Effect of preparation methods on the morphology of jarosite and its adsorption performance for U(VI)

Jarosite has shown excellent adsorption capacity in heavy metal adsorption processes. In this study, jarosite was synthesized using different methods, including the bio-oxidation by Acidithiobacillus ferrooxidans (BAF), rapid addition of H 2 O 2 (RAH), and slow addition of H 2 O 2 (SAH). The synthesized jarosite samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The influence of pH, adsorption time, and adsorbent dosage on the adsorption performance of U(VI) by jarosite was investigated through static adsorption experiments. The results revealed that jarosite with petal-like, granular, and spherical morphologies was obtained using the BAF, RAH, and SAH methods, respectively. Among jarosite synthesized by the three methods, bio-synthesized jarosite exhibited the best adsorption performance, with a maximum adsorption capacity of 96.2 mg/g for U(VI). Under the conditions of pH 7 and an adsorbent dosage of 0.8 g/L, the adsorption equilibrium was reached within 80 min. The adsorption process of U(VI) by jarosite synthesized through three methods all followed the Langmuir model. Adsorption kinetics follow a pseudo-second-order rate expression, indicating a chemical interaction between the adsorbent and the presence of U(VI). These results suggest that bio-synthesized jarosite has great potential for adsorbing U(VI) from U(VI)-contaminated wastewater.