Search

Alternative alkali activators are a growing research area in the field of alkali-activated materials (AAMs) because conventional chemical-based activators, such as sodium hydroxide and sodium silicate, have a large environmental footprint and high costs. Industrial residues are widely studied as substitutional cementitious materials in concrete and precursors in AAMs but not much as activators. In the present study, sodium rich waste from pulp mill was used as an alkali source in AAMs. Recovery boiler fly ash (RBA) is dust-like waste fraction removed from flue gases of recovery boiler by electrostatic precipitators. It consists mainly of alkalis, sulfate, and carbon while sodium sulfate is the main phase. This work utilized RBA as a sole one-part alkali activator for a precursor mixture containing 95 wt% of blast furnace slag and 5 wt% of cement, and the results were compared with two references, one without activator and the other activated with commercial sodium sulfate. The setting properties and strength gain were comparable between the RBA-activated and commercial activator-activated samples. Calorimetry data showed also similar reactivity between them, and X-ray diffractometry, thermogravimetric analysis, and scanning electron microscopy measurements revealed that the same phases were formed. The main issue was the microcracking of the paste samples when using RBA as an activator. Results confirm the earlier findings from the literature, the activator dosage did not greatly impact the properties: in this study, the initial proportion of 1% or 3% Na2O was the most suitable.

This recommendation is devoted to testing the resistance of natural stone and fired-clay brick units against salt crystallization. The procedure was developed by the RILEM TC 271-ASC to evaluate the durability of porous building materials against salt crystallization through a laboratory method that allows for accelerated testing without compromising the reliability of the results. The new procedure is designed to replicate salt damage caused by crystallization near the surface of materials as a result of capillary transport and evaporation. A new approach is proposed that considers the presence of two stages in the salt crystallization test. In the first, the accumulation stage, salts gradually accumulate on or near the surface of the material due to evaporation. In the second, the propagation stage, damage initiates and develops due to changes in moisture content and relative humidity that trigger salt dissolution and crystallization cycles. To achieve this, two types of salt were tested, namely sodium chloride and sodium sulphate, with each salt tested separately. A methodology for assessing the salt-induced damage is proposed, which includes visual and photographical observations and measurement of material loss. The procedure has been preliminarily validated in round robin tests.

This recommendation is devoted to testing the resistance of natural stone and fired-clay brick units against salt crystallization. The procedure was developed by the RILEM TC 271-ASC to evaluate the durability of porous building materials against salt crystallization through a laboratory method that allows for accelerated testing without compromising the reliability of the results. The new procedure is designed to replicate salt damage caused by crystallization near the surface of materials as a result of capillary transport and evaporation. A new approach is proposed that considers the presence of two stages in the salt crystallization test. In the first, the accumulation stage, salts gradually accumulate on or near the surface of the material due to evaporation. In the second, the propagation stage, damage initiates and develops due to changes in moisture content and relative humidity that trigger salt dissolution and crystallization cycles. To achieve this, two types of salt were tested, namely sodium chloride and sodium sulphate, with each salt tested separately. A methodology for assessing the salt-induced damage is proposed, which includes visual and photographical observations and measurement of material loss. The procedure has been preliminarily validated in round robin tests., Heritage & Architecture

This research aims to examine the sulfate and chloride durability behaviors of geopolymer composites synthesized by the alkali activation of metakaolin (MK), reinforced by boron waste colemanite (C), silica fume (SF), and slag (S). The resultant geopolymer composites were subjected to magnesium sulfate (MgSO4) solution (concentration 10%), sodium sulfate (Na2SO4) solution (concentration 10%), and sodium chloride (NaCl) solution (concentration 10%) for up to 12 months. The compressive and flexural strengths, microstructure (X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)), weight changes, and visual inspection of the geopolymer composites were investigated to evaluate their durability behavior. The conclusion proved that the mix of a metakaolin with the addition of 10% C, and 20% SF shows the highest compressive strength for the studied range of mixture design. In geopolymer mortar samples, compressive strength increase was observed due to sodium chloride and sodium and magnesium sulfate effects after three months, while a decrease was observed after six months. These fluctuations were due to the diffusion of solutions in the matrix, formed during the transition of alkali ions from the samples to the solution. The loss of strength after three months could be due to the presence of microcracks, as a consequence of ettringite and gypsum creation in the pores, as well as the transition of alkalis from the sample matrix to the solution.

Perfluorooctane sulfonic acid (PFOS) has been produced in large quantities for the use in various applications. As a consequence, PFOS is ubiquitous in the environment. Managing transportation of PFOS requires a clear understanding of PFOS mobilization in soils and their interactions with different soil components. The current study investigated a pH-dependent sorption of PFOS isomers onto soil and the effect of dissolved humic substances and Na2 SO 4 . Sorption experiments of PFOS isomers was conducted on top and subsoils to assess their capacity to retain PFOS. Topsoil and subsoil samples were sampled from two areas in Kvarntorp, Kumla, Sweden. Sorption experiments were performed by shaking a mixture of soil and soil solutions spiked with PFOS isomers. One way ANOVA showed that linear PFOS (L-PFOS) and branched PFOS (Br-PFOS) isomers showed different sorption behavior onto soils. Calculated logarithmic partition coefficients revealed that L-PFOS is readily sorbed onto soils sampled at area 1) at very low pH (<4.5) whereas it was the least sorbed onto soils collected at area 2) under the studied pH range. Electrostatic interactions governed the sorption of PFOS isomers during acidic conditions whereas other mechanism controlled the sorption during neutral to alkaline conditions. The presence of humic acid enhanced the sorption of all PFOS isomers whereas fulvic acid inhibited their sorption onto soil. Sorption results revealed that the topsoil had a high capacity to sorb all PFOS isomers compared to the subsoil from the same area. For soils collected from an area covered by young oak trees, a high sorption on the topsoil was attributed to a high organic content [measured as loss on ignition (LOI)] and cation exchange capacity (CEC). However, there was no correlation between sorption capacity and LOI or CEC content for soil collected from another area covered by spruce forest. This suggested that the sorption on latter soils was controlled by other physicochemica

Perfluorooctane sulfonic acid (PFOS) has been produced in large quantities for the use in various applications. As a consequence, PFOS is ubiquitous in the environment. Managing transportation of PFOS requires a clear understanding of PFOS mobilization in soils and their interactions with different soil components. The current study investigated a pH-dependent sorption of PFOS isomers onto soil and the effect of dissolved humic substances and Na2 SO 4 . Sorption experiments of PFOS isomers was conducted on top and subsoils to assess their capacity to retain PFOS. Topsoil and subsoil samples were sampled from two areas in Kvarntorp, Kumla, Sweden. Sorption experiments were performed by shaking a mixture of soil and soil solutions spiked with PFOS isomers. One way ANOVA showed that linear PFOS (L-PFOS) and branched PFOS (Br-PFOS) isomers showed different sorption behavior onto soils. Calculated logarithmic partition coefficients revealed that L-PFOS is readily sorbed onto soils sampled at area 1) at very low pH (<4.5) whereas it was the least sorbed onto soils collected at area 2) under the studied pH range. Electrostatic interactions governed the sorption of PFOS isomers during acidic conditions whereas other mechanism controlled the sorption during neutral to alkaline conditions. The presence of humic acid enhanced the sorption of all PFOS isomers whereas fulvic acid inhibited their sorption onto soil. Sorption results revealed that the topsoil had a high capacity to sorb all PFOS isomers compared to the subsoil from the same area. For soils collected from an area covered by young oak trees, a high sorption on the topsoil was attributed to a high organic content [measured as loss on ignition (LOI)] and cation exchange capacity (CEC). However, there was no correlation between sorption capacity and LOI or CEC content for soil collected from another area covered by spruce forest. This suggested that the sorption on latter soils was controlled by other physicochemica

High amounts of fly ash generated as a by-product of coal combustion in thermal power generation plants have been a concern for years due to their negative environmental impact; in Colombia, for example, this fly ash represents 6,000,000 tons per year. The use of this material in industrial processes is among the many solutions proposed, provided that it has pozzolanic properties useful in cement and concrete industries. The aim of this study is evaluating concrete resistance to compression at different ages, replacing cement by fly ash of 40%, using alkaline activation with NaOH, Sodium Sulfate, and limestone in different proportions. The results show that activation improves fly ash performance and it is possible to achieve better mechanical properties than with mixtures without activation., Las grandes cantidades de cenizas volantes que se obtienen como subproducto de la combustión del carbón en las termoeléctricas han generado preocupación por su impacto ambiental, por ejemplo, en Colombia este residuo representa la cantidad de 6.000.000 Toneladas al año. Dentro de las estrategias de solución está el aprovechamiento de este residuo en procesos industriales. El residuo cuenta con propiedades puzolánicas útiles en industrias como la del cemento y concreto. La presente investigación tiene como objetivo de evaluar la resistencia a la compresión a diferentes edades de concretos con reemplazando cemento por ceniza volante de 40%, utilizando activación alcalina con NaOH y activación con sulfato de sodio y caliza, en diferentes proporciones; los resultados muestran que la activación mejora el desempeño de la ceniza y se logra obtener mejores propiedades mecánicas que sin activación.

The possibility of monitoring the volume of stones deteriorated by accelerated aging cycles has been formulated, as a complement to the records using dry weight, since the latter is altered in the first cycles by up to 10% due to the formation of internal crystals, in the porous network of the samples. For this, five samples of volcanic Tuff stones have been deteriorated through crystallization cycles with a 12% concentrated sodium sulfate brine at room temperature ranging between 18 and 20 ° C. Data collection occurs in two categories: first in “cycles” involving dry weight and volume by photogrammetry; and second in “periods” that involves dry weight, volume by Archimedes’ principle and volume by photogrammetry. With this, it has been observed that the volume is also affected by the crystallization of salts, presenting an increase in the first three cycles, in addition, the ability of photogrammetry to acquire the volume of small-scale objects has been demonstrated, achieving a percentage error lower than that of 4%., Foi apresentada a possibilidade de acompanhar o volume de pedras deterioradas por ciclos de envelhecimento acelerado, como um complemento para os registos através do peso seco, pois este último vê-se alterado nos primeiros ciclos até 10% pela formação de cristais internos na rede porosa das amostras. Para isso, cinco amostras de pedras Tobas vulcânicas foram deterioradas por ciclos de cristalização com uma salmoura de sulfato de sódio concentrada a 12% à temperatura ambiente que oscila entre 18 e 20 °C. A coleta dos dados ocorre em duas categorias: primeiro em “ciclos” que envolvem peso seco e volume por fotogrametria; e segundo em “períodos” que envolve peso seco, volume por princípio de Arquimedes e volume por fotogrametria. Observou-se que o volume também é afectado pela cristalização de sais, com um aumento nos primeiros três ciclos. Foi demonstrada a capacidade da fotogrametria para adquirir o volume de objetos de pequena escala, obtendo um erro percentual inferior a 4%., Se ha formulado la posibilidad de dar seguimiento al volumen de piedras deterioradas por ciclos de envejecimiento acelerado, como un complemento para los registros mediante el peso seco, pues este último se ve alterado en los primeros ciclos hasta un 10% por la formación de cristales internos en la red porosa de las muestras. Para esto, cinco muestras de piedras Tobas volcánicas se han deteriorado mediante ciclos de cristalización con una salmuera de sulfato de sodio concentrada al 12% a temperatura ambiente que oscila entre los 18 y 20 °C. La recolección de los datos se produce en dos categorías: primero en “ciclos” que involucran peso seco y volumen por fotogrametría; y segundo en “periodos” que involucra peso seco, volumen por principio de Arquímedes y volumen por fotogrametría. Con esto se ha observado que el volumen también es afectado por la cristalización de sales, presentando un incremento en los primeros tres ciclos, además se ha demostrado la capacidad de la fotogrametría para adquirir el volumen de objetos de pequeña escala consiguiendo un error porcentual inferior al 4%.

The study's primary goal is to determine carbamate pesticide methomyl's kinetic parameters and degradation efficiency from water solution by direct electrochemical oxidation using IrOX anode. Also, define the dependence of the efficiency of methomyl decomposition by direct electrochemical oxidation on the initial concentration of pesticide and electrolyte, applied current, and pH value. The results of methomyl degradation by direct electrochemical oxidation obey the pseudo-first kinetic order. Ultraviolet-visible (UV-Vis) spectroscopy followed the methomyl concentration during the study. The degradation products were studied using the Fourier transform infrared (FT-IR) spectroscopy. Also, this study determines the energy consumption and optimal initial conditions. The phytotoxicity of pesticide and degradation products was studied using mung beans.

Perfluorooctane sulfonic acid (PFOS) has been produced in large quantities for the use in various applications. As a consequence, PFOS is ubiquitous in the environment. Managing transportation of PFOS requires a clear understanding of PFOS mobilization in soils and their interactions with different soil components. The current study investigated a pH-dependent sorption of PFOS isomers onto soil and the effect of dissolved humic substances and Na2 SO 4 . Sorption experiments of PFOS isomers was conducted on top and subsoils to assess their capacity to retain PFOS. Topsoil and subsoil samples were sampled from two areas in Kvarntorp, Kumla, Sweden. Sorption experiments were performed by shaking a mixture of soil and soil solutions spiked with PFOS isomers. One way ANOVA showed that linear PFOS (L-PFOS) and branched PFOS (Br-PFOS) isomers showed different sorption behavior onto soils. Calculated logarithmic partition coefficients revealed that L-PFOS is readily sorbed onto soils sampled at area 1) at very low pH (<4.5) whereas it was the least sorbed onto soils collected at area 2) under the studied pH range. Electrostatic interactions governed the sorption of PFOS isomers during acidic conditions whereas other mechanism controlled the sorption during neutral to alkaline conditions. The presence of humic acid enhanced the sorption of all PFOS isomers whereas fulvic acid inhibited their sorption onto soil. Sorption results revealed that the topsoil had a high capacity to sorb all PFOS isomers compared to the subsoil from the same area. For soils collected from an area covered by young oak trees, a high sorption on the topsoil was attributed to a high organic content [measured as loss on ignition (LOI)] and cation exchange capacity (CEC). However, there was no correlation between sorption capacity and LOI or CEC content for soil collected from another area covered by spruce forest. This suggested that the sorption on latter soils was controlled by other physicochemica

Perfluorooctane sulfonic acid (PFOS) has been produced in large quantities for the use in various applications. As a consequence, PFOS is ubiquitous in the environment. Managing transportation of PFOS requires a clear understanding of PFOS mobilization in soils and their interactions with different soil components. The current study investigated a pH-dependent sorption of PFOS isomers onto soil and the effect of dissolved humic substances and Na2 SO 4 . Sorption experiments of PFOS isomers was conducted on top and subsoils to assess their capacity to retain PFOS. Topsoil and subsoil samples were sampled from two areas in Kvarntorp, Kumla, Sweden. Sorption experiments were performed by shaking a mixture of soil and soil solutions spiked with PFOS isomers. One way ANOVA showed that linear PFOS (L-PFOS) and branched PFOS (Br-PFOS) isomers showed different sorption behavior onto soils. Calculated logarithmic partition coefficients revealed that L-PFOS is readily sorbed onto soils sampled at area 1) at very low pH (<4.5) whereas it was the least sorbed onto soils collected at area 2) under the studied pH range. Electrostatic interactions governed the sorption of PFOS isomers during acidic conditions whereas other mechanism controlled the sorption during neutral to alkaline conditions. The presence of humic acid enhanced the sorption of all PFOS isomers whereas fulvic acid inhibited their sorption onto soil. Sorption results revealed that the topsoil had a high capacity to sorb all PFOS isomers compared to the subsoil from the same area. For soils collected from an area covered by young oak trees, a high sorption on the topsoil was attributed to a high organic content [measured as loss on ignition (LOI)] and cation exchange capacity (CEC). However, there was no correlation between sorption capacity and LOI or CEC content for soil collected from another area covered by spruce forest. This suggested that the sorption on latter soils was controlled by other physicochemica

Perfluorooctane sulfonic acid (PFOS) has been produced in large quantities for the use in various applications. As a consequence, PFOS is ubiquitous in the environment. Managing transportation of PFOS requires a clear understanding of PFOS mobilization in soils and their interactions with different soil components. The current study investigated a pH-dependent sorption of PFOS isomers onto soil and the effect of dissolved humic substances and Na2 SO 4 . Sorption experiments of PFOS isomers was conducted on top and subsoils to assess their capacity to retain PFOS. Topsoil and subsoil samples were sampled from two areas in Kvarntorp, Kumla, Sweden. Sorption experiments were performed by shaking a mixture of soil and soil solutions spiked with PFOS isomers. One way ANOVA showed that linear PFOS (L-PFOS) and branched PFOS (Br-PFOS) isomers showed different sorption behavior onto soils. Calculated logarithmic partition coefficients revealed that L-PFOS is readily sorbed onto soils sampled at area 1) at very low pH (<4.5) whereas it was the least sorbed onto soils collected at area 2) under the studied pH range. Electrostatic interactions governed the sorption of PFOS isomers during acidic conditions whereas other mechanism controlled the sorption during neutral to alkaline conditions. The presence of humic acid enhanced the sorption of all PFOS isomers whereas fulvic acid inhibited their sorption onto soil. Sorption results revealed that the topsoil had a high capacity to sorb all PFOS isomers compared to the subsoil from the same area. For soils collected from an area covered by young oak trees, a high sorption on the topsoil was attributed to a high organic content [measured as loss on ignition (LOI)] and cation exchange capacity (CEC). However, there was no correlation between sorption capacity and LOI or CEC content for soil collected from another area covered by spruce forest. This suggested that the sorption on latter soils was controlled by other physicochemica

Diplomová práce se zabývá implementací elektrodialýzy pro zahušťování vodných roztoků solí do vysokého stupně nasycení v ZLD systémech. V teoretické části je zpracován stručný přehled membránových procesů využívaných v ZLD systémech, jejich popis a omezení pro tuto aplikaci. Praktická část diplomové práce se zabývá stanovením a ověřením metodiky stanovení maximálně dosažitelných koncentrací solí v koncentrátovém okruhu elektrodialyzační jednotky. Dále je diskutován vliv počáteční koncentrace roztoků, zpětné difúze soli a osmózy vody na transport hmoty přes iontově selektivní membránu., The thesis deals with implementation of electrodialysis for concentration of aqueous saline solutions to a high degree of saturation in ZLD technologies. The theoretical part is focused on basic description and the main problems of the most used membrane ZLD processes. The practical part of the work deals with development and verification of methodology for determination of maximum possible achievable saline solutions concentration in concentrate loop of electrodialysis unit. Hereafter, the effects of initial solutions concentration, back salt diffusion and water osmosis on mass transfer through ion exchange membrane are discussed., Fakulta chemicko-technologická, Posluchač seznámil komisi s obsahem své diplomové práce a následně zodpověděl dotazy členů komise. Správně upravené obrázky. Chybí hodnocení celkové účinnosti. Práce s vyšší teplotou, jak se mění vodivost a viskozita s teplotou? Otázka k času jednotlivých experimentů. Komise pro SZZ konstatuje, že posuzovaná práce není plagiátem, ale originálním dílem Bc. Filipa Slováka., Dokončená práce s úspěšnou obhajobou

This research aims to examine the sulfate and chloride durability behaviors of geopolymer composites synthesized by the alkali activation of metakaolin (MK), reinforced by boron waste colemanite (C), silica fume (SF), and slag (S). The resultant geopolymer composites were subjected to magnesium sulfate (MgSO4) solution (concentration 10%), sodium sulfate (Na2SO4) solution (concentration 10%), and sodium chloride (NaCl) solution (concentration 10%) for up to 12 months. The compressive and flexural strengths, microstructure (X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)), weight changes, and visual inspection of the geopolymer composites were investigated to evaluate their durability behavior. The conclusion proved that the mix of a metakaolin with the addition of 10% C, and 20% SF shows the highest compressive strength for the studied range of mixture design. In geopolymer mortar samples, compressive strength increase was observed due to sodium chloride and sodium and magnesium sulfate effects after three months, while a decrease was observed after six months. These fluctuations were due to the diffusion of solutions in the matrix, formed during the transition of alkali ions from the samples to the solution. The loss of strength after three months could be due to the presence of microcracks, as a consequence of ettringite and gypsum creation in the pores, as well as the transition of alkalis from the sample matrix to the solution.

The study's primary goal is to determine carbamate pesticide methomyl's kinetic parameters and degradation efficiency from water solution by direct electrochemical oxidation using IrOX anode. Also, define the dependence of the efficiency of methomyl decomposition by direct electrochemical oxidation on the initial concentration of pesticide and electrolyte, applied current, and pH value. The results of methomyl degradation by direct electrochemical oxidation obey the pseudo-first kinetic order. Ultraviolet-visible (UV-Vis) spectroscopy followed the methomyl concentration during the study. The degradation products were studied using the Fourier transform infrared (FT-IR) spectroscopy. Also, this study determines the energy consumption and optimal initial conditions. The phytotoxicity of pesticide and degradation products was studied using mung beans.

This research aims to examine the sulfate and chloride durability behaviors of geopolymer composites synthesized by the alkali activation of metakaolin (MK), reinforced by boron waste colemanite (C), silica fume (SF), and slag (S). The resultant geopolymer composites were subjected to magnesium sulfate (MgSO4) solution (concentration 10%), sodium sulfate (Na2SO4) solution (concentration 10%), and sodium chloride (NaCl) solution (concentration 10%) for up to 12 months. The compressive and flexural strengths, microstructure (X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)), weight changes, and visual inspection of the geopolymer composites were investigated to evaluate their durability behavior. The conclusion proved that the mix of a metakaolin with the addition of 10% C, and 20% SF shows the highest compressive strength for the studied range of mixture design. In geopolymer mortar samples, compressive strength increase was observed due to sodium chloride and sodium and magnesium sulfate effects after three months, while a decrease was observed after six months. These fluctuations were due to the diffusion of solutions in the matrix, formed during the transition of alkali ions from the samples to the solution. The loss of strength after three months could be due to the presence of microcracks, as a consequence of ettringite and gypsum creation in the pores, as well as the transition of alkalis from the sample matrix to the solution.

This research aims to examine the sulfate and chloride durability behaviors of geopolymer composites synthesized by the alkali activation of metakaolin (MK), reinforced by boron waste colemanite (C), silica fume (SF), and slag (S). The resultant geopolymer composites were subjected to magnesium sulfate (MgSO4) solution (concentration 10%), sodium sulfate (Na2SO4) solution (concentration 10%), and sodium chloride (NaCl) solution (concentration 10%) for up to 12 months. The compressive and flexural strengths, microstructure (X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)), weight changes, and visual inspection of the geopolymer composites were investigated to evaluate their durability behavior. The conclusion proved that the mix of a metakaolin with the addition of 10% C, and 20% SF shows the highest compressive strength for the studied range of mixture design. In geopolymer mortar samples, compressive strength increase was observed due to sodium chloride and sodium and magnesium sulfate effects after three months, while a decrease was observed after six months. These fluctuations were due to the diffusion of solutions in the matrix, formed during the transition of alkali ions from the samples to the solution. The loss of strength after three months could be due to the presence of microcracks, as a consequence of ettringite and gypsum creation in the pores, as well as the transition of alkalis from the sample matrix to the solution.

In this work we link experimental results of SrSO precipitation with a nucleation model based on mesoscopic nucleation theory (MeNT) to stride towards a cohesive view of the nucleation process that integrates both classical and non-classical views. When SrCl and NaSO are co-titrated at slow dosing rates, time-resolved turbidity, conductivity and ion-specific data reveal that the initial stage of the nucleation process is driven by neutral species, i.e. ion-pairs or larger, akin to the prenucleation cluster model. However, when co-titrations are conducted at higher rates, the onset of nucleation is dominated by the consumption of free ions, akin to the explanation provided by classical nucleation theory (CNT). The occurrence of both mechanisms for the same system is explained by a toy model that includes both the thermodynamics (consisting of a single energy barrier) and kinetics of cluster formation formally obtained from MeNT. This gives rise to an effective energy barrier exhibiting a local intermediate minimum, which does not originate from a minimum in the thermodynamic free energy. Rather, it is associated with an increased probability of observing a specific class (in terms of size/density) of precursor clusters due to their slower kinetics. At high supersaturations this minimum in the kinetics of cluster formation becomes less pronounced and the effective barrier is also significantly lowered. Consequently, the probability of observing an intermediate state is blurred and we recover a nucleation pathway more closely following the one envisaged by the classical model. Thus, our model is capable of capturing both single and multistep nucleation mechanisms observed experimentally considering only a single energy barrier.

Now when the interest is increasing to reach a sustainable infrastructure, one possibility SCA is experimenting with is the possibility to produce renewable hydrocarbons from black liquor which can be extracted from a Kraft process. However, when extracting the black liquor, a lot of sodium-based compounds are removed from the recovery process and when hydrocarbons are produced in SCA’s biorefinery, these compounds are caught in an aqueous solution. The aqueous solution is received at 50°C, and the sodium-based compounds are mainly sodium sulfate and sodium carbonate, where the solution do also contain organic compounds and a solvent that is used in the biorefinery. This thesis focused on building a concept to extract sodium sulfate from the aqueous solution. The thesis did also include if any additional preparatory work needs to be done to the solution before extracting sodium sulfate. Finally, a flow chart that maps the energy needed for the process was created. The method that was used was crystallisation by cooling the solution. By cooling the solution, sodium sulfates solubility decreases which will result in that sodium sulfate falls out of the solution as crystals. It was determined that the solvent that the solution contains should be extracted if the solvents boiling temperature is below 100°C. Further, by cooling the solution under stirring to 15°C with a residence time of 3 hours, unwanted compounds can be extracted. By later cooling the solution under stirring to 5°C with a residence time of 1 hour, it gave sodium sulfate decahydrate (Na2SO4·10H2O) with small amounts of organic compounds. By removing the water, the dry product reached a purity of 94wt% sodium sulfate with a yield of 12% (mass of dry product/mass of aqueous solution). This result reached the specific objectives that were set at the start of this thesis, which was to reach a purity of 90wt% sodium sulfate with a yield of 5%. The energy intensity for evaporating the solvent is expected t, Nu när intresset ökar, för att nå en hållbar infrastruktur, så experimenterat SCA med möjligheten att producera förnybara kolväten från svartlut som kan extraheras från en sulfatprocess. Vid extrahering av svartluten tas dock mycket natriumbaserade föreningar bort från återvinningsprocessen och när kolväten produceras i SCA:s bioraffinaderi fastnar dessa föreningar i en vattenlösning. Den lösningen tas emot vid 50°C och de natriumbaserade föreningarna är huvudsakligen natriumsulfat och natriumkarbonat, där lösningen också innehåller organiska föreningar och ett lösningsmedel som används i bioraffinaderiet. Denna avhandling fokuserade på att bygga ett koncept för att extrahera natriumsulfat från vattenlösningen. Avhandlingen omfattade också om ytterligare förberedande arbete måste göras av lösningen innan man extraherar natriumsulfat. Slutligen skapades ett flödesschema som kartlägger den energi som behövs för processen. Metoden som bestämde sig för att användas var kristallisering genom kylning av lösningen. Genom att kyla lösningen minskar lösligheten av natriumsulfater vilket leder till att natriumsulfat faller ut ur lösningen som kristaller. Det bestämdes att lösningsmedlet som lösningen innehåller skulle extraheras om lösningsmedlets koktemperatur är under 100°C. Vidare, genom att kyla lösningen under omrörning till 15°C med en uppehållstid på 3 timmar, kan oönskade ämnen extraheras. Genom att senare kyla lösningen under omrörning till 5°C med en uppehållstid på 1 timme gav natriumsulfatdekahydrat (Na2SO4·10H2O) med små mängder organiska föreningar. Genom att avlägsna vattnet nådde den torra produkten en renhet av 94 vikt% natriumsulfat med ett utbyte av 12% (massa torr produkt/massa vattenlösning). Detta resultat nådde de specifika mål som sattes i början av denna avhandling, vilket var att nå en renhet av 90 vikt% natriumsulfat med ett utbyte på 5%. Energiintensiteten för att förånga lösningsmedlet förväntas vara hög. Det beror mycket på vilket lösningsmedel s

Several industrial activities produce metal sulfates, which are controlled by strict limitations for wastewater concentrations of sulfate. One emerging area where these activities occur is the production of lithium-ion battery chemicals in which sodium sulfates are formed because of cathode precursor co-precipitation. Several solutions for sulfate removal exist, but one option is to reuse the sulfate side stream in other processes to increase circular economy and atom efficiency. In this paper, the reuse of sodium sulfate solution in a steel industry pickling solution is considered. Neutral electrolytic pickling experiments were carried out to compare the pickling behavior of the electrolyte dissolved from pure sodium sulfate and the electrolyte diluted from a side stream solution. Effect of impure electrolyte was evaluated using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectrometry (EDS). Concentrations of the metal ions were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The results indicated a slight increase in current efficiency with the side stream electrolyte solution, while overall the pickling behavior remained similar. This suggests that a side stream sodium sulfate solution could be used as a pickling electrolyte, reducing the need for pure reagents.

Now when the interest is increasing to reach a sustainable infrastructure, one possibility SCA is experimenting with is the possibility to produce renewable hydrocarbons from black liquor which can be extracted from a Kraft process. However, when extracting the black liquor, a lot of sodium-based compounds are removed from the recovery process and when hydrocarbons are produced in SCA’s biorefinery, these compounds are caught in an aqueous solution. The aqueous solution is received at 50°C, and the sodium-based compounds are mainly sodium sulfate and sodium carbonate, where the solution do also contain organic compounds and a solvent that is used in the biorefinery. This thesis focused on building a concept to extract sodium sulfate from the aqueous solution. The thesis did also include if any additional preparatory work needs to be done to the solution before extracting sodium sulfate. Finally, a flow chart that maps the energy needed for the process was created. The method that was used was crystallisation by cooling the solution. By cooling the solution, sodium sulfates solubility decreases which will result in that sodium sulfate falls out of the solution as crystals. It was determined that the solvent that the solution contains should be extracted if the solvents boiling temperature is below 100°C. Further, by cooling the solution under stirring to 15°C with a residence time of 3 hours, unwanted compounds can be extracted. By later cooling the solution under stirring to 5°C with a residence time of 1 hour, it gave sodium sulfate decahydrate (Na2SO4·10H2O) with small amounts of organic compounds. By removing the water, the dry product reached a purity of 94wt% sodium sulfate with a yield of 12% (mass of dry product/mass of aqueous solution). This result reached the specific objectives that were set at the start of this thesis, which was to reach a purity of 90wt% sodium sulfate with a yield of 5%. The energy intensity for evaporating the solvent is expected t, Nu när intresset ökar, för att nå en hållbar infrastruktur, så experimenterat SCA med möjligheten att producera förnybara kolväten från svartlut som kan extraheras från en sulfatprocess. Vid extrahering av svartluten tas dock mycket natriumbaserade föreningar bort från återvinningsprocessen och när kolväten produceras i SCA:s bioraffinaderi fastnar dessa föreningar i en vattenlösning. Den lösningen tas emot vid 50°C och de natriumbaserade föreningarna är huvudsakligen natriumsulfat och natriumkarbonat, där lösningen också innehåller organiska föreningar och ett lösningsmedel som används i bioraffinaderiet. Denna avhandling fokuserade på att bygga ett koncept för att extrahera natriumsulfat från vattenlösningen. Avhandlingen omfattade också om ytterligare förberedande arbete måste göras av lösningen innan man extraherar natriumsulfat. Slutligen skapades ett flödesschema som kartlägger den energi som behövs för processen. Metoden som bestämde sig för att användas var kristallisering genom kylning av lösningen. Genom att kyla lösningen minskar lösligheten av natriumsulfater vilket leder till att natriumsulfat faller ut ur lösningen som kristaller. Det bestämdes att lösningsmedlet som lösningen innehåller skulle extraheras om lösningsmedlets koktemperatur är under 100°C. Vidare, genom att kyla lösningen under omrörning till 15°C med en uppehållstid på 3 timmar, kan oönskade ämnen extraheras. Genom att senare kyla lösningen under omrörning till 5°C med en uppehållstid på 1 timme gav natriumsulfatdekahydrat (Na2SO4·10H2O) med små mängder organiska föreningar. Genom att avlägsna vattnet nådde den torra produkten en renhet av 94 vikt% natriumsulfat med ett utbyte av 12% (massa torr produkt/massa vattenlösning). Detta resultat nådde de specifika mål som sattes i början av denna avhandling, vilket var att nå en renhet av 90 vikt% natriumsulfat med ett utbyte på 5%. Energiintensiteten för att förånga lösningsmedlet förväntas vara hög. Det beror mycket på vilket lösningsmedel s

Práce se zabývá stanovením selektivity při membránové separaci mezi kationty o stejném a různém náboji za použití elektrodialýzy jako separační metody. Za modelové roztoky byly zvoleny směsi síranu sodného se síranem draselným a chloridu sodného s chloridem vápenatým. Byl zkoumán vliv různých poměrů molárních koncentrací zmíněných roztoků na výslednou selektivitu a zároveň byl změřen vliv velikosti elektrického proudu na selektivitu., The work deals with the determination of selectivity in membrane separation between cations of the same and different charge using electrodialysis as a separation method. Mixtures of sodium sulfate with potassium sulfate and sodium chloride with calcium chloride were chosen as model solutions. The influence of different ratios of molar concentrations of the mentioned solutions on the resulting selectivity was investigated and at the same time the influence of the magnitude of the electric current on the selectivity was measured., Fakulta chemicko-technologická, Posluchač seznámil komisi s obsahem své diplomové práce a následně zodpověděl dotazy členů komise., Dokončená práce s úspěšnou obhajobou

Herein, excellent non-volatile memory and aqueous battery properties of solution-processable nickel ferrite (NFO) nanomaterial were demonstrated. In the case of non-volatile memory property, the device operates on ±2 V resistive switching voltage and shows double valued charge-magnetic flux characteristics. Excellent endurance (103) and retention (104 s) non-volatile memory properties with a good memory window (103) were observed for NFO memristive device. The conduction and resistive switching mechanisms based on experimental data are provided. Furthermore, the present work investigates the electrochemical performance of the NFO thin film electrode in the different electrolytes (viz. Na2SO4, Li2SO4, and Na2SO4: Li2SO4). It was revealed that the NFO thin film shows improved electrochemical performance in Na2SO4 electrolyte with a high specific capacity of 18.56 mAh/g at 1 mA/cm2 current density. The electrochemical impedance spectroscopic results reveal that the NFO thin film electrode shows low series and charge transfer resistance values for Na2SO4 electrolyte than other electrolytes. The diffusion coefficient of different ions (DNa+, DLi+ and DNa+:Li+) were found to be 9.975 × 10−10 cm2 s−1, 3.292 × 10−11 cm2 s−1, 2 × 10−10 cm2 s−1, respectively. A high diffusion coefficient was found for Na+ ions, indicating rapid Na+ transport with NFO thin-film electrodes © 2021 The Authors, f

[EN] In this work, ecotoxicological bioassays based on Lactuca sativa seeds and bioluminescent bacterium (Vibrio fischeri) have been carried out in order to quantify the toxicity of Norfloxacin (NOR) and sodium sulfate solutions, before and after treating them using electrochemical advanced oxidation. The effect of some process variables (anode material, reactor configuration and applied current) on the toxicity evolution of the treated solution has been studied. A NOR solution shows an EC50 (5 days) of 336 mg L-1 towards Lactuca sativa. This threshold NOR concentration decreases with sodium sulfate concentration, in solutions that contain simultaneously Norfloxacin and sodium sulfate. In every case considered in this work, the electrochemical advanced oxidation process increased the toxicity (towards both Lactuca sativa and Vibrio fischeri) of the solution. This toxicity increase is mainly due to the persulfate formation during the electrochemical treatment. From a final solution toxicity point of view, the best results were obtained using a BDD anode in a divided reactor applying the lowest current intensity.

This paper gives a new sight into the effect of raised temperature on the capillary transport and interaction of sodium sulfate with calcium silicate hydrate (C-S-H). Molecular dynamics is utilized and temperature parameters are set as 300, 330, 360, and 390 K, respectively. Elevated temperature promotes the transport of water in the nanometer C-S-H channel, however, the transport rate of sodium and sulfate ions in the channel is significantly reduced as a result of the formation and adsorption of ionic clusters on C-S-H channel. This unexpected phenomenon can be explained by three factors. Under elevated temperature, first, hydration shell of ions is weakened and thus increasing the probability of ion-ion and ion-substrate contact. Second, more calcium is dissociated from C-S-H channel and resulting in the formation and precipitation of calcium sulfate, the precursor of gypsum. Third, the local structure of C-S-H channel is changed under elevated temperature, such as the dissociation of calcium from C-S-H channel, the strong stretching vibration of Si-Os bond and surficial hydroxyls, and increases in mean bond length of surficial hydroxyls. All of these increase the chemical activity of partial oxygen sites on C-S-H channel surface, contributing to more aqueous sodium ions adsorbed on C-S-H surface by electrostatic attraction from surficial oxygen. © 2019 Elsevier Ltd

This paper gives a new sight into the effect of raised temperature on the capillary transport and interaction of sodium sulfate with calcium silicate hydrate (C-S-H). Molecular dynamics is utilized and temperature parameters are set as 300, 330, 360, and 390 K, respectively. Elevated temperature promotes the transport of water in the nanometer C-S-H channel, however, the transport rate of sodium and sulfate ions in the channel is significantly reduced as a result of the formation and adsorption of ionic clusters on C-S-H channel. This unexpected phenomenon can be explained by three factors. Under elevated temperature, first, hydration shell of ions is weakened and thus increasing the probability of ion-ion and ion-substrate contact. Second, more calcium is dissociated from C-S-H channel and resulting in the formation and precipitation of calcium sulfate, the precursor of gypsum. Third, the local structure of C-S-H channel is changed under elevated temperature, such as the dissociation of calcium from C-S-H channel, the strong stretching vibration of Si-Os bond and surficial hydroxyls, and increases in mean bond length of surficial hydroxyls. All of these increase the chemical activity of partial oxygen sites on C-S-H channel surface, contributing to more aqueous sodium ions adsorbed on C-S-H surface by electrostatic attraction from surficial oxygen. © 2019 Elsevier Ltd

The Taylor dispersion technique has been used for measuring the tracer diffusion coefficients, D0 Tracer, for poly (vinyl alcohol) (PVA) in aqueous systems containing two specific electrolytes (i.e., NaCl and Na2SO4) at three different concentrations (0.020, 0.050 and 0.10 mol dm−3), and at 25 °C. The selection of these salts has been based on the Hofmeister series of cations and anions, which order the ions with respect to the behavior of some macroscopic properties (such as, surface tension) and that can be interpreted as an effect salting-out or salting-in, depending if the target ions are strongly (kosmotropic) or a weakly hydrated (chaotropic). In this work, we have been used the combination of two kosmotropic ions (Na2SO4) and another one with a kosmotropic cation and a chaotropic anion (NaCl). These data, complemented by NMR measurements, permit us to have a better understanding about the effect of these sodium salts on transport and thermodynamic behaviour of PVA. © 2020 Elsevier B.V.

Survey Notes is an informative, non-technical magazine on noteworthy and interesting geologic topics in Utah. It is the official Utah Geological Survey newsletter and is produced three times a year. Regular columns include Glad You Asked, GeoSights, Teacher's Corner, Energy News, Survey News, Core Center News, and New Publications. Published as Quarterly Review (1967-1975) and Survey Notes (1976- ). Articles in this issue include: 1) Utah's Ancient Mega-Landslides, by Robert F. Biek, Peter D. Rowley, and David B. Hacker; 2) The Uinta–Toole structural zone–what's in a name?, by Donald L. Clark; 3) Energy News: Increased battery demand spurs interest in Utah's metallic resources, by Stephanie Mills; 4) Glad You Asked: What were those strange white mounds in Great Salt Lake?, by Mark Milligan and Elliot Jagniecki; and 5) GeoSights: Wind Cave, Logan, Utah, by Stephanie Carney.

Survey Notes is an informative, non-technical magazine on noteworthy and interesting geologic topics in Utah. It is the official Utah Geological Survey newsletter and is produced three times a year. Regular columns include Glad You Asked, GeoSights, Teacher's Corner, Energy News, Survey News, Core Center News, and New Publications. Published as Quarterly Review (1967-1975) and Survey Notes (1976- ). Articles in this issue include: 1) Utah's Ancient Mega-Landslides, by Robert F. Biek, Peter D. Rowley, and David B. Hacker; 2) The Uinta–Toole structural zone–what's in a name?, by Donald L. Clark; 3) Energy News: Increased battery demand spurs interest in Utah's metallic resources, by Stephanie Mills; 4) Glad You Asked: What were those strange white mounds in Great Salt Lake?, by Mark Milligan and Elliot Jagniecki; and 5) GeoSights: Wind Cave, Logan, Utah, by Stephanie Carney.

Veziva sa velikim udelom elektrofilterskog pepela (EFP) se odlikuju dugim vremenima vezivanja i malim početnim čvrstoćama. Primenom metoda mehaničke i/ili hemijske aktivacije moguće je značajno povećati reaktivnost EFP, te poboljšati svojstva veziva. U ovom radu ispitivan je uticaj mehaničke aktivacije EFP na svojstva veziva sa 70% EFP i 30% portland cementa. Dodatno, analiziran je uticaj hemijske aktivacije veziva primenom natrijum-sulfata kao aktivatora. Primenom kombinacije postupaka mehaničke i hemijske aktivacije dobijeno je vezivo koje je imalo najveće čvrstoće u početnom periodu (do 7 dana) i najkraće vreme vezivanja. Ipak, najveću čvrstoću posle 90 dana imalo je vezivo na bazi mehanički aktiviranog EFP., High volume fly ash (FA) binders are characterized by long setting times and low early strength. By applying mechanical and/or chemical activation methods, it is possible to increase the reactivity of FA and improve the properties of the binder. In this paper, influence of mechanical activation of FA on the properties of binders prepared with 70% FA and 30% Portland cement was investigated. Additionally, effect of chemical activation of the binder by using sodium sulfate as activator was evaluated. The binder obtained by combining mechanical and chemical activation had the highest early strength (up to 7 days) and the shortest setting times. However, the highest strength of the binder after 90 days was obtained by applying only mechanical activation of FA.

This paper gives a new sight into the effect of raised temperature on the capillary transport and interaction of sodium sulfate with calcium silicate hydrate (C-S-H). Molecular dynamics is utilized and temperature parameters are set as 300, 330, 360, and 390 K, respectively. Elevated temperature promotes the transport of water in the nanometer C-S-H channel, however, the transport rate of sodium and sulfate ions in the channel is significantly reduced as a result of the formation and adsorption of ionic clusters on C-S-H channel. This unexpected phenomenon can be explained by three factors. Under elevated temperature, first, hydration shell of ions is weakened and thus increasing the probability of ion-ion and ion-substrate contact. Second, more calcium is dissociated from C-S-H channel and resulting in the formation and precipitation of calcium sulfate, the precursor of gypsum. Third, the local structure of C-S-H channel is changed under elevated temperature, such as the dissociation of calcium from C-S-H channel, the strong stretching vibration of Si-Os bond and surficial hydroxyls, and increases in mean bond length of surficial hydroxyls. All of these increase the chemical activity of partial oxygen sites on C-S-H channel surface, contributing to more aqueous sodium ions adsorbed on C-S-H surface by electrostatic attraction from surficial oxygen. © 2019 Elsevier Ltd

The Taylor dispersion technique has been used for measuring the tracer diffusion coefficients, D0 Tracer, for poly (vinyl alcohol) (PVA) in aqueous systems containing two specific electrolytes (i.e., NaCl and Na2SO4) at three different concentrations (0.020, 0.050 and 0.10 mol dm−3), and at 25 °C. The selection of these salts has been based on the Hofmeister series of cations and anions, which order the ions with respect to the behavior of some macroscopic properties (such as, surface tension) and that can be interpreted as an effect salting-out or salting-in, depending if the target ions are strongly (kosmotropic) or a weakly hydrated (chaotropic). In this work, we have been used the combination of two kosmotropic ions (Na2SO4) and another one with a kosmotropic cation and a chaotropic anion (NaCl). These data, complemented by NMR measurements, permit us to have a better understanding about the effect of these sodium salts on transport and thermodynamic behaviour of PVA. © 2020 Elsevier B.V.

Olovna alkalna šljaka je otpad koji se generiše u pirometalurškom procesu prerade olovnih sirovina, sa dodatkom topitelja natrijum(I)-karbonata (Na2CO3). U izradi doktorske disertacije ispitivan je kombinovani proces prerade olovnih sirovina iz primarnih i sekundarnih izvora, kao i mogućnost predtretmana, stabilizacije i solidifikacije industrijskog uzorka olovne alkalne šljake iz procesa reciklaže istrošenih olovnih akumulatora. U prvom delu istraživanja analiziran je proces topljenja olovnih sirovina u kratkoj rotacionoj peći, u laboratorijskim uslovima. U procesu su korišćeni olovni koncentrat (primarna sirovina) i desumporizovana olovna pasta (sekundarna sirovina), posle njihove detaljne karakterizacije, ispitivanja hemijskog i granulometrijskog sastava olovnog koncentrata, kao i hemijskog sastava desumporizovane olovne paste. Topljenje je ispitano u funkciji sastava šarže, temperature, rotacije i vremena zadržavanja materijala u peći. Efikasnost procesa topljenja je procenjena na osnovu ostvarenog stepena ekstrakcije olova iz sirovina, fizičko-hemijskih osobina (hemijski sastav, bazicitet, viskozitet) i količine generisane šljake. Najbolji rezultat efikasnosti ekstrakcije olova (98,38 %) je ostvaren u eksperimentu sa kombinovanim topljenjem olovnog koncentrata (50 %) i desumporizovane olovne paste (50 %). Generisana je šljaka u količini od 32 % u odnosu na masu polaznih sirovina, sa sadržajem 3,34 % olova, u kojoj su metodom rentgenske difrakcije (XRD - X-ray diffraction) identifikovane faze Na4Ca4(Si6O18), Fe2SiO4 i FeO(OH), manje količine faze CaFe2O4, i najmanje faze FeO. Zbog korišćenja relativno čistih sirovina u pogledu primesa, količina As u generisanoj šljaci je bila niska (0,003 %). Viskozitet generisane šljake od 60 P (kg/(m·s)), na temperaturi 1100 °C, bio je zadovoljavajući u pogledu dobrog razdvajanja šljake od metala, a izračunata vrednost baziciteta od 0,85 je ukazala na njen blago kiseli karakter. Drugi deo istraživanja obuhvatio je ispitivanje, Alkaline lead slag is a waste generated in the pyrometallurgical process of the recycling of materials based on lead with the addition of a sodium(I)-carbonate (Na2CO3) as a flux. The doctoral dissertation includes investigation of a combined process of recycling of lead materials from primary and secondary sources, as well as the possibility of pre-treatment, stabilization and solidification of the industrial sample of lead alkaline slag from the recycling process of spent lead acid batteries. In the first part of the research, the smelting process of lead materials in a short rotary furnace was examined in laboratory conditions. In the process, lead concentrate (primary raw material) and desumporized lead paste (secondary raw material) were used, after their detailed characterization including chemical and granulometric composition of the lead concentrate, as well as the chemical composition of the desumporized lead paste. The smelting process was tested in the function of the batch composition, temperature, rotation and process time in the furnace. The efficacy of the smelting process was estimated based on the achieved degree of extraction of lead from raw materials, physical and chemical properties (chemical composition, basicity, viscosity) and quantities of generated slag. The best result of the extraction efficiency of lead (98.38 %) was obtained in an experiment with combined smelting of lead concentrate (50 %) and desumporized lead paste (50 %). Slag is generated in the amount of 32 % in relation to the weight of the charge, with a content of 3.34% of lead. XRD analysis of the slag showed Na4Ca4 (Si6O18), Fe2SiO4 and FeO as the main phases (OH), less CaFe2O4, whereas FeO was the least present. Due to the use of relatively pure raw material in charge mixture, the amount of As in the generated slag was low (0.003 %). The viscosity of the generated slag was 60 P (kg/(m·s)) at 1100 ° C, which was satisfactory in terms of the good separation of the slag from th

Secondary alkaline lead slag (SALS), generated during lead–acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+ 1 mm) was returned to the recycling process. Finer fraction (− 1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg−1, 600 min−1, 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol−1. Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Secondary alkaline lead slag (SALS), generated during lead–acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+ 1 mm) was returned to the recycling process. Finer fraction (− 1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg−1, 600 min−1, 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol−1. Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Secondary alkaline lead slag (SALS), generated during lead-acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+1 mm) was returned to the recycling process. Finer fraction (-1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg(-1), 600 min(-1), 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol(-1). Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Alkaline lead slag is a waste generated in the pyrometallurgical process of the recycling of materials based on lead with the addition of a sodium(I)-carbonate (Na2CO3) as a flux. The doctoral dissertation includes investigation of a combined process of recycling of lead materials from primary and secondary sources, as well as the possibility of pre-treatment, stabilization and solidification of the industrial sample of lead alkaline slag from the recycling process of spent lead acid batteries. In the first part of the research, the smelting process of lead materials in a short rotary furnace was examined in laboratory conditions. In the process, lead concentrate (primary raw material) and desumporized lead paste (secondary raw material) were used, after their detailed characterization including chemical and granulometric composition of the lead concentrate, as well as the chemical composition of the desumporized lead paste. The smelting process was tested in the function of the batch composition, temperature, rotation and process time in the furnace. The efficacy of the smelting process was estimated based on the achieved degree of extraction of lead from raw materials, physical and chemical properties (chemical composition, basicity, viscosity) and quantities of generated slag. The best result of the extraction efficiency of lead (98.38 %) was obtained in an experiment with combined smelting of lead concentrate (50 %) and desumporized lead paste (50 %). Slag is generated in the amount of 32 % in relation to the weight of the charge, with a content of 3.34% of lead. XRD analysis of the slag showed Na4Ca4 (Si6O18), Fe2SiO4 and FeO as the main phases (OH), less CaFe2O4, whereas FeO was the least present. Due to the use of relatively pure raw material in charge mixture, the amount of As in the generated slag was low (0.003 %). The viscosity of the generated slag was 60 P (kg/(m·s)) at 1100 ° C, which was satisfactory in terms of the good separation of the slag from th, Olovna alkalna šljaka je otpad koji se generiše u pirometalurškom procesu prerade olovnih sirovina, sa dodatkom topitelja natrijum(I)-karbonata (Na2CO3). U izradi doktorske disertacije ispitivan je kombinovani proces prerade olovnih sirovina iz primarnih i sekundarnih izvora, kao i mogućnost predtretmana, stabilizacije i solidifikacije industrijskog uzorka olovne alkalne šljake iz procesa reciklaže istrošenih olovnih akumulatora. U prvom delu istraživanja analiziran je proces topljenja olovnih sirovina u kratkoj rotacionoj peći, u laboratorijskim uslovima. U procesu su korišćeni olovni koncentrat (primarna sirovina) i desumporizovana olovna pasta (sekundarna sirovina), posle njihove detaljne karakterizacije, ispitivanja hemijskog i granulometrijskog sastava olovnog koncentrata, kao i hemijskog sastava desumporizovane olovne paste. Topljenje je ispitano u funkciji sastava šarže, temperature, rotacije i vremena zadržavanja materijala u peći. Efikasnost procesa topljenja je procenjena na osnovu ostvarenog stepena ekstrakcije olova iz sirovina, fizičko-hemijskih osobina (hemijski sastav, bazicitet, viskozitet) i količine generisane šljake. Najbolji rezultat efikasnosti ekstrakcije olova (98,38 %) je ostvaren u eksperimentu sa kombinovanim topljenjem olovnog koncentrata (50 %) i desumporizovane olovne paste (50 %). Generisana je šljaka u količini od 32 % u odnosu na masu polaznih sirovina, sa sadržajem 3,34 % olova, u kojoj su metodom rentgenske difrakcije (XRD - X-ray diffraction) identifikovane faze Na4Ca4(Si6O18), Fe2SiO4 i FeO(OH), manje količine faze CaFe2O4, i najmanje faze FeO. Zbog korišćenja relativno čistih sirovina u pogledu primesa, količina As u generisanoj šljaci je bila niska (0,003 %). Viskozitet generisane šljake od 60 P (kg/(m·s)), na temperaturi 1100 °C, bio je zadovoljavajući u pogledu dobrog razdvajanja šljake od metala, a izračunata vrednost baziciteta od 0,85 je ukazala na njen blago kiseli karakter. Drugi deo istraživanja obuhvatio je ispitivanje

Secondary alkaline lead slag (SALS), generated during lead–acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+ 1 mm) was returned to the recycling process. Finer fraction (− 1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg−1, 600 min−1, 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol−1. Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Weathering of porous building materials caused by the crystallization of soluble salts is a ubiquitous problem in the built cultural heritage. Especially lime-based mortars are susceptible to salt decay, due to both their bimodal pore size distribution and low mechanical strength. The addition of crystallization modifiers to mortars during mixing may confer them an improved resistance to salt decay. In this research, lime-based mortars additivated with ferrocyanide or borax (modifiers for sodium chloride and sodium sulfate, respectively) were prepared. An accelerated salt crystallization test was carried out to assess the effect of the modifiers on the salt resistance of the mortars. The development of damage was assessed by visual and photographical observations and by quantifying the salt and material loss. At the end of the test, SEM observations were performed on the surface and cross-section of the specimens, to study the effect of the modifiers on the crystallization habit of the salts. The ferrocyanide and borax additivated mortars showed a considerably improved durability with respect to salt crystallization damage. Both modifiers altered the growth morphology of the salt crystals inside the pores of the mortars., Accepted Author Manuscript, Heritage & Technology

Secondary alkaline lead slag (SALS), generated during lead–acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+ 1 mm) was returned to the recycling process. Finer fraction (− 1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg−1, 600 min−1, 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol−1. Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Alkaline lead slag is a waste generated in the pyrometallurgical process of the recycling of materials based on lead with the addition of a sodium(I)-carbonate (Na2CO3) as a flux. The doctoral dissertation includes investigation of a combined process of recycling of lead materials from primary and secondary sources, as well as the possibility of pre-treatment, stabilization and solidification of the industrial sample of lead alkaline slag from the recycling process of spent lead acid batteries. In the first part of the research, the smelting process of lead materials in a short rotary furnace was examined in laboratory conditions. In the process, lead concentrate (primary raw material) and desumporized lead paste (secondary raw material) were used, after their detailed characterization including chemical and granulometric composition of the lead concentrate, as well as the chemical composition of the desumporized lead paste. The smelting process was tested in the function of the batch composition, temperature, rotation and process time in the furnace. The efficacy of the smelting process was estimated based on the achieved degree of extraction of lead from raw materials, physical and chemical properties (chemical composition, basicity, viscosity) and quantities of generated slag. The best result of the extraction efficiency of lead (98.38 %) was obtained in an experiment with combined smelting of lead concentrate (50 %) and desumporized lead paste (50 %). Slag is generated in the amount of 32 % in relation to the weight of the charge, with a content of 3.34% of lead. XRD analysis of the slag showed Na4Ca4 (Si6O18), Fe2SiO4 and FeO as the main phases (OH), less CaFe2O4, whereas FeO was the least present. Due to the use of relatively pure raw material in charge mixture, the amount of As in the generated slag was low (0.003 %). The viscosity of the generated slag was 60 P (kg/(m·s)) at 1100 ° C, which was satisfactory in terms of the good separation of the slag from th, Olovna alkalna šljaka je otpad koji se generiše u pirometalurškom procesu prerade olovnih sirovina, sa dodatkom topitelja natrijum(I)-karbonata (Na2CO3). U izradi doktorske disertacije ispitivan je kombinovani proces prerade olovnih sirovina iz primarnih i sekundarnih izvora, kao i mogućnost predtretmana, stabilizacije i solidifikacije industrijskog uzorka olovne alkalne šljake iz procesa reciklaže istrošenih olovnih akumulatora. U prvom delu istraživanja analiziran je proces topljenja olovnih sirovina u kratkoj rotacionoj peći, u laboratorijskim uslovima. U procesu su korišćeni olovni koncentrat (primarna sirovina) i desumporizovana olovna pasta (sekundarna sirovina), posle njihove detaljne karakterizacije, ispitivanja hemijskog i granulometrijskog sastava olovnog koncentrata, kao i hemijskog sastava desumporizovane olovne paste. Topljenje je ispitano u funkciji sastava šarže, temperature, rotacije i vremena zadržavanja materijala u peći. Efikasnost procesa topljenja je procenjena na osnovu ostvarenog stepena ekstrakcije olova iz sirovina, fizičko-hemijskih osobina (hemijski sastav, bazicitet, viskozitet) i količine generisane šljake. Najbolji rezultat efikasnosti ekstrakcije olova (98,38 %) je ostvaren u eksperimentu sa kombinovanim topljenjem olovnog koncentrata (50 %) i desumporizovane olovne paste (50 %). Generisana je šljaka u količini od 32 % u odnosu na masu polaznih sirovina, sa sadržajem 3,34 % olova, u kojoj su metodom rentgenske difrakcije (XRD - X-ray diffraction) identifikovane faze Na4Ca4(Si6O18), Fe2SiO4 i FeO(OH), manje količine faze CaFe2O4, i najmanje faze FeO. Zbog korišćenja relativno čistih sirovina u pogledu primesa, količina As u generisanoj šljaci je bila niska (0,003 %). Viskozitet generisane šljake od 60 P (kg/(m·s)), na temperaturi 1100 °C, bio je zadovoljavajući u pogledu dobrog razdvajanja šljake od metala, a izračunata vrednost baziciteta od 0,85 je ukazala na njen blago kiseli karakter. Drugi deo istraživanja obuhvatio je ispitivanje

Secondary alkaline lead slag (SALS), generated during lead-acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+1 mm) was returned to the recycling process. Finer fraction (-1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg(-1), 600 min(-1), 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol(-1). Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Secondary alkaline lead slag (SALS), generated during lead–acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+ 1 mm) was returned to the recycling process. Finer fraction (− 1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg−1, 600 min−1, 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol−1. Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Weathering of porous building materials caused by the crystallization of soluble salts is a ubiquitous problem in the built cultural heritage. Especially lime-based mortars are susceptible to salt decay, due to both their bimodal pore size distribution and low mechanical strength. The addition of crystallization modifiers to mortars during mixing may confer them an improved resistance to salt decay. In this research, lime-based mortars additivated with ferrocyanide or borax (modifiers for sodium chloride and sodium sulfate, respectively) were prepared. An accelerated salt crystallization test was carried out to assess the effect of the modifiers on the salt resistance of the mortars. The development of damage was assessed by visual and photographical observations and by quantifying the salt and material loss. At the end of the test, SEM observations were performed on the surface and cross-section of the specimens, to study the effect of the modifiers on the crystallization habit of the salts. The ferrocyanide and borax additivated mortars showed a considerably improved durability with respect to salt crystallization damage. Both modifiers altered the growth morphology of the salt crystals inside the pores of the mortars., Accepted Author Manuscript, Heritage & Technology

Secondary alkaline lead slag (SALS), generated during lead-acid batteries recycling, is a hazardous waste due to its high reactivity, solubility, and migration of toxic elements. After pulverization caused by storage under atmospheric condition for 30 days, the SALS was sieved and coarse fraction (+1 mm) was returned to the recycling process. Finer fraction (-1 mm) was treated by water leaching to remove soluble compounds. SALS compositions prior and after the pre-treatment and effects of liquid-to-solid ratio, stirring rate, and temperature on Na, S, Fe, As, and Pb leaching from SALS were analyzed. The results show that maximal leaching degrees were 95.78%, 75.32%, and 79.89% for Na, S, and As, respectively (20 l kg(-1), 600 min(-1), 333 K, 120 min). Leachability of Na and S from SALS was controlled by dissolution of Na2SO4 that could be recovered from leaching solution. Isothermal As leaching is described by diffusion mechanism with activation energy of 15.5 kJ mol(-1). Insoluble Pb and Fe sulfates, sulfides, and oxides remained in the SALS. Pre-treated SALS, with reduced mass up to 32%, was solidified in cement matrix. The results of toxicity characteristic leaching procedure and unconfined compressive strength confirmed effectiveness of As removal from SALS by water leaching and Pb immobilization in cement matrix containing 20% of SALS.

Elektrodialýza s bipolárními membránami umožňuje vyrábět z odpadních roztoků solí odpovídající zředěnou kyselinu a hydroxid. Tyto produkty je následně možné začlenit zpět do zdrojové technologie a alespoň částečně snížit provozní náklady a ekologickou zátěž řady realizovaných procesů. Předkládaná disertační práce se zabývá experimentálním studiem tohoto procesu zaměřeným na využití heterogenních bipolárních a monopolárních membrán při zpracování solí silných elektrolytů. V rámci experimentální části práce bylo proměřeno a porovnáno pět různých konfigurací svazku elektrodialyzační jednotky s bipolární membránou. Na základě provedených měření byly poté popsány vnitřní migrační děje. Pro tříkomorovou konfiguraci svazku byl detailně studován vliv koncentrace produktů a proudové hustoty na množství a čistotu produkované kyseliny a hydroxidu. S využitím experimentálních dat byl navržen statistický regresní model procesu, který umožňuje predikci předpokládaného množství a čistoty vyráběných produktů pro kombinace jak koncentrací kyseliny a hydroxidu, tak i proudové hustoty. Dále byly proměřeny voltampérové charakteristiky bipolárních membrán a hledány jejich vazby na procesní charakteristiky elektrodialýzy s bipolární membránou. Bylo prokázáno, že poloha prvního inflexního bodu na U-I křivce v symetrickém i asymetrickém uspořádání je mírou průniku koiontů vrstvami BPM a lze ji využít pro prvotní kvalitativní odhad znečištění produktů EDBPM při provozu reálného membránového svazku., Electrodialysis with the bipolar membrane is a process that allows recovery acid and base from corresponding salt. Produced acid and base can be used back in the waste salt source technology. Due to this fact, it is possible to decline the OPEX and to decrease the environmental impact of many chemical technologies. The present thesis focuses on the recovery of acid and base from the solution of strong electrolyte salt using heterogeneous bipolar membranes. During the experimental part, five different stack configurations were tested. Based on the data obtained, the basic migration effects in the membrane stack were described. The effects of current density and product concentration on both the purity and quantity of acid and base produced were studied in the three compartment configuration. Obtained experimental data were analyzed and used to generate a statistical prediction model of the process. Furthermore, the volt-ampere characteristics of the bipolar membrane were determined and correlated with the co-ion migration through the bipolar membrane and the coordinate value of the first plateau of U-I curve. The results show that the value of the first plateau can preliminary predict the quality of the product of electrodialysis with the bipolar membrane., Fakulta chemicko-technologická, Dokončená práce s úspěšnou obhajobou

The paper presents a new approach to the processing of gas cleaning solutions of aluminum production. The technology of electrochemical purification of solutions was developed and proposed for consideration in order to reduce the environmental impact, regenerate cryolite, and obtain commercial sodium sulfate., В работе изложен новый подход к переработке растворов газоочистки алюминиевого производства. Разработана и предложена к рассмотрению технология электрохимической очистки растворов с целью снижения воздействия на окружающую среду, регенерации криолита, получения товарного сульфата натрия.

After the kraft or soda pulping of lignocellulosic materials to produce pulp suitable for papermaking, the spent pulping liquor typically has been recovered by multi-effect evaporation, followed by incineration in a recovery boiler. This review article considers one unit operation, eutectic freeze crystallization (EFC), that may have potential to save some of the energy that is presently consumed in the evaporation step during recovery of inorganic chemicals from spent pulping liquor. Based on a review of the literature it appears that EFC can be employed to obtain relatively pure sodium sulfate and sodium carbonate, along with relatively pure water (in the form of ice) from the spent liquor, under the assumption that lignin previously has been removed by acidification and precipitation. Issues of inorganic scale formation, during the operation of an EFC process applied to lignin-free black liquor, will require research attention. The chemical reactions to regenerate the active pulping chemicals sodium hydroxide and sodium sulfide from sodium carbonate, sodium sulfate, and other compounds isolated by EFC can be carried out either in a separate operation or by returning the materials to the feed of an existing recovery boiler., QC 20190116