The Application of Response Surface Methodology for 2,4,6-Trichlorophenol Removal from Aqueous Solution Using Synthesized Zn2+-Al3+-Tartrate Layered Double Hydroxides

Abstract

Trichlorophenols are on the US environmental protection agency’s list of priority pollutants due to their serious damage to water safety. With the aim of adsorbing the 2,4,6-trichlorophenol (2,4,6-TCP), Zn2+-Al3+-tartrate layered double hydroxides (Zn2+-Al3+-C4H4O62−-LDHs) adsorbent was synthesized via homogeneous precipitation method. X-ray powder diffraction (XRD), Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to characterize Zn2+-Al3+-C4H4O62−-LDHs. The concentration of 2,4,6-TCP was determined using gas chromatography–mass spectrometry (GC-MS). Zn2+-Al3+-C4H4O62−-LDHs exhibited a good adsorption performance of 2,4,6-trichlorophenol, since a bigger layer spacing of Zn2+-Al3+-C4H4O62−-LDHs was obtained than that in Zn2+-Al3+-CO32−-LDHs. Adsorption parameters of adsorption temperature, contact time, adsorbent dosage, and solution pH were investigated, the initial concentration of 2,4,6-TCP was 2.0 g/L. Response surface methodology (RSM) was employed to provide an investigative approach towards optimization of the adsorption process. The highest removal rate of 89.94% and the average removal rate of 88.74% were achieved under a temperature of 20.0 °C, a contact time of 2.5 h, an adsorbent dosage of 0.15 g, and a solution pH of 3. the capacity of the adsorbent is 599.6 mg/g. Meanwhile, the reusable properties of Zn2+-Al3+-C4H4O62−-LDHs were evaluated by the same adsorption system, and the removal rate of 2,4,6-TCP was 85.57% at the fifth regeneration. The obtained results confirmed that the Zn2+-Al3+-C4H4O62−-LDHs can be used as a potential introduction in practical applications for the removal of 2,4,6-TCP.