The Role of Clay Mineral-Derived Photocatalysts in Insights of Remediation

Clay minerals have advantages to be used as supports for obtaining new catalysts, in which colloidal and surface characteristics play a significant role. In addition to their favorable physicochemical properties, clay minerals allow different modifications to form structures with broad photochemical capabilities. This review collects pertinent works of semiconductor nanoparticles loaded onto clay minerals and their potential application in hazardous contaminant photodegradation. Web of Science, Scopus, and Science Direct were used for bibliographic research databases. The sol–gel method is the most frequent technique used to obtain semiconductors immobilized onto clay minerals, but other methods have also proven helpful in forming these structures. Thence, the types of synthesis and different parameters that influence their photocatalytic efficiency will be discussed. Pillared clay minerals have been applied to photo-oxidation reactions involving photodecomposition of environmental contaminants. The homogeneous dispersion of nanoparticles on the surface of clay minerals, reduction of fine particles, its non-toxicity, and the generation of a suitable suspension for photocatalytic reactions may be the main characteristics of these inorganic supports to obtain successful photoactive materials

The Role of Clay Mineral-Derived Photocatalysts in Insights of Remediation

Clay minerals have advantages to be used as supports for obtaining new catalysts, in which colloidal and surface characteristics play a significant role. In addition to their favorable physicochemical properties, clay minerals allow different modifications to form structures with broad photochemical capabilities. This review collects pertinent works of semiconductor nanoparticles loaded onto clay minerals and their potential application in hazardous contaminant photodegradation. Web of Science, Scopus, and Science Direct were used for bibliographic research databases. The sol–gel method is the most frequent technique used to obtain semiconductors immobilized onto clay minerals, but other methods have also proven helpful in forming these structures. Thence, the types of synthesis and different parameters that influence their photocatalytic efficiency will be discussed. Pillared clay minerals have been applied to photo-oxidation reactions involving photodecomposition of environmental contaminants. The homogeneous dispersion of nanoparticles on the surface of clay minerals, reduction of fine particles, its non-toxicity, and the generation of a suitable suspension for photocatalytic reactions may be the main characteristics of these inorganic supports to obtain successful photoactive materials

TiO2/Karaya Composite for Photoinactivation of Bacteria

TiO2/Karaya composite was synthesized by the sol-gel method for the photoinactivation of pathogens. This is the first time that we have reported this composite for an antimicrobial approach. The structure, morphology, and optical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-rays (EDS), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance, and the surface area was characterized by the BET method. The XRD and EDS results showed that the TiO2/Karaya composite was successfully stabilized by the crystal structure and pore diameter distribution, indicating a composite of mesoporous nature. Furthermore, antibacterial experiments showed that the TiO2/Karaya composite under light was able to photoinactivate bacteria. Therefore, the composite is a promising candidate for inhibiting the growth of bacteria

TiO₂/Arabic Gum for Degradation of Pollutants in Water

Emerging contaminants and pollution are environmental problems threatening public health. Antibiotic ciprofloxacin and methylene blue dye are pollutants frequently detected in water systems worldwide. Photocatalysis is a process for water treatment. TiO2-based catalysts synthesized with natural gums show improved photocatalytic properties. Here, the sol–gel method synthesized TiO2/Arabic gum for photocatalytic performance. The innovation of this work was synthesized at 400 °C and investigated their photocatalytic proprieties using methylene blue and ciprofloxacin as model pollutants. XRD showed that the photocatalyst was in the anatase phase. The result showed that TiO2 with a band gap of 3.29 eV was achieved at a calcination temperature of 400 °C. Corresponding FTIR results suggest only the existence of functional groups related to TiO2. The SEM and BET method characterization indicated that TiO2/Arabic gum were spherical-shaped nanoparticles arranged in clusters with a mesoporous structure, contributing to photocatalytic performance. In addition, photocatalytic studies showed that the methylene blue dye and ciprofloxacin antibiotic degradation rates reached 99% and 94% under UV light, respectively. The hole (h+) and OH ⦁ radicals are essential in photodegradation. The synthesized material showed excellent photostability and maintained almost the same degradation percentage in the three consecutive cycles tested on the different pollutants. The TiO2/Arabic gum is an excellent candidate for future use in treating contaminants in aqueous media using photocatalysis. Therefore, TiO2/Arabic gum nanoparticles are a promising material for wastewater treatment

Improved remediation of contaminated water using ZnO systems via chemical treatment: applications, implications and toxicological mitigation

Environmental remediation is an alternative field of science that can solve various environmental challenges based on numerous treatment methods. In particular, heterogeneous photocatalysis is an advanced oxidative process that has been the subject of many studies related to environmental control. Globally, pollution by organic pollutants represents risks to environmental health that compromise public health and directly affect the scientific knowledge of public policies that potentially improve quality of life from a sustainable point of view. ZnO systems are receiving special attention due to their attractive characteristics (non-toxic nature, high surface area, thermal/chemical stability), availability of being chemically modified by various strategies, and particularly good environmental remediation. This review focuses on the efforts of ZnO-based photocatalysts, such as the methods, chemical modifications, operational parameters, and the effects after the release of effluents in aquatic matrices. Therefore, we investigated the recent advances in zinc systems aimed at treating contaminated water and their direct application in environmental remediation.Fil: Osajima, Josy A.. Universidade Federal Do Piaui.; BrasilFil: Sá, Alexandro S.. Universidade Federal Do Piaui.; BrasilFil: Feitosa, Rodrigo P.. Universidade Federal Do Piaui.; BrasilFil: Furtini, Marcelo B.. Universidade Federal Do Piaui.; BrasilFil: Honorio, Luzia M. C.. Universidade Federal de Pernambuco; BrasilFil: Fonseca, Maria G.. Universidade Federal de Pernambuco; BrasilFil: Trigueiro, Pollyana. Universidade Federal Do Maranhao.; BrasilFil: Caregnato, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Triboni, Eduardo R.. Universidade de Sao Paulo; BrasilFil: Silva Filho, Edson C.. Universidade Federal Do Piaui.; Brasi

Polyurethane/Vermiculite Foam Composite as Sustainable Material for Vertical Flame Retardant

Rigid polyurethane foams were prepared by the one-step expandable foam method using casting molding followed by forming clay-based composites. Polyurethane/vermiculite foam composites (PU/VMT) were controlled based on adding the percentage of clay in the formulation. The effects of composite modifications were evaluated by X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), and scanning electron microscopy (SEM/EDS) applied to the flame retardancy explored by the vertical burn test. The results indicated that adding clay controlled the particle size concerning polyurethane (PU) foams. However, they exhibited spherical structures with closed cells with relatively uniform distribution. XRD analysis showed the peaks defined at 2θ = 18° and 2θ = 73° relative to the crystallinity in formation and interaction of rigid segments were identified, as well as the influence of crystallinity reduction in composites. In the flame test, the flame retardant surface was successful in all composites, given the success of the dispersibility and planar orientation of the clay layers and the existence of an ideal content of vermiculite (VMT) incorporated in the foam matrix