Figure 4

(a) Nitrogen adsorption–desorption isotherms of \(\text{g} - {\text{C}}_{3}{\text{N}}_{4}\), (b) Average values of \(\text{g} - {\text{C}}_{3}{\text{N}}_{4}\) zeta potential in aqueous suspensions at different pH, (c) nitrogen adsorption–desorption isotherms and (d) pore size distribution of the membrane.