Activity

Maximum utilization of the full solar spectrum has been considered as a holy grail in the field of photocatalysis and has emerged important in the recent years, as the world needs to move towards renewable energy sources and also to maintain environmental health. In the search for a sustainable solution, we have come up with a strategic combination of materials, which can be active under all the three regions, namely ultraviolet (UV), visible and near infrared (NIR) of the sunlight. Specifically, we have developed a series of nanocomposites comprising of two dimensional nanosheets of zinc oxide (ZnO) and graphitic carbon nitride (GCN), and successfully coupled them with upconversion nanoparticles (UCNP). These nanocomposites have been successfully utilized for the photocatalytic chromium (Cr(VI)) reduction. The prepared nanocomposites exhibit an excellent photocatalytic activity toward reduction of Cr(VI) under different light region. A plausible mechanism for the photocatalytic process has been proposed based on the detailed study. This work is expected to pave way for the strategic design and development of many photocatalytic systems, which can utilize sunlight to the maximum extent.Amine-containing pharmaceuticals formed nitrosamines that are nitrogenous disinfection byproducts of public concerns due to their carcinogenicity. The objective of this study was to investigate the co-effect of additional inorganic nitrogen in different forms (ammonium, nitrite, and nitrate) and different disinfection approaches (chlorination, monochloramination, dichloramination, and two-step chlorination) on eight nitrosamine formation from four widely used pharmaceuticals. N-nitrosodimethylamine (NDMA) was the main species formed. The presence of N-nitrosomethylethylamine (NMEA), nitrosomorpholine (NMor), and N-nitrosopiperidine (NPip) was found in certain experiments. For one-step chlorination, the influential factors, in decreasing order of importance, were the molecular structural characteristics of the pharmaceutical, oxidation method, and presence and form of additional nitrogen. In four pharmaceuticals with comparative structures, the availability of amine intermediates during degradation was the key to higher nitrosamine yields. Monochloramine significantly enhanced nitrosamine formation from four pharmaceuticals. selleck chemicals llc NDMA formation by adding hypochlorous acid and ammonium separately were lower than those during monochloramination. During two-step chlorination, NDMA formation was enhanced at certain pre-chlorine doses (e.g., a Cl/N molar ratio of 20 or 4). The pre-chlorine dose changed the Cl/N ratio. As the ratio was increased, the combined chlorine residual was formed and decreased. When the ratio was high, breakpoint chlorination possibly occurred enhancing NDMA formation. While NDMA formation was successfully inhibited by two-step chlorination, ammonium brought the NDMA yields of these pharmaceuticals back to the range observed in chloramination, suggesting the importance of ammonium control for limiting NDMA formation from pharmaceuticals during two-step chlorination.Thorium is a radionuclide highly widespread in the earth’s crust with a relevant contribution to the exposure to radiation of living organisms. Natural concentrations of thorium in the soil can be altered due to human activities such as mining, agriculture, and cattle industry. Mining and related industry have been operating for centuries in Zacatecas State, Mexico, leaving mining waste dumps that can release trace elements to the topsoil. There are not enough previous studies of thorium concentration in this area. Thirty-three soil samples from different locations from Zacatecas State were analyzed, using alpha-spectrometry and ICP-MS, to estimate the reference value for thorium in surface soil in order to provide regulatory agencies with a tool to verify possible disturbances due to anthropogenic activities. Geoaccumulation indexes and enrichment factors did not reveal significant alterations in topsoil thorium concentration. The average concentration was 13.6 ± 7.6 mg kg-1, which is consistent with the estimated average concentration in the earth crust and is then proposed as average basal concentration for this region. A slight disequilibrium has been found between the natural isotopes of thorium due to the semi-arid nature of the areas and climatic factors.Hormones as a group of emerging contaminants have been increasingly used worldwide, which has increased their concern at the environmental level in various matrices, as they reach the water bodies through effluents due to the ineffectiveness of conventional treatments. Here we review the environmental scenario of hormones estriol (E3), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2), explicitly their origins, their characteristics, interactions, how they reach the environment, and, above all, the severe pathological and toxicological damage to animals and humans they produce. Furthermore, studies for the treatment of these endocrine disruptors (EDCs) are deepened using electrochemical processes as the remediation methods of the respective hormones. In the reported studies, these micropollutants were detected in samples of surface water, underground, soil, and sediment at concentrations that varied from ng L-1 to μg L-1 and are capable of causing changes in the endocrine system of various organisms. However, although there are studies on the ecotoxicological effects concerning E3, E2, and EE2 hormones, little is known about their environmental dispersion and damage in quantitative terms. Moreover, biodegradation becomes the primary mechanism of removal of steroid estrogens removal by sewage treatment plants, but it is still inefficient, which shows the importance of studying electrochemically-driven processes such as the Electrochemical Advanced Oxidation Processes (EAOP) and electrocoagulation for the removal of emerging micropollutants. Thus, this review covers information on the occurrence of these hormones in various environmental matrices, their respective treatment, and effects on exposed organisms for ecotoxicology purposes.