Agnieszka Miśkiewicz | Institute of Nuclear Chemistry and Technology, (original) (raw)

Papers by Agnieszka Miśkiewicz

Membranes

The paper deals with checking the possibility of using fly ash (FA) as a sorbent in the batch ads... more The paper deals with checking the possibility of using fly ash (FA) as a sorbent in the batch adsorption method of removing radionuclides from aqueous solutions. An adsorption-membrane filtration (AMF) hybrid process with a polyether sulfone ultrafiltration membrane with a pore size of 0.22 μm was also tested as an alternative to the commonly used column-mode technology. In the AMF method, metal ions are bound by the water-insoluble species prior to the membrane filtration of the purified water. Thanks to the easy separation of the metal-loaded sorbent, it is possible to improve water purification parameters using compact installations and reduce operating costs. This work evaluated the influence of such parameters on cationic radionuclide removal efficiency (EM): initial pH and composition of the solution, contact time of the phases, and the FA doses. A method for removing radionuclides, ordinarily present in an anionic form (e.g., TcO4−), from water, has also been presented. The r...

UJ Press eBooks, Nov 10, 2022

This paper presents research on the application of the sorption-assisted membrane process for the... more This paper presents research on the application of the sorption-assisted membrane process for the removal of hazardous elements from aqueous solutions. As adsorbent in this process, metal-organic-framework compounds (MOFs) have been tested. The hybrid process was carried out in the Amicon-stirred cell and in the Couette-Tylor helical flow membrane contactor equipped with a metallic tubular membrane.

Membranes

Mercury is considered to be one of the most important chemicals of public health concern. Therefo... more Mercury is considered to be one of the most important chemicals of public health concern. Therefore, it is necessary to develop an effective method of removing mercury ions from aqueous solutions to protect people from exposure to this element. This paper presents research on the application of a sorption-assisted microfiltration (SAMF) hybrid process for the removal of Hg2+ from aqueous solutions. As adsorbents used in the process, the metal-organic-framework-UiO-66-type materials have been considered. The methods of synthesis of two types of metal-organic-framework (MOF) sorbents were developed: UiO-66_MAA modified with mercaptoacetic acid (MAA) and a composite of UiO-66 with cellulose. The results of the experiments performed proved that the separation of Hg2+ from water solutions conducted in such a system was effective; however, a relatively long initial contact time of reagents before filtration was required. The experimental results can be used to optimize the parameters of t...

DESALINATION AND WATER TREATMENT, 2018

The application of the radiometric method with the use of radiotracers for the investigation of m... more The application of the radiometric method with the use of radiotracers for the investigation of membrane fouling was tested. The radiotracer method allows for a more complete control of membrane modules' performance, which may contribute to a longer working time due to the reduction of a frequency and an intensity of a periodic cleaning. The experiments were carried out with the crossflow membrane module equipped with flat-sheet ultrafiltration membranes made of polyether sulfone. A suspension of the bentonite labeled by the radioactive isotope of lanthanum-140 La was used as a feed solution. The influence of process parameters such as cross-flow velocity and pressure as well as feed concentration on the rate of membrane blocking indicated by the change in the specific radioactivity of deposit formed on the membrane surface was tested. The performed studies demonstrated that radiometric method enabled to estimate the thickness of the cake layer deposited on the membrane during the filtration process. It was noticed that thickness of the bentonite layer formed on the membrane surface increased with the increasing concentration of the feed solution and decreased with the increasing flow velocity and applied pressure. Experiments also showed the ability of applied method for in situ determination of both kinetics of the deposit formation on the membrane as well as the permeability of the deposit layer and its resistance.

Journal of Radiological Protection, 2016

Chemistry

The paper presents results of studies on the possibility of using the ultrafiltration method supp... more The paper presents results of studies on the possibility of using the ultrafiltration method supported by sorption on low-cost, easily accessible aluminosilicates to purify water contaminated with radionuclides. An aqueous solution contaminated with radionuclides in the form of cations at different oxidation states—Cs(I)-137, Co(II)-60 and Am(III)-241—as well as pertechnetate anions—TcO4−-99m—was treated by the proposed hybrid method. In the presented work, the influence of the important process parameters (i.e., pH, sorbent dosage, temperature and feed flow rate) on the removal efficiency of radionuclides was studied. The obtained results showed that hazardous impurities, both in the form of cations and anions, may be effectively removed from water by the application of sorption-assisted UF (SAUF) using the clay-salt slimes as a sorbent. As a final stage of the work, we treated the simulated liquid radioactive waste using the SAUF method, also showing satisfactory results in its pu...

Membranes

In this work, the possibility of using electrodialysis for the treatment of liquid low-level radi... more In this work, the possibility of using electrodialysis for the treatment of liquid low-level radioactive waste was investigated. The first aim of the research was to evaluate the influence of the process parameters on the treatment of model solutions with different compositions. Subsequent experimental tests were conducted using solutions containing selected radionuclides (60Co and 137Cs), which are potential contaminants of effluents from nuclear power plants, as well as components often found in waste generated from industrial and medical radioisotope applications. The results of the experiments performed on real radioactive waste confirmed that electrodialysis was a suitable method for the treatment of such effluents because it ensured high levels of desalination and rates of decontamination. The most important parameters impacting the process were the applied voltage and electrical current. Moreover, this research shows that the application of the ED process enables the separati...

Energies, 2022

Throughout the world, and especially in the European Union, numerous technologies for the thermal... more Throughout the world, and especially in the European Union, numerous technologies for the thermal treatment of radioactive waste are available or being developed. These technologies can be applied to a large range of different radioactive waste streams, including non-standard types of waste that present specific waste management challenges. Thermal treatment can result in a significant reduction in volume and hazard, which are beneficial for safe storage and disposal. Thermal treatment also removes organic material that can form complexing agents and increase the mobility of radionuclides in the landfill. In the paper, basic thermal techniques are presented, and some examples of the installations are shown. Common knowledge of these methods may result in an increased public acceptance of nuclear energy in a country just introducing it, as Poland is.

Radioactive liquid wastes originating from production and application of radioisotopes contain ra... more Radioactive liquid wastes originating from production and application of radioisotopes contain radionuclides that are predominantly small metal ions like Sr or Co 2 +. This ions can be removed from radioactive solutions by such membrane methods like reverse osmosis or ultrafiltration if they are large enough to be retained by the membrane. Contrary to reverse osmosis, ultrafiltration is a process that does not need high pressures to be applied. Furthermore, it can involve ceramic or metallic membranes, which are chemically and thermally resistant. They exhibit also high resistivity to ionising radiation that makes them suitable for various applications in nuclear industry. However, when ultrafiltration membranes are applied for retention of metal ions present in low-level radioactive wastes, such small species have to be formerly bound with macromolecular compounds to form complexes that can be easily retained by the membrane.

Journal of Membrane Science, 2019

Photoacoustic spectroscopy as a potential method for studying fouling of flat-sheet ultrafiltrati... more Photoacoustic spectroscopy as a potential method for studying fouling of flat-sheet ultrafiltration membranes In this study, the application of photoacoustic spectroscopy (FT-IR/PAS) is proposed to investigate membrane fouling phenomena. Ultrafiltration membranes made of polyether sulfone (PES) in modules operated at different flow regimes (dead-end and cross-flow) were used in this paper. Solutions of water-soluble poly(acrylic acid) and suspensions of a natural red clay were used as model media during the filtration tests. The research performed involved the possibility of tracking the in-situ rate of membrane fouling during filtration of these two types of media. Moreover, the influence of the molecular weight of the separated particles on the intensity of the membrane blocking was studied. The results of the experiments showed that fouling phenomena progress for various types of media filtrated is characterized by different particle sizes and can be simply detected using photoacoustic spectroscopy. It was also noted that an increase in the molecular weight of the filtrated medium, e.g., poly(acrylic acid) from 30 to 250 kDa, increased the intensity of membrane blocking of 57 and 87 % for membrane installation with dead-end and cross-flow regime, respectively. The performed studies demonstrated that FT-IR/PAS can be also used to assess the efficiency of the methods used for membrane cleaning. The obtained results were confirmed by two other methods: a radiotracer technique and scanning electron microscopy.

Separation Science and Technology, 2017

Hydraulic fracturing is a process which is used for stimulation of the impermeable rocks in order... more Hydraulic fracturing is a process which is used for stimulation of the impermeable rocks in order to release the trapped natural gas. Flowback fluid contains many different chemical ingredients used in fracturing process; it holds also compounds leached from the bedrock. The production of a large amount of toxic fluids causes necessity of purification for recycling to reduce environmental impact. In this paper the results of studies on purification of flowback fluids by combination of various processes as filtration, advanced oxidation, and ion exchange are presented. The technological scheme of the treatment is proposed.

Hydrometallurgy, 2016

The paper presents the studies of the possibility of leaching uranium ores using a membrane conta... more The paper presents the studies of the possibility of leaching uranium ores using a membrane contactor. Membrane contactor with helical flow equipped with tubular metallic membrane was used as an alternative to the traditional method of leaching using the stirred tank. The influence of such process parameters as: the feed flow rate and rotation frequency of the inner cylinder placed in the membrane module on leaching efficiency was investigated. High effectiveness of leaching uranium and associated metals was achieved by using the membrane contactor equipped with the rotor. Among many advantages of a new approach of conducting the leaching process, energy saving and the possibility of combining two process steps in one apparatus: leaching and separation of solid phase from post-leaching solutions, should be mentioned. Furthermore, the application of helical membrane contactor allows the control of hydrodynamic conditions inside the apparatus and promotes turbulence. This ensured stable and efficient separation of phases after leaching process by decreasing the intensity of the membrane blocking phenomenon by suspended particles of uranium ore.

Nukleonika, 2015

The main objective of the present study was an assessment of the possibility of uranium recovery ... more The main objective of the present study was an assessment of the possibility of uranium recovery from domestic resources in Poland. In the first stage uranium was leached from the ground uranium ore by using acidic (sulfuric acid or hydrochloric acid) or alkaline (carbonate) solutions. The leaching efficiencies of uranium were dependent on the type of ore and it reached 81% for Dictyonemic shales and almost 100% for sandstones. The novel leaching routes, with the application of the helical membrane contactor equipped with rotating part were tested. The obtained postleaching solutions were concentrated and purified using solvent extraction or ion exchange chromatography. New methods of solvent extraction, as well as hybrid processes for separation and purification of the product, were studied. Extraction with the use of membrane capillary contactors that has many advantages above conventional methods was also proposed as an alternative purification method. The final product U3O8 coul...

Nukleonika, 2015

Safety of radioactive waste repositories operation is associated with a multibarrier system desig... more Safety of radioactive waste repositories operation is associated with a multibarrier system designed and constructed to isolate and contain the waste from the biosphere. Each of radioactive waste repositories is equipped with system of barriers, which reduces the possibility of release of radionuclides from the storage site. Safety systems may differ from each other depending on the type of repository. They consist of the natural geological barrier provided by host rocks of the repository and its surroundings, and an engineered barrier system (EBS). The EBS may itself comprise a variety of sub-systems or components, such as waste forms, canisters, buffers, backfills, seals and plugs. The EBS plays a major role in providing the required disposal system performance. It is assumed that the metal canisters and system of barriers adequately isolate waste from the biosphere. The evaluation of the multibarrier system is carried out after detailed tests to determine its parameters, and afte...

DESALINATION AND WATER TREATMENT, 2021

This paper presents research on the application of a biosorption-assisted ultrafiltration process... more This paper presents research on the application of a biosorption-assisted ultrafiltration process for the removal of selected radionuclides from radioactive liquid waste. Alginic acid and sodium alginate were used as binding agents owing to their availability and excellent sorption capacities for various metal ions. The first stage of investigations involved kinetic and adsorption studies using model solutions that contained non-radioactive surrogates of the 60 Co, 85 Sr, and 137 Cs radionuclides. After determining the optimal binding conditions for these ions (e.g., reagent ratio, pH, reaction time), the hybrid process was tested using the optimal biosorbent (i.e., sodium alginate) in a hybrid system equipped with a ceramic tubular membrane. The obtained results confirmed the high efficiency of the proposed method for removing radionuclides from model solutions and raw radioactive wastewater. The application of such a hybrid process in a waste treatment plant would allow for the generated concentrate to be further concentrated and then solidified, while the permeate could be safely discharged into the environment or used as process water.

Lanthanides

Along with the increasing development of electric and electronic industries, the demand for rare ... more Along with the increasing development of electric and electronic industries, the demand for rare earth elements is also growing due to their high position in many applications. In Poland, there are minerals containing REE; however, the concentration of these elements in raw materials is rather low, so they do not have a big impact on the national economy. The potential source of REE is secondary materials; among them are phosphogypsum, uranium tailings, and the waste electrical and electronic equipment (WEEE). Lanthanides as accompanying metals of uranium in Polish uranium ores were leached in the technology of uranium recovery from these resources. The recovery of REE from pregnant liquors was conducted by solvent extraction and ion exchange. Novel apparatus solutions like membrane contactors in extraction stage were tested. Different types of matrices (uranium ore, phosphorites, etc.) were used.

The kinetics of sorption and intraparticulate diffusivities of Zn2+ and Ni2+ using chitosan and a... more The kinetics of sorption and intraparticulate diffusivities of Zn2+ and Ni2+ using chitosan and activated carbon was studied. The amount of the metal ions adsorbed increased with time: 28.6 mg Zn 2+ / g chitosan and 23 mg Ni2+/ g activated carbon was the maximum adsorption obtained in the experimental conditions from this work. The rate coefficients for particle diffusion

Membranes

The paper deals with checking the possibility of using fly ash (FA) as a sorbent in the batch ads... more The paper deals with checking the possibility of using fly ash (FA) as a sorbent in the batch adsorption method of removing radionuclides from aqueous solutions. An adsorption-membrane filtration (AMF) hybrid process with a polyether sulfone ultrafiltration membrane with a pore size of 0.22 μm was also tested as an alternative to the commonly used column-mode technology. In the AMF method, metal ions are bound by the water-insoluble species prior to the membrane filtration of the purified water. Thanks to the easy separation of the metal-loaded sorbent, it is possible to improve water purification parameters using compact installations and reduce operating costs. This work evaluated the influence of such parameters on cationic radionuclide removal efficiency (EM): initial pH and composition of the solution, contact time of the phases, and the FA doses. A method for removing radionuclides, ordinarily present in an anionic form (e.g., TcO4−), from water, has also been presented. The r...

UJ Press eBooks, Nov 10, 2022

This paper presents research on the application of the sorption-assisted membrane process for the... more This paper presents research on the application of the sorption-assisted membrane process for the removal of hazardous elements from aqueous solutions. As adsorbent in this process, metal-organic-framework compounds (MOFs) have been tested. The hybrid process was carried out in the Amicon-stirred cell and in the Couette-Tylor helical flow membrane contactor equipped with a metallic tubular membrane.

Membranes

Mercury is considered to be one of the most important chemicals of public health concern. Therefo... more Mercury is considered to be one of the most important chemicals of public health concern. Therefore, it is necessary to develop an effective method of removing mercury ions from aqueous solutions to protect people from exposure to this element. This paper presents research on the application of a sorption-assisted microfiltration (SAMF) hybrid process for the removal of Hg2+ from aqueous solutions. As adsorbents used in the process, the metal-organic-framework-UiO-66-type materials have been considered. The methods of synthesis of two types of metal-organic-framework (MOF) sorbents were developed: UiO-66_MAA modified with mercaptoacetic acid (MAA) and a composite of UiO-66 with cellulose. The results of the experiments performed proved that the separation of Hg2+ from water solutions conducted in such a system was effective; however, a relatively long initial contact time of reagents before filtration was required. The experimental results can be used to optimize the parameters of t...

DESALINATION AND WATER TREATMENT, 2018

The application of the radiometric method with the use of radiotracers for the investigation of m... more The application of the radiometric method with the use of radiotracers for the investigation of membrane fouling was tested. The radiotracer method allows for a more complete control of membrane modules' performance, which may contribute to a longer working time due to the reduction of a frequency and an intensity of a periodic cleaning. The experiments were carried out with the crossflow membrane module equipped with flat-sheet ultrafiltration membranes made of polyether sulfone. A suspension of the bentonite labeled by the radioactive isotope of lanthanum-140 La was used as a feed solution. The influence of process parameters such as cross-flow velocity and pressure as well as feed concentration on the rate of membrane blocking indicated by the change in the specific radioactivity of deposit formed on the membrane surface was tested. The performed studies demonstrated that radiometric method enabled to estimate the thickness of the cake layer deposited on the membrane during the filtration process. It was noticed that thickness of the bentonite layer formed on the membrane surface increased with the increasing concentration of the feed solution and decreased with the increasing flow velocity and applied pressure. Experiments also showed the ability of applied method for in situ determination of both kinetics of the deposit formation on the membrane as well as the permeability of the deposit layer and its resistance.

Journal of Radiological Protection, 2016

Chemistry

The paper presents results of studies on the possibility of using the ultrafiltration method supp... more The paper presents results of studies on the possibility of using the ultrafiltration method supported by sorption on low-cost, easily accessible aluminosilicates to purify water contaminated with radionuclides. An aqueous solution contaminated with radionuclides in the form of cations at different oxidation states—Cs(I)-137, Co(II)-60 and Am(III)-241—as well as pertechnetate anions—TcO4−-99m—was treated by the proposed hybrid method. In the presented work, the influence of the important process parameters (i.e., pH, sorbent dosage, temperature and feed flow rate) on the removal efficiency of radionuclides was studied. The obtained results showed that hazardous impurities, both in the form of cations and anions, may be effectively removed from water by the application of sorption-assisted UF (SAUF) using the clay-salt slimes as a sorbent. As a final stage of the work, we treated the simulated liquid radioactive waste using the SAUF method, also showing satisfactory results in its pu...

Membranes

In this work, the possibility of using electrodialysis for the treatment of liquid low-level radi... more In this work, the possibility of using electrodialysis for the treatment of liquid low-level radioactive waste was investigated. The first aim of the research was to evaluate the influence of the process parameters on the treatment of model solutions with different compositions. Subsequent experimental tests were conducted using solutions containing selected radionuclides (60Co and 137Cs), which are potential contaminants of effluents from nuclear power plants, as well as components often found in waste generated from industrial and medical radioisotope applications. The results of the experiments performed on real radioactive waste confirmed that electrodialysis was a suitable method for the treatment of such effluents because it ensured high levels of desalination and rates of decontamination. The most important parameters impacting the process were the applied voltage and electrical current. Moreover, this research shows that the application of the ED process enables the separati...

Energies, 2022

Throughout the world, and especially in the European Union, numerous technologies for the thermal... more Throughout the world, and especially in the European Union, numerous technologies for the thermal treatment of radioactive waste are available or being developed. These technologies can be applied to a large range of different radioactive waste streams, including non-standard types of waste that present specific waste management challenges. Thermal treatment can result in a significant reduction in volume and hazard, which are beneficial for safe storage and disposal. Thermal treatment also removes organic material that can form complexing agents and increase the mobility of radionuclides in the landfill. In the paper, basic thermal techniques are presented, and some examples of the installations are shown. Common knowledge of these methods may result in an increased public acceptance of nuclear energy in a country just introducing it, as Poland is.

Radioactive liquid wastes originating from production and application of radioisotopes contain ra... more Radioactive liquid wastes originating from production and application of radioisotopes contain radionuclides that are predominantly small metal ions like Sr or Co 2 +. This ions can be removed from radioactive solutions by such membrane methods like reverse osmosis or ultrafiltration if they are large enough to be retained by the membrane. Contrary to reverse osmosis, ultrafiltration is a process that does not need high pressures to be applied. Furthermore, it can involve ceramic or metallic membranes, which are chemically and thermally resistant. They exhibit also high resistivity to ionising radiation that makes them suitable for various applications in nuclear industry. However, when ultrafiltration membranes are applied for retention of metal ions present in low-level radioactive wastes, such small species have to be formerly bound with macromolecular compounds to form complexes that can be easily retained by the membrane.

Journal of Membrane Science, 2019

Photoacoustic spectroscopy as a potential method for studying fouling of flat-sheet ultrafiltrati... more Photoacoustic spectroscopy as a potential method for studying fouling of flat-sheet ultrafiltration membranes In this study, the application of photoacoustic spectroscopy (FT-IR/PAS) is proposed to investigate membrane fouling phenomena. Ultrafiltration membranes made of polyether sulfone (PES) in modules operated at different flow regimes (dead-end and cross-flow) were used in this paper. Solutions of water-soluble poly(acrylic acid) and suspensions of a natural red clay were used as model media during the filtration tests. The research performed involved the possibility of tracking the in-situ rate of membrane fouling during filtration of these two types of media. Moreover, the influence of the molecular weight of the separated particles on the intensity of the membrane blocking was studied. The results of the experiments showed that fouling phenomena progress for various types of media filtrated is characterized by different particle sizes and can be simply detected using photoacoustic spectroscopy. It was also noted that an increase in the molecular weight of the filtrated medium, e.g., poly(acrylic acid) from 30 to 250 kDa, increased the intensity of membrane blocking of 57 and 87 % for membrane installation with dead-end and cross-flow regime, respectively. The performed studies demonstrated that FT-IR/PAS can be also used to assess the efficiency of the methods used for membrane cleaning. The obtained results were confirmed by two other methods: a radiotracer technique and scanning electron microscopy.

Separation Science and Technology, 2017

Hydraulic fracturing is a process which is used for stimulation of the impermeable rocks in order... more Hydraulic fracturing is a process which is used for stimulation of the impermeable rocks in order to release the trapped natural gas. Flowback fluid contains many different chemical ingredients used in fracturing process; it holds also compounds leached from the bedrock. The production of a large amount of toxic fluids causes necessity of purification for recycling to reduce environmental impact. In this paper the results of studies on purification of flowback fluids by combination of various processes as filtration, advanced oxidation, and ion exchange are presented. The technological scheme of the treatment is proposed.

Hydrometallurgy, 2016

The paper presents the studies of the possibility of leaching uranium ores using a membrane conta... more The paper presents the studies of the possibility of leaching uranium ores using a membrane contactor. Membrane contactor with helical flow equipped with tubular metallic membrane was used as an alternative to the traditional method of leaching using the stirred tank. The influence of such process parameters as: the feed flow rate and rotation frequency of the inner cylinder placed in the membrane module on leaching efficiency was investigated. High effectiveness of leaching uranium and associated metals was achieved by using the membrane contactor equipped with the rotor. Among many advantages of a new approach of conducting the leaching process, energy saving and the possibility of combining two process steps in one apparatus: leaching and separation of solid phase from post-leaching solutions, should be mentioned. Furthermore, the application of helical membrane contactor allows the control of hydrodynamic conditions inside the apparatus and promotes turbulence. This ensured stable and efficient separation of phases after leaching process by decreasing the intensity of the membrane blocking phenomenon by suspended particles of uranium ore.

Nukleonika, 2015

The main objective of the present study was an assessment of the possibility of uranium recovery ... more The main objective of the present study was an assessment of the possibility of uranium recovery from domestic resources in Poland. In the first stage uranium was leached from the ground uranium ore by using acidic (sulfuric acid or hydrochloric acid) or alkaline (carbonate) solutions. The leaching efficiencies of uranium were dependent on the type of ore and it reached 81% for Dictyonemic shales and almost 100% for sandstones. The novel leaching routes, with the application of the helical membrane contactor equipped with rotating part were tested. The obtained postleaching solutions were concentrated and purified using solvent extraction or ion exchange chromatography. New methods of solvent extraction, as well as hybrid processes for separation and purification of the product, were studied. Extraction with the use of membrane capillary contactors that has many advantages above conventional methods was also proposed as an alternative purification method. The final product U3O8 coul...

Nukleonika, 2015

Safety of radioactive waste repositories operation is associated with a multibarrier system desig... more Safety of radioactive waste repositories operation is associated with a multibarrier system designed and constructed to isolate and contain the waste from the biosphere. Each of radioactive waste repositories is equipped with system of barriers, which reduces the possibility of release of radionuclides from the storage site. Safety systems may differ from each other depending on the type of repository. They consist of the natural geological barrier provided by host rocks of the repository and its surroundings, and an engineered barrier system (EBS). The EBS may itself comprise a variety of sub-systems or components, such as waste forms, canisters, buffers, backfills, seals and plugs. The EBS plays a major role in providing the required disposal system performance. It is assumed that the metal canisters and system of barriers adequately isolate waste from the biosphere. The evaluation of the multibarrier system is carried out after detailed tests to determine its parameters, and afte...

DESALINATION AND WATER TREATMENT, 2021

This paper presents research on the application of a biosorption-assisted ultrafiltration process... more This paper presents research on the application of a biosorption-assisted ultrafiltration process for the removal of selected radionuclides from radioactive liquid waste. Alginic acid and sodium alginate were used as binding agents owing to their availability and excellent sorption capacities for various metal ions. The first stage of investigations involved kinetic and adsorption studies using model solutions that contained non-radioactive surrogates of the 60 Co, 85 Sr, and 137 Cs radionuclides. After determining the optimal binding conditions for these ions (e.g., reagent ratio, pH, reaction time), the hybrid process was tested using the optimal biosorbent (i.e., sodium alginate) in a hybrid system equipped with a ceramic tubular membrane. The obtained results confirmed the high efficiency of the proposed method for removing radionuclides from model solutions and raw radioactive wastewater. The application of such a hybrid process in a waste treatment plant would allow for the generated concentrate to be further concentrated and then solidified, while the permeate could be safely discharged into the environment or used as process water.

Lanthanides

Along with the increasing development of electric and electronic industries, the demand for rare ... more Along with the increasing development of electric and electronic industries, the demand for rare earth elements is also growing due to their high position in many applications. In Poland, there are minerals containing REE; however, the concentration of these elements in raw materials is rather low, so they do not have a big impact on the national economy. The potential source of REE is secondary materials; among them are phosphogypsum, uranium tailings, and the waste electrical and electronic equipment (WEEE). Lanthanides as accompanying metals of uranium in Polish uranium ores were leached in the technology of uranium recovery from these resources. The recovery of REE from pregnant liquors was conducted by solvent extraction and ion exchange. Novel apparatus solutions like membrane contactors in extraction stage were tested. Different types of matrices (uranium ore, phosphorites, etc.) were used.

The kinetics of sorption and intraparticulate diffusivities of Zn2+ and Ni2+ using chitosan and a... more The kinetics of sorption and intraparticulate diffusivities of Zn2+ and Ni2+ using chitosan and activated carbon was studied. The amount of the metal ions adsorbed increased with time: 28.6 mg Zn 2+ / g chitosan and 23 mg Ni2+/ g activated carbon was the maximum adsorption obtained in the experimental conditions from this work. The rate coefficients for particle diffusion