F

6

C

3

F

8

C

3

F

6

and CF

4

exhibit a strong toxicity and poor insulation performance. In this paper

we propose calcium sulfate (CaSO

4

) as a promising gas adsorbent to scavenge such four toxic species in order to guarantee the safe operation of C

4

F

7

N-based insulation devices. Experimental findings show that CaSO

4

behaves a strong adsorption performance upon the moisture inner the devices and achieves dynamic equilibrium at about 70

$h$

. The adsorption behavior upon four gases is in order of C

2

F

6

> CF

4

> C

3

F

8

> C

3

F

6

with the adsorbed gas content ranging at 1.5~9 ppm. Theoretical results illustrate that CaSO

4

(010) surface behaves physisorption upon four toxic gases with E

ad

ranging a

t −0.77 to −0.67eV

and its electronic behavior changes are consistent with the order of QT. Both aspects indicate the strong potential of CaSO

4

as a promising scavenger for moisture removal

toxic gas sweeping and safe operation of C

4

F

7

N-based insulation devices. Our study puts forward a novel adsorbent for toxic gas removal in the gas insulation devices and can stimulate some other cutting-edge researches about adsorbent exploration in this field.