Zinc–aluminum layered double hydroxide as a nano-sorbent for removal of Reactive Yellow 84 dye from textile wastewater effluents

Abstract

In this research, the zinc–aluminum layered double hydroxide (Zn–Al LDH) was synthesized and structurally and morphologically characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and N2 adsorption–desorption techniques. The obtained nano-structured inorganic material was employed as an innovative nano-sorbent for separation of Reactive Yellow 84 (RY84) dye from aqueous solutions, which can be spectrophotometrically monitored at λ = 359 nm. The effect of several parameters such as type of interlayer anion in Zn–Al LDH structure, pH, sample flow rate, elution conditions, amount of nano-sorbent, sample volume and co-existing ions on the retention efficiency was investigated and optimized. The results showed that trace amounts of the RY84 could be retained using a column packed with 300 mg of the Zn–Al(NO3 −) LDH at pH 8 and stripped by 2.5 mL of 3.0 mol L−1 NaOH. Under the optimum experimental conditions, the limit of detection and the relative standard deviation were 0.04 μg mL−1 and 1.8 %, respectively. The calibration graph using the presented solid phase extraction system was linear in the range of 0.15–1.5 μg mL−1 with a correlation coefficient of 0.9982. The method was successfully applied to removal of RY84 from several textile wastewater effluents.