Structural and morphological properties of hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All the microstructures were synthesized at a very low temperature of 70 °C with a reduced reaction time of 3 h. An increase in the pH from 0.8 to 2.1 decreased the particle sizes from 3 µm to 200 nm and an increase in the aging time from zero, three, and seven days resulted in semispherical, spherical, and euhedral jarosite structures, respectively. The Rietveld analysis also confirmed that the amount of hydronium substitution by potassium in the cationic site increased with an increase in pH. The percentages of hydronium jarosite (JH)/potassium jarosite (JK) for pH values of 0.8, 1.1, and 2.1 were 77.72/22.29%, 82.44/17.56%, and 89.98/10.02%, respectively. Microstructures obtained in this work were tested as alternative anode materials and the voltage measured using these electrodes made with hydronium-potassium jarosite microstructures and graphite ranged from 0.89 to 1.36 V. The results obtained in this work show that with reduced particle size and euhedral morphology obtained, modified jarosite microstructures can be used as anode materials for improving the lifetime of lithium-ion batteries.

Structural and morphological properties of the hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All microstructures were synthesized at a reasonable temperature of 343 K with a reduced reaction time of 3 hours. Increase in the pH from 0.8 to 2.1 decreased the particle sized from 3 µm to 200 nm and increasing the aging time from 0, 3 to 7 days resulted in semispherical, spherical and euhedreal jarosite structures, respectively. A Rietveld analysis also was done, finding that increasing pH, the amount of hydronium substitution by potassium in the cationic site also increases, having a 77.72 % of hydronium jarosite (JH) plus 22.29 % potassium jarosite (JK) at pH 0.8; 82.44 % (JH) and 17.56 % (JK) at pH 1.1, and 89.98 % (JH) plus 10.02 % (JK) at pH 2.1. The results obtained in this work show that the obtained hydronium potassium jarosite microstructures with reduced particle size and euhedreal morphology can be used as anode materials for improving the life time of lithium ion batteries, due that during the analysis of the voltage obtained using electrodes made with this particles and graphite, this ranged from 0.89 to 1.36 V.

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.