A novel diatomite supported layered double hydroxide as reusable adsorbent for efficient removal of acidic dyes

Abstract

ABSTRACT It would be of significance to design agreen composite for highly efficient uptake of contaminants. In this study, we fabricated an environmental friendly composite via insitu deposition of positively charged layered double hydroxide (LDH) on the surface of the negatively charged diatomite for efficient uptake of dye pollutants from aqueous solutions. The resulting LDH/diatomite (LDH/DIA) composites were characterised by X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), and N2 adsorption–desorption technique. The uptake performances of the resulting LDH/DIA composites were evaluated for the uptake of anionic tartrazine (TR) and erythrosine (ER) dyes. The uptake test of dyes was performed at ambient temperature by dispersing 10mg of the LDH/DIA in 10mL of dye solutions at pH 8 and 6 for TA and ER, respectively. The results show that composite can rapidly reduce the concentration of dyes in aqueous solutions from 20mg L−1 to 0.0001mg L−1. In addition, the uptake behaviour of this new adsorbent fits well with the Freundlich isotherm and the pseudo-second-order kinetic model. Langmuir isotherm study showed that the maximum uptake capacities of TR and ER dyes over the LDH/DIA composite were 555.6 and 625.2mg g−1, respectively, which were much higher than those of the known adsorbents. Our results suggested that the LDH/DIA has great potential applications as environmentally friendly materials for the treatment of wastewater with high concentration of anionic dyes.