Adsorption of inorganic ions from aqueous solutions using mineral sorbent - tripoli

The present research considers the adsorption of H[2]AsO[4] -, CrO[4]{2-}, Ni{2+}, Fe{3+} ions from their aqueous solutions by mineral sorbent - tripoli. Tripoli was characterized by different physico-chemical methods such as X-ray phase analysis, inductively coupled plasma atomic emission spectrometry, method of thermal desorption of nitrogen. Contact time, specific surface area, specific pore volume and surface charge of tripoli have been determined. The effect of tripoli surface area modification by iron (III) oxide-hydroxide on tripoli sorption capacity for the arsenic anions has been investigated. The maximum adsorption was found to occur within 30 minutes of contact time. Different models including the pseudofirst-order kinetic and the pseudo-second-order kinetic equations were used to analyse kinetic data. All the models being considered, it has been stated that the pseudo-second-order kinetic model is the most appropriate to describe the adsorption behaviour of Fe{3+} ions on tripoli. The adsorption has been explained in terms of Langmuir and Freundlich isotherms. Based on values of correlation coefficients, H[2]AsO[4]{-}, CrO[4]{2-}, Ni{2+}, Fe{3+} sorption isotherm data were better fitted by Langmuir model. It has been detected that the modification of mineral sorbent (tripoli) leads to the increase in H[2]AsO[4]{-} adsorbing capacity of tripoli. In general, the results indicated that tripoli can be an efficient low-cost sorbent for removing H[2]AsO[4]{-}, Ni{2+}, Fe{3+} ions from aqueous solutions

The backbone of research in modern education in the context of the competence approach

Modern society, which sets problems of translating culture in a new way, determines new criteria for the educational paradigm. Globalization tendencies in modern educational environment induce the problem of necessity to integrate educational and scientific resources into Russian education. The aim of this article is to demonstrate a significant part of scientific research as a consistent factor in formation of the competence-based model of a professional. It is shown that students’ research work beyond the process of education becomes a unique sort of teaching activity, which has a number of essential differences from the main traditional teaching techniques for compulsory courses. The results of students’ research work in the ecological situation of Siberian region are presented. The competencies acquired by students during this work are revealed. It is noticed that integrating the theme of students’ research work with compulsory courses is one of the most important teaching peculiarities in formation of personal attributes of a future highly-qualified professional, which form the basis of professional mobility and competitiveness. It is summarized that an interdisciplinary character of research work in the modern educational paradigm is aimed at solving innovative tasks of integrating educational, scientific and practice-oriented constituents in the context of the competency building approach

Investigation of the mechanism of microplasma impact on iron and aluminum load using solutions of organic substances

The paper reports on the study of mechanism of electroeffects on iron and aluminum and pellets with using solutions of organic substances. Methylene blue solution, furacilin and eosin were used. It is observed the reactions of the pulse at the time and after switching off the voltage source. It is shown that there are two developing process in the conditions studied. The first process depends on material of electrodes and pulse parameters. The second process occurs spontaneously and it is determined by the redox reaction and sorption processes. The products of electrode erosion and active particles react in the redox reactions. Active particles are formed in solution by the action of pulsed electric discharge in water. The highest efficiency of the process was demonstrated on an iron pellets

Pulsed Electric Discharge in Active Metallic Grains for Water Purification Processes

Chemical reactions in electric metal pulse dispersion in the aqueous solutions of inorganic substance (НSiO[3]{–}, Ni{2+}, Н[2]AsO[4]{–}, Mn{2+}, Cr[2]O[7]{2–}) were determined through IR spectroscopy, X-ray phase, chemical, kinetic, and thermodynamic analyses. Under such conditions, both reduction and oxidation reactions occur, as well as, locally initiated by heating, hydrolysis and exchange reactions without changing the oxidation rate of the dissolved substance itself. Reduction and oxidation of dissolved substances is determined by the generation and activation of high dispersed Fe in an electric discharge. Physical and chemical processes which take place under the action of pulse electric discharges upon the layer of metallic grains in salt solution, containing НSiO[3]{–}, Ni{2+}, Н[2]AsO[4]{–}, Mn{2+}, Cr[2]O[7]{2–} ions were determined on the basis of product composition, obtained experimentally and the thermodynamic data. It was shown, that PED discharge in heterogeneous mediums can be used for waste and natural water purification

Electropulse treatment of water solution of humic substances in a layer iron granules in process of water treatment

The present work is a part of a continuations study of the physical and chemical processes complex in natural waters containing humic-type organic substances at the influence of pulsed electrical discharges in a layer of iron pellets. The study of humic substances processing in the iron granules layer by means of pulsed electric discharge for the purpose of water purification from organic compounds humic origin from natural water of the northern regions of Russia is relevant for the water treatment technologies. In case of molar humate sodium - iron ions (II) at the ratio 2:3, reduction of solution colour and chemical oxygen demand occur due to the humate sodium ions and iron (II) participation in oxidation-reduction reactions followed by coagulation insoluble compounds formation at a pH of 6.5. In order to achieve this molar ratio and the time of pulsed electric discharge, equal to 10 seconds is experimentally identified. The role of secondary processes that occur after disconnection of the discharge is shown. The time of contact in active erosion products with sodium humate, equal to 1 hour is established. During this time, the value of permanganate oxidation and iron concentration in solution achieves the value of maximum permissible concentrations and further contact time increase does not lead to the controlled parameters change

Study of adsorption process of iron colloid substances on activated carbon by ultrasound

The paper reports on the adsorption of iron colloid substances on activated carbon (PAC) Norit SA UF with using ultrasound. It is found that time of adsorption is equal to three hours. High-frequency electrical oscillation is 35 kHz. The adsorption capacity of activated carbon was determined and it is equal to about 0.25 mg iron colloid substances /mg PAC. The iron colloid substances size ranging from 30 to 360 nm was determined. The zeta potential of iron colloid substances which consists of iron (III) hydroxide, silicon compounds and natura organic substances is about (-38mV). The process of destruction iron colloid substances occurs with subsequent formation of a precipitate in the form of Fe(OH)[3] as a result of the removal of organic substances from the model solution

Destruction of humic substances by pulsed electrical discharge

Currently, the water recourses in the territory of Tomsk region are groundwater which is limited to the high concentration of iron and manganese ions and organic substances. These impurities present in water in different forms such as soluble salts ant the colloid forms. Therefore, the present work is a part of a continuations researcher of the processes in natural waters containing humic substances at the influence of pulsed electrical discharges in a layer of iron pellets. It is shown that the main stage of water purification process of humic substances during treatment by pulsed electric discharge in the layer of iron granules is a difficult process including several stages such as formation of iron oxyhydroxide colloid particles, sorption and coagulation with humic macromolecules substances, growth of particle dispersed phase and precipitation. The reason for the formation and coagulation of the dispersed phase is a different state of charge of the colloid particles (zeta potentials of (Fe (OH)3) is +8 mV, zeta potentials of (Humic substances) is -70 mV. The most intense permanganate oxidation reduction to the maximum permissible concentration occurs at the processing time equal to 10 seconds. The contact time of active erosion products with sodium humate is established and it equals to 1 hour. The value of permanganate oxidation achieves maximum permissible concentration during this time and iron concentration in solution achieves maximum permissible concentration after filtration

Adsorption of petroleum substances and inorganic ions from aqueous solutions using mineral sorbent

Relevance. Nowadays among different water purification techniques, sorption method is generally preferred. Intension to improve the efficiency of sorption in water purification makes the problem of developing and investigating the sorption mechanism and practical application of low-cost and effective adsorbents the focus of attention for many studies. The main aim is to study adsorption of water soluble petroleum substances and H2AsO4 -, CrO4 2-, Ni2+, Fe3+ ions from their aqueous solutions by mineral sorbent tripoli, and investigate the effect of various parameters affecting sorption behaviour for better understanding adsorption process and ways of possible usage of the mineral sorbent (tripoli) for wastewater purification. Object. Low-cost locally available tripoli (Zikeevsk deposit, Russia) was selected as a natural mineral sorbent.Methods: X-ray phase analysis, inductively coupled plasma atomic emission spectrometry, method of thermal desorption of nitrogen, Indicator method Results. Tripoli was characterized by different physico-chemical methods such as X-ray phase analysis, atomic emission spectrometry with inductively coupled plasma, method of thermal desorption of nitrogen. The authors have determined contact time, specific surface area, specific pore volume of tripoli and adsorption kinetic data. The adsorption isotherms of petroleum substances and H2AsO4 -, CrO4 2-, Ni2+,Fe3+ ions from their aqueous solutions using tripoli were studied. The adsorption was explained in terms of Langmuir and Freundlich isotherms. Indicator method was applied to detect the fact that the tripoli active sites are negatively charged. It was determined that modification of mineral sorbent (tripoli) leads to increase in H2AsO4 - adsorbing capacity of tripoli. This work suggests that the mineral sorbent tripoli can be effectively used in water purification from petroleum substances and Ni2+, Fe3+ ions as low-cost, effective, environmentally friendly adsorbent

Electropulse treating of humic substance aqueous solutions in a layer of iron granules at water purification

The authors have studied the processing of humic substances in a layer of iron pellets with pulsed electric discharge for natural water purification from organic compounds of humic origin in northern regions of Russia, that is relevant for water treatment technologies. The aim of the research is to determine the quantitative characteristics of water purification from humic substances in electric pulse processing in the layer of iron pellets. Methods: photocolorimeter, pH-meter, catalytic oxidation, titrometry. Results. The authors determined the quantitative characteristic of critical micelle concentration in the system sodium humate - iron ions (II), which corresponds to a mole ratio of the components of 2:3. The color of solution and demand of chemical oxygen occur at the specified ratio due to the participation of sodium humate and iron ions (II) in oxidation-reduction reactions with further coagulation and formation of insoluble compounds at pH of 6,5. It is shown that sodium humate increases the efficiency of Fe (II) oxidation in Fe (III). In order to achieve this molar ratio, the action time of pulsed electric discharge was determined experimentally. It is 10 seconds. The paper demonstrates the role of the secondary processes after discharge disconnection. The authors determined the contact time of erosion active products with sodium humate, which is 1 hour. During this time, the values of permanganate oxidation and iron ions concentration in solution achieve the value of maximum permissible concentrations and further increase of the contact time does not result in changing the controlled parameters