Synthesis, characterization and isothermal studies of Mg-Fe Layered hydroxide with bentonite clay for the removal of alizarin blue dye from aqueous solution

Abstract

This research aimed to prepare and characterize Mg-Fe layered Hydroxide clay for removal of alizarin blue dye from aqueous media using batch adsorption technique. The Mg-Fe layered Hydroxide prepared was characterized by SEM, FT-IR and XRD before and after adsorption. The result obtained from SEM shows a large surface area before and a rough and filled surface after adsorption. The presence of OH, C=O and N-CH stretching at 3644 cm^-1, 1771 cm^-1 and 2884 cm^-1 respectively was analyzed by FT-IR. It was verified that the crystalline structure was not altered during the pillaring process as evidenced by XRD. Various parameters such as initial dye concentration (10 – 50 mg/l), contact time (10 – 50 mins), adsorbent dose (0.1 – 0.5 g) and Temperature (30 – 70^oC) were investigated. The experiments showed the following results; dye concentration decreased from 95.70% - 72.6%, contact time increased from 87.70% - 98.0% and adsorbent dose showed 87.7% - 92.3% removal respectively. The Adsorption isotherms of Freundlich, Langmuir, Temkin and Harkin’s-Jura Isotherms were used to observe the adsorption condition. Freundlich adsorption Isotherm fitted best with maximum removal of 6.97 mg/g and R² value of 0.999. In this work, Mg-Fe layered hydroxide with bentonite clay which is low cost became effective adsorbent for the removal of Alizarin blue dye.