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.

The global problem of water scarcity is exacerbated by the continued contamination of potable water sources. This preliminary study investigates the potential of a hazardous industrial jarosite waste to adsorb As(V) and Cr(III) from contaminated waters. The results showed that this mining waste effectively adsorbed both As(V) and Cr(III), demonstrating its potential as a low-cost and sustainable solution for water remediation along with the use of a hazardous waste that also contaminates. The adsorption process was optimized, and the effects of various parameters on the adsorption capacity were investigated. The findings of this study suggest that the use of toxic mining residues in porous concrete could provide a promising approach for the removal of toxic heavy metals from polluted water sources, contributing to the development of more sustainable and environmentally friendly water treatment technologies. A maximum adsorption of 90.6% of As(V) and 96.3% of Cr(III) was achieved, and it was verified that the industrial jarosite initially contained about 0.44% As, which was later leached during decomposition; again, the industrial jarosite was able to re-adsorb both As(V) and Cr(III).

China, Vietnam, Brazil, and Russia have the largest deposits of rare earths. However, in recent works, the occurrence of light rare earth elements has been demonstrated in an exhalative sedimentary type mineral (SEDEX) in Mexico, with adequate Ce and Nd contents. Additionally, it is this mineral that has been used to study the cation exchange capacity of non-metallic minerals and organic materials, such as bentonite, diatomite, and eggshell. To carry out this work, the crushed and ground SEDEX ore was leached using HCl, H₂SO₄, and HNO₃. Subsequently, the liquid containing the Ce and Nd ions extracted from the mineral was put in contact with the respective ion exchangers, evaluating the effect of temperature and pH to determine the cation exchange efficiency of each exchanger tried. It was found that the best leaching results were achieved with the H₂SO₄, obtaining an extraction of Ce and Nd of 97.6% and 95.7%, respectively. On the other hand, in the case of cation exchange, the best results found for the extraction of Ce and Nd were using diatomite at a temperature of 323 K and a pH of 3, obtaining an extraction of 99.06% Ce and 99.07% Nd.

The mining process has always generated residues that often still contain valuable metals. This work focuses on the re-processing of these residues by evaluating and comparing two reagents that can extract valuable silver from tailings. A preliminary kinetic study of silver leaching was conducted in both cyanide and thiosulfate media, and a comparative analysis was performed to determine the optimal leaching conditions. The mining residue was found to contain 83 g/ton of Ag and 0.28 g/ton of Au. This study, carried out for both cyanide and thiosulfate, involved determining the effects of the reagent concentration, temperature, and pH. For the reagent concentration, apparent reaction orders of n = 0.0531 and n = 0.41 were determined for cyanide and thiosulfate, respectively. The apparent activation energies were E_a = 21.7 kJ/mol for cyanide and E_a = 23.13 kJ/mol for thiosulfate, indicating mixed-control kinetics in both systems. Under the conditions studied, maximum silver recoveries of 92% and 93% were achieved using cyanide at 323 K and thiosulfate at 328 K, respectively. Notably, pH had no significant effect on the cyanide system, whereas for thiosulfate, the reaction order was n = 3.27. The results show similar behavior in both systems, but the thiosulfate system is more attractive due to its non-toxic nature and lower cost.

Mining operations for the extraction and processing of useful geological materials are common anthropogenic activities that generate enormous quantities of waste that can alter the natural balance. In this way, soil, water and air are contaminated with waste that contains heavy metals, acids and many other compounds that are toxic to the environment and health. Minimizing and eradicating these pollutants is an arduous but necessary task. That is why, in the present work, the physical, chemical and mineralogical characterization of metallurgical mining waste was carried out using analytical techniques. Tests and trials were also carried out to assess the degree of toxicity, corrosiveness and chemical capacity to generate acid mine drainage. In general, it was found that this waste does not contain active toxic elements or elements that could be corrosive. However, due to the residual content of sulfide minerals, it can generate acid mine drainage, which could contaminate groundwater. Likewise, it can be seen that due to the content of heavy metals and minerals such as quartz and feldspars, this waste can be reprocessed to recover metals and subsequently separate, by flotation, the associated silica and feldspar, which can be used in the glass and cement industry.

En la Ciudad de México se desechan grandes cantidades de comida, incluyendo residuos de cebolla, que pueden aprovecharse mejor. A partir de estos residuos se obtuvieron puntos cuánticos de carbono (CQDs). Estos puntos cuánticos tienen variadas aplicaciones debido a su biocompatibilidad, resistencia a su fotodegradación y destacable fluorescencia. Entre otras cosas, los CQDs buscan controlar el flujo iónico entre células al inactivar ciertos canales, lo cual es relevante para tratar enfermedades afectadas por factores genéticos, lesiones estructurales o alteraciones celulares. Mediante síntesis verde asistida por microondas, se sintetizaron CQDs con curcumina y magnesio para desarrollar un nuevo posible tratamiento contra la epilepsia. Se realizó un análisis morfológico y topográfico de las muestras mediante SEM, y se calculó la distribución de tamaño de partícula. Además, a través de FTIR se identificaron los grupos funcionales de las muestras.