“…Typical redox-active organic molecules for acidic aqueous system and their solubility, number of electrons transferred, and theoretical capacity. 9,10-Anthraquinone-2,7-disulfonic acid (2,7-AQDS), 4,5-dihydroxy-1,3-benzenedisulfonic acid (BQDSH 2 , tiron), , anthraquinone-2-sulfonic acid (AQS), 3,4-dihydroxy-9,10-anthraquinone-2-sulfonic acid (ARS), quinizarin-SO 3 -TKMP, alizarin S. Red-TKMP, 3,6-dihydroxy-2,4-dimethylbenzenesulfonic acid (DHDMBS), 1,8-dihydroxyanthraquinone-2,7-disulfonic acid (DHAQDS), 1,4-dihydroxyanthraquinone-2,3-dimethylsulfonic acid (DHAQDMS), 4,4′-biphenol-3,3′,5,5′-tetrasulfonic acid (4,4′-BPTS), lignosulfonate, polyhydroquinone (PHQ), 2,3,5,6-tetrakis((dimethylamino)methyl)hydroquinone (FQH 2 ), 2,3-diaza-9,10-anthracenedione (DAD), 2,3-diaza-6-methoxy-anthracene-9,10-dione (DAD(MeO)), 2,3-diaza-5,8-dihydroxy-anthracene-9,10-dione (DADdi(OH)), 5,8-dihydroxy-2,3-phthalazine (DHP), 5,8-dihydroxy-6-methoxy-2,3-phthalazine (DHP(MeO), 5,8-dihydroxy-6,7-dimethyl-2,3-phthalazine (DHP(Me) 2 , dopamine (DP), 3,3′,5,5′-tetramethylaminemethylene-4,4′-biphenol (TABP), 2-methoxy-1,4-hydroquinone (MHQ), 2-((2,5-dihydroxyphenyl)sulfanyl)ethan-1-aminium chloride (SEAHQ), methylene blue (MB), , Neutral Red (NR) or desalted Basic Red 5 (d-BR5), Azure A, promethazine (PMZ), chlorpromazine (CPZ), quaternary amine-functionalized naphthalenediimide (NDI), naphthalene-1,4,5,8-tetracarboxylic acid dianhydride–ethylenediamine copolymer (PI1), naphthalene-1,4,5,8-tetracarboxylic acid dianhydride- p -phenylenediamine copolymer (PI2), N -hydroxyphthalimide (NHPI), and 5,5′-indigodisulfonic acid (IC-H) …”