Some biomolecules are well known for the complexation of heavy metals from wastewater: cellulose, alginate, pectins, and starches for example. However, less used natural molecules could also be efficient to chelate heavy metals. Indeed, some cells contain polypeptides that can help detoxifying living organisms containing heavy metals. This natural detoxification process is of great interest, and particularly the molecules taking part in it. The amino acids composing these polypeptides, especially cysteine, tyrosine, and histidine, can be used for water purification. The efficiency of biomolecules containing aromatic rings on heavy metals complexation is also investigated. All these biomolecules are able to chelate heavy metals thanks to some chemical groups and atoms: the most well-known and efficient chemical groups are listed in the article. Finally, some potential environmental applications of biomolecules are suggested at the end of the article.