Concentration Of Iron Compounds Research Articles

Ceramika siwa i czarna - przyczyny powstania określonej barwy

The article describes the causes of gray and black color formation during firing of ceramics made by several contemporary creators basedin eastern Poland (CzarnaWieś Kościelna) and western Lithuania (Pelekiške), Belarus (Kaliuga), and Ukraine (Czerwonograd). The paper presents the current state of research, including firing temperature measurements and the preliminary results of XRF examinations of clay. The results of the analyzes, which followed the observation andinterpretation of firing processes, point to (1) the construction and seal of a kiln and atmosphere within; (2) the type of firewood used at the final stage of firing and its amount relative to the kiln size; and (3) the duration of the process itself as the most probable factors determining color formation – rather than the concentration of iron compounds in the analyzed clays and ceramics samples or firing temperature. That said, there is a need for additional, detailed studies, which would involve a bigger sample of creators, in order to verify the performer analyzes.

Investigation of ultrasonic treatment of wastewater from iron compounds

The high level of wastewater pollution in the mining and metallurgical industries by compounds of heavy metals, including iron, enhances their migration into the environment. Due to the lack of universal high-performance and inexpensive methods of wastewater treatment and purification, the development of new technologies is very relevant. The article discusses the possibility of wastewater treatment by ultrasonic coagulation of iron compounds in a suspended colloidal state. It has been shown that the frequency of ultrasound does not affect the coagulation rate. The concentration of iron compounds in wastewater is inversely proportional to the intensity of ultrasound. It was also found that the dependence of the residual content of iron compounds on the processing time is extreme, which is associated with the formation of agglomerates and their subsequent destruction. The results obtained served as the basis for the development of the technological scheme.

Domoic Acid-Producing Diatoms of the Genus Pseudo-nitzschia H. Peragallo, 1900 (Bacillariophyta) from the North Pacific

Information on diatoms of the genus Pseudo-nitzschia, known as producers of domoic acid (DA), from the North Pacific is summarized. The differences in the negative impact of toxic diatoms on ecosystems in the western and eastern North Pacific are shown. The possible causes that determine the degree of these different impacts are discussed: a different composition of dominant species; a difference in the intracellular DA concentration in bloom-forming species; the hydrological, climatic, and hydrochemical factors that are responsible for the formation of toxic blooms (upwelling events, patterns of water circulation, concentration of iron compounds in sea water, etc.). The conclusion is made that the prospects of further studies of toxic diatoms are based on comparative investigations into the species and genetic diversity of Pseudo-nitzschia and associated bacteria, as well as the environmental parameters that control the formation of toxic blooms and the accumulation of DA in microalgae and other marine organisms in the eastern and western North Pacific.

NATURAL WATER DEFERRIZATION BY DEEP AERATION METHOD

Natural water, both groundwater and surface water, is characterized by high hardness, content of iron and partly manganese, and also dissolved gases. However, prolonged consumption of water with high content of iron compounds can cause the accumulation of its colloidal form in the liver and lead to its destruction. Therefore, water deferrization is an important step in water treatment. Therefore, the purpose of the study is to choose an effective device for water processing and deferrization, and to define optimal conditions of work. The main unit is a horizontal absorber with bucket dispersant. This is a hollow cylindrical device with a diameter of 0.5 m and a length of 0.33 m. The study is conducted with a simulator that contains Fe2+ (mg/dm3): 13.2; 20.6; 30.2; 40.8 and 50.2. When working with low content of iron compounds (from 10 to 20 mg/dm3), 50 % of it can be removed in 30-50 seconds and 100 % – in 2 minutes. The duration of the complete extraction of iron compounds increases significantly with an increase in concentration of Fe2+ and can reach up to 10 minutes (СFe2+ ≥ 40 mg/dm3). Nevertheless, two regions of the process can be observed for all concentrations. The first region is characterized by a sharp decrease in the concentration of iron compounds, namely, oxidation at high speed, and in the second region, these processes are slower. Fictitious oxidation flow rate of Fe2+ to Fe3+ in this region decreases with an increase in iron compounds concentrations and ranges from 9,15 to 5.75 g/m3·min. The oxygen that dissolves in water reacts immediately. In the second region, the concentration of Fe2+ ions is lower, so the probability of their collision and interaction decreases, and the process slows down. This is evident from the fictitious values of the process speed as they are reduced from 4.0 to 0.51 g/m3 ·min for all concentrations. The watering density between the volumes of liquid and gas phases positively affects the process of deferrization of water containing up to 40 mg/dm3 of iron compounds. In this case, the speed of the process increases. Increase in concentration of iron compounds over 40 mg/dm3 slows down the process and affects the quality of water purification. Thus, the absorber with horizontal bucket dispersants can be used for deep aeration and effective purification of natural water from iron compounds.

Mössbauer study of oxide films of Fe-, Sn-, Cr- doped zirconium alloys during corrosion in autoclave

Mossbauer investigations were used to compare iron atom states in oxide films of binary Zr-Fe, ternary Zr-Fe-Cu and quaternary Zr-Fe-Cr-Sn alloys. Oxide films are received in an autoclave at a temperature of 350–360 °C and at pressure of 16.8 MPa. The corrosion process decomposes the intermetallic precipitates in alloys and forms metallic iron with inclusions of chromium atoms α–Fe(Cr), α–Fe(Cu), α–Fe 2O3 and Fe 3O4 compounds. Some iron ions are formed in divalent and in trivalent paramagnetic states. The additional doping influences on corrosion kinetics and concentration of iron compounds and phases formed in oxide films. It was shown the correlation between concentration of iron in different chemical states and corrosion resistance of alloys.

Differentiation of concentration level of iron compounds in water reservoirs in subsidence depressions in the Katowice Upland

Differentiation of concentration level of iron compounds in water reservoirs in subsidence depressions in the Katowice Upland The aim of investigations was to evaluate the influence of varied anthropopression on the concentration of iron compounds in water reservoirs located in subsidence depressions treated as geosystems. Investigations were carried out during period of three hydrological years 2003-2005 within 10 reservoirs located in the Katowice Upland. The presence of iron was systematically measured in water and one time in bottom deposits. Measurements in taken samples were made by means of spectrometer of atomic absorption SOLAAR M6. Results confirmed varied influence of anthropopression on concentration of iron compounds in described reservoirs. It refers to waters and bottom deposits as well. Large differences between reservoirs occurred in a case of iron concentration in bottom deposits. The smallest amounts of it (3.10 g kg-1) were stated in transfer (flow-through) reservoir in Sosnowiec. Maximum values occurred also in reservoir in Sosnowiec, and the level of iron concentration in its deposits amounted to 44.28 g kg-1. Waters were also characterized by varied level of iron concentration. The lowest average values (0.0437 mg Fe l-1) were typical for one of reservoirs in Sosnowiec, whereas the maximum average iron concentration in amount of 0.4331 mg Fe l-1 referred to one of reservoirs in Zabrze. In the described reservoirs dynamic temporal changes in iron concentration in limnic waters was also stated. In every reservoir periods of complete disappearance of this metal occurred, whereas the maximum amounts of it in particular objects changed from 0.1132 mg Fe l-1 in reservoir in the borderland of Bytom and Chorzów up to 1.3744 mg Fe l-1 in reservoir located in Zabrze. The presence of iron compounds in the described water reservoirs on the one hand is shaped by environmental conditions, but on the other hand varied influence of anthropopression decides significantly of their spatial and temporal cycle in the nature.

Peculiarities of annual variations in the concentration of iron compounds in the water-bottom sediments system of the Mozhaisk Reservoir

Annual variations in concentrations of Fe forms in the bottom water (0–70 cm from the bottom, by layers), pore water, and in solid phase of silts (25 cm, by layers) of the Krasnovidovo Pool channel area of the Mozhaisk Reservoir are studied. A drastic increase in the concentration and ratio of Fesusp/Fedis in the water layer 0–20 cm from the bottom is detected. Fe(II) dominates in dissolved and suspended forms. The concentrations of Fe(III) reaching 2–3 mg/l were for the fist time revealed in the pore water of silts (Eh ∼ −120 mV). The factors responsible for this phenomenon are discussed. Fe flux from sediments is tentatively assessed as 0.2–0.6 mg Fe m2/day.

Relation of Manganese and Some other Metals to the Iron Status of Plants

IT has been shown with piants growing in water culture that iron deficiency symptoms may be readiiy induced by excessive concentrations of manganous saits1-6. A reciprocai effect on the incidence of manganese deficiency in the presence of high concentrations of iron compounds has aiso been shown for soya bean6 and some fruit crops4. These resuits have been interpreted6 as suggesting that iron deficiency and manganese toxicity are but reiative terms for the same disorder resuiting from too wide Fe/Mn ratios, and that manganese deficiency and iron toxicity are simiiariy reiative. It is generaiiy assumed that metaboiicaiiy active iron exists in piants in the ferrous state, and becomes inactive after oxidation to the ferric state. In one of the experiments referred to6, this oxidation was assumed to foiiow reaction with manganese compounds previousiy oxidized to a higher vaiency state. A simiiar abiiity to induce iron deficiency was forecast for cobait on account of its still higher oxidation-reduction potentiai than the manganese system postuiated, and some indication was obtained that iron deficiency was induced more readiiy by cobait saits.