Removal of dyes from aqueous solution using novel C@C composite adsorbents

In the present work, novel porous C@C composite adsorbents were prepared and applied for the adsorption of methylene blue (MB) and rhodamine B (RB). The adsorbents were prepared by carbonizing resorcinol–formaldehyde (RF) resins-coated ZIF-8 composites that obtained using an in-situ deposition method. The effect of RF/ZIF-8 ratio and carbonization temperature on the particle size, specific surface area and pore size was investigated. High adsorption capacity resulted from the high surface area of 1842 m²/g and a sufficient pore size of 4.4 nm. The effect of temperature, initial dyes concentration and pH on the adsorption capacity was investigated to optimize the adsorption conditions, and maximum adsorption capacity of 681 and 462 mg/g was observed for MB and RB, respectively. Langmuir model and pseudo-second-order adsorption kinetics model can be used to well describe the obtained adsorption isotherms. The estimated saturated adsorption capacity for MB and RB was 806 and 476 mg/g, respectively. The used C@C-1000 could be regenerated in methanol solution, and after 5 cycles, the adsorption capacity was maintained above 92% of the maximum.