Removal Of Iron Ions Research Articles

Water deironing through the reagent and biosorption treatment and utilization of iron-rich sediments and biosornets in cement production

ABSTRACT The processes of reagent and sorption removal of iron ions from water were investigated and the efficiency of deironing was evaluated. Lime and biosorbents based on walnut shells were used through experiments. The range of iron ions concentrations from 2 to 100 mg/L was studied. The efficiency of deironing is reached maximum efficiency during biosorbtion. In order to create resource-efficient technologies, it is important to develop effective methods of sludge and spent sorbents utilisation. The sediments formed as a result of reagent and sorption purification of water from iron were utilised in the composition of cement with the consumption 3%. The effect of additives application in cement production was evaluated according to the following properties: normal density, coefficient of water separation, time of hardening, compressive strength at the age of 2 and 28 days.

Self-hydrolyzing Submerged Flow Technology for Acid Coal Mine Drainage Treatment: Effective Removal of Iron Ions

In this study, mine wastewater from Leiyang, Hunan Province was taken as the research object to investigate the effect of using the method of self-hydrolytic submerged sedimentation to treat acid coal mine drainage. It was found in this study that the removal rate of sulfate ions and iron ions from the acidic coal mine drainage stock solution at pH=2.7 was very limited by self-hydrolytic sedimentation experiments relying only on pure vertical sedimentation flow treatment, but the hydrolytic treatment could greatly improve the solution environment and promote the formation of secondary minerals of sulfate ions and iron ions in the acidic coal mine drainage, which greatly improved the removal rate of iron ions. Both suspended and precipitated materials produced in the self-hydrolysis sedimentation experiments were hydroxylated iron sulfate secondary minerals- Schwertmannite [Fe8O8(OH)8-2X(SO4)X (1 ≤ x ≤ 175)], the formation of which is inextricably linked to the low pH environment and high concentration of sulfate and iron ions in coal mine wastewater. Self-hydrophoretic submerged flow can remove iron ions from acidic coal mine drainage at low cost and high efficiency, and the total iron removal rate of this system can reach 90.93% after 24 h of treatment, which has a favorable comprehensive utilization value.

Flower-like tin oxide membranes with robust three-dimensional channels for efficient removal of iron ions from hydrogen peroxide

Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide (H2O2). But due to the oxidation degradation of the organic membranes (e.g. polyamide) by the strong oxidative radicals (e.g. OH) generated via the activation of H2O2 by iron ions (Fe3+), the short effective lifetime of membranes remains a challenge. Inorganic nano tin oxide (SnO2) has great potential for the removal of Fe3+ in strongly oxidative H2O2 because of its ability to stabilize H2O2 and preferentially adsorb Fe3+. Herein, we have designed for the first time a flower-like robust SnO2 membrane on the ceramic support by in situ template-free one-step hydrothermal method. The three-dimensional loose pore structure in the membrane built by interlacing SnO2 nanosheets endows the SnO2 membrane with a high specific surface area and abundant adsorption sites (OH). Based on the coordination complexation and electrostatic attraction between the SnO2 surface and Fe3+, the membrane shows a high Fe3+ removal efficiency (83%) and permeability (24 L·m−2·h−1·MPa−1) in H2O2. This study provides an innovative and simple approach to designing robust SnO2 membranes for highly efficient removal of Fe3+ in harsh environments, such as strong oxidation conditions.

Removal of Fe(III)/Al(III)/Mg(II) by phosphonic group functionalized resin in wet-process phosphoric acid: Mechanism and intrinsic selectivity.

The removal of iron ions (Fe(III)), aluminum ions (Al(III)), and magnesium ions (Mg(II)) in phosphoric acid (H3PO4) solution is vital for the production of H3PO4 and supply of phosphate fertilizer. However, the mechanism and intrinsic selectivity for removal of Fe(III), Al(III), and Mg(II) from wet-process phosphoric acid (WPA) by phosphonic group (-PO3H2) functionalized MTS9500 are still unclear. In this work, the removal mechanisms were determined via combined analysis of FT-IR, XPS, molecular dynamics (MD), and quantum chemistry (QC) simulations based on density functional theory (DFT). The metal-removal kinetics and isotherms were further studied to confirm the removal mechanisms. The results indicate that Fe(III), Al(III), and Mg(II) interact with the -PO3H2 functional groups in MTS9500 resin with sorption energies of -126.22 kJ·mol-1, -42.82 kJ·mol-1, and -12.94 kJ·mol-1, respectively. Moreover, the intrinsic selectivities of the resin for Fe(III), Al(III), and Mg(II) removal were quantified by the selectivity coefficient (Si/j). The SFe(III)/Al(III), SFe(III)/Mg(II) and SAl(III)/Mg(II)are 18.2, 55.1 and 3.02, respectively. This work replenishes sorption theory that can be used in the recycling of electronic waste treatment acid, sewage treatments, hydrometallurgy, and purification of WPA in industry.

Customized copper/cobalt-rich ferrite spinel-based construction ceramic membrane incorporating gold tailings for enhanced treatment of industrial oily emulsion wastewater

New ceramic membranes (CM) using environment-oriented materials instead of rare materials are more attractive and easier to large-scale engineering and promotion. In this study, the feasibility of customizing low-cost and robust CM, is investigated by sintering typical available solid wastes (Fe-S-rich gold tailings and Si-rich marine shellfish powder) as the matrix with copper/cobalt-rich precursors. Analysis results indicate that the precursors (Cobaltate and Cuprate) with the proposed ratio (1:1 by mass, 1300 °C) can be chemically stable crystallized in the more durable structure of customized copper/cobalt-rich ferrite spinel-based construction CM (CM-(Cu-Co)Fe2O4). The composite membrane can operate stably and consumes no additional energy. After detailed characterization of the pore structure, the purification treatment of industrial oily wastewater (rejection rate > 99.9), emulsion oily wastewater (rejection rate > 97.9) and alizarin red wastewater (rejection rate > 99.3) was fully evaluated. Surprisingly, the waste-to-resource CM of CM-(Cu-Co)Fe2O4 exhibits significant heavy metal iron ion removal performance (>94%) due to electrostatic attraction and adsorption. The successful preparation and application of environment-oriented multifunctional CM from a typical solid waste matrix provide a promising strategy of resource recovery for beneficial utilization of ordinary solid wastes with stock as ceramic raw materials.

Chemical adsorption of iron ions from drinking water using Jordanian zeolitic tuff

Jordanian natural zeolitic tuff is distributed in the northeast, central and southern parts of Jordan. Zeolitic tuff used in this work was brought from Al Hala Volcano piles located in the southern part of Jordan to investigate its capability to remove iron ions from drinking water. The main zeolitic minerals identified in Al Hala are phillipsite and chabazite. The effects of iron concentration, pH values, contact time, zeolite grain size and amounts of used zeolitic tuff were examined in the removal process using batch experiments. Two zeolitic tuff grain sizes with two different amounts were used and designated as HZ1 and HZ2, two iron concentrations from two different water wells were investigated and designated as W1 and W2 were examined for different contact time periods. Batch tests were performed to determine the ability of zeolite to remove Fe3+ (iron III) from drinking water. In static regime experiments, the use of the HZ2 type shows a higher percentage of Fe3+ removal as compared to the HZ1 type for the same time and concentration. The results indicate that iron ions can be removed from drinking water with approximately 100% efficiency at the beginning of the contact time regardless the concentration of iron ions in the water. Al Hala zeolitic tuff used in iron removal showed a high capability with complete Fe3+ removal from drinking water. The HZ2 is more efficient in iron ions removal than HZ1, the pH value is not significantly affected.

SORPTION OF FERUM IONS ON NATURAL AND MODIFIED CLINOPTYLOLITE. INFLUENCE OF OXYDANTS

The health of the population depends on the state of the environment, so the study of opportunities to improve the condition of water, air and soil does not lose its actual.
 The presence of substances in waters in concentrations is higher than the maximum permissible concentration can be caused by both human economic activity and the peculiarities of the geological structure of the lithosphere of the region. For example, high iron content is observed in the natural waters of many regions of the world. Although iron is an important element in human life, its excess in the body can cause many diseases.
 Removal of iron ions from water has a high cost, so reducing the cost of this process is an urgent issue. One of the options to reduce the cost of the process is to use natural zeolites, such as clinoptilolite. One of the largest deposits of clinoptilolite in Europe is located in the village Sokyrnytsia, Transcarpatian region.
 In this work, the sorption of iron ions on the natural clinoptilolite of the Sokyrnytsia deposit and its modified forms under static conditions has been studied. Any of the proposed modification methods has a positive effect on the sorption properties of clinoptilolite with respect to iron ions, the amount of Fe ions sorption increases for hydrogen form by 30%, ammonium form by 60% and sodium form by 65% are shown.
 The influence of oxidants (hydrogen peroxide) on the sorption of iron ions on clinoptilolite of the Sokyrnytsia deposit (Ukraine) has been studied. The significant influence of iron oxidation before sorption on the growth of its extraction from water by natural clinoptilolite is shown, which is confirmed by thermodynamic calculations performed by the semi-empirical method GFN2- xTB (density functional theory), which indicate that only ion exchange reaction involving Fe3+. And if the exchange ion is a Na+ ion, ion exchange sorption can occur with both Fe3+ and Fe2+.
 Isotherms of ion-exchange sorption of iron in the range of concentrations from 0.05 mmol/l to 1 mmol/l are well described by the Langmuir equation. Sorption isotherms in the coordinates 1 / A = f (1 / C) are linear.
 Keywords: clinoptilolite; iron; ion exchange; oxydants.

Eco-friendly activated carbon developed from rice hulls for chromium and iron ion removal

Rice hulls, a harmful biowaste, were used to produce nanosized activated carbon (RHAC) by combustion and phosphoric acid treatment. The developed RHAC was characterised using various structural and morphological techniques (scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and nitrogen (N2) adsorption). The prepared RHAC was used to remove heavy metal ions (iron (III) (Fe3+) and chromium (VI) (Cr6+)) by using the adsorption mechanism. Adsorption parameters, such as contact time, dose and initial concentration of the heavy metal ions, were investigated. Five adsorption models (two and three parameters) were studied. Also, the adsorption kinetics through the intraparticle diffusion model was applied. RHAC showed adsorption capacities of 47.00 and 45.00 mg/g for iron (III) and chromium (VI), respectively. The findings recommend using RHAC as a low-cost and eco-friendly adsorbent for metal ion removal and water-treatment applications.

Removal of iron from salt water entering the chlor-alkali membrane system using activated carbon adsorbent to reduce environmental damage

Heavy metal ions have deadly and deadly effects on all life forms and enter the food chain through the disposal of waste in water channels. One of the most important heavy metals is iron. There are several methods used to remove heavy metal ions. The adsorption method is widely used due to its easy operation, low energy consumption, easy maintenance, high adsorption capacity and high efficiency. Activated carbon as an adsorbent with high adsorption capacity and low cost, has many applications in heavy metal removal processes. The purpose of this paper is to remove iron (III) ions from brine entering the chlorinated alcohol system using activated carbon adsorbent to reduce environmental damage.In order to achieve this goal, after preparation of activated carbon adsorbent, and its contact with salt water of chlor-alkali unit containing iron (III) ion, the effect of adsorbent amount factors (0.5 to 2 g / l), contact time (15 to 120 minutes) and pH (3 to 9) were assessed.Based on the results of this study, pH = 7 was determined as the optimal pH and 90 minutes as the equilibrium time. with increasing the amount of adsorbent, the removal percentage increased and the maximum removal percentage of iron ions in the amount of 2 g / l of activated carbon adsorbent was obtained. Also, the effect of contact time, pH and the amount of activated carbon adsorbent on the process of iron ion removal was significant (p <0/05).

The influence of water filtration rate on the efficiency of its oxidization on iron-containing redoxite

Experimet to determine the effectiveness of iron-containing redoxites on the efficiency of water deoxidation. In the course of the study, the dependence of the efficiency of water deoxidation on the filtration rate was determined. &#x0D; The filtration rate was varied in the range from 5 to 25 mph. The residual oxygen content and the dissolved iron content in the water were determined. It was shown that with increasing filtration rate within these limits, the residual oxygen concentration increases from 0.1-0.2 mg/dm3 to 0.9-1.0 mg/dm3. The residual oxygen content depends not only on the filtration rate but also on the reaction of the medium. An increase in the residual oxygen concentration with increasing pH of the medium from 6.7 to 10.0.&#x0D; Residual iron content depends little on both the filtration rate and the reaction medium and in all cases did not exceed 0.2 mg / dm3. In this work, the dissolution of iron in general was determined by preliminary preparation for the work of iron-containing redoxite.&#x0D; When used in the installation scheme, in addition to the column with iron-containing redoxite, also columns with cation exchange resin KU-2-8 in Na-form, almost complete removal of iron ions from the water and natriation softening of tap water was noted. In the case of sodium-cationized water, the extraction of iron from water will be observed for a long time, given the low concentration of iron ions in the water and the high capacity of the cation exchange resin in iron ions. In addition, sorbed iron (II) ions on the cation exchange resin are oxidized by oxygen residues to iron (III). The latter, at elevated pH, are hydrolyzed, which is the reason for the restoration of capacity and cation exchange resin by divalent iron cations.&#x0D; In the case when after the column with iron-containing redoxite used anion exchange resin AB-17-8 in sulfite form, complete extraction of oxygen from water was achieved.&#x0D; Given that the oxygen concentration in water with the use of iron-containing composite decreased by 10-40 times, the load on the anion exchange redox will decrease proportionally, which means that the duration of the anion exchange redox filter cycle will increase in the same proportion.&#x0D; The use of iron in the second stage of the anion exchange resin in the SO32- form remained unchanged, but complete oxygen extraction was achieved. The option is quite promising for implementation.

Application of GETFLOWS Coupled with Chemical Reactions to Arsenic Removal through Ferrihydrite Coprecipitation in an Artificial Wetland of a Japanese Closed Mine

Passive systems that utilize a natural power such as a pond, plant, or microorganisms, is expected to be a cost-effective method for acid mine drainage (AMD) treatment. The Ningyo-toge mine, a non-operational uranium mine located in Okayama Prefecture, Japan, generates AMD containing arsenic and iron. To quantitatively study arsenic and iron ion removal in an artificial wetland and pond, chemical reactions were modeled and incorporated into the GETFLOWS (general-purpose terrestrial fluid-flow simulator) software. The chemical reaction models consisted of arsenite and ferrous oxidation equations and arsenic adsorption on ferrihydrite. The X-ray diffraction analysis of sediment samples showed ferrihydrite patterns. These results were consistent with the model for arsenite/ferrous oxidation and arsenic adsorption on ferrihydrite. Geofluid simulation was conducted to simulate mass transfer with the utilized topographic model, inlet flow rate, precipitation, and evaporation. The measured arsenic and iron ions concentrations in solution samples from the wetland and pond, fitted well with the model. This indicated that the main removal mechanism was the oxidation of arsenite/ferrous ions and that arsenic was removed by adsorption rather than dilution.

Iron Adsorption from Textile Industrial Effluent on Activated Carbon Prepared from Tamarind Seeds (Tamarindus indica L.)

Water pollution contributes the major environmental pollution in many countries which shows great impact on human life and biodiversity. The important source of water pollution is industrial effluent. General contaminants in effluent water are heavy metals, phenols, dyes, harmful organics, ligands and suspended solids .Treatment of effluent water plays vital role in many industries, the treatment of adsorption proved to be most important well known and economical process. The ability of certain solids of preferentially concentrate specific substance on their surface is the basic principle for adsorption. Water with high content of iron can be very objectionable. In our research work the activated carbon prepared from tamarind seeds was employed to take up selected heavy metal that is iron ions. Tamarind seeds which are an agricultural waste and also waste product in many industries was activated by phosphoric acid treatment, is investigated for the removal of iron ions from textile industrial effluent sample.

Two-dimensional metal-organic framework nanobelts for selective Fe3+ removal from aqueous solution with high adsorption capacity

Ultrathin metal-organic frameworks (MOFs) have emerged as a novel class of two-dimensional materials for their unique properties, such as the larger surface area, enriched unsaturated coordination centers and more accessible active sites, which are beneficial for improving their performances in catalysis, sensing and separation. In this work, the MOF (named YNU-1 nanobelts) was exploited to selectively remove Fe3+ from aqueous solutions, which showed an excellent adsorption performance with the adsorption capacity of 456.37 mg/g. The value is the highest among all reported adsorbents of Fe3+, owing to the coordination between the Fe3+ and abundant carboxyl groups on the surface of YNU-1 nanobelts. The adsorption behavior can be well-described with a pseudo-second-order kinetic model, which revealed a chemisorption process. The α-Fe2O3 on the surface of YNU-1 nanobelts after adsorption was confirmed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and element mapping measurements. The YNU-1 nanobelts was successfully applied for iron treatment in real sample. Our study provided a facile and efficient method for the removal of iron ions from water.

Semiholoenzyme optimizes activity and stability of a hyperthermostable iron-superoxide dismutase

Metal ion coordination is an essential step for the maturation of metalloenzymes. Generally, the metal coordination sites are thought to be fully occupied to achieve the maximum activity and stability. In this research, we compared the structural features, activity and stability of the apo-, semiholo- and holo-forms of a hyperthermostable tetrameric Fe-superoxide dismutase (SOD). Strikingly, the three forms of enzymes had similar compact tetrameric structures. Removal of iron ions destabilized subunit-subunit interactions during guanidine hydrochloride-induced unfolding. The partially metalized semiholoenzyme possessed most of the activity and identical hyperthermostability of the holoenzyme, but weaker propensity to aggregate. Furthermore, both of the iron content and activity of the semiholoenzyme were unaffected by a 200-fold excess iron ions in solutions, suggesting that conformation of the apo-subunits were forced to the close state by the iron-containing subunits. These observations suggest that fully metalized enzyme is probably nonessential for multimeric metalloenzymes and the semiholoenzyme may be a better choice. The unique properties of semiholoenzyme also provide the organisms a compromised solution to survival under metal deficiency conditions.

РАЗРАБОТКА СПОСОБА УТИЛИЗАЦИИ ОТХОДОВ ГОРНО-ОБОГАТИТЕЛЬНЫХ КОМБИНАТОВ СОЗДАНИЕМ АКТИВНЫХ ФИЛЬТРУЮЩИХ ОБЕЗЖЕЛЕЗИВАЮЩИХ МАТЕРИАЛОВ

Актуальность исследования обусловлена тем, что техногенные образования в виде отвалов горно-обогатительных комбинатов являются причиной безвозвратных потерь природных сырьевых ресурсов, отчуждения земель из сельскохозяйственного оборота и загрязнения огромных территорий. Утилизация отходов горно-обогатительных и горнодобывающих предприятий считается одной из труднорешаемых задач Уральских регионов. Вследствие этого на сегодняшний день возникла необходимость в разработке технологии, которая смогла бы обеспечить эффективную переработку отходов горно-обогатительных комбинатов и вовлечение ценных сырьевых компонентов, до этого не утилизировавшихся отходов обогащения в производственный цикл. Одним из перспективных направлений на сегодняшний день является возможность использования отходов предприятий с получением товарного продукта. Цель исследования: разработать способ утилизации отходов горно-обогатительных комбинатов, а именно осадков хвостохранилищ горно-обогатительных комбинатов, депонированием их в искусственные фильтрующие материалы в максимальном количестве. Объекты: химические и физико-механические характеристики разработанных материалов, качество сточной воды, зависимость качества очистки от состава искусственных фильтрующих материалов. Методы: анализ фильтрующих элементов на основе отходов горно-обогатительного комбината, на прочность и износоустойчивость методом истирания; исследование фильтрующей способности разработанного фильтрующего элемента, в состав которого в определенных соотношениях входят отходы горно-обогатительного производства, жидкое стекло и кремнефтористый натрий. Представлена таблица эффективности обезжелезивания сточной воды на данном материале и математические модели продолжительности процесса фильтрования и эффекта подщелачивания. Приведены методы удаления железа с помощью природных фильтрующих материалов и искусственных фильтрующих материалов, содержащих отходы хвостохранилищ и отвалов горно-обогатительных комбинатов. Результаты. Приведен способ утилизации осадков хвостохранилищ горно-обогатительных комбинатов, определены факторы, влияющие на эффективную утилизацию отходов горно-обогатительных предприятий в фильтрующие материалы, исследованы физико-химические и фильтрационные свойства полученных материалов, определен состав фильтрующего элемента с максимальным содержанием отхода.

Increase in the efficiency of removal of iron ions from wastewater by aquatic plant ‘Lemna minor‘

Wastewater from food production enterprises could have significant concentrations of total iron that must be decreased. Aquatic macrophytes, for example ?Lemna genera?, have a high potential for iron ions removal, but kinetics and treatment parameters should be qualified. The aim of the work is to increase in the efficiency of removal of iron ions from wastewater in the process of biological wastewater treatment using ?Lemna minor? and to determine rational parameters of the treatment (biomass, process duration, hydraulic load). The kinetics of the removal of iron ions from the water was studied in the batch mode of a biological reactor operation under various biomass quantities. Verification of the obtained rational parameters of the process was carried out under continuous mode conditions. The results obtained from the kinetics of the batch mode the bioreactor operation process indicate an increase in the degree of removal of ferrous ions from wastewater from 61.0% to 91.7% with an increase in the plant biomass concentration from 8 mg/L to 25 mg/L during the wastewater treatment process of 24 hours. The rational parameters of removal of iron ions from wastewater in the batch mode of the bioreactor operation are determined: biomass of duckweed is 25 mg/L; the treatment process duration is 8 hours; the hydraulic load is 0,126 L/(h?L). The purification effect was 89.8%.

DISPOSAL OF WATER FILTERING DOWNLOADING FROM CALCIUM CARBONATE

The article presents the results of the study of the efficiency of removal of iron ions from aqueous solutions by filtration through a filter with loading from the particles of calcium carbonate. It is established that as a result of such an operation, the characteristics of the water significantly change. Thus, when filtering distilled water, there is an increase in pH from the initial 6.3 to 8.8 - 10.0 after passing through calcium carbonate. Moreover, the lower the rate of filtration, the greater the growth of pH. The rigidity of distilled water at low filtration rates increases from 0.1 mg-ekv/dm3 to 0.9 mg-ekv/dm3, but with an increase in filtration rate to 2 m/h, it decreases to 0.5 mg‑ekv/dm3. Water from the Kiev water supply system also significantly changes its parameters. As in the previous case, the hydrogen index rises from the initial 7.0 to 8.6 - 10.1. With regard to stiffness, it is worth noting that with increasing filtration rate it begins to increase, which can be associated with a decrease in pH. When filtering through loading of sewage with different pH values it is observed their neutralization and transfer of pH to the alkaline area. This fact essentially affects the conditions for the removal of heavy metals and does not allow the use of this method for the treatment of drinking water. It should also be noted that with a hydrogen index below 4.0 there is an intense decomposition of calcium carbonate with carbon dioxide emissions and the destruction of loading. This can be considered as one of the negative effects of using the method. Water filtration through loading from the particles of calcium carbonate is accompanied by an increase in the alkalinity of treated water. Thus, at a filtration rate of 0.6 m / h, the alkalinity of distilled water increases from 0.7 to 1.0 mmol/dm3, and the alkalinity of the tap water is from 0.8 to 2.0 mmol/dm3. Such changes are not always acceptable, especially in the case of re-use of treated water. The degree of water purification from Fe2+ and Fe3+ ions depends to a large extent on both the initial content and the rate of filtration. Thus, at initial concentrations of ions in a solution of 24 mg/dm3, 12 mg/dm3 and 6 mg/dm3, their concentration after passing the solution through a column at a rate of 0.2-0.3 m/h was 0.65 mg/dm3, respectively, 0.55 mg/dm3 and 0.5 mg/dm3. Moreover, in all three cases, the purification of Fe2+ and Fe3+ ions is more effective at lower filtration rates. Repeated flow of treated water through the same filter with the same speed reduces the content of iron ions to trace concentrations.Key words: non-ironification, calcium carbonate, filtration, water treatment, iron ions.

Removal of Iron and Copper Ions from the Liquid Phase by Modified Polymeric Membranes

Preparation of polymeric membranes based on cellulose acetate and modified by adding different amounts of a pore generating agent, which was polyvinylpyrrolidone (PVP), is presented and potential application of the membranes obtained for the removal of iron and copper ions from liquid phase is examined. Addition of various amounts of PVP has an impact on the physical (porosity, equilibrium water content and permeability) and chemical (content of the surface oxygen group, pH) properties of the membranes obtained. Filtration of iron and cupper solution leads to significant changes in the total content of surface oxygen groups, however the acidic oxygen groups remain dominant. With the content of PVP increasing within a certain range, the membrane permeability is improved. The membranes obtained show higher efficiency in removal of Fe3+ than Cu2+ ions, but with increasing content of PVP the efficiency in iron ions removal decreases and the total filtration resistance decreases after filtration of iron ions solutions.

The Survey of Sorption Ion-Exchange Properties of Paleozoic Zeolites Before and After Regeneration

The presented results of experimental studies on the removal of iron ions, manganese, ammonium nitrogen, strontium and cadmium from aqueous solutions by the paleozoic zeolites of the Urals in dynamic conditions. Experiments have been carried out on the regeneration of mineral zeolite filters in order to restore the sorption properties of the explored minerals. The results of the researches show that ion-exchange minerals can be used as highly effective sorbents, with a large ion-exchange capacity and a multifaceted ability to restore the original properties.

Removal of iron from industrial lean methyldiethanolamine solvent by adsorption on sepiolite

ABSTRACTSepiolite clay was used as an adsorbent for the removal of iron ions from industrial methyldiethanolamine (MDEA) solvent. The raw sepiolite clay was modified by different chemical and thermal treatments, and was characterized by FTIR, XRD, SEM-EDX, and BET-specific surface area analysis. Treating sepiolite with nitric acid significantly improved the adsorption capacity of iron ions from lean MDEA. The experimental equilibrium data were represented by Henry, Freundlich, and Langmuir isotherm models. The thermodynamic parameters indicated that the adsorption of iron ions on sepiolite was spontaneous and endothermic process. The kinetic studies showed that the adsorption followed pseudo-second order model.