Hexavalent chromium ion removal from wastewater using novel nanocomposite based on the impregnation of zero-valent iron nanoparticles into polyurethane foam.

In this study, we developed a novel nanocomposite, polyurethane foam impregnated with zero-valent iron nanoparticles (PU@nZVI), for the effective removal of chromium(VI) from various water sources. The characterization of nanocomposite (PU@nZVI) was performed by XRD, SEM-EDS, TEM and FT-IR techniques. Using the response surface methodology, we optimized the removal conditions, achieving an optimal pH of 2 and a dose of 0.5 g/L. The PU@nZVI demonstrated an excellent maximum adsorption capacity of 600.0 mg/g for Cr6+. The adsorption kinetics and isotherms were best described by the pseudo-second-order model and the Freundlich isotherm, respectively. Significantly, the nanocomposite removed 99.98% of Cr6+ from tap water, 96.81% from industrial effluent, and 94.57% from treated sewage wastewater. Furthermore, the PU@nZVI maintained its efficiency over five adsorption-desorption cycles, highlighting its reusability. These results suggest that the PU@nZVI nanocomposite is a highly efficient and sustainable option for chromium(VI) removal in water treatment applications.

Recent Advances in the Catalytic Conversion of Methane to Methanol: From the Challenges of Traditional Catalysts to the Use of Nanomaterials and Metal-Organic Frameworks.

Methane and carbon dioxide are the main contributors to global warming, with the methane effect being 25 times more powerful than carbon dioxide. Although the sources of methane are diverse, it is a very volatile and explosive gas. One way to store the energy content of methane is through its conversion to methanol. Methanol is a liquid under ambient conditions, easy to transport, and, apart from its use as an energy source, it is a chemical platform that can serve as a starting material for the production of various higher-value products. Accordingly, the transformation of methane to methanol has been extensively studied in the literature, using traditional catalysts as different types of zeolites. However, in the last few years, a new generation of catalysts has emerged to carry out this transformation with higher conversion and selectivity, and more importantly, under mild temperature and pressure conditions. These new catalysts typically involve the use of a highly porous supporting material such as zeolite, or more recently, metal-organic frameworks (MOFs) and graphene, and metallic nanoparticles or a combination of different types of nanoparticles that are the core of the catalytic process. In this review, recent advances in the porous supports for nanoparticles used for methane oxidation to methanol under mild conditions are discussed.

One-Pot Synthesis of Some New s-Triazole Derivatives and Their Potential Application for Water Decontamination.

A rapid, efficient, and one-pot protocol has been developed for the synthesis of cyclized 2,6-dimethyl-5-substituted-thiazolo[3,2-b]-s-triazoles (3a-c) through the interaction of 5-methyl-1H-s-triazole-3-thiol (1) with aliphatic ketones (2a-d) in refluxing acetic acid in the presence of a catalytic amount of sulfuric acid (AcOH/H+) while with aromatic ketones (5a-d), a mixture of uncyclized 3-methyl-s-triazolylthioacetophenone derivatives (6a-d) and cyclized 6-aryl-2-methyl-thiazolo[3,2-b]-s-triazoles (7a-d) has been produced. With this catalytic system, inexpensive sulfuric acid was utilized as a catalyst, which prevented the production of poisonous and irritating halo carbonyl compounds. On the other hand, the interaction of s-triazole 1 with cyano compounds (9a,b) afforded the corresponding 6-amino-2-methyl-5-substituted-thiazolo[3,2-b]-s-triazoles (10a,b). Similarly, treatment of 4-amino-3-methyl-s-triazole-5-thiol (12) with aliphatic and aromatic ketones (2c and 5a-e) afforded directly 3-methyl-7H-s-triazolo[3,4-b]-1,3,4-thiadiazines (13a and 14a-e). Further, reaction of 12 with cyano compounds (9a,b) under the same reaction conditions yielded the corresponding 3-methyl-s-triazolo[3,4-b]-1,3,4-thiadiazole derivatives (15a,b). The reaction mechanism was studied, and the structures of all novel compounds were verified using spectroscopy and elemental analysis. Moreover, the potential application of the synthesized compounds toward heavy metal ions and inorganic anion removal from aqueous solution has been investigated. The removal effectiveness for metal ions reached up to 76.29%, while for inorganic anions it reached up to 100%, indicating that such synthesized compounds are promising adsorbents for water remediation.

Markers of Local and Systemic Estrogen Metabolism in Endometriosis.

Estrogen metabolites (EMs) can work independently from their parent hormones. We hypothesize that in endometriosis, estrogen is metabolized preferentially along hormonally active pathways. We recruited 62 women with endometriosis (proven laparoscopically and histologically) and 52 control women (normal findings with laparoscopy) among patients undergoing surgery for pelvic pain and/or infertility during the proliferative phase of the menstrual cycle. Urinary samples were collected preoperatively. Biopsies from eutopic endometrium of control women and women with endometriosis were collected during surgery. EMs in urine and endometrial tissues were extracted and determined using Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS). These included: 2-hydroxyestrone (2OHE1), 16-α hydroxyestrone (16α-OHE1), 2OHE1/16α-OHE1 ratio, 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), and 4-hydroxyestradiol (4OHE2). Eutopic endometrium of endometriosis patients, as compared to control endometrium, contained significantly higher level of 4OHE1 (0.03 (IQR: 0.03-0.265) versus 0.03 (IQR: 0.03-0.03) µg/g, respectively, P = 0.005), 2-OHE2 (0.241 (IQR: 0.1-0.960) versus 0.1 (IQR: 0.1-0.1) µg/g, respectively, P < 0.001), and 4-OHE2 (0.225 (IQR: 0.22-1.29) versus 0.0.2 (IQR: 0.2-0.2) µg/g, respectively, P < 0.001). Only 2OHE1 showed higher concentration in urine of women with endometriosis than controls (9.9 (IQR: 3.64-14.88) versus 4.5 (IQR: 1.37-17.00) µg/mg creatinine, respectively, P = 0.042). Eutopic endometrium of women with endometriosis metabolizes estrogen preferentially to the biologically active 2OHE2, and potentially genotoxic 4OHE1 and 4OHE2 metabolites. This contributes to further understanding of endometriosis etiology, its link to ovarian cancer, and could help identifying an endometrial biomarker of the disease.