RESUMO
Due to the extensive application of pesticides and their hazardous effects on organisms, there is an urgent need to remove them effectively from wastewater. Metal-incorporated carbon-mineral composites (Ni/Mn-CMC and Ni/Fe-CMC) described in this paper can certainly be applied for this purpose. They were synthesized by combining mechanochemical and pyrolytic processes and their physicochemical properties were investigated using numerous methods (SEM-EDS, N2 adsorption/desorption, XRD, surface charge, FTIR). Adsorption capacity towards diuron and carboxin with and without impurities commonly detected in natural ecosystems, cadmium ions or arsenite, was measured. The obtained results indicated that Ni/Fe-CMC is more efficient adsorbent of pesticides due to its well-developed surface. It was able to bind 158.34 mg g-1 of diuron and 133.58 mg g-1 of carboxin in the solutions, where only one pesticide was present. In turn, these values for the Ni/Mn-CMC sample were 126.49 mg g-1 and 102.08 mg g-1, respectively. It should be noted that the composites maintained their high adsorption capacity in the multicomponent solutions, i.e., containing both pesticide and metal ions. Then, the maximum reduction in pesticide adsorption was only 8.36. Ni/Mn-CMC and Ni/Fe-CMC were successfully regenerated with ethanol without changing their structure and adsorption capacity. Also, the extracts from investigated materials did not have negative impact on plant growth. This confirmed suitability of carbon-mineral composites for repeated multiple use without toxic effects to organisms.
Assuntos
Carbono , Níquel , Praguicidas , Poluentes Químicos da Água , Adsorção , Poluentes Químicos da Água/química , Níquel/química , Praguicidas/química , Carbono/química , Minerais/química , Águas Residuárias/química , Ferro/química , Manganês/química , Diurona/químicaRESUMO
A novel photocatalytic nanomaterial, Ho2YSbO7, was successfully synthesized for the first time using the solvothermal synthesis technique. In addition, a Ho2YSbO7/Bi2MoO6 heterojunction photocatalyst (HBHP) was prepared via the hydrothermal fabrication technique. Extensive characterizations of the synthesized samples were conducted using various instruments, such as an X-ray diffractometer, a Fourier transform infrared spectrometer, a Raman spectrometer, a UV-visible spectrophotometer, an X-ray photoelectron spectrometer, and a transmission electron microscope, as well as X-ray energy dispersive spectroscopy, photoluminescence spectroscopy, a photocurrent test, electrochemical impedance spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance. The photocatalytic activity of the HBHP was evaluated for the degradation of diuron (DRN) and the mineralization of total organic carbon (TOC) under visible light exposure for 152 min. Remarkable removal efficiencies were achieved, with 99.78% for DRN and 97.19% for TOC. Comparative analysis demonstrated that the HBHP exhibited markedly higher removal efficiencies for DRN compared to Ho2YSbO7, Bi2MoO6, or N-doped TiO2 photocatalyst, with removal efficiencies 1.13 times, 1.21 times, or 2.95 times higher, respectively. Similarly, the HBHP demonstrated significantly higher removal efficiencies for TOC compared to Ho2YSbO7, Bi2MoO6, or N-doped TiO2 photocatalyst, with removal efficiencies 1.17 times, 1.25 times, or 3.39 times higher, respectively. Furthermore, the HBHP demonstrated excellent stability and reusability. The mechanisms which could enhance the photocatalytic activity remarkably and the involvement of the major active species were comprehensively discussed, with superoxide radicals identified as the primary active species, followed by hydroxyl radicals and holes. The results of this study contribute to the advancement of efficient heterostructural materials and offer valuable insights into the development of sustainable remediation strategies for addressing DRN contamination.
Assuntos
Bismuto , Diurona , Luz , Molibdênio , Fotólise , Bismuto/química , Catálise , Molibdênio/química , Diurona/química , Poluentes Químicos da Água/químicaRESUMO
In this work, the interaction between different chloro-substituted phenylurea herbicides (diuron (DIU) and chlortoluron (CHL)) and BSA were investigated and compared at three different temperatures (283 K, 298 K and 310 K) adopting UV-vis, fluorescence, and circular dichroism spectra. The quenching mechanism of the interaction was also proposed. The energy transfer between BSA and DIU/CHL was investigated. The binding sites of DIU/CHL and BSA and the variations in the microenvironment of amino acid residues were studied. The changes of the secondary structure of BSA were analyzed. The results indicate that both DIU and CHL can significantly interact with BSA, and the degree of the interaction between DIU/CHL and BSA increases with the increase of the DIU/CHL concentration. The fluorescence quenching of BSA by DIU/CHL results from the combination of static and dynamic quenching. The DIU/CHL has a weak to moderate binding affinity for BSA, and the binding stoichiometry is 1:1. Their binding processes are spontaneous, and hydrophobic interaction, hydrogen bonds and van der Waals forces are the main interaction forces. DIU/CHL has higher affinity for subdomain IIA (Site I) of BSA than subdomain IIIA (Site II), and also interacts with tryptophan more than tyrosine residues. The energy transfer can occur from BSA to DIU/CHL. By comparison, the strength of the interaction of DIU-BSA is always greater than that of CHL-BSA, and DIU can destroy the secondary structure of BSA molecules greater than CHL and thus the potential toxicity of DIU is higher due to DIU with more chlorine substituents than CHL. It is expected that this study on the interaction can offer in-depth insights into the toxicity of phenylurea herbicides, as well as their impact on human and animal health at the molecular level.