Separations

A phosphogypsum flotation tailings-derived zeolite (PGTZ) was synthesized from the tailings produced during the reverse flotation of phosphogypsum through alkaline fusion and hydrothermal treatment. The response surface methodology (RSM) utilizing a three-level Box–Behnken design (BBD) was used to assess the adsorption of MB by PGTZ. Polynomial regression models were developed to analyze the effects of process parameters on adsorption capacity (q_e). The maximum MB adsorption occurred under the following optimized conditions: PGTZ dosage = 5.31 g·L⁻¹; initial MB concentration = 294.59 mg·L⁻¹; pH = 7.42; and adsorption time = 187.89 min. Additionally, adsorption isotherm and kinetic models were fitted to the experimental data to determine model parameters. The Langmuir isotherm model and pseudo-second-order kinetic model incorporating intraparticle diffusion were able to effectively predict MB adsorption onto PGTZ. Thermodynamic analyses indicated that the adsorption process was spontaneous, with strong chemical interactions between MB and PGTZ.

Vanadium is a strategic metal with critical applications in steel alloys, aerospace, chemical catalysis, and energy storage. However, conventional extraction methods such as high-temperature salt roasting are energy-intensive and environmentally challenging. This study investigated the extraction of V, Ti, and Fe from titanomagnetite ore using aqueous solutions of two ionic liquids (IL), 1-butyl-3-imidazolium hydrogen sulphate ([Bmim][HSO₄], and 1-butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF₆]) as well as two deep eutectic solvents (DESs) (choline chloride:oxalic acid and choline chloride:succinic acid). Na₂CO₃ and Na₂SO₄ roasting were used as benchmarks for comparison purposes. Leaching was performed across a range of concentrations and temperatures, and metal recoveries were quantified by atomic absorption spectroscopy (AAS). Among all methods, ChCl:OA DES achieved the best leaching efficiencies of 97.6% for V, 76.1% for Ti, and 68.8% for Fe at 50% (v/v) and 100 °C, outperforming [Bmim][HSO₄] and conventional roasting. Kinetic analysis using the shrinking core model indicated that leaching is predominantly diffusion-controlled, with apparent activation energies of 35.1 kJ/mol for V, 28.3 kJ/mol for Ti, and 29.8 kJ/mol for Fe. The results demonstrate that ChCl:OA DES provides a low-temperature, biodegradable, and cost-effective approach for V, Ti and Fe extraction, offering a sustainable alternative to conventional salt roasting methods.

Platinum’s unique properties, such as its high resistance to corrosion and high temperatures, are driving an increased use in modern technologies and advanced chemistry. However, the World Platinum Investment Council has projected, for the third consecutive year, a global deficit of platinum for 2025 and a negative forecast until 2029, highlighting the need for the development of new metallurgical methodologies to recover platinum but also to recycle product containing it. The use of alkaline amino acid (glycine) promises a highly selective and more environmentally friendly recovery methodology. Over the Platinum Group Metals, recovery studies have been performed only on palladium, but no published literature over platinum was found. This study investigated the feasibility of platinum adsorption from alkaline glycine solutions under various operational conditions using activated carbon. Results are demonstrating that platinum can be successfully recovered under the effects tested: 92.37–97.93% (carbon dosage), 70.00–95.72% (temperature), 94.08–97.39% (pH), 95.16–96.23% (platinum concentration), 95.72–96.53% (glycine concentration), and 95.72–97.12% (cyanide concentration). The scientific significance of this study lies in the confirmation for the potential use of a more environmentally friendly approach to recover platinum as opposed to the current cyanide and acidic chloride system.