Surface modification of activated carbon cloth with calcium silicate and hydroxyapatite: bioactive composite material

In this study new compounds consisting of activated carbon cloths (ACC) modified with calcium silicate (CaSiO₃) were prepared for hydroxyapatite (HAP) generation. ACC samples were oxidized with 8 M HNO₃ at different times (15 min and 2 h), to increase oxygenated functional groups. The CaSiO₃ fine powders were prepared by chemical coprecipitation using Ca(NO₃)₂∙4H₂O and Si(OC₂H₅)₄, and 5 M NaOH was used as precipitant. The resulting powders were mixed with ethanol by ultrasound stirring and the previously oxidized activated carbon fibers were placed leaving under stirring for 30 min to allow particle dispersion. Once the formed compounds were dried, the samples were immersed in a simulated body fluid (SBF) solution for 21 days in conical tubes at 36.5 °C to allow the HAP formation on the ACC/CaSiO₃ composite surface. The results indicated that the increase in oxidation time improves HAP formation on the surface from ACC/CaSiO₃ compounds and this bioactive composite may be a potential material for bone regeneration.