The Effects of NaOH Concentration on the Hydrothermal Synthesis of a Hydroxyapatite-Zeolite Composite Using Blast Furnace Slag

Abstract

This study investigated the effect of NaOH concentration on the assemblage, crystallinity, and dimension of crystalline phases in hydroxyapatite-zeolite composites made with blast furnace slag. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy measurement, scanning electron microscopy (SEM), and nitrogen adsorption-desorption tests were conducted to characterize the synthesized composites. In addition, the cesium adsorption potential of the synthesized composites was evaluated to assess the feasibility of using hydroxyapatite-zeolite composites synthesized from blast furnace slag. The composite samples using a 3 M NaOH solution showed the formations of Na-P1 and Faujasite (FAU) zeolites along with hydroxyapatite, which led to the highest adsorption capacity for cesium (44.90 mg/g).