Synthesis and adsorption studies of NiO nanoparticles in the presence of H2acacen ligand, for removing Rhodamine B in wastewater treatment

Cost efficient NiO nanoparticles were synthesized by hydrothermal production of nano-scale Ni(OH)2, using Ni(NO3)2·6H2O and NaOH as precursors, in the presence of H2acacen ligand, followed by calcinations of the produced Ni(OH)2. Prepared samples were then characterized using X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectra, Brunauer-Emmet-Teller (BET) and transmission electron microscopy (TEM). BET analysis revealed high surface area for pure nano sized NiO, averaging 176.56 m2/g and confirming its application as an efficient adsorbent. Experimental studies for Rhodamine B (RB) removal from aqueous solutions in batch systems revealed that the adsorption equilibrium was best represented by Langmuir isotherm, with the maximum monolayer capacity of 111 mg/g for RB. The kinetic data was well described by a pseudo-second-order kinetic model, having intraparticle diffusion model as a rate limiting step.