Microbiologically Influenced Corrosion of Iron by Nitrate Reducing Bacillus Sp

Iron has played a crucial role in the human ecosystem currently in transportation, manufacturing, and infrastructure. Iron oxide is known as rust, usually the reddish-brown oxide formed by iron and oxygen reactions in moisture from water or air. Microbiologically influenced corrosion (MIC) is a significant problem to the economic damage, especially in industrial sectors and its direct presence with nitrate/iron-reducing bacteria. This paper aims to explore the MIC of iron by nitrate-reducing Bacillus sp. including the redox reaction occurs, microbiologically influenced corrosion, iron/nitrate-reducing and mechanisms of microbial iron/nitrate reduction.

Photocatalytic Reduction of CO2 over Iron-Modified g-C3N4 Photocatalysts

Pure g-C3N4 sample was prepared by thermal treatment of melamine at 520 °C, and iron-modified samples (0.1, 0.3 and 1.1 wt.%) were prepared by mixing g-C3N4 with iron nitrate and calcination at 520 °C. The photocatalytic activity of the prepared materials was investigated based on the photocatalytic reduction of CO2, which was conducted in a homemade batch reactor that had been irradiated from the top using a 365 nm Hg lamp. The photocatalyst with the lowest amount of iron ions exhibited an extraordinary methane and hydrogen evolution in comparison with the pure g-C3N4 and g-C3N4 with higher iron amounts. A higher amount of iron ions was not a beneficial for CO2 photoreduction because the iron ions consumed too many photogenerated electrons and generated hydroxyl radicals, which oxidized organic products from the CO2 reduction. It is clear that there are numerous reactions that occur simultaneously during the photocatalytic process, with several of them competing with CO2 reduction.

Variations in and environmental controls of primary productivity in the Amundsen Sea

The Amundsen Sea is one of the regions with the highest primary productivity in the Antarctic. To better understand the role of the Southern Ocean in the global carbon cycle and in climate regulation, a better understanding of the variations in and environmental controls of primary productivity is needed. Using cluster analysis, the Amundsen Sea was divided into nine bioregions. The biophysical differences among bioregions enhanced confidence to identify priorities and regions to study the temporal and spatial variations in primary productivity. Four nearshore bioregions with high net primary productivity or rapidly increasing rates were selected to analyze temporal and spatial variations in primary productivity in the Amundsen Sea. Due to changes in net solar radiation and sea ice, primary production had significant seasonal variation in these four bioregions. The phenology had changed at two bioregions (3 and 5), which has the third and fourth highest primary production, due to changes in the dissolved iron, nitrate, phosphate, and silicate concentrations. Annual primary production showed increasing trends in these four bioregions. The variation in primary production in the bioregion (9), which has the highest primary production, was mainly affected by variations in sea surface temperatures. In the bioregion, which has the second-highest primary production (8), the primary production was significantly positively correlated with sea surface temperature and significantly negatively correlated with sea ice thickness. The long-term changes of primary productivity in bioregions 3 and 5 were thought to be related to changes in the dissolved iron, nitrate, phosphate, and silicate concentrations, and dissolved iron was the limiting factor in these two bioregions. Bioregionalization not only disentangle multiple factors that control the spatial differences, but also disentangle limiting factors that affect the phenology, decadal and long-term changes in primary productivity.

BIOCATALYTIC SYNTHESIS OF D-GLUCONIC ACID

D-глюконовая кислота является широко потребляемым продуктом в пищевой и фармацевтической промышленностях. Данная работа посвящена разработке биокатализатора окисления D-глюкозы до D-глюконовой кислоты. Биокаталитические системы были выполнены на основе глюкозооксидазы, иммобилизованной на магнитоотделяемые мезопористые оксиды SiO и AlO, которые были синтезированы путем образования наночастиц магнетита в порах оксидов кремния и алюминия в результате термического разложения нитрата железа, инкорпорированного пропиткой. В работе подобраны оптимальные значения рН и температуры, при которых синтезированные биокатализаторы способны работать. Произведена сравнительная характеристика работы биокаталитических систем по сравнению с нативной формой глюкозооксидазы. D-gluconic acid is a widely consumed product in the food and pharmaceutical industries. This work is devoted to the development of a biocatalyst for the oxidation of D-glucose to D-gluconic acid. Biocatalytic systems were based on hycose oxidase immobilized on magnetically detachable mesoporous oxides SiO and AlO, which were synthesized by the formation of magnetite nanoparticles in the pores of silicon and aluminum oxides as a result of thermal decomposition of iron nitrate incorporated by impregnation. In this work, the optimal pH and temperature values were selected, at which the synthesized biocatalysts are able to work. A comparative characteristic of the work of biocatalytic systems in comparison with the native form of glucose oxidase has been made.

Iron Nitrate Modified Cotton and Polyester Textile Fabric Applied for Reactive Dye Removal from Water Solution

In this work, we investigated the use of cotton scraps in natura and modified with iron nitrate,in the adsorption of one of the main water contaminants of the textile industries, the reactive black dye. Special attention was paid to the appropriate destination of the spent adsorbent, in compliance with the precepts of the circular economy. Cotton and polyester are excellent candidates for adsorbents and are produced on a large scale worldwide, but fabric wastes do not yet have a wellestablished method of application. We found that fabrics containing different types of fibers or colors maintain the ability to remove dye. The retention promoted by the cotton fabric in natura reached 18.8 mg g-1. After treatment with iron ions, there was an increase in the dye adsorption capacity to 31.0 mg g-1. In addition, the spent iron-containing adsorbent was pyrolyzed at 973 K, resulting in an activated magnetic carbon with a specific surface area ranging from 300 to 565 m2 g-1. Thus, it was possible to convert the used adsorbent into a new material with wide application possibilities.

COMPOSITION AND STRUCTURE OF COMPOSITE COATINGS BASED ON METAL OXIDES AND POLYTETRAFLUOROETHYLENEDEPOSITED UNDER CONDITIONS OF ELECTRON-INITIATED ENDOTHERMIC PROCESSES

In this article features of physicochemical processes initiated by the low-energy electron flow between the components of the target based on nitrates of metals and metals, their influence on the kinetics of the formation of volatile products, the chemical composition and structure of the deposited coatings are established. When electrons act on a mixture of aluminum nitrate and dispersed aluminum, zinc oxide coatings containing zinc nanorods are formed. The impact of the electron flow on a mechanical mixture of powders of iron nitrate and dispersed aluminum is accompanied by explosive evaporation of the target, and a large number of microdroplet formations deposited at the final stage of exothermic reactions in the surface layers of the target are fixed on the surface of the coating containing oxides and metal nanoparticles. The features of the structure and chemical composition of coatings deposited from the volatile products of electron beam dispersion of a mechanical mixture of polytetrafluoroethylene, iron nitrate, and aluminum are determined. It is shown that under such conditions of generation of the gas phase, coatings are formed consisting of a polymer matrix and containing particles of oxide, a free metal, and a certain amount of the initial undecomposed salt. The result of exothermic reactions in the crucible is partial defluorination and increased defectiveness of the molecular structure of the fluoroplastic matrix.

Impact of drought on water quality in the Youssef Ben Tachafine dam (Souss-Massa region, Morocco)

The Massa catchment area has been experiencing an acute rainfall deficit for several years, which has had direct effects on the filling level of the Youssef Ben Tachafine dam. The objective of this work is to study the impact of the drought on the physicochemical quality and the biological balance of this aquatic ecosystem. A monitoring and bi-monthly analyses of the physicochemical and biological parameters (temperature, dissolved oxygen, pH, conductivity, transparency, manganese, iron, nitrate, ammonium, silica, phosphorus, and chlorophyll-a) were carried out from January to December 2019. The considerable drop in the level of the reservoir has had a major impact on the degradation of the water quality of the lake and its trophic status. The analysis of the results showed that the trophic state of the Youssef Ben Tachafine dam is between mesotrophic and hypereutrophic.