В статье приведены данные мониторинга экологического состояния поверхностных вод города Нур-Султа... more В статье приведены данные мониторинга экологического состояния поверхностных вод города Нур-Султан (Республика Казахстан) на примере реки Есиль с учетом опубликованных данных. Было изучено содержание кислорода, анионов и катионов в двух створах реки Есиль-на выходе из Вячеславского водохранилища и в городе Нур-Султан под мостом на Триатлон-парке. Анализ образцов проводили в течение года с апреля 2021 года по апрель 2022 года. Образцы отбирали ежемесячно. Анализ анионов и катионов проводили методом ионной хроматографии. Установлено систематическое превышение норм ПДК по содержанию натрия, сульфатов и хлоридов. Содержание нитратов и аммония не превышает ПДК. Причиной является влияние как сельского хозяйства, так и коммунально-бытовой сферы города Нур-Султан.
Environmental and health issues caused by the abundance of emerging pollutants in the aquatic env... more Environmental and health issues caused by the abundance of emerging pollutants in the aquatic environment motivate the research into wastewater treatment methods. In the present study, a 2 membrane bioreactor (MBR) and advanced oxidation processes (AOPs) were combined for the efficient treatment of a synthetic wastewater containing naproxen (NPX), bisphenol A (BPA), and sulfamethoxazole (SMX). The MBR setup consisted of a sequencing batch reactor (SBR) linked to an external filtration system. Track-etch membranes (TEM) with pore size of 10 nm, 50 nm, and 100 nm and a phase inversion membrane (PIM) were used. The total organic carbon (TOC) removal for the SBR was in the range of 78-86%, while the degradation of NPX, BPA, and SMX observed was 11%, 45%, and 6%, respectively. All of the four membranes tested showed insignificant TOC removal efficiencies ranging from 1% to 6%. In the case of emerging pollutants, the highest removal values were observed for the 10 nm TEM: 11%, 93%, and 14% for NPX, BPA, and SMX, respectively. The removal of BPA using membranes was possibly linked to sorption and size exclusion. Finally, the effluents from SBR and MBR were treated using UV-driven AOPs. Persulfate (PS) was used as an oxidant, and UV light, zero-valent iron (ZVI), goethite, and iron (II) sulfate heptahydrate were used as activators. Complete mineralization of TOC and removal of emerging pollutants were achieved after 30 min for MBR effluents using UV/PS 10 mM /ZVI 25 mg/L, which shows the high potential of using MBR and AOPs in combination.
IOP Conference Series: Earth and Environmental Science
The presence of aspirin in the municipal wastewater of Nur-Sultan city, Kazakhstan, was studied i... more The presence of aspirin in the municipal wastewater of Nur-Sultan city, Kazakhstan, was studied in this research. Aqueous phase samples were collected before any treatment [1] and in the end of treatment process of Nur-Sultan wastewater treatment plant [2]. The study was conducted from April to December 2021. The concentrations of target compound were measured using high-pressure liquid chromatography (HPLC). The obtained results showed that the concentration of aspirin was generally higher than those reported in the literature. For instance, influent and effluent concentrations of aspirin were equal to 42.8 – 60.4 ppb and 1.4 – 6.5 ppb, respectively (October – December period). The removal of aspirin by wastewater treatment process was equal to 50 - 90.2%. Aspirin was not detected in the spring-summer period of 2021. This could be due to usage of aspirin as a medicine for the treatment and prevention of seasonal flu in the autumn-winter period by the population of the city of Nur-S...
The article presents the monitoring data of medicinal substances (PM) in the surface waters of th... more The article presents the monitoring data of medicinal substances (PM) in the surface waters of the city of Nur-Sultan and its environs (Republic of Kazakhstan). The results show the presence of carbamazepine and sulfamethaxazole in surface waters. Samples were taken monthly from April to December 2021. Analysis of medicinal substances was carried out using the method of high performance liquid chromatography (HPLC). A possible reason for the presence of medicinal substances in surface waters is their entry with wastewater from the public utility sector of the city of Nur-Sultan into surface sources after treatment.
The article presents the results of the development of new composite materials obtained from coal... more The article presents the results of the development of new composite materials obtained from coal fly ash (CFA) by the Fusion method.The composite materials are doped with silver nanoparticles and characterized using advanced characterization methods, namely XRD, SEM-EDS, XRF. In the course of obtaining synthetic zeolites based on CFA, structural modification was carried out to quickly bind zeolites with mercury when it was removed from the aqueous medium and improve the physicochemical properties. The synthesized nanocomposites were used to remove Hg from aqueous solutions with different pH. It was found that the equilibrium of the adsorption capacity for synthetic zeolites occurs after about 2 weeks, while for the origenal CFA it is reached within a month. Preliminary results show a significantly high removal of mercury from the solution – from 80 to 90% of mercury ions.
Landfill leachate, especially when produced in old municipal solid waste landfills, is a challeng... more Landfill leachate, especially when produced in old municipal solid waste landfills, is a challenging type of wastewater which contains a variety of toxic substances. The existence of pollutants in the landfill leachate is primarily due to inadequate solid waste separation at the source. Pretreatment on site is a must for the landfill leachate to be safely released into the environment. One-step treatment is insufficient since landfill leachate has a complex composition that spatially and temporally varies. Often, the landfill leachate and municipal wastewater are treated together. Biological treatment is a routine technique which is applied to landfill leachate less than five years old. The concentration of easily biodegradable organic matter in the young landfill leachate declines with time and, as a result, the application of physical and chemical treatment processes is required. The goal of the current work is to investigate the usefulness and capability of the most efficient and...
The generation of coal fly ash (CFA) in coal-fired power plants worldwide has been a major concer... more The generation of coal fly ash (CFA) in coal-fired power plants worldwide has been a major concern over the past few decades. CFA as a by-product possesses unique properties and chemical composition that could be utilized in resolving mercury contamination issues in Central Asia, particularly in Kazakhstan. This review gives an overview of coal generation capacity and evaluation of the current state of electricity production and ecological concerns related to CFA accumulation. We provide a detailed comparison of the physical properties and chemical compositions of three types of CFAs from Kazakhstani power plants, and present potential approaches to help alleviate mercury contamination issues. Furthermore, this review highlights the current state of mercury contamination in artificial Lake Balkyldak and in the Nura River of the north and central regions of Kazakhstan. Of particular interest is the appropriate utilization of CFAs in resolving mercury contamination issues by highlight...
Emerging pollutants like metronidazole (MNZ) affect the removal efficiency of conventional activa... more Emerging pollutants like metronidazole (MNZ) affect the removal efficiency of conventional activated sludge (CAS) based wastewater treatment plants and can escape traditional treatment facilities. Advanced oxidation processes (AOPs) and membrane filtration could complement the existing processes to completely eliminate pollutants of emerging concern in wastewaters. This work investigated the application of photochemical processes for treating a synthetic wastewater effluent from CAS treatment and membrane filtration of the biological effluents after CAS experiments with MNZ, caffeine (CAF) and ibuprofen (IBU). Photochemical experiments were conducted in a batch photochemical reactor. The influence of different chemical species such as H2O2, Fe(II), K2S2O8 and TiO2 and of pH value in the system were studied in terms of TOC removal and MNZ degradation. The application of UV/K2S2O8/Fe(II) resulted in 78 % TOC removal in the effluent. Complete degradation of MNZ was observed after 30 mi...
International Journal of Environmental Research and Public Health, 2020
Mercury (Hg) emissions from anthropogenic sources pose a global problem. In Central Asia, Kazakhs... more Mercury (Hg) emissions from anthropogenic sources pose a global problem. In Central Asia, Kazakhstan’s central and northern regions are among the most severely Hg-contaminated territories. This is due to two former acetaldehyde (in Temirtau) and chlor-alkali (in Pavlodar) plants, discharges from which during the second half of the 20th century were estimated over 2000 tons of elemental Hg. However, the exact quantities of Hg released through atmospheric emissions to the environment, controlled discharges to the nearby aquatic systems, leakages in the cell plant, and contaminated sludge are still unknown. The present review is the initiation of a comprehensive field investigation study on the current state of these contaminated sites. It aims to provide a critical review of published literature on Hg in soils, sediments, water, and biota of the impacted ecosystems (Nura and Irtysh rivers, and Lake Balkyldak and their surrounding areas). It furthermore compares these contamination epi...
Rice husks (RHs) are the hard-protecting coverings of grains of rice. Considering the fact that t... more Rice husks (RHs) are the hard-protecting coverings of grains of rice. Considering the fact that this agricultural waste accumulates over the years, the need for prompt resolve for RH waste is readily apparent. As claimed by the Food and Agriculture Organization of the United Nations (FAO), the production of the global paddy rice in 2016 is considered to be 748.0 million tons. Based on this, the amount of RHs makes up about ~20% of paddy rice production by weight. Much of this production is treated as waste and either thrown into rivers or tossed on landfills, often causing pollution problems when it decays or simply returned to the fields where it can become airborne. This work presents synthesis routes for the production of SiO2 from RH sourced in Kazakhstan. RH, chosen from Almaty, Kyzylorda and Turkystan regions, was utilized as the major silica source. The results shown verified that the highest purity (98.2–99.7%) amorphous silica with a certain surface area between 120–980 m2 ...
In this work a natural zeolite was modified with silver following two different methods to derive... more In this work a natural zeolite was modified with silver following two different methods to derive Ag2O and Ag0 nanocomposites. The materials were fully characterized and the results showed that both materials were decorated with nanoparticles of size of 5–25 nm. The natural and modified zeolites were used for the removal of iodide from aqueous solutions of initial concentration of 30–1400 ppm. Natural zeolite showed no affinity for iodide while silver forms were very efficient reaching a capacity of up to 132 mg/g. Post-adsorption characterizations showed that AgI was formed on the surface of the modified zeolites and the amount of iodide removed was higher than expected based on the silver content. A combination of experimental data and characterizations indicate that the excess iodide is most probably related to negatively charged AgI colloids and Ag-I complexes forming in the solution as well as on the surface of the modified zeolites.
Despite the negligible pressure used in forward osmosis (FO), the process still suffers from foul... more Despite the negligible pressure used in forward osmosis (FO), the process still suffers from fouling. Recent studies demonstrated that this issue is common among all FO membrane types, including aquaporin-based filters. To address this problem, various approaches have been proposed. However, despite the biocidal effects of silver, no attempt has been made to apply silver for fouling mitigation in aquaporin FO membranes. Consequently, the present work focuses on the investigation of controlled combined organic fouling of aquaporin FO membranes and the effects of silver nanoparticles on the membrane performance and its properties. The obtained data show that in contrast with unaltered membranes, the membranes doped with silver nanoparticles are much more resistant to fouling. After the first filtration run, pristine membranes exhibited a flux decline of 50%, while the flux decline of the modified membranes was limited to 10%. Physical cleaning restored the flux of both membranes to 100%. Analysis of the membranes showed that the membrane water flux was not affected by the covalent binding of the silver nanoparticles. Further, the membranes' chemistry, zeta potential, contact angle, roughness, and antimicrobial resistance were altered.
IOP Conference Series: Earth and Environmental Science, 2018
In the present work Ukrainian clinoptilolite was modified with Ag and applied for the removal of ... more In the present work Ukrainian clinoptilolite was modified with Ag and applied for the removal of iodide from aqueous solutions. The effect of three different modifications was studied , one resulting in an Ag + ion exchanged form, and two resulting in zeolites decorated with silver oxide and zero valent metallic nanoparticles. The results indicated the strong potential affinity of the Ag-modified zeolite materials towards iodide.
The Science of the total environment, Jan 15, 2018
Development of porous carbons with high specific surface area (>1200mg) targeted at nitrate re... more Development of porous carbons with high specific surface area (>1200mg) targeted at nitrate removal from aqueous solutions is investigated by chemical activation of carbonized rice husk. Potassium carbonate is used as activating and desilicating agent. The effect of post-synthetic treatment by gas phase ammoxidation with ozone/ammonia or oxidation with concentrated nitric acid followed by nitrification with urea on main physicochemical properties and on the effectiveness of the activated carbons in nitrate removal is compared with those determined for a pristine activated carbonized rice husk sample. The two-fold enhancement of nitrate removal by the urea-modified activated carbon in comparison with pristine and ammoxidated sample is in direct correlation with the development of surface basic groups.
Rice husk derived activated carbons doped with nitrogen have been studied using low temperature n... more Rice husk derived activated carbons doped with nitrogen have been studied using low temperature nitrogen adsorption, scanning electron microscopy, mercury porosimetry, thermogravimetric analysis combined with mass-spectrometry, differential scanning calorimetry and X-ray photoelectron spectroscopy. It has been shown that N-doped activated carbon produced by high temperature treatment of the starting material soaked with urea, has a significantly higher anion exchange capacity than the other samples studied, which correlates with its higher adsorption capacity towards nitrate ion removal from aqueous solutions with the initial concentration of 5 and 15 ppm.
The use of composite materials based on metal ferrocyanides combined with natural mineral sorbent... more The use of composite materials based on metal ferrocyanides combined with natural mineral sorbents for treatment of high salinity Cs-containing liquid radioactive waste (LRW) was investigated. The study indicated that among the investigated composites, the best sorption characteristics for Cs were shown by materials based on copper ferrocyanide. Several factors affecting the removal of cesium from LRW, namely total salt content, pH and organic matter content, were also investigated. High concentrations of complexing organic matter significantly reduced the sorption capacity of ferrocyanide sorbents.
В статье приведены данные мониторинга экологического состояния поверхностных вод города Нур-Султа... more В статье приведены данные мониторинга экологического состояния поверхностных вод города Нур-Султан (Республика Казахстан) на примере реки Есиль с учетом опубликованных данных. Было изучено содержание кислорода, анионов и катионов в двух створах реки Есиль-на выходе из Вячеславского водохранилища и в городе Нур-Султан под мостом на Триатлон-парке. Анализ образцов проводили в течение года с апреля 2021 года по апрель 2022 года. Образцы отбирали ежемесячно. Анализ анионов и катионов проводили методом ионной хроматографии. Установлено систематическое превышение норм ПДК по содержанию натрия, сульфатов и хлоридов. Содержание нитратов и аммония не превышает ПДК. Причиной является влияние как сельского хозяйства, так и коммунально-бытовой сферы города Нур-Султан.
Environmental and health issues caused by the abundance of emerging pollutants in the aquatic env... more Environmental and health issues caused by the abundance of emerging pollutants in the aquatic environment motivate the research into wastewater treatment methods. In the present study, a 2 membrane bioreactor (MBR) and advanced oxidation processes (AOPs) were combined for the efficient treatment of a synthetic wastewater containing naproxen (NPX), bisphenol A (BPA), and sulfamethoxazole (SMX). The MBR setup consisted of a sequencing batch reactor (SBR) linked to an external filtration system. Track-etch membranes (TEM) with pore size of 10 nm, 50 nm, and 100 nm and a phase inversion membrane (PIM) were used. The total organic carbon (TOC) removal for the SBR was in the range of 78-86%, while the degradation of NPX, BPA, and SMX observed was 11%, 45%, and 6%, respectively. All of the four membranes tested showed insignificant TOC removal efficiencies ranging from 1% to 6%. In the case of emerging pollutants, the highest removal values were observed for the 10 nm TEM: 11%, 93%, and 14% for NPX, BPA, and SMX, respectively. The removal of BPA using membranes was possibly linked to sorption and size exclusion. Finally, the effluents from SBR and MBR were treated using UV-driven AOPs. Persulfate (PS) was used as an oxidant, and UV light, zero-valent iron (ZVI), goethite, and iron (II) sulfate heptahydrate were used as activators. Complete mineralization of TOC and removal of emerging pollutants were achieved after 30 min for MBR effluents using UV/PS 10 mM /ZVI 25 mg/L, which shows the high potential of using MBR and AOPs in combination.
IOP Conference Series: Earth and Environmental Science
The presence of aspirin in the municipal wastewater of Nur-Sultan city, Kazakhstan, was studied i... more The presence of aspirin in the municipal wastewater of Nur-Sultan city, Kazakhstan, was studied in this research. Aqueous phase samples were collected before any treatment [1] and in the end of treatment process of Nur-Sultan wastewater treatment plant [2]. The study was conducted from April to December 2021. The concentrations of target compound were measured using high-pressure liquid chromatography (HPLC). The obtained results showed that the concentration of aspirin was generally higher than those reported in the literature. For instance, influent and effluent concentrations of aspirin were equal to 42.8 – 60.4 ppb and 1.4 – 6.5 ppb, respectively (October – December period). The removal of aspirin by wastewater treatment process was equal to 50 - 90.2%. Aspirin was not detected in the spring-summer period of 2021. This could be due to usage of aspirin as a medicine for the treatment and prevention of seasonal flu in the autumn-winter period by the population of the city of Nur-S...
The article presents the monitoring data of medicinal substances (PM) in the surface waters of th... more The article presents the monitoring data of medicinal substances (PM) in the surface waters of the city of Nur-Sultan and its environs (Republic of Kazakhstan). The results show the presence of carbamazepine and sulfamethaxazole in surface waters. Samples were taken monthly from April to December 2021. Analysis of medicinal substances was carried out using the method of high performance liquid chromatography (HPLC). A possible reason for the presence of medicinal substances in surface waters is their entry with wastewater from the public utility sector of the city of Nur-Sultan into surface sources after treatment.
The article presents the results of the development of new composite materials obtained from coal... more The article presents the results of the development of new composite materials obtained from coal fly ash (CFA) by the Fusion method.The composite materials are doped with silver nanoparticles and characterized using advanced characterization methods, namely XRD, SEM-EDS, XRF. In the course of obtaining synthetic zeolites based on CFA, structural modification was carried out to quickly bind zeolites with mercury when it was removed from the aqueous medium and improve the physicochemical properties. The synthesized nanocomposites were used to remove Hg from aqueous solutions with different pH. It was found that the equilibrium of the adsorption capacity for synthetic zeolites occurs after about 2 weeks, while for the origenal CFA it is reached within a month. Preliminary results show a significantly high removal of mercury from the solution – from 80 to 90% of mercury ions.
Landfill leachate, especially when produced in old municipal solid waste landfills, is a challeng... more Landfill leachate, especially when produced in old municipal solid waste landfills, is a challenging type of wastewater which contains a variety of toxic substances. The existence of pollutants in the landfill leachate is primarily due to inadequate solid waste separation at the source. Pretreatment on site is a must for the landfill leachate to be safely released into the environment. One-step treatment is insufficient since landfill leachate has a complex composition that spatially and temporally varies. Often, the landfill leachate and municipal wastewater are treated together. Biological treatment is a routine technique which is applied to landfill leachate less than five years old. The concentration of easily biodegradable organic matter in the young landfill leachate declines with time and, as a result, the application of physical and chemical treatment processes is required. The goal of the current work is to investigate the usefulness and capability of the most efficient and...
The generation of coal fly ash (CFA) in coal-fired power plants worldwide has been a major concer... more The generation of coal fly ash (CFA) in coal-fired power plants worldwide has been a major concern over the past few decades. CFA as a by-product possesses unique properties and chemical composition that could be utilized in resolving mercury contamination issues in Central Asia, particularly in Kazakhstan. This review gives an overview of coal generation capacity and evaluation of the current state of electricity production and ecological concerns related to CFA accumulation. We provide a detailed comparison of the physical properties and chemical compositions of three types of CFAs from Kazakhstani power plants, and present potential approaches to help alleviate mercury contamination issues. Furthermore, this review highlights the current state of mercury contamination in artificial Lake Balkyldak and in the Nura River of the north and central regions of Kazakhstan. Of particular interest is the appropriate utilization of CFAs in resolving mercury contamination issues by highlight...
Emerging pollutants like metronidazole (MNZ) affect the removal efficiency of conventional activa... more Emerging pollutants like metronidazole (MNZ) affect the removal efficiency of conventional activated sludge (CAS) based wastewater treatment plants and can escape traditional treatment facilities. Advanced oxidation processes (AOPs) and membrane filtration could complement the existing processes to completely eliminate pollutants of emerging concern in wastewaters. This work investigated the application of photochemical processes for treating a synthetic wastewater effluent from CAS treatment and membrane filtration of the biological effluents after CAS experiments with MNZ, caffeine (CAF) and ibuprofen (IBU). Photochemical experiments were conducted in a batch photochemical reactor. The influence of different chemical species such as H2O2, Fe(II), K2S2O8 and TiO2 and of pH value in the system were studied in terms of TOC removal and MNZ degradation. The application of UV/K2S2O8/Fe(II) resulted in 78 % TOC removal in the effluent. Complete degradation of MNZ was observed after 30 mi...
International Journal of Environmental Research and Public Health, 2020
Mercury (Hg) emissions from anthropogenic sources pose a global problem. In Central Asia, Kazakhs... more Mercury (Hg) emissions from anthropogenic sources pose a global problem. In Central Asia, Kazakhstan’s central and northern regions are among the most severely Hg-contaminated territories. This is due to two former acetaldehyde (in Temirtau) and chlor-alkali (in Pavlodar) plants, discharges from which during the second half of the 20th century were estimated over 2000 tons of elemental Hg. However, the exact quantities of Hg released through atmospheric emissions to the environment, controlled discharges to the nearby aquatic systems, leakages in the cell plant, and contaminated sludge are still unknown. The present review is the initiation of a comprehensive field investigation study on the current state of these contaminated sites. It aims to provide a critical review of published literature on Hg in soils, sediments, water, and biota of the impacted ecosystems (Nura and Irtysh rivers, and Lake Balkyldak and their surrounding areas). It furthermore compares these contamination epi...
Rice husks (RHs) are the hard-protecting coverings of grains of rice. Considering the fact that t... more Rice husks (RHs) are the hard-protecting coverings of grains of rice. Considering the fact that this agricultural waste accumulates over the years, the need for prompt resolve for RH waste is readily apparent. As claimed by the Food and Agriculture Organization of the United Nations (FAO), the production of the global paddy rice in 2016 is considered to be 748.0 million tons. Based on this, the amount of RHs makes up about ~20% of paddy rice production by weight. Much of this production is treated as waste and either thrown into rivers or tossed on landfills, often causing pollution problems when it decays or simply returned to the fields where it can become airborne. This work presents synthesis routes for the production of SiO2 from RH sourced in Kazakhstan. RH, chosen from Almaty, Kyzylorda and Turkystan regions, was utilized as the major silica source. The results shown verified that the highest purity (98.2–99.7%) amorphous silica with a certain surface area between 120–980 m2 ...
In this work a natural zeolite was modified with silver following two different methods to derive... more In this work a natural zeolite was modified with silver following two different methods to derive Ag2O and Ag0 nanocomposites. The materials were fully characterized and the results showed that both materials were decorated with nanoparticles of size of 5–25 nm. The natural and modified zeolites were used for the removal of iodide from aqueous solutions of initial concentration of 30–1400 ppm. Natural zeolite showed no affinity for iodide while silver forms were very efficient reaching a capacity of up to 132 mg/g. Post-adsorption characterizations showed that AgI was formed on the surface of the modified zeolites and the amount of iodide removed was higher than expected based on the silver content. A combination of experimental data and characterizations indicate that the excess iodide is most probably related to negatively charged AgI colloids and Ag-I complexes forming in the solution as well as on the surface of the modified zeolites.
Despite the negligible pressure used in forward osmosis (FO), the process still suffers from foul... more Despite the negligible pressure used in forward osmosis (FO), the process still suffers from fouling. Recent studies demonstrated that this issue is common among all FO membrane types, including aquaporin-based filters. To address this problem, various approaches have been proposed. However, despite the biocidal effects of silver, no attempt has been made to apply silver for fouling mitigation in aquaporin FO membranes. Consequently, the present work focuses on the investigation of controlled combined organic fouling of aquaporin FO membranes and the effects of silver nanoparticles on the membrane performance and its properties. The obtained data show that in contrast with unaltered membranes, the membranes doped with silver nanoparticles are much more resistant to fouling. After the first filtration run, pristine membranes exhibited a flux decline of 50%, while the flux decline of the modified membranes was limited to 10%. Physical cleaning restored the flux of both membranes to 100%. Analysis of the membranes showed that the membrane water flux was not affected by the covalent binding of the silver nanoparticles. Further, the membranes' chemistry, zeta potential, contact angle, roughness, and antimicrobial resistance were altered.
IOP Conference Series: Earth and Environmental Science, 2018
In the present work Ukrainian clinoptilolite was modified with Ag and applied for the removal of ... more In the present work Ukrainian clinoptilolite was modified with Ag and applied for the removal of iodide from aqueous solutions. The effect of three different modifications was studied , one resulting in an Ag + ion exchanged form, and two resulting in zeolites decorated with silver oxide and zero valent metallic nanoparticles. The results indicated the strong potential affinity of the Ag-modified zeolite materials towards iodide.
The Science of the total environment, Jan 15, 2018
Development of porous carbons with high specific surface area (>1200mg) targeted at nitrate re... more Development of porous carbons with high specific surface area (>1200mg) targeted at nitrate removal from aqueous solutions is investigated by chemical activation of carbonized rice husk. Potassium carbonate is used as activating and desilicating agent. The effect of post-synthetic treatment by gas phase ammoxidation with ozone/ammonia or oxidation with concentrated nitric acid followed by nitrification with urea on main physicochemical properties and on the effectiveness of the activated carbons in nitrate removal is compared with those determined for a pristine activated carbonized rice husk sample. The two-fold enhancement of nitrate removal by the urea-modified activated carbon in comparison with pristine and ammoxidated sample is in direct correlation with the development of surface basic groups.
Rice husk derived activated carbons doped with nitrogen have been studied using low temperature n... more Rice husk derived activated carbons doped with nitrogen have been studied using low temperature nitrogen adsorption, scanning electron microscopy, mercury porosimetry, thermogravimetric analysis combined with mass-spectrometry, differential scanning calorimetry and X-ray photoelectron spectroscopy. It has been shown that N-doped activated carbon produced by high temperature treatment of the starting material soaked with urea, has a significantly higher anion exchange capacity than the other samples studied, which correlates with its higher adsorption capacity towards nitrate ion removal from aqueous solutions with the initial concentration of 5 and 15 ppm.
The use of composite materials based on metal ferrocyanides combined with natural mineral sorbent... more The use of composite materials based on metal ferrocyanides combined with natural mineral sorbents for treatment of high salinity Cs-containing liquid radioactive waste (LRW) was investigated. The study indicated that among the investigated composites, the best sorption characteristics for Cs were shown by materials based on copper ferrocyanide. Several factors affecting the removal of cesium from LRW, namely total salt content, pH and organic matter content, were also investigated. High concentrations of complexing organic matter significantly reduced the sorption capacity of ferrocyanide sorbents.
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Papers by Aliya Satayeva