Fabrication of chitosan and ilmenite sand-based novel photocatalysts through the catalytic graphitization of chitosan is reported. Nanocomposites consisted of TiO₂, Fe₂O₃ and Fe nanoparticles dispersed on a nitrogen-doped graphitic carbon framework. The surface area, pore volume and macropore structure of the carbon matrix is disturbed by the heterogeneously distributed nanoparticles. The extent of graphitization expanded with increasing metal loading as indicated by variation in the I_D/I_G ratio. The nanomaterial’s surface consists of Fe³⁺ and Ti⁴⁺, and graphitic, pyridinic and pyrrolic nitrogen were found in the carbon matrix. The band gap values of the composites varied in the 2.06–2.26 eV range. The photocatalytic activity of the synthesized nanomaterials was determined, and the highest rate constant for the photodegradation of methylene blue under sunlight was 4.4 × 10⁻³ min⁻¹, which resulted with 10 mg/L MB and 25 mg of the best-performing catalyst. The rate constant rose with increasing concentrations of persulfate added to the medium. The rate constant greatly diminished with the addition of isopropyl alcohol as it scavenged hydroxyl radicals. The presence of co-pollutants including Pb²⁺, rhodamine B, PO₄³⁻ and Cl⁻ curtailed the rate of reaction. The activity reduced with an increasing number of uses of the catalyst.

Ilmenite is a mineral whose crystallinity can be altered by chemical treatment, producing TiO2 and iron and titanium-based metal nanocomposites, which are applicable mainly for photocatalysis. Porous and crystalline biomass-derived carbon materials include graphene oxide, reduced graphene oxide, graphitic carbon nitride, catalytically graphitized sucrose and chitosan, and activated carbon. Ilmenite-based metal oxides coupled with biomass-based carbon materials are effective in environmental remediation, especially in dye photodegradation, adsorption, and antibacterial activity. This review summarizes the synthesis and applications of ilmenite and biomass-based composites nanomaterials.