Kinetic, equilibrium, adsorption mechanisms of cationic and anionic dyes on N-doped porous carbons produced from zeolitic-imidazolate framework.

Nowadays, the pollution relating to organic dyes imposes many endangering risk on the aqueous ecosystems and mankind. There is a raising interest in the purification of synthetic dyes-polluted waters by the advanced technologies. Herein, we reported the direct and facile synthesis of N-doped porous carbons by pyrolyzing ZIF-8 as a self-sacrificial precursor for removing a wide range of synthetic dyes involving crystal violet, Congo red, malachite green, methyl orange. N-doped porous carbons were featured by some advanced analytic techniques. Moreover, the influence of pyrolyzing temperature (600–800 °C), adsorption time (0–180 min), and dyes content (10–100 mg/L) on uptake capacity on N-doped porous carbons was optimized. Nonlinearized kinetic and isotherm fittings aided to more understand the nature of organic dyes uptake. The highlight outcome indicated the presence of vital surface functional groups such as phenolic, carboxyl, lactone, and basic groups on N-doped porous carbon. Adsorption kinetics indicated the adherence of both pseudo-first-order equation, and pseudo-second-order equations. Equilibrium uptake of crystal violet, Congo red, as well as methyl orange, obeyed Langmuir model, while that of malachite green followed Freundlich model. With five cycle recyclability and sufficient adsorption capacity, N-doped porous carbon may be a suitable adsorbent for removing organic dyes in water. [ABSTRACT FROM AUTHOR]