The relevance of this work lies in its contribution to water purification through two approaches. On the one hand, using sorbents made from foamed nanographite-structured materials, and on the other,employing eco-safe nanocomposites of carbon nitride with titanium dioxide, which is widely applied as a photocatalyst for water treatment via an advanced method: the generation of reactive oxygen species (ROS).

In the first stage of this work, the hypothesis posited that the earlier TiO₂ engages with and simultaneously synthesizes C₃N₄ during its formation , the more effective the resultant photocatalyst will be.

The first stage of this work included several steps:

1. SiO₂∙xEtOH and HₓTiᵧO₂∙H₂SO₄ sols were prepared and converted into gels: SiO₂∙8.6H₂O and TiO₂∙25.9H₂O (TGA).
2. Annealing in an inert atmosphere (3 h at 500°C; 3°C/min) was performed for melamine and its mixtures with desulfated titanyl sols: SiO₂‧8.6H₂O; TiO₂‧25.9H₂O and nano-TiO₂ P25. TGA modeling demonstrated that mass loss in the presence of TiO₂ was lower than with SiO₂.
3. AFM data revealed that the smallest particle size was observed in the thermolysis products of melamine mixtures either with the sol derived from (NH₄)₂TiO(SO₄)₂ (STA) or with the TiO₂‧25.9H₂O gel.
4. From the mixture of melamine with the STA-derived sol, semi-amorphous nanocrystalline g-C₃N₄ and rutile were formed (XRD). The mixture with the TiO₂‧25.9H₂O gel yielded the same phases, plus anatase.
5. The most effective photocatalyst for methyl orange degradation was C₃N₄ with TiO₂ from the STA-derived sol.

If, under the same temperature program, foamed melamine is subjected to thermolysis, a foamed product reproducibly crystallizes, which, according to XRD, is single-phase nanographite. The nanostructured layered morphology is confirmed by SEM. At the same time, according to CHNS analysis, this product contains carbon and 44% nitrogen. As a sorbent, this material absorbs 11 g/g of gasoline.