Magister Scientiae - MSc / The current study investigated application of natural adsorbents in brine treatment. Brines are hypersaline waters generated in power stations and mining industries rich in Mg2+, K+, Ca2+, Na+, SO4 2- , Cl- and traces of heavy metals, thus there is a need for these brines to be treated to recover potable water and remove problematic elements. Natural adsorbents have been successfully used in waste water treatment because of their high surface area and high adsorptive properties when they are conditioned with acid or base. The investigation of pH showed that natural adsorbents did not perform well at low pH of 4 and 6. The adsorbents were able to work efficiently at the natural pH of 8.52 of the brine solution. These results show that natural adsorbents hold great potential to remove cationic major components and selected heavy metal species from industrial brine waste water. Heterogeneity of natural adsorbents samples, even when they have the same origin, could be a problem when wastewater treatment systems utilizing natural clinoptilolite and bentonite are planned to be developed. Therefore, it is very important to characterize the reserves fully in order to make them attractive in developing treatment technologies. / South Africa

>Magister Scientiae - MSc / Studies involving the use of natural clays such as bentonite, montmorillonite and natural zeolite clinoptilolite in water treatment have been reported. Researchers suggested cost effective processes, such as ion-exchange and adsorption for the removal of heavy metals from waste waters by using naturally occurring and synthetic materials. The current study investigated application of natural adsorbents in brine treatment. Brines are hypersaline waters generated in power stations and mining industries rich in Mg2+, K+, Ca2+,Na+, so,': cr and traces of heavy metals, thus there is a need for these brines to be treated to recover potable water and remove problematic elements. Natural adsorbents have been successfully used in waste water treatment because of their high surface area and high adsorptive properties when they are conditioned with acid or base. The natural adsorbents used in this study were obtained from Ecca Holdings company (Cape bentonite mine) Western Cape in South Africa, comprising bentonite clay and natural zeolite (clinoptilolite) and another clinoptilolite sample was obtained from Turkey. These adsorbents were investigated in their natural and pretreated form for removal of toxic elements in brine water. The pretreatment was aimed at removing Na+, K+, Ca2+, Mg2+ from the clinoptilolite as well as the bentonite and replacing these cations with the H+ cation to activate the materials. The cation exchange capacity (CEC) of natural zeolite from South Africa was found to be 2.14 meq/ g, Turkish Clinoptilolite was 2.98 meq/ g while South African bentonite was 1.73 meq/g. at 25°C using ammonium acetate (pH 8.2) method. Characterization of these natural adsorbents was done prior to pretreatment and after the treatment. ICP-AES analysis was used for determination of toxic elements in brines before and after sorption. The morphology of clays was characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (N2-BET) and Scanning electron microscopy (SEM) for confirmatory purposes and X-ray Fluorescent spectroscopy (XRF) was used for the composition analysis of the natural adsorbent. The results from batch experiments prior to pretreatment of the natural adsorbents showed that these natural adsorbents contained Mg2+, K+, Ca2+, Na+ in their structures as charge balancing cations, thus needed pretreatment to remove the cations. The natural adsorbents were pre-treated with 0.02M HCI. After the pretreatment of natural adsorbents it was possible to enhance the percentage removal of the major cations from brine, and the Na+ and Mg2+ removal achieved (86 % and 85% respectively) from brine was more than C02+ (70% ) the SC was the adsorbent one that gave highest removal of cations in the brines. Trace elements removal was high with Cu2+and Zn2+ being the highest of toxic elements in brine. The optimum contact for the toxic element removal was found to be 30 min for the Turkish clinoptilolite and 1 hr for the South African clinoptilolite and South African bentonite clay. Leaching of Ae+ and Si4+ during adsorption was also investigated and it was found that less than 1 ppm of A13+ and Si4+ were leached into the solution during adsorption experiments indicating that these materials were stable. The investigation of pH showed that natural adsorbents did not perform well at low pH of 4 and 6. The adsorbents were able to work efficiently at the natural pH of 8.52 of the brine solution. These results show that natural adsorbents hold great potential to remove cationic major components and selected heavy metal species from industrial brine wastewater. Heterogeneity of natural adsorbents samples, even when they have the same origin, could be a problem when wastewater treatment systems utilizing natural clinoptilolite and bentonite are planned to be developed. Therefore, it is very important to characterize the reserves fully in order to make them attractive in developing treatment technologies.

<p>Biogas är benämningen för metangas (CH₄) som är producerad via anaerob (syrefri) rötning av biologiskt material. I Linköping finns en av Sveriges största biogasanläggningar. Anläggningen drivs av Svensk Biogas AB som ägs av Tekniska Verken i Linköping AB (publ.). I anläggningen rötas stora mängder proteinrikt substrat vilket leder till höga halter av ammoniak (NH₃) och ammonium (NH₄⁺) i rötkammaren. Ammoniak (NH₃) är toxiskt för de metanbildare som i en välmående process står för den största delen av metangasproduktionen. Höga halter av ammoniak (NH₃) och ammonium (NH₄⁺) kan inhibera dessa metanbildare vilket leder till minskad gasproduktion.</p><p>Detta examensarbete syftar främst till att genom ett kontinuerligt rötkammarexperiment utreda om zeoliter är ett lämpligt hjälpmedel för att reducera ammonium (NH₄⁺) i en anaerob process. Vid sänkta halter ammonium (NH₄⁺) är hypotesen att de mikroorganismer som är aktiva i den mest effektiva metanbildningsvägen återetableras. Arbetet syftar även till att experimentellt utreda vilka effekter zeoliter i sin helhet har på den anaeroba processen. Zeoliters effekt vid låga zeolitkoncentrationer utreds i en serie utrötningsexperiment i batch. Dessutom har en materialstudie kring zeoliternas kapacitet i olika miljöer genomförts.</p><p>Materialstudien visade att den valda zeoliten som studerades, clinoptilolite, hade en maximal katjonbytarkapacitet på ≈ 19 mg NH₄⁺/g zeolit. Vidare konstaterades att zeoliter med mindre diameter än 1 mm har avsevärt bättre kapacitet än zeoliter med större diameter. I det kontinuerliga rötkammarexperimentet konstaterades att clinoptilolite kan användas i en rötkammare för att reducera ammoniumhalten (NH₄⁺). Detta utan att några allvarliga processtörningar uppstår. Cirka 175 g zeolit/l krävdes för att reducera ammoniumhalten (NH₄⁺) från 5300 mg NH₄⁺/l till 3200 mg NH₄⁺/l. Det är inte realistisktatt använda så stora mängder zeoliter i en fullskalig anläggning. Mikrobiologiskt sett observerades ingen förändring av de metanbildarna som dominerar den effektivaste metanbildningsvägen.</p><p>Resultaten från utrötningsförsöket i batch visade att zeolittillsatser av 5 g/l respektive 10 g/l hade en klart positiv effekt på metanbildningen jämfört utan zeolittillsats. I de batcher med 1-10 g zeolit/l startade metangasproduktionen ≈ 14 dagar tidigare än batcherna med 0 g zeolit/l. 16 dagar efter att experimentet startade hade batcherna med 5-10 g zeolit/l producerat ≈ 500 ml metangas (CH₄) jämfört med serien utan zeoliter som vid samma tidpunkt producerat ≈ 75 ml metangas (CH₄). Utrötningsgraden ökade i samtliga serier med zeolittillsats jämfört med serien utan zeoliter. Tillsatsen av 5 g zeolit/l ökade den specifika metangasproduktionen med ≈ 19 % jämfört med utan zeolittillsatser. Slutsatsen är att clinoptilolite i små koncentrationer, mellan 5-10 g/l, påverkar så väl kinetiken som utrötningsgraden för den anaeroba processen på ett positivt sett. Den optimala koncentrationen av clinoptilolite i en mesofil anaerob process bör ligga mellan 5-10 g zeolit/l.</p> / <p>Methane (CH₄) is formed by anaerobic (oxygen-free) digestion of biological materials. One of Sweden's largest biogas plants is placed in Linköping. The plant is operated by Svensk Biogas AB, which is owned by Tekniska Verken i Linköping AB (publ.). In their biogas plant a large amount of protein rich material is handled. High amounts of protein leads to high levels of ammonia (NH₃) and ammonium (NH₄⁺) in the digestion chamber. High levels of ammonia (NH₃) are toxic to the most dominant methane forming microorganism. High concentrations of ammonia (NH₃) and ammonium (NH₄⁺) can inhibit these methane forming microorganisms which may lead to a reduction in gas production.</p><p>This aim with this master thesis was to reduce high ammonium levels by adding zeolites to a lab scale continuous digestion chamber. The hypothesis is that at reduced levels of ammonium (NH₄⁺) the most effective methane forming microorganism will reestablish. This thesis also aims to experimentally investigate all types of effects that zeolites may have in an anaerobic digestion process. Which effect zeolites at low concentration have in a digestion chamber will be investigated by using lab scale batch digestion chambers. In addition, a material study on the capacity of the zeolites in different environments will be investigated.</p><p>The material study showed that the selected zeolite, clinoptilolite, had a cat ion exchange capacity around 19 mg NH₄⁺/g zeolite. It was also found that the zeolites with a diameter less than 1 mm had significantly better capacity than zeolites with larger diameter. In the continuous digestion experiment it was found that clinoptilolite can be used in a digestion chamber to reduce high levels of ammonium (NH₄⁺). This without any serious disorder on the process. Around 175 g zeolite/l was needed to reduce ammonium levels (NH₄⁺) from 5300 mg NH₄⁺/l to 3200 mg NH₄⁺/l. However, it is not realistic to use such large amounts of zeolites in a full-scale digestion chamber. No changes in the culture of methane forming microorganisms were found.</p><p>The results of the batch experiment showed that concentrations of 5 g zeolite/l and 10 g zeolite/l had a positive effect on the methanogenesis compared to batches without additives. In the batches with 1-10 g zeolite/l the forming of methane began about 14 days earlier than in the batches without any zeolites. After 16 days, batches with 5-10 g zeolite/l had produced about 500 ml of methane (CH₄), compared with series without additives, which at the same time had produced about 75 ml of methane (CH₄). The methane yield increased in all series which included zeolites compared to the batches without zeolites. Addition of 5 g zeolite/l increased the specific methane production by approximately 19 % compared to no additives. The conclusion is that clinoptilolite in small concentrations; 5-10 g/l have a positive effect on as well the kinetics as on the methane yield for the anaerobic process. The best concentration of zeolites in a mesophile anaerobic digestion chamber appears to be between 5-10 g zeolite/l.</p>

Biogas är benämningen för metangas (CH4) som är producerad via anaerob (syrefri) rötning av biologiskt material. I Linköping finns en av Sveriges största biogasanläggningar. Anläggningen drivs av Svensk Biogas AB som ägs av Tekniska Verken i Linköping AB (publ.). I anläggningen rötas stora mängder proteinrikt substrat vilket leder till höga halter av ammoniak (NH3) och ammonium (NH4+) i rötkammaren. Ammoniak (NH3) är toxiskt för de metanbildare som i en välmående process står för den största delen av metangasproduktionen. Höga halter av ammoniak (NH3) och ammonium (NH4+) kan inhibera dessa metanbildare vilket leder till minskad gasproduktion. Detta examensarbete syftar främst till att genom ett kontinuerligt rötkammarexperiment utreda om zeoliter är ett lämpligt hjälpmedel för att reducera ammonium (NH4+) i en anaerob process. Vid sänkta halter ammonium (NH4+) är hypotesen att de mikroorganismer som är aktiva i den mest effektiva metanbildningsvägen återetableras. Arbetet syftar även till att experimentellt utreda vilka effekter zeoliter i sin helhet har på den anaeroba processen. Zeoliters effekt vid låga zeolitkoncentrationer utreds i en serie utrötningsexperiment i batch. Dessutom har en materialstudie kring zeoliternas kapacitet i olika miljöer genomförts. Materialstudien visade att den valda zeoliten som studerades, clinoptilolite, hade en maximal katjonbytarkapacitet på ≈ 19 mg NH4+/g zeolit. Vidare konstaterades att zeoliter med mindre diameter än 1 mm har avsevärt bättre kapacitet än zeoliter med större diameter. I det kontinuerliga rötkammarexperimentet konstaterades att clinoptilolite kan användas i en rötkammare för att reducera ammoniumhalten (NH4+). Detta utan att några allvarliga processtörningar uppstår. Cirka 175 g zeolit/l krävdes för att reducera ammoniumhalten (NH4+) från 5300 mg NH4+/l till 3200 mg NH4+/l. Det är inte realistisktatt använda så stora mängder zeoliter i en fullskalig anläggning. Mikrobiologiskt sett observerades ingen förändring av de metanbildarna som dominerar den effektivaste metanbildningsvägen. Resultaten från utrötningsförsöket i batch visade att zeolittillsatser av 5 g/l respektive 10 g/l hade en klart positiv effekt på metanbildningen jämfört utan zeolittillsats. I de batcher med 1-10 g zeolit/l startade metangasproduktionen ≈ 14 dagar tidigare än batcherna med 0 g zeolit/l. 16 dagar efter att experimentet startade hade batcherna med 5-10 g zeolit/l producerat ≈ 500 ml metangas (CH4) jämfört med serien utan zeoliter som vid samma tidpunkt producerat ≈ 75 ml metangas (CH4). Utrötningsgraden ökade i samtliga serier med zeolittillsats jämfört med serien utan zeoliter. Tillsatsen av 5 g zeolit/l ökade den specifika metangasproduktionen med ≈ 19 % jämfört med utan zeolittillsatser. Slutsatsen är att clinoptilolite i små koncentrationer, mellan 5-10 g/l, påverkar så väl kinetiken som utrötningsgraden för den anaeroba processen på ett positivt sett. Den optimala koncentrationen av clinoptilolite i en mesofil anaerob process bör ligga mellan 5-10 g zeolit/l. / Methane (CH4) is formed by anaerobic (oxygen-free) digestion of biological materials. One of Sweden's largest biogas plants is placed in Linköping. The plant is operated by Svensk Biogas AB, which is owned by Tekniska Verken i Linköping AB (publ.). In their biogas plant a large amount of protein rich material is handled. High amounts of protein leads to high levels of ammonia (NH3) and ammonium (NH4+) in the digestion chamber. High levels of ammonia (NH3) are toxic to the most dominant methane forming microorganism. High concentrations of ammonia (NH3) and ammonium (NH4+) can inhibit these methane forming microorganisms which may lead to a reduction in gas production. This aim with this master thesis was to reduce high ammonium levels by adding zeolites to a lab scale continuous digestion chamber. The hypothesis is that at reduced levels of ammonium (NH4+) the most effective methane forming microorganism will reestablish. This thesis also aims to experimentally investigate all types of effects that zeolites may have in an anaerobic digestion process. Which effect zeolites at low concentration have in a digestion chamber will be investigated by using lab scale batch digestion chambers. In addition, a material study on the capacity of the zeolites in different environments will be investigated. The material study showed that the selected zeolite, clinoptilolite, had a cat ion exchange capacity around 19 mg NH4+/g zeolite. It was also found that the zeolites with a diameter less than 1 mm had significantly better capacity than zeolites with larger diameter. In the continuous digestion experiment it was found that clinoptilolite can be used in a digestion chamber to reduce high levels of ammonium (NH4+). This without any serious disorder on the process. Around 175 g zeolite/l was needed to reduce ammonium levels (NH4+) from 5300 mg NH4+/l to 3200 mg NH4+/l. However, it is not realistic to use such large amounts of zeolites in a full-scale digestion chamber. No changes in the culture of methane forming microorganisms were found. The results of the batch experiment showed that concentrations of 5 g zeolite/l and 10 g zeolite/l had a positive effect on the methanogenesis compared to batches without additives. In the batches with 1-10 g zeolite/l the forming of methane began about 14 days earlier than in the batches without any zeolites. After 16 days, batches with 5-10 g zeolite/l had produced about 500 ml of methane (CH4), compared with series without additives, which at the same time had produced about 75 ml of methane (CH4). The methane yield increased in all series which included zeolites compared to the batches without zeolites. Addition of 5 g zeolite/l increased the specific methane production by approximately 19 % compared to no additives. The conclusion is that clinoptilolite in small concentrations; 5-10 g/l have a positive effect on as well the kinetics as on the methane yield for the anaerobic process. The best concentration of zeolites in a mesophile anaerobic digestion chamber appears to be between 5-10 g zeolite/l.

Clinoptilolite samples obtained from two deposits in Turkey were tested for their potential in removing cadmium from aqueous solutions. Preliminary experiments in batch mode revealed inferior cadmium uptake at low pH. Particle size was found to have no effect on cadmium removal efficiency suggesting the use of exchangeable cations found in the internal/available sites. Increasing temperature yielded positive, whereas prewashing had no effect on cadmium removal using both clinoptilolite samples. The Langmuir model fitted the equilibrium data for both samples better than the Freundlich model. The capacity reached after conditioning represents about 4 and 3 fold increase for G&ouml / rdes and Bigadi&ccedil / samples, respectively. The relatively poor performance of Bigadi&ccedil / clinoptilolite was due to low clinoptilolite/high impurity contents. Further studies were carried out only with G&ouml / rdes clinoptilolite. The performance of the G&ouml / rdes samples conditioned with various chemicals were NaCl&gt / KCl&gt / As-received&gt / CaCl2&gt / HCl. 20BV of NaCl solution was found to be sufficient with no pH adjustment or water quality requirement during column conditioning. In column experiments, among the tested flowrates 5, 10 and 15 BV/hr, highest flowrate indicated inferior utilization of the removal capacity. No significant difference by decreasing particle size indicated pore diffusion resistance not to be a limiting factor. In five conditioning and regeneration cycles, clinoptilolite exhibited 36% increase in operating capacity. Cadmium removed by clinoptilolite in progressing cycles was concentrated by about 7 times. Overall, this study shows that Manisa-G&ouml / rdes clinoptilolite is advantageous for the removal of cadmium ions from aqueous solutions and hold great potential to be used in practical applications.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / The South African economy relies heavily on mining. The residues of these activities contain harmful metals that are discharged into the environment as industrial wastes, contaminating the air, soil, surface and ground water. A lot of people who live in remote areas in South Africa rely on ground water to drink and cook. They also cultivate their own vegetables increasing the risk of metal toxicity. Some of these metals are very toxic and can cause adverse effects upon being ingested. Toxic metals are well known to be harmful to humans. Some of these metals are carcinogenic or nephrotoxic when a large amount is accumulated in the human body causing cancer and destroying tissues such as the kidneys. The detrimental health effects of these metals may take months to years before manifestation causing people to sideline them as hazards. One of the major toxic elements that are discharged into the environment is lead. A natural zeolite called clinoptilolite has been widely used as an adsorbent for toxic metals from contaminated water and from the human body because of its properties such as ion-exchange capacity and pore size. However, this natural zeolite clinoptilolite is not pure and may contain traces of toxic elements of which the nature and concentration depend on the origin of clinoptilolite. The structural stability of clinoptilolite in acidic or alkaline media is not well documented. The lack of documented information about the leachates of clinoptilolite and their long term effects on the human body may cause harm to people who ingest this zeolite. This has led to investigation of synthetic zeolites such as faujasite which has already been used for decontamination of sludge, industrial effluents and other waste water by removing toxic metals such as Pb, Cd, Cu, Zn and As. This study focuses on comparing the toxic metal removal efficiency of natural zeolite clinoptilolite (C), clinoptilolite-based faujasite (FAU3) and clinoptilolite-based ultrastable Y zeolite (USY3), from contaminated water and simulated gastric juice containing lead and cadmium and to evaluate the extent of leaching of other elements from these zeolites. Clinoptilolite was used as a starting material for the synthesis of faujasite (FAU3) which was further treated with oxalic acid to get an ultrastable Y zeolite (USY3). Various techniques were used to characterise the as-received clinoptilolite, faujasite zeolite and USY, namely XRD, SEMEDS, FTIR, solid state NMR (27Al and 29Si) and BET-N2. These characterisation techniques confirmed that clinoptilolite was successfully transformed into faujasite and that the treatment of faujasite with oxalic acid yielded USY3. A comparative adsorption study was conducted using three zeolite samples: namely Clinoptilolite (C), clinoptilolite-based faujasite (FAU3) and ultrastable Y zeolite (USY3). ICP was used to characterise the liquid samples and it was concluded that zeolites were efficient in removing lead and cadmium from contaminated water samples as well as from simulated gastric juice. Some leachates from these zeolites were also observed. A contaminated water sample containing lead and cadmium was used as a medium where the removal capacity and percentage removal with C, FAU3 and USY3 was investigated. It was observed that the optimum dosage varied from one zeolite to the other and also from one metal to the other. The optimum dosage for C, FAU3 and USY3 for the uptake of lead was found to be 0.2 g, 0.2 g and 0.05 g respectively while for cadmium it was 0.4 g, 005 g and 0.1 g, respectively. It was also shown in this study that the removal capacity for lead and cadmium could be hindered by the Na content in FAU3 and USY3 due to the fact that these metals could be in an uptake competition with Na and other cations that leached out or exchanged from the zeolites. It was observed that the optimum metal concentration for lead uptake as well as for cadmium with few metals being released back into the solution was 0.1 mg/L. The optimum contact time for both lead and cadmium was 15 minutes. The factor that varied depending on the type of metal was pH, which was at its optimum at 3.5 for lead and at 5.5 for cadmium. A simulated gastric juice was contaminated with toxic metals (lead and cadmium) and the zeolites were used to treat the contaminated samples. It was shown that the removal capacity of these zeolites increased with the increase in initial concentration of the metal. Time proved to be one factor that affected the behaviour of zeolites. The modification of the synthesised faujasite into an ultrastable Y zeolite proved to have played a role in increasing the removal of toxic metals and in preventing the high leaching of some elements out of the zeolite. / 2018-12-14

Aflatoxins are metabolites from fungi, that may be injurious to animal health, resulting in reduced production and affecting poultry industry by decrease the growth rate and worsening feed conversion. A study was carried out to evaluate the electrophoresis profile of serum protein in broilers fed with diets containing aflatoxins and natural clinoptilolite clay. A total of 528 male broilers Ross were used, distributed in 6 treatments with 4 replications each: T1 control (without aflatoxins or clinoptilolite), T2 5ppm of aflatoxins, T3 0.25% of clinoptilolite, T4 5ppm of aflatoxins and 0.25% of clinoptilolite, T5 0.5% of clinoptilolite and T6 5ppm of aflatoxins and 0.5% of clinoptilolite. The broilers were placed in 24 boxes and submitted to treatments from 1 to 42 days, when they were slaughtered. Were analyzed the total proteins, albumin fractions, alpha 1, alpha 2, beta and gamma. The aflatoxins decreased (P<0.05) total protein, albumin, and globulins (alpha and beta fractions). However, no effect (P<0.05) of aflatoxins was observed about gamma fraction. The clinoptilolite no modify (P<0.05) the serum proteins. Related to control, broilers fed with diets containing aflatoxins and clinoptilolite presented low (P<0.05) levels of total protein, albumin, and globulins (alpha and beta fractions). In conclusion, aflatoxins change the electrophoresis profile and clinoptilolite is not able to protect against this change / Aflatoxinas são metabólitos de fungos, que podem causar danos à saúde do animal, resultando em redução da produção e afetando à indústria avícola, pela diminuição da taxa de crescimento e péssima conversão alimentar. O objetivo do presente trabalho foi avaliar o perfil eletroforético das proteínas séricas de frangos de corte alimentados com dietas contendo aflatoxinas e/ou argila clinoptilolita natural. Foram utilizados 528 frangos de corte, machos, da linhagem Ross, distribuídos em 6 tratamentos com 4 repetições cada: T1 testemunha (ração sem aflatoxinas ou clinoptilolita), T2 ração com 5ppm de aflatoxinas, T3 ração com 0,25% de clinoptilolita, T4 ração com 5ppm de aflatoxinas e 0,25% de clinoptilolita, T5 ração com 0,5% de clinoptilolita e T6 ração com 5ppm de aflatoxinas e 0,5% de clinoptilolita. Os animais ficaram alojados em 24 boxes, e submetidos aos tratamentos do 1º ao 42º dia, quando foram sacrificados. Foram analisadas as proteínas totais, as frações albumina, alfa 1, alfa 2, beta e gama. Com exceção das médias da fração gama, o teste de Tukey revelou diferenças significativas (P<0,05) nas médias de todas as proteínas totais e frações protéicas nos tratamentos onde as aflatoxinas estavam presentes. A ação das aflatoxinas nas proteínas totais ocorre na síntese de albumina e globulinas (frações alfa e beta). As gamaglobulinas não são afetadas pelas aflatoxinas. Em relação ao controle, as aves alimentadas com dietas com aflatoxinas e clinoptilolita apresentaram baixos (P<0,05) níveis de proteína total, albumina e globulinas (alfa e beta). Conclui-se que as aflatoxinas alteram o perfil eletroforético e a clinoptilolita adicionada na ração, não é capaz de evitar essa alteração

No description available.

This PhD project studied the caesium and strontium removal capacities of six nanoporous materials. Indeed, it was linked in with the SIXEP plant present at Sellafield site, UK, which is currently using natural clinoptilolite, originally mined from the Mojave Desert, to remove radioactive caesium and strontium ions from wastewater effluents. At the moment the feeds entering the SIXEP plant correspond to the best working conditions for clinoptilolite. As the feeds are moving toward more acidic pH and complex solutions and as clinoptilolite works at neutral pH, new nanoporous materials are required. This project had been divided into sub-projects, which all had the same purpose of finding the best material for caesium and strontium removal under complex solutions. The first part of the PhD focused on the synthesis of CST, SNT, ETS-4 and ETS-10 materials following literature reviews. The two last materials studied were provided by Fortum Power and Heat Oy for CsTreat material and by Sellafield Ltd for clinoptilolite material. The second part of the PhD consisted in studying the exchange capacities for caesium and strontium ions for each material studied under batch conditions using several water compositions relevant to Sellafield Ltd. Each water composition had different competing ions or pH and were used to classify the materials between them. From that it was found that Clinoptilolite stays the best materials for caesium and strontium removal. The third part of the project was the gamma irradiation of the materials. This irradiation had an aim to check the stability of the structure of the studied materials under gamma irradiation. The materials were exposed to four different gamma doses which were 0.5; 1; 3 and 6 MGy, the last one corresponding to the maximum dose were structural changes could happen. This revealed that all the materials, except ETS-4 material, were stable under gamma irradiation and that no structural changes were observable. The fourth part of the project was an extension of the third part in which the materials were Cs exchanged before being gamma irradiated to a dose of 6 MGy. This showed that the caesium exchange process is not affected by radiation. Finally, the unexchanged materials were alpha irradiated using a 15 MeV He2+ beam at the Dalton Cumbria Facility. Two irradiations were performed on CsTreat, CST, ETS-4, ETS-10 and clinoptilolite material. It was found that all the materials were damaged by alpha irradiation and displayed amorphous framework To resume, it appeared that clinoptilolite still stays one of the best materials for the removal of caesium and strontium ions in a wide range of wastewater composition. Additionally, it was discovered that ETS-10 material could be a good alternative to clinoptilolite material as its structure is stable under gamma irradiation and it displayed good exchange capacities when competing ions were present in the feeds. CST could also be a substitute as it shows good ion exchange properties under a broad range of pH. SNT material was great for strontium removal while CsTreat was working well for caesium removal. Even though ETS- 4 revealed good ion exchange capacities they were lower than clinoptilolite, ETS- 10 or CST materials.

Made available in DSpace on 2016-06-02T19:55:36Z (GMT). No. of bitstreams: 1 TeseJCTF.pdf: 3670025 bytes, checksum: 32289c02fa0f16236c28137ea6d2a96c (MD5) Previous issue date: 2004-12-13 / Universidade Federal de Sao Carlos / Natural zeolites are the most important inorganic cationic exchangers exhibiting high ion exchange capacity, selectivity and environment compatibility. Heavy metals are well known for toxicity and their disposal is a significant industrial waste problem. The goal of this work was directed to evaluate the selectivity of a purified homo-ionic clinoptilolite mineral for aqueous Pb2+, Zn2+, Cu2+ and Na+ ions at 0,005 eq/L and 303 K, interpreted through the application of empirical thermodynamic models to the zeolite phase (Margules, Van Laar, Wilson) coupled with a well established ion-interaction approach for the electrolyte solution (Pitzer). The present study considered the following stages: (1) adsorbent material: preparation and characterization; (2) aqueous solutions: nitrates of sodium, lead, zinc and copper; (3) equilibration of weighed amounts of homo-ionic clinoptilolite with a series of solutions containing the two competing cations; (4) analysis for aqueous cations by AAE; (5) construction of the equilibrium points; isotherm analysis; (6) test for thermodynamic reversibility; (7) empirical models for the zeolite phase (admitted as a solid solution) jointed to the ion-interaction model chosen for the aqueous solution; (8) equilibrium constant and Gibbs free energy for the ion-exchange reactions; phenomenological interpretation of the thermodynamic parameters obtained by means of the application of empirical models to the zeolite phase. The above procedure was, in the same way, followed for the ternary systems. The results obtained in this work shown that the empirical models adopted for the solid phase coupled to Pitzer s model for the activity coefficients in the electrolyte solution describe successfully the binary ion-exchange equilibria. The calculated equilibrium constant and the corresponding Gibbs free energy for each binary-exchange reaction resulted in a selectivity sequence, at the normality and temperature of this study, easily deduced as: 2 2 2 Pb Na Cu Zn + + + + > > . Besides, the parameters estimated applying the Margules , Van Laar s and Wilson s equations for cations in the solid binary mixture resulted in useful values quantifying adequately the cation zeolite framework interactions, thus, an alternative way to interpret the adsorbent selectivity from the charge and cationic radius effect. The ternary parameters obtained applying multi-component empirical models do not explain properly the non-ideality of ions in a solid mixture containing more than two components. This is in accordance with the results encountered in a number of publications on crystal structure of heulandite-group zeolites: these aluminosilicates are found to contain crystallographically distinct set of sites throughout the exchanger framework and that normally each set of sites is partially populated by the exchanging ions. As a consequence, activity coefficients for a multi-component exchange reaction cannot be predicted from appropriate binary data for a heterogeneous exchanger, since the phenomenological binary coefficients are complicated functions of each site set, population and composition, and both these properties will change on introducing other species of ion in the exchanger. In this sense, and from what were obtained here, is believed that multi-component solid phase nonideality must, at least, be interpreted through the application of statistical thermodynamic models considering the energetic heterogeneity of a number of site set and the charge density of the specific zeolite framework. / Obs.: Devido a restrições dos caracteres especias, verifcar resumo em texto completo para download. As zeólitas naturais constituem os trocadores iônicos inorgânicos mais importantes, as quais mostram elevada capacidade de troca iônica, seletividade e compatibilidade com o ambiente natural. Os metais pesados são conhecidos pela sua toxicidade e seus depósitos constituem o maior problema quanto a despejos industriais. Os objetivos básicos deste trabalho foram a interpretação do equilíbrio de adsorção e a avaliação da seletividade de um mineral de clinoptilolita purificado e homo-iônico por Pb2+, Zn2+, Cu2+ e Na+ aquosos à normalidade de 0,005 eq/L e temperatura de 303 K. O estudo proposto foi feito obedecendo as seguintes etapas: (1) preparação e caracterização do material adsorvente; (2) preparação e análise de soluções eletrolíticas; (3) equilíbrio termodinâmico de clinoptilolita homo-iônica com soluções contendo os dois cátions competitivos; (4) análises, no equilíbrio, das soluções mediante EAA; (5) construção dos pontos experimentais e análise das isotermas; (6) testes de reversibilidade termodinâmica; (7) uso de modelos empíricos para a fase zeólita, admitida como uma pseudo-solução, e modelos de interação iônica para a solução eletrolítica; (8) análise da constante de equilíbrio e da energia livre de Gibbs das reações de troca binárias e interpretação fenomenológica dos parâmetros termodinâmicos. Os resultados obtidos mostraram que os modelos adotados para a fase zeólita, considerada como uma mistura, junto com o modelo de Pitzer para os coeficientes de atividade na solução eletrolítica descrevem com sucesso o equilíbrio de troca binária dos sistemas estudados. A constante de equilíbrio calculada e a correspondente energia livre de Gibbs, para cada reação de troca binária à normalidade e temperatura estudadas, resultaram numa seqüência de seletividade dada por: 2 2 2 Pb Na Cu Zn + + + + > > . Paralelamente, os parâmetros estimados através do o uso das equações de Margules, Van Laar e Wilson para os cations na mistura binária resultaram em valores úteis na quantificação das interações cátion estrutura. Desta forma, a avaliação destes parâmetros constituiu uma alternativa na interpretação da seletividade do adsorvente pelos diferentes cátions de troca a partir do efeito do raio e da carga dos cátions. Os parâmetros ternários obtidos através da aplicação de modelos clássicos de estrutura multicomponente resultaram não satisfatórios na interpretação fenomenológica da mistura de mais de dois componentes. Este resultado confirma o encontrado em estudos sobre a estrutura cristalina das zeólitas tipo heulandita: estes aluminosilicatos geralmente contêm grupos de sítios cristalográficos distinguíveis e, por outro lado, que os coeficientes de atividade dos íons em cada tipo de sítios é uma função fortemente dependente da composição e população destes. Desta forma, a inclusão de um terceiro componente torna extremamente complicada a predição e interpretação dos coeficientes de atividade fenomenológicos na mistura sólida multicomponente. Neste sentido e, a partir dos resultados deste estudo, acredita-se que a interpretação da não idealidade da mistura sólida multicomponente deve ser feita através do uso de modelos que considerem a heterogeneidade energética dos diferentes grupos de sítios dentro da zeólita, acoplado a considerações da termodinâmica estatística que têm em conta a população e composição em cada grupo de sítios, além da densidade de carga da rede cristalina do adsorvente.