Synergistic biocomposites (HAp/AC) of rice husk-based activated carbon (AC) and turkey bone-derived hydroxyapatite (HAp) for degradation of toxic dyes, antibacterial efficacy, and in vitro evaluation of anticancer activity in human hepatocellular carcinoma HepG2 cell line

In this study, activated carbon derived from rice husk (AC) and the hydroxyapatite/activated carbon biocomposite with varying concentrations of AC (AH1 and AH2) were successfully synthesized and comprehensively analyzed using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, elemental dispersive spectroscopy, and UV–vis techniques. Photocatalytic degradation experiments were conducted for Congo red and methylene blue dyes under UV light using the synthesized samples as catalysts. Results showed that all samples exhibited enhanced efficiency and fitted well with pseudo-first-order kinetics, with AH2 composite demonstrating superior efficiency and rate constant compared to other samples. Recycling tests conducted over two cycles confirmed the sustained efficiency of AC, HAp, and HAp/AC composites. The degradation of Congo red dye was investigated using photocatalytic methods, with analysis facilitated by Gas Chromatography-Mass Spectrometry (GC–MS) to identify and characterize the breakdown products formed during the photodegradation process. Furthermore, antibacterial tests revealed that the AC and HAp/AC composites possess significant antibacterial properties against Bacillus subtilis, Staphylococcus aures, Escherichia coli, and Pseudomonas aeruginosa strains. In vitro assessment using the MTT assay on different concentrations of the liver cancer cell line (HepG2) for AC, HAp, and AH2 samples showed an IC₅₀ value of 24.96 μg/ml, 43.68 μg/ml, and 21.8 μg/ml. Significantly, the cell viability of HepG2 cells with AH2 composite was significantly higher compared to AC, indicating enhanced proliferation. Overall, the HAp/AC biocomposite holds great potential for biomedical applications, given its capacity to mitigate bacterial infections and stimulate cancer cell proliferation. Furthermore, its capability for the photodegradation of synthetic dyes utilized in textile industries hints at significant environmental and clinical benefits.