Dear Farzaneh Khoshoei, styrene/divinyl benzene porous copolymers are examples, with the acid group (carboxylic or sulfonic) as a substitute on the benzene ring are being produced for decades. Also acrylic acids may be used instead of styrene. My Regards
thank you for your interesting technical question. As already indicated, such types of porous polymers containing free carboxylic groups are well-established. As a typical reference please have a look at the following article:
Carboxylic Acid Enriched Porous Organic Polymer as a Platform for Highly Efficient Removal of Methylene Blue from Aqueous Solution
Article Carboxylic Acid Enriched Porous Organic Polymer as a Platfor...
I also suggest that you use the "Search" function of ResearchGate to find and access other relevant research articles.