Silver nanoparticles-loaded titanium dioxide coating towards immobilized photocatalytic reactor for water decontamination and bacterial deactivation under natural sunlight irradiation
The environmental implications of rapid industrialization, including rising pollution, depleted resources, the effects of climate change brought on by global warming, and unrestrained groundwater extraction, are contributing to a growing water scarcity crisis [1-3]. The improvements in quality of life are largely attributable to the innovations in manufacturing technology made possible by the Industrial Revolution, but these innovations also pose risks to the natural world and human health [1-3]. The textile business uses a wide variety of raw materials, including natural fibers like cotton as well as synthetic and woolen fibers, and the chemical components of dyes are just one example. The annual output of synthetic dyes is around 700,000 tons, and there are over 10,000 different varieties available. As much as 200,000 tons of synthetic dyes are released into the environment every year due to the inefficient dyeing technique commonly employed in the textile industry. According to the World Bank, the processing of textiles for dyeing and finishing accounts for between 17 and 20 percent of industrial wastewater [1-3]. Textile wastewaters contain a high biological oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, color, acidity, high suspended particles, high dissolved solids, surfactants, dyestuffs, heavy metals, and other soluble chemicals [3] due to the variety of dyes used to color textile items. In particular, water-soluble reactive and azo dyes are employed to obtain the required color. Ten to twenty percent of the dyes used end up in the effluents, where they might harm wildlife and the ecosystem (carcinogenic or mutagenic). Headaches, nausea, skin irritation, respiratory difficulties, and congenital deformities are only some of the health problems linked to exposure to textile wastewater. There are repercussions for aquatic ecology, environmental biodiversity, and the quality of receiving water bodies. New, low-cost, and highly effective water treatment methods are needed to deal with polluted wastewater. Adsorption and coagulation, two common water purification methods, just concentrate pollutants by shifting them to other phases; they do not "eliminate" or "destroy" them. Sedimentation, filtration, chemical oxidation, and biotechnology are all examples of conventional water treatment methods, but they all have their drawbacks. These include insufficient removal, high chemical reagent consumption, high treatment costs, long treatment times, and the creation of toxic secondary pollutants. New water treatment procedures are needed to improve the quality of treated effluent [1-3]. The use of semiconductor particles in photocatalysis is gaining appeal as a solution to global pollution problems due to its shown efficiency in degrading a wide variety of contaminants. Photocatalyst-coated surfaces-based reactors have proven to be practical for long-term operation over photocatalytic powder-based reactors (i.e., slurry-based reactors) [4-5]. As a promising photo-electrode and photocatalyst, titanium dioxide (TiO2) has enjoyed wider applicability in photocatalytic hydrogen generation, solar cells, and remediation of organic contaminants among other photo-catalytic applications [4-6]. TiO2 has been recognized as one of the low-cost, most effective, and fascinating photo-catalyst as a result of its interesting thermal and chemical stability, desirable electronic features, others, and environmental benignity [6-8]. Pristine TiO2 semiconductor is characterized by a wide band gap that can only utilize the UV part of the light spectrum with a wavelength of less than 385 nm, which is just 5% of the sunlight energy capacity. Spectrum usability extension to visible regions warrants further and extensive research study [8-10]. Additionally, the quickness of the recombination of photo-generated holes and electrons further restricts the practical applicability of the semiconductor [10-12]. It is highly desirable to develop a cost-effective scalable strategy to over these drawbacks toward sustainable development and a clean environment using only natural sunlight irradiation [5-11]. In addition, it is preferred to fabricate them as films rather than powders as photocatalytic immobilized reactors are more practical than powder-based reactors [4-8]. Dye sensitization, supports, magnetic separation, and surface modification by doping with non-metals, metals, and transition metals and coupling with other semiconductors have all been used to enhance the photocatalytic activity of TiO2 photocatalyst. Higher photonic efficiency can be attained through the synergistic fine-tuning of features such as physical, chemical, and electronic, and these composites and hybrid materials based on TiO2 are creating a big trend. Doping has been widely studied as a means of altering the surface of TiO2. Rare earth metals, noble metals, and transition metals are all discussed in the existing literature on the surface modification of TiO2 doped with cations [4-12]. In this study, for the first time, Ag nanoparticles loaded mesoporous TiO2 coating was prepared and applied as an immobilized photocatalytic reactor for water decontamination and bacterial deactivation under natural sunlight irradiation.
ENVIRONMENTALLY FRIENDLY UPCYCLING APPROACH TO INCREASE IMPACT RESISTANCE OF REINFORCED CONCRETE STRUCTURES: USE OF INDUSTRIAL WASTE AS CONSERVATION MATERIAL
Within the scope of sustainable cities and responsible consumption, which are among the goals of sustainable development, it is aimed to contribute to life safety, defense industry, protection from disasters and economy with the new generation environmental building technologies and materials to be developed in the field of construction. It is a critical issue to protect reinforced concrete structures, piers, bridge piers, overpasses against impacts, and to reduce the damages and economic losses in disaster situations. Reinforced concrete scaffolding is the load-bearing component of the structure and its impact resistance is crucial to the overall safety of the concrete structure. Therefore, there is a need to develop technologies that can protect structures against explosion and impact loads. Within the scope of the project, environmentally friendly and low-cost concrete materials with industrial waste glass, aluminum, plastic material additives, which can be used in columns, which are the most important part in the strength of reinforced concrete structures to prevent explosion and impact damage, were produced and their strengths were analyzed. The use and design of these materials in the strength of concrete creates the originality of the project. When the results obtained in the project were examined, it was observed that the steel fiber concretes with the addition of waste glass, aluminum ring, disc, beverage can and plastic bottle were resistant to high pressure when compared with the control groups without additives, and the change in surface height after the impact test, visual analysis and load-time graphics showed this. It is seen that the additives have a cushioning effect against the impact, absorbing the energy against the force by 87.6% and increasing the strength significantly. In this project, where it is aimed to increase the strength of concrete structures by using the impact energy absorption feature of waste glass, plastic and aluminum, products with high added value are developed, contributing to the literature and the construction sector. With the large-scale use of the project, the costs spent on the disposal of waste materials will be reduced, the upcycling based on re-using the waste products will be contributed, and the loss of life and property due to impacts and explosions will be prevented.
Bifunctional Nanostructured TiO2 photoelectrocatalyst for Improving Overall Water splitting performance
Titanium dioxide TiO2 is a semiconductor, that has great chemical and physical properties, such as remarkable resistance against corrosion, chemical stability, and it’s a non-toxic material. Due to these properties, it rises as an excellent candidate for a wide range of different applications, such as being a popular material for solar cells, paints, cosmetics, energy storge devices, and water splitting. For photoelectrochemical water splitting to generate Hydrogen, a large surface area is essential, to be maximized to enhance photocatalytic redox processes and hence improve overall efficiency. Therefore, different methods have been utilized to fabricate TiO2 nanotubular structure. However, they either encounter a difficult process because of a long synthesis time or the need of expensive precursors. In our work, we demonstrated a study of enhancing 1 D TiO2 film to perform as a bifunctional catalyst (works as cathode and anode). As it is known that TiO2 is kinetically hampered as cathode for producing hydrogen from water, this is due to sluggish electron transfer at the interface between TiO2 and water and the conduction band of the TiO2, which is more negative than H+/H2. To tackle this problem, TiO2 film should be modified. In this work, we modified the TiO2 as bifunctional by investigating different parameters in detail, like the anodic oxidation solution content, anodic oxidation time, and the role of the polyethylene glycol chain. Electrochemical characterization and SEM, and XPS were utilized to prevent the nanotubes structure and to confirm the chemical bonding as well as investigating the physical properties such as resistance and electron kinetic mobility.