Synthesis, Characterization and Decomposition of Potassium Jarosite for Adsorptive As(V) Removal in Contaminated Water: Preliminary Study

Abstract

Jarosite-type compounds precipitated in the zinc industry for iron control can also incorporate arsenic and can be used for wastewater treatment for As elimination. According with the last, this work is related to arsenic incorporation at room temperature in decomposed potassium jarosite. The work began with the synthesis of the compound at 75 °C for 9 h using Fe2(SO4)3 and K2SO4 at a pH of 1.1. Once jarosite was obtained, solids were subjected to an alkaline decomposition using NaOH at pH 10 for 30 min, and then As was added to the solution as HAsNaO4 and the pH modified by adding HNO3 until it reached a value of 1.1. The initial, intermediate, and final products were wholly characterized by scanning electron microscopy (SEM) in conjunction with energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (RS), and X-ray photoelectron spectrometry (XPS). The obtained results show that As(V) can be adsorbed by ionic exchange in the amorphous FeOH structure of decomposed jarosite and when pH decreased to 1.1, the compound recrystallized, incorporating up to 6% As on average, which is indicative that this process can be used to reduce As in contaminated waters.

Bifunctional Adsorbents Based on Jarosites for Removal of Inorganic Micropollutants from Water

“…The results obtained are shown in Figure 2. All the jarosites present the XRD pattern established in the crystallographic charts corresponding to each jarosite and are consistent with the XRD patterns already reported [22]. A slight shift in some of the XRD peaks distinguishes the Na−, K− and NH 4 −jarosites.…”

“…Synthetic jarosites can be obtained via biological and chemical methods [21]. Chemical methods typically use conventional heating, low temperature (60-100 • C), long time (3-24 h), and low pH (1.1) [22]. Jarosites have been obtained for enhancing the retrieval procedure for zinc and high-value metals such as silver, gold, or copper from industrial waste in the mining and metallurgical fields [23].…”

“…The crystallization parameters, such as the source of iron, reagent ratio, stirring speed, pH, temperature, and pressure, have significantly affected the morphology and the particle size of the jarosite [20]. The jarosites and their chemical and thermal decomposition products have been barely studied as anion adsorbents of metals [22,26].…”