Simultaneous removal of anionic and cationic dyes from aqueous solutions using nickel-iron layered double hydroxide nanosheets

The removal of multiple organic dyes contained in industrial wastewater poses a significant challenge, and the underlying mechanisms involved in their simultaneous removal are still not fully understood. In this work, Nickel-Iron layered double hydroxides nanosheets were successfully synthesized by coprecipitation method at constant pH and were characterized by powder x-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and their effectiveness in removing anionic dyes Remazol Red 23, and Indigo Carmine was investigated by studying several parameters such as initial solution pH, adsorbent dose, dye concentration, and temperature effect. The asprepared nanocomposite exhibited excellent removal efficiency for Remazol Red 23 and Indigo Carmine reaching the maximum adsorption capacities of 133.04 mg.g(-1) and 115.59 mg.g(-1), respectively. The simultaneous removal of binary anionic dye mixture was studied and proved the high performance of the synthesized material due to the electrostatic attraction. Also, a cationic dye Basic Yellow 28 was successfully removed when it was added to the binary anionic dyes ' mixture, and this was explained by two proposed mechanisms: surface charge modification and the synergetic effect of dyes molecules.