Sorption of chloride-ion, sulfate-ion and phosphate-ion in calcium silicate hydrates

This study discusses the capacity of sorption of various ions in calcium si licate hydrates. Chloride-ion, sulfate-ion and phosphate-ion were sorbed in synthesized calcium silicate hydrates (C-S-H). The amount of sorbed chlori de-ion, sulfate-ion and phosphate-ion in C-S-H were 172 mg/g, 54 mg/g and 6 67 mg/g, respectively, In the case of sorption of phosphate-ion, phosphate- ion and C-S-H reacted to produce hydroxyapatite. In the leaching test, 15% of chloride-ion, 18% of sulfate-ion and 34% of phosphate-ion were dissolved from C-S-H sorbing respective anions. On the other hand, 65% of fixed chlo ride-ion in Friedel's salt was dissolved in the leaching test. Therefore, t he fixing ability of chloride-ion in C-S-H is higher than that. in Friedel' s salt.