Synthesis of Complex/Multifunctional Metal (Hydr)oxide/Graphite Oxide/AuNPs or AgNPs Adsorbents and Analysis of their Interactions with Chemical Warfare Agents

One of the most widely used chemical warfare agent (CWA) is mustard gas, which is a highly toxic blistering agent. In this study we investigated the interactions of mustard gas surrogates’ vapors on zinc and zirconium hydroxides and their composites with graphite oxide (GO) and/or Au or Ag nanoparticles. Even though a small quantity of reports about the detoxification of CWAs on metal oxides is reported in the literature, almost all of these studies are performed in the liquid phase. Both herein reported Zn(OH)2 and Zr(OH)4 showed a good adsorption performance, with the former being photoactive under visible light irradiation. The synthesis of the composites with graphite oxide resulted in materials with improved detoxification ability due to the synergistic effect on the structural and chemical features. The density of the hydroxyl groups per surface area showed to play the most crucial role. The further addition of nanoparticles led to an increased catalytically decomposition of mustard gas surrogate to less or non-toxic products. Based on the analysis of the volatile products and those retained on the surface of the adsorbents, the involved mechanisms are concluded

Building MOF Nanocomposites with Oxidized Graphitic Carbon Nitride Nanospheres: The Effect of Framework Geometry on the Structural Heterogeneity

Composite of two MOFs, copper-based Cu-BTC (HKUST-1) and zirconium-based Zr-BDC (UiO-66), with oxidized graphitic carbon nitride nanospheres were synthesized. For comparison, pure MOFs were also obtained. The surface features were analyzed using x-ray diffraction (XRD), sorption of nitrogen, thermal analysis, and scanning electron microscopy (SEM). The incorporation of oxidized g-C3N4 to the Cu-BTC framework caused the formation of a heterogeneous material of a hierarchical pores structure, but a decreased surface area when compared to that of the parent MOF. In the case of UiO-66, functionalized nanospheres were acting as seeds around which the crystals grew. Even though the MOF phases were detected in both materials, the porosity analysis indicated that in the case of Cu-BTC, a collapsed MOF/nonporous and amorphous matter was also present and the MOF phase was more defectous than that in the case of UiO-66. The results suggested different roles of oxidized g-C3N4 during the composite synthesis, depending on the MOF geometry. While spherical units of UiO-66 grew undisturbed around oxidized and spherical g-C3N4, octahedral Cu-BTC units experienced geometrical constraints, leading to more defects, a disturbed growth of the MOF phase, and to the formation of mesopores at the contacts between the spheres and MOF units. The differences in the amounts of CO2 adsorbed between the MOFs and the composites confirm the proposed role of oxidized g-C3N4 in the composite formation

Ultrasound-assisted decoration of CuOx nanoclusters on TiO2 nanoparticles for additives free photocatalytic hydrogen production and biomass valorization by selective oxidation

The herein presented ultrasound-assisted ultra-wet (US-UWet) impregnation synthetic approach was followed in order to avoid the drawbacks of the conventional wet impregnation synthesis. The goal was to homogeneously decorate the surface of the TiO2 nanoparticles with nanometric sized (< 4 nm) clusters of mixed cupric and cuprous oxides. The physicochemical features of the nanocomposite (TiO2CuOx) were determined by high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and Diffuse reflectance (DR) spectroscopy. TiO2CuOx showed an enhanced and continuous capability to generate molecular hydrogen upon low power ultraviolet irradiation. The benchmark commercial TiO2 P25 did not reveal any H2 formation under these conditions. TiO2CuOx presented also a high efficiency for the additives-free selective partial oxidation of two well established biomass derived model platform chemicals/building blocks, 5-hydroxymethylfurfural (HMF) and benzyl alcohol (BnOH) to the value-added chemicals 2,5-diformylfuran (DFF) and benzyl aldehyde (PhCHO), respectively. The nanocomposite showed higher DFF and PhCHO yield compared to P25

Agricultural biomass/waste as adsorbents for toxic metal decontamination of aqueous solutions

Toxic metals can be present in the environment, causing negative effects on the ecosystem and human health. Although several technologies have been used for decontamination purposes, biosorption is an environmentally friendly and cost-effective alternative to remove toxic metals from wastewater. Agricultural biomasses are a class of biosorbents that offer several advantages, including their low cost, availability in nature, simplicity to be obtained and used as adsorbents. This review article is focused on the use of agricultural biomass materials for the removal of toxic metal(oid)s from contaminated aqueous matrices. In addition, raw and modified forms of these biosorbents are considered as precursors for the preparation of other adsorbents like biochar. Following agricultural biomasses are discussed: i) watermelon, ii) potato, iii) cucumber, iv) peanut, v) almond, vi) walnut and hazelnut, vii) pistachio, and viii) tea waste-based biosorbents. The adsorption potential of the biomasses is exhibited under the optimum experimental conditions, and their characterization and possibility to reuse is also considered. Moreover, isotherm and equilibrium parameters of the metal(oid) adsorption by the biomasses are discussed. Specifically, thermodynamic studies are described in order to better understand the nature of the biosorption process between contaminant and biomass. All these considerations reflect the high potential of agricultural waste-based adsorbents for toxic metal(oid)s removal related to wastewater treatment technologies.Fil: Anastopoulos, Ioannis. University Of Cyprus; ChipreFil: Pashalidis, Ioannis. University Of Cyprus; ChipreFil: Hosseini Bandegharaei, Ahmad. Sabzevar University Of Medical Sciences; Irán. Islamic Azad University; IránFil: Giannakoudakis, Dimitrios A.. Polish Academy of Sciences; PoloniaFil: Robalds, Artis. Animal Health And Environment Bior; LetoniaFil: Usman, Muhammad. University Of Agriculture; PakistánFil: Escudero, Leticia Belén. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Zhou, Yaoyu. Hunan Agricultural University; ChinaFil: Colmenares, Juan Carlos. Polish Academy of Sciences; PoloniaFil: Núñez Delgado, Avelino. Universidad de Santiago de Compostela; EspañaFil: Lima, Éder Claudio. Universidade Federal do Rio Grande do Sul; Brasi

Green photosensitisers for the degradation of selected pesticides of high risk in most susceptible food: a safer approach

Pesticides are the leading defence against pests, but their unsafe use reciprocates the pesticide residues in highly susceptible food and is becoming a serious risk for human health. In this study, mint extract and riboflavin were tested as photosensitisers in combination with light irradiation of different frequencies, employed for various time intervals to improve the photo-degradation of deltamethrin (DM) and lambda cyhalothrin (λ-CHT) in cauliflower. Different source of light was studied, either in ultraviolet range (UV-C, 254 nm or UV-A, 320–380 nm) or sunlight simulator (> 380–800 nm). The degradation of the pesticides varied depending on the type of photosensitiser and light source. Photo-degradation of the DM and λ-CHT was enhanced by applying the mint extracts and riboflavin and a more significant degradation was achieved with UV-C than with either UV-A or sunlight, reaching a maximum decrement of the concentration by 67–76%. The light treatments did not significantly affect the in-vitro antioxidant activity of the natural antioxidants in cauliflower. A calculated dietary risk assessment revealed that obvious dietary health hazards of DM and λ-CHT pesticides when sprayed on cauliflower for pest control. The use of green chemical photosensitisers (mint extract and riboflavin) in combination with UV light irradiation represents a novel, sustainable, and safe approach to pesticide reduction in produce

Building MOF Nanocomposites with Oxidized Graphitic Carbon Nitride Nanospheres: The Effect of Framework Geometry on the Structural Heterogeneity

Composite of two MOFs, copper-based Cu-BTC (HKUST-1) and zirconium-based Zr-BDC (UiO-66), with oxidized graphitic carbon nitride nanospheres were synthesized. For comparison, pure MOFs were also obtained. The surface features were analyzed using x-ray diffraction (XRD), sorption of nitrogen, thermal analysis, and scanning electron microscopy (SEM). The incorporation of oxidized g-C3N4 to the Cu-BTC framework caused the formation of a heterogeneous material of a hierarchical pores structure, but a decreased surface area when compared to that of the parent MOF. In the case of UiO-66, functionalized nanospheres were acting as seeds around which the crystals grew. Even though the MOF phases were detected in both materials, the porosity analysis indicated that in the case of Cu-BTC, a collapsed MOF/nonporous and amorphous matter was also present and the MOF phase was more defectous than that in the case of UiO-66. The results suggested different roles of oxidized g-C3N4 during the composite synthesis, depending on the MOF geometry. While spherical units of UiO-66 grew undisturbed around oxidized and spherical g-C3N4, octahedral Cu-BTC units experienced geometrical constraints, leading to more defects, a disturbed growth of the MOF phase, and to the formation of mesopores at the contacts between the spheres and MOF units. The differences in the amounts of CO2 adsorbed between the MOFs and the composites confirm the proposed role of oxidized g-C3N4 in the composite formation

Editorial for the Special Issue on &ldquo;Graphene-Related Materials: Synthesis and Applications&rdquo;

Since the groundbreaking discovery of graphene by Geim and Novoselov in 2004, there has been continuous research focused on the utilization of graphene (GR) and graphene-related materials (GRms) in technologically high-impact applications, spanning from electronics, sensing, and spintronics, to catalysis, energy storage, and environmental remediation [...

Green sustainable approach toward plastic waste upcycling to graphene-based nanomaterials

Accumulation of disposable plastic products with an estimated life-time of at least 400 years overcomes the world's capability to deal with them. Only a relatively small portion of plastics is being recycled mostly due to their chemical composition and high remanufacturing cost. Consequently, plastic waste accumulation in the environment became one of the most pressing environmental problems of the XXI century leading to the rapid increase in the plastic pollution crisis, with a characteristic example to be the Oceans “plastic” island. The possibility of plastic waste conversion into valuable materials such as graphene, a 2D nanomaterial with extraordinary properties and potential for utilization for a plethora of applications from electronics to biomedicine, could be a key technology in promoting green and sustainable alternatives. This chapter aims to underline the prospects and limitations of plastic waste conversion into graphene/graphite and graphene-based nanomaterials (Graphical Abstract). An emphasis would be given to the type of the source material, and the correlation of their chemical nature toward the quality and quantity of the obtained graphene nanomaterial. Furthermore, through a comparison of the conventional methods and precursors for graphene production to the plastic waste upcycling method, the ecological impact of used chemicals and byproducts will be discussed. Finally, the overview of the potential application of the produced graphene and graphene-based nanomaterials as well as the prospects of using waste materials for graphene production will be introduced