Recovery of Platinum and Palladium from Spent Automotive Catalysts: Study of a New Leaching System Using a Complete Factorial Design

The recovery of materials and energy from end-of-life products is increasingly a fundamental factor in the sustainable development of various countries. Recovering metals from different types of waste is not only a practice in support of the environment, but is also a profitable economic activity. For this reason, exhausted automotive catalysts can become renewable sources of critical raw materials such as Pt, Pd, and Rh. However, recovering Pt and Pd from spent catalysts through an efficient, economical, and green method remains a challenge. This article presents a new leaching process for the hydrometallurgical recovery of Pt and Pd from exhausted automotive catalysts. The leaching solution consists of an aqueous mixture of hydrochloric acid, two organic acids (citric acid and acetic acid) and hydrogen peroxide. A complete factorial plan on two levels (2k) was performed in order to evaluate the main effects of the analyzed factors and their interactions. The factors that were presumed to be the most influential on the leaching of Pt and Pd were the concentrations of the different reagents and the reaction time. The optimal circumstances for achieving the largest recovery (over 80% Pt and 100% Pd) were achieved using the following conditions: a concentration of HCl of 5 M, a concentration of H2O2 of 10% wt./vol., a concentration of C2H4O2 of 10%vol./vol., and a reaction time of 3 h.

Sanitization of fruits and vegetables: a review

Recently, with the coronavirus pandemic, the eating habits of the population have been modified, observing the search for healthy diet. In this sense, the consumption of fruits and vegetables has increased, and the hygiene is a fundamental step in quality control, since fruits and vegetables can be consumed in natura. The objective of the work was to elaborate a review about the main chemical sanitizers used in the sanitization of fruits and vegetables. The study is a review based on scientific publications, using the combination of the following descriptors: hygiene, fruits and vegetables, sanitizers and sanitizing. It was possible to verify that the most used sanitizer in the sanitization of fruits and vegetables is chlorine and its derivatives, in concentrations from 100 to 200 ppm, normally for 15 minutes. Ozone could destroy numerous microorganisms and for its sanitizing effect it is necessary to have a longer exposure time, on average up to 30 minutes. When using organic acids (acetic, citric, lactic and peracetic acid), the concentrations vary up to 2% and the average exposure time is a few minutes, which can be used in combination or not. However, its use is not always effective. It is concluded that the application of each type of sanitizer varies according to its concentrations, pH, exposure time to the treatment and the type of fruit or vegetable to be sanitized.

Metabolic Profiling of Mimusops elengi Linn. Leaves extract and in silico anti-inflammatory assessment targeting NLRP3 inflammasome

Mimusops elengi Linn. Secondary metabolites of flavonoids, phenolic acids, coumarin classes and stilbene were identified by UPLC/ESI-QTOF-HRMS/MS technique with negative ion detection. Major Mimusops elengi flavonoids included Myricitrin, Myricetin, and Kaempferol-3-O-alpha-L-rhamnoside. The most abundant Coumarin and phenolic acids detected in the chromatogram included aesculin and quinic acid respectively. Down regulation of NLRP3 inflammasome activation inhibits the severe inflammatory responses caused by virus infection. Studying in silicobinding affinity of flavonoids, coumarins and phenolic acid in M. elengi leaves extract against the ADP binding site of NLRP3 protein (PDB code: 6NPY) demonstrated that investigated compounds have docking scores ranged from −6.20 to −12.30 kcal/mol. The best score was achieved by kaempferol-3-O-(6-p-coumaroyl) -glucoside(Compound 9) followed by aesculin (Compound 25) while Quinic acid (Compound 20) showed the lowest affinity toward ADP-binding site of NLRP3. © 2023 The Authors

Multifunctional properties of probiotic strains Lactococcus lactis ssp. lactis

The analysis of the literature of the RSCI and Web of Science on the multifunctionality of useful properties of mesophilic lactic acid bacteria Lactococcus lactis ssp. lactis, which have been used by humans for centuries in the preparation of fermented products as a way to preserve milk and food raw materials. Lactococcus lactis ssp. lactiscan become a resource for various biologically active substances - potential metabiotics, such as: bacteriocins, organic acids, short-chain fatty acids, antioxidants, adhesins, neurotransmitters. New areas of their application as suppliers of bioprotective agents for preventive therapy and the development of oral vaccines are described, which is important for the prevention and control of infections that pose an additional danger to patients during the COVID-19 pandemic.

Green products from herbal medicine wastes by subcritical water treatment.

Herbal medicine wastes (HMWs) are byproducts of medicine factories, which are mainly landfilled for their environmental problems. Only bearing in mind the contamination and concerns caused by the COVID-19 pandemic and environmental emissions, the worth of herbal medicine wastes management and conversion to green products can be understood. In this work, subcritical water treatment was carried out batch-wise in a stainless tube reactor in the pressure range of 0.792-30.0 MPa, varying the temperature (127-327 °C) and time (1-60 min) of extraction. This resulted in new and green material sources, including organic acids, amino acids, and sugars. Amazingly, at very low extraction times (below 5 min) and high temperatures (above 277 °C), about 99% of HMWs were efficaciously converted to clean products by subcritical hydrothermal treatment. The results of hydrothermal extraction after 5 min indicated that at low temperatures (127-227 °C), the total organic carbon in the aqueous phase increased as the residual solid phase decreased, reaching a peak around 220 °C. Acetone soluble extracts or fat phase appeared above 227 °C and reached a maximum yield of 21% at 357 °C. Aspartic acid, threonine, and glycine were the primary amino acids; glycolic acid, formic acid, lactic acid, and acetic acid were obtained as the main organic acids, glucose, fructose, and cellobiose were substantial sugars produced from the aqueous phase after 5 min of hydrothermal subcritical hydrolysis extraction.