Fig. 5. Organic dye adsorption capacities of various porous materials based on coal gangue, as reported in the literature. (1) Porous ceramic microspheres, basic fuchsine, (2) porous ceramic microspheres, cationic blue, (3) porous ceramic microspheres, cationic red, (4) porous zeolite/activated carbon composites, rhodamine B, (5) porous carbon, rhodamine B, (6) porous gangue/palygorskite composites, methylene blue, (7) porous activated material, methylene blue, (8) porous alkali-activated material, methylene blue, and (9) porous ceramic microspheres, methylene blue.
