Fewer toxic and cost-effective catalysts such as organic-inorganic polymer composites are highly necessary for the water purification. This work describes the sono-assisted fabrication of photocatalyst including multi-walled carbon nanotubes (CNTs), carbon dots (Cdots), magnesium fluorohydroxyapatite (FA), and TiO nanoparticles (NPs) (CNT/Cdot/FA/TiO) for methylene blue (MB) degradation in the water solution. This hybrid was employed for the reinforcement of crosslinked alginate (CAlg) and fabrication of CAlg/CNT/Cdot/FA/TiO composite. The photocatalytic behavior of this composite was examined for the MB degradation. To examine TiO NPs effect on the as- products, the mentioned samples were prepared without TiO, as well. Photodegradation yields of the samples followed in the order of CNT/CD/FA/TiO > TiO NPs > CAlg/CNT/Cdot/FA/TiO composite > pure FA. The outcomes indicated that the TiO hybridization not only could postpone the recombination of photo-created electron-hole pairs but also prevented aggregation of TiO NPs, which led to enhancement in the photodegradation yield of MB.