Дослідження ефективності очищення води від сполук заліза за допомогою модифікованих фільтрувальних завантажень

Recently, the modified media have become widely used in the processes of iron removal from water. These media are based on the natural granular material with a catalytically-active surface layer, which promotes a more efficient oxidation of iron ions. However, their application raises some problems associated with restoring their oxidative capacity, reliability and duration of use.The paper presents the results of removal of iron ions from water by catalytic oxidation. The method of modifying the filter medium for iron removal from water is developed. The efficiency of iron oxidation with the zeolite and cation-exchange resins modified with iron and manganese compounds is evaluated.It is shown that the modified zeolite is ineffective compared to the modified cation-exchange resin Dowex Mac-3. The manganese-modified cation-exchange resin provides efficient removal of iron ions from water. The iron removal degree was initially 97 % and then gradually decreased to 86 %. The iron concentration in the treated water did not exceed 0.3 mg/dm3. When using the iron-modified cation-exchange resin, the iron concentration decreased from 15 to 0.1–0.2 mg/dm3. The iron removal degree was more than 99 % over a long time.It is found that efficient iron oxidation in water occurs in the presence of sufficient oxygen, that is pre-aeration is required.The drawback of the proposed modified media is a slight loss of oxidative capacity after filter washing.Исследованы процессы удаления железа из воды путем его каталитического окисления. Проведена оценка эффективности окисления железа на цеолите и катионитах, модифицированных соединениями железа и марганца. Показано, что эффективное окисление железа в воде происходит при аэрировании воды. При отсутствии кислорода в воде очистка воды от железа проходит неэффективно.Досліджено процеси вилучення заліза із води шляхом його каталітичного окислення. Проведено оцінку ефективності окислення заліза на цеоліті та катіонітах, модифікованих сполуками заліза та марганцю. Показано, що ефективне окислення заліза у воді відбувається при аеруванні води. За відсутності кисню у воді очищення води від заліза проходить неефективно

Usage of Sorbent-Catalyst to Accelerate the Oxidation of Manganese

The work was supported by National research fund of Ukraine, grant No.144/01.2020.The processes of removal of manganese (II) ions from water using sorbent catalysts, ion exchange materials modified with iron oxides have been studied. It is shown that manganese ions oxidize very slowly in artesian water even when the pH is adjusted to 9.0. Intensive aeration of solutions due to stirring also does not promote oxidation of manganese (II) ions. The degree of manganese extraction due to oxidation is reduced from 20–30 % for solutions with a concentration of manganese ions of 1 and 5 mg/dm3 to 11–15 % for solutions with a concentration of 15 and 30 mg/dm3. A significant increase in the oxidation efficiency of manganese ions was achieved by using magnetite as a sorbent catalyst. The efficiency of water demanganization increases with increasing intensity of water aeration when mixing solutions. It has been established that strongly acid cation exchangers provide efficient extraction of manganese ions from water. At the same time, a high exchange capacity of strong acid cation exchange resin KU-2-8 in acid and salt form was noted. It is shown that the capacity of manganese ions of this cation exchange resin in the Ca2+-form is slightly lower. When using the cation exchange resin KU-2-8 in Ca2+-form to remove manganese ions from the solution already in the first samples, the leakage of manganese ions at the level of 10 mg/dm3 and above was observed. This indicates that this form of ion exchanger is not suitable for deep purification of water from manganese (II) ions. To increase the efficiency of manganese ion extraction from water, increase the duration of the filter cycle, magnetite and magnetite-modified cation exchange resin KU-2-8 were used as a sorbent-catalyst. It was shown that the cation exchange resin modified with magnetite provides the removal of a significant part of manganese ions due to catalytic oxidation on magnetite. The conditions of effective manganese extraction in static and dynamic conditions are determined

Evaluation of the contribution of ion exchange in the process of demanganization with modified cation exchange resin KU-2-8.

An effective method of water purification from manganese compounds is the use of magnetite, so it is advisable to improve the way it is used. The main disadvantage of using dispersed microcrystalline magnetite is the difficulty of implementing water purification in dynamic conditions, due to the significant resistance to water filtration. In the case of the use of magnetite in static conditions, there is a constant consumption of magnetite after settling and filtration, and the demanganization process requires the use of bulky and poorly mobile installations (mixers, settling tanks and filters). Therefore, water purification from manganese ions was carried out under dynamic conditions by filtering water through a layer of strong acid cation exchange resin KU-2-8 in H+, Na+, Ca2+ forms modified with magnetite. This allows constant contact of the solution with the ion exchange material and reduces the role of the limiting diffusion factor on the water purification process. When evaluating the effectiveness of cation exchange resin KU-2-8 in the extraction of Mn2+ ions from water depending on the form of the resin, it was found that the FEDC for the resin in H+ form is 2198 mg-eq/dm3, for Na+ it is 2175 mg-eq/dm3 and for Ca2+ the value is 1717 mg-eq/dm3. Therefore, during the transition from H+ to Na+ and to Ca2+ form there is a decrease in the sorption capacity for Mn2+ ions in the cation exchange resin KU-2-8. On the cation exchange resin in Ca2+ form the efficiency of demanganization decreases with increasing concentration of manganese ions. When increasing the initial concentration from 5 to 10 and 30 mg/dm3 in distilled water, the residual concentration increases from 0.14 to 0.35 and up to 1.95 mg/dm3 when filtered through 10 cm3 of resin in Ca2+ form. When removing Mn2+ ions from artesian water, the residual concentration was 4.0; 7.0 and 27.0 mg/dm3 respectively. Thus, on magnetite-modified cation exchange resin, manganese ions are removed only partially due to ion exchange and their complete removal from water is possible only due to catalytic oxidation and deposition on magnetite

Sorbent-Catalyst for Acceleration of The Iron Oxidation Process

In this work, the process of water deironing by using magnetite as a catalyst to accelerate the oxidation of iron ions in an aqueous medium was investigated. It was shown that the efficiency of iron ion extraction depends on the solution concentration, sorbent dose and contact time. In all cases, the use of magnetite accelerated the process of extraction of iron by more than an order of magnitude in comparison with similar experiments on the oxidation of iron without the addition of a catalyst. At the pH values greater than 6, the use of magnetite as a catalyst contributes to the deep purification of water from iron ions

Usage of Sorbent-Catalyst to Accelerate the Oxidation of Manganese

The processes of manganese (II) ions removal from water using sorbent catalysts and ion exchange materials modified with iron oxides were studied. It was shown that manganese ions oxidize very slowly in artesian water, even when the pH is adjusted to 9.0. Intensive aeration of solutions due to stirring also does not promote the oxidation of manganese (II) ions. The degree of manganese extraction due to oxidation is reduced from 20–30% for solutions with a concentration of manganese ions of 1 and 5 mg/dm3 to 11–15% for solutions with a concentration of 15 and 30 mg/dm3. A significant increase in the oxidation efficiency of manganese ions was achieved by using magnetite as a sorbent catalyst. The efficiency of water demanganization increases along with the intensity of water aeration when mixing solutions. It was established that strongly acid cation exchangers provide efficient extraction of manganese ions from water. At the same time, a high exchange capacity of strong acid cation exchange resin KU-2–8 in acid and salt form was noted. It was shown that the capacity of manganese ions of this cation exchange resin in the Ca2+-form is slightly lower. When using the KU-2–8 in Ca2+-form of cation exchange resin to remove manganese ions from the solution already in the first samples, the leakage of manganese ions at the level of 10 mg/dm3 and above was observed. This indicates that this form of ion exchanger is not suitable for deep purification of water from manganese (II) ions. In order to increase the efficiency of manganese ion extraction from water, increase the duration of the filter cycle, magnetite and magnetite-modified KU-2–8 cation exchange resin were used as a sorbent-catalyst. It was shown that the cation exchange resin modified with magnetite provides the removal of a significant part of manganese ions due to catalytic oxidation on magnetite. The conditions of effective manganese extraction under static and dynamic conditions are determined

Low waste technology for mine waters treatment using lime and aluminum coagulants

In this paper the process of reagent desalination of mineralized mine waters was studied. The peculiarity of mine waters in many regions of Ukraine is that, along with hardness ions, they also contain sulphates in fairly high concentrations. Therefore, the task of desalination of mineralized waters consists in effective removal of sulphates along with softening of the solution. For effective purification of water from sulphates and hardness ions, 5/6 aluminum hydroxychloride (Al2(OH)5Cl) and sodium tetrahydroxoaluminate (Na[Al(OH)4]) were used during liming. A significant increase in efficiency of the treatment process was achieved when the solution was acidified with carbon dioxide after treatment with reagents. The directions of processing of the formed sediments as part of building materials have been determined. Complex processing of the generated waste in the process of water treatment allows creating a low-waste technology for the purification of mineralized water

Sorbent-Catalyst for Acceleration of The Iron Oxidation Process

In this work, the process of water deironing by using magnetite as a catalyst to accelerate the oxidation of iron ions in an aqueous medium was investigated. It was shown that the efficiency of iron ion extraction depends on the solution concentration, sorbent dose and contact time. In all cases, the use of magnetite accelerated the process of extraction of iron by more than an order of magnitude in comparison with similar experiments on the oxidation of iron without the addition of a catalyst. At the pH values greater than 6, the use of magnetite as a catalyst contributes to the deep purification of water from iron ions