Ca–Al, Ni–Al and Zn–Al LDH powders as efficient materials to treat synthetic effluents containing o-nitrophenol

Abstract

Abstract Powdered layered double hydroxides (LDH) based on calcium-aluminum (Ca–Al), nickel-aluminum (Ni–Al), and zinc-aluminum (Zn–Al) were synthesized with the purpose to evaluate the removal of o-nitrophenol from synthetic effluents by adsorption. It was verified that Ca–Al, Ni–Al, and Zn–Al LDHs presented a typical layered structure confirming the successful synthesis. o-nitrophenol adsorption on the LDH powders was favored at a pH of 5.0, being attained removal percentages from 70 to 90%, depending on the material. Kinetic experimental data obeyed the general order model, while, Sips represented the experimental equilibrium behavior of the three materials adequately. The maximum adsorption capacities were 135.1 mg g−1,122.1 mg g−1 and 130.3 mg g−1 for Ca–Al, Ni–Al, and Zn–Al LDHs, respectively. For simulated effluent, it was attained a removal of up to 60.3% using Ni–Al LDH. In a general way, the layered double hydroxides based on Ca–Al, Ni–Al, and Zn–Al exhibited an interesting potential as adsorbent materials for the treatment of simulated effluents containing o-nitrophenol. Ni–Al is preferred due to its better performance in the treatment of simulated effluents and higher regeneration potential.