De or het sorptie?

The correct Dutch article is:

de sorptie

Rule Words ending in -tie and -sie: almost always de. See the rule
Meaning (Dutch) adsorptie

How to use sorptie

the sorptiede sorptie
this sorptiedeze sorptie
that sorptiedie sorptie
our sorptieonze sorptie
your sorptiejouw sorptie
every sorptieelke sorptie
which sorptie?welke sorptie?
a big sorptie / the big sorptieeen grote sorptie, de grote sorptie

Dutch words ending in sorptie

absorptie | reabsorptie | malabsorptie | adsorptie | desorptie | resorptie | chemisorptie

In compound words, the last part decides the article. See the rule

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).