## 4 Significance of g-C\({}_{3}\)N\({}_{4}\) towards Energy Storage and Environmental Impacts
### Environmental Applications  
Scientists are very interested in these materials because of their outstanding electrical and chemical properties. Carbon nitride is found in nature in five different crystalline forms, according to research. Along with its chemical reactivity, mobility, and sensitivity, graphitic carbon nitride (g-C\({}_{3}\)N\({}_{4}\)) has received much interest [64; 65]. The g-C\({}_{3}\)N\({}_{4}\) is made up of tris-triazine subunits with a lot of extra electrons and has a planar-conjugated shape [46]. Due to the obvious chemical bonding formed between g-C\({}_{3}\)N\({}_{4}\) and metal ions, it is applied to eliminate pollutants from wastewater. To interpret a hybrid iron-oxides nanocomposite (Fe\({}_{3}\)O\({}_{4}\)-g-C\({}_{3}\)N\({}_{4}\)), Fe\({}_{3}\)O\({}_{4}\) nanostructures loaded on g-C\({}_{3}\)N\({}_{4}\) were designed by [PERSON] et al. [46] under the ultrasonication method. They used SEM, X-ray diffraction, vibrating sample magnetometer (VSM), Fourier transform infrared, thermogravimetric analysis, and particle size analyzer to investigate the morphology and compositions of the formed catalysts, and the magnetic adsorbent Fe\({}_{3}\)O\({}_{4}\)-g-C\({}_{3}\)N\({}_{4}\) was used to extract Cd(II), Pb(II), and Zn(II) from aqueous medium. Adsorption in real samples: Experiments in electrolytic zinc residue percolate were used to study the adsorption ability of as-prepared Fe\({}_{3}\)O\({}_{4}\)-g-C\({}_{3}\)N\({}_{4}\). The effluent was made up to conduct the adsorption studies by purifying it through a membrane filter. The obtained adsorption capacities for the Fe\({}_{3}\)O\({}_{4}\)-g-C\({}_{3}\)N\({}_{4}\) nanocatalysts for Cd(II), Pb(II), and Zn(II) were 50.41, 69.38, and 82.31 mg/g, respectively (Figure 6). However, melamine and industrial waste residue (red mud) were taken as source components in a one-step thermal polymerization process to create the red mud/g-C\({}_{3}\)N\({}_{4}\) (RM-CN) composite [66]. Because of the synergistic effect of adsorption and photocatalysis, RM-CN composites have a massive impact on the removal of organic contaminants from sewage. The surface morphology of RM-CN was considerably enlarged, concerning only CN, due to the inclusion of RM. The refined 0.8 percent RM-CN product (with RM mass concentration of 0.8 wt% in precursor) exhibited considerable photodegradation effectiveness for antibiotics and organic molecules with excellent recycling ability when exposed under visible spectrum (Figure 7). Figure 6: (a) Impact of metal competition on adsorption capacity (metal ion concentration, 200 mg/L), (b) cycle adsorption studies of Zn(II), Cd(II), and Pb(II) by Fe\({}_{3}\)O\({}_{4}\)–g-C\({}_{3}\)N\({}_{4}\)[46]. Therefore, these are some basic studies performed for wastewater learning to protect environmental health. Additionally, numerous nanomaterials and their functionalized phases were studied for their environmental impacts and biomedical significance due to their modified surface, shape, sizes, and band structures [28; 62; 63]. In the present article, wider information of carbon nitride-based materials is focused on including manufacturing and their applications in medical science and environmental technologies [69; 70; 71]. Figure 8: Photocatalytic-based H\({}_{2}\) production process (**a**) and stability for H\({}_{2}\) production (**b**) of Zn-tri-PcNc/g-C\({}_{3}\)N\({}_{4}\) materials. Figure 7: (**a**) Trapping studies of active moieties throughout photocatalytic degradation of TC over 0.8% RM-CN. (**b**) ESR bands of % O\({}_{2}\)\({}^{-}\) trapped by DMPO over 0.8% RM-CN sample in dark and light irradiation [66]. Cu(I)-loaded conjugated carbon nitride structures (Cu–CNF) along with the heteroatom N and O were structured followed by the ligand charge transfer [67]. Cu–CNF catalysts were employed efficiently to catalyze chlorotetracycline hydrochloride chemicals from the deionized water. The elimination rate was high in the case of the river water (68.2%) corresponding to the tap water (45.7%), and swine wastewater (45.7%) (33.1 percent).