Nutrients (nitrogen and phosphorus) should be removed and recycled from wastewater in order to reduce the nutrient load to recipient waters, avoiding contamination of groundwater and conserve resources. There is a need to pay more attention to phosphorus (P) removal and recycling from wastewater due to limited availability of phosphorus recourses. For such purpose reactive filter media can be used to remove nutrient from wastewater as a sustainable technology. The present study was aimed to evaluate calcium silicate hydrate crystallization in Absol as a reactive filter media for removal and recycle of phosphorus from household wastewater and assess physical and chemical characteristics of Absol. A study of the color removing capacity of Absol was also performed. Several batch experiments were done for comparing absorption mechanism. Collected data were applied to Langmuir and Freundlich isotherm models to study type of adsorption isotherms and pseudofirst- order and second order models were run for study of adsorption kinetics. The experiment demonstrated a very high P and Methylene Blue (MB) sorption capacity. The amount of adsorbed P and MB vary with initial solution concentrations, contact time, and adsorbent dosage. Both equilibrium data (P, MB) were fitted very well in the Langmuir isotherm equation, confirming the monolayer physical sorption and adsorption kinetic followed by the pseudo-second order kinetic model. It is concluded that Absol can have potential to be use for the removal of P, textile dye contaminants and probably also pharmaceuticals present in wastewater.

A interação de elementos potencialmente tóxicos com solos e a caracterização quanto à mobilidade e potencial de liberação ao ambiente são importantes para avaliação de risco ambiental. No caso de solos altamente intemperizados, como os Latossolos, a interação pode ser diferenciada devido à elevada acidez, baixa densidade de cargas negativas, maiores quantidades de minerais de argila 1:1 e de (hidr)óxidos de Fe, Al e Mn, em que predominam cargas negativas variáveis com o pH. O objetivo nesta tese foi caracterizar a capacidade de sorção, a distribuição entre as frações do solo, a especiação temporal, a predição da capacidade de sorção e a dessorção com método dinâmico de extração de Cd(II) em seis solos tropicais, incluindo três Latossolos. Amostras dos seis solos foram utilizadas para avaliação da interação com Cd(II), utilizando extração sequencial e especiação por espectroscopia de absorção de raios-X próximo à estrutura da borda (XANES) para avaliação da cinética de sorção. Dados de 29 solos foram utilizados para desenvolvimento de modelo de regressão linear para predição das capacidades de sorção de Cd(II). A caracterização da dessorção de Cd por extração convencional e dinâmica foi feita em solos de textura médio-arenosa, argilosa e em um solo de referência certificado. Os resultados de sorção foram ajustados ao modelo de Langmuir. As capacidades de sorção e as energias livres padrão de Gibbs variaram de 37 à 1296 mg kg-1 e de -16,6 até -27,0 kJ mol-1, respectivamente. A sorção foi fraca e reversível, e mais de 90% do Cd estava sorvido como espécies disponíveis. A especiação temporal indicou evidências fracas e variáveis para as alterações químicas do Cd no solo, sugerindo que o elemento liberado nessas amostras se ligou à matéria orgânica do solo e aos óxidos minerais ou permaneceu dissolvido, com pequenas alterações na especiação nos meses seguintes. O modelo linear representou 98% dos resultados empíricos apenas em função de uma variável, que foi o ensaio de sorção simplificado com apenas uma concentração de Cd(II). Apesar de a capacidade de sorção prevista com o modelo ter apresentado variação de cerca de 20% em relação ao empírico, o modelo de predição apresenta potencialidade de aplicação para avaliações iniciais e rápidas. A dessorção avaliada em batelada e em fluxo indicou dessorção próxima de 100% nas frações que representam disponibilidade no ambiente, enquanto o sistema desenvolvido para extração dinâmica foi adequado na mistura das soluções com a amostra de solo e propiciou rápida troca de extratores. De modo geral os atributos do solo, bem como a classe, influenciaram, mas não definiram a interação do Cd(II) com o solo. Por sua vez, o Cd(II) incorporado ao solo apresenta grande risco ambiental e de interação com a biota / The interaction of potentially toxic elements in soils and characterization as mobility and potential of environmental release are important for environmental risk assessment. In the case of highly weathered soils, as Oxisols, interaction can be differentiated, due to the high acidity, low density of negative charges, and higher amounts of 1:1 clay minerals and Fe, Al and Mn (hidr)oxides, in which negative charges are variables with pH. The objectives in this thesis was to characterize the Cd(II) sorption capacity, distribution between soil fractions, temporal speciation, prediction of sorption capacity and desorption with dynamic extraction method in six tropical soils, including three Oxisols. Samples of the six soils were used to assess the interaction with Cd(II) using sequential extraction and the speciation with X-ray absorption near edge structure spectroscopy (XANES) to evaluate the adsorption kinetics. Data of 29 soils were used to develop a linear regression model for prediction of Cd(II) sorption capacity. The Cd desorption characterization trough conventional and dynamics extractions was performed in a medium-sandy, a clayey and a certified reference soils. The sorption results were fitted to the Langmuir model. Sorption capacities and standard Gibbs free energy ranged from 37 to 1296 mg kg-1 and from -16.6 to -27.0 kJ mol-1, respectively. Sorption was weak and reversible, and more 90% Cd was sorbed as available species. The temporal speciation indicated weak and variables evidence of chemical changes of Cd in the soil, suggesting that this element released in these soils bound to the soil organic matter and to mineral oxides or remained dissolved, with minor changes in speciation in the following months. The linear model accounted for 98% of empirical results only on the basis of a single variable, which was the sorption simplified experiment with only one Cd(II) concentration. Although the sorption capacity predicted with the model ranged about 20% of the empirical, prediction model has potential of application for initial and rapid assessments. The desorption evaluated in batch and flow indicated desorption of about 100% in the fractions representing availability in the environment, meanwhile the system developed for dynamic extraction was adequate to mix the solutions with the soil sample and provided rapid exchange of extractants. Overall, the soil characteristics and the class had influence, but did not define the interaction of Cd(II) with the soil. On the other hand, the Cd(II) incorporated into the soil has a great environmental risk and to interact with the biota

A interação de elementos potencialmente tóxicos com solos e a caracterização quanto à mobilidade e potencial de liberação ao ambiente são importantes para avaliação de risco ambiental. No caso de solos altamente intemperizados, como os Latossolos, a interação pode ser diferenciada devido à elevada acidez, baixa densidade de cargas negativas, maiores quantidades de minerais de argila 1:1 e de (hidr)óxidos de Fe, Al e Mn, em que predominam cargas negativas variáveis com o pH. O objetivo nesta tese foi caracterizar a capacidade de sorção, a distribuição entre as frações do solo, a especiação temporal, a predição da capacidade de sorção e a dessorção com método dinâmico de extração de Cd(II) em seis solos tropicais, incluindo três Latossolos. Amostras dos seis solos foram utilizadas para avaliação da interação com Cd(II), utilizando extração sequencial e especiação por espectroscopia de absorção de raios-X próximo à estrutura da borda (XANES) para avaliação da cinética de sorção. Dados de 29 solos foram utilizados para desenvolvimento de modelo de regressão linear para predição das capacidades de sorção de Cd(II). A caracterização da dessorção de Cd por extração convencional e dinâmica foi feita em solos de textura médio-arenosa, argilosa e em um solo de referência certificado. Os resultados de sorção foram ajustados ao modelo de Langmuir. As capacidades de sorção e as energias livres padrão de Gibbs variaram de 37 à 1296 mg kg-1 e de -16,6 até -27,0 kJ mol-1, respectivamente. A sorção foi fraca e reversível, e mais de 90% do Cd estava sorvido como espécies disponíveis. A especiação temporal indicou evidências fracas e variáveis para as alterações químicas do Cd no solo, sugerindo que o elemento liberado nessas amostras se ligou à matéria orgânica do solo e aos óxidos minerais ou permaneceu dissolvido, com pequenas alterações na especiação nos meses seguintes. O modelo linear representou 98% dos resultados empíricos apenas em função de uma variável, que foi o ensaio de sorção simplificado com apenas uma concentração de Cd(II). Apesar de a capacidade de sorção prevista com o modelo ter apresentado variação de cerca de 20% em relação ao empírico, o modelo de predição apresenta potencialidade de aplicação para avaliações iniciais e rápidas. A dessorção avaliada em batelada e em fluxo indicou dessorção próxima de 100% nas frações que representam disponibilidade no ambiente, enquanto o sistema desenvolvido para extração dinâmica foi adequado na mistura das soluções com a amostra de solo e propiciou rápida troca de extratores. De modo geral os atributos do solo, bem como a classe, influenciaram, mas não definiram a interação do Cd(II) com o solo. Por sua vez, o Cd(II) incorporado ao solo apresenta grande risco ambiental e de interação com a biota / The interaction of potentially toxic elements in soils and characterization as mobility and potential of environmental release are important for environmental risk assessment. In the case of highly weathered soils, as Oxisols, interaction can be differentiated, due to the high acidity, low density of negative charges, and higher amounts of 1:1 clay minerals and Fe, Al and Mn (hidr)oxides, in which negative charges are variables with pH. The objectives in this thesis was to characterize the Cd(II) sorption capacity, distribution between soil fractions, temporal speciation, prediction of sorption capacity and desorption with dynamic extraction method in six tropical soils, including three Oxisols. Samples of the six soils were used to assess the interaction with Cd(II) using sequential extraction and the speciation with X-ray absorption near edge structure spectroscopy (XANES) to evaluate the adsorption kinetics. Data of 29 soils were used to develop a linear regression model for prediction of Cd(II) sorption capacity. The Cd desorption characterization trough conventional and dynamics extractions was performed in a medium-sandy, a clayey and a certified reference soils. The sorption results were fitted to the Langmuir model. Sorption capacities and standard Gibbs free energy ranged from 37 to 1296 mg kg-1 and from -16.6 to -27.0 kJ mol-1, respectively. Sorption was weak and reversible, and more 90% Cd was sorbed as available species. The temporal speciation indicated weak and variables evidence of chemical changes of Cd in the soil, suggesting that this element released in these soils bound to the soil organic matter and to mineral oxides or remained dissolved, with minor changes in speciation in the following months. The linear model accounted for 98% of empirical results only on the basis of a single variable, which was the sorption simplified experiment with only one Cd(II) concentration. Although the sorption capacity predicted with the model ranged about 20% of the empirical, prediction model has potential of application for initial and rapid assessments. The desorption evaluated in batch and flow indicated desorption of about 100% in the fractions representing availability in the environment, meanwhile the system developed for dynamic extraction was adequate to mix the solutions with the soil sample and provided rapid exchange of extractants. Overall, the soil characteristics and the class had influence, but did not define the interaction of Cd(II) with the soil. On the other hand, the Cd(II) incorporated into the soil has a great environmental risk and to interact with the biota

No description available.

Σκοπός της παρούσας μελέτης είναι η κατανόηση του μηχανισμού ρόφησης του φαινανθρενίου σε δείγματα γαιανθράκων και των αντίστοιχων χουμικών τους οξέων και η διερεύνηση της καταλληλότητας τους ως ροφητικών υλικών για την απορρύπανση ποτάμιων και λιμναίων συστημάτων, στα οποία υπάρχει πρόβλημα ρύπανσης από πολυκυκλικούς αρωματικούς υδρογονάνθρακες. Για την επίτευξη του σκοπού αυτού μελετήθηκαν τέσσερα δείγματα λιγνίτη και δύο δείγματα τύρφης και τα αντίστοιχα δείγματα των χουμικών οξέων. Η μεθοδολογία που ακολουθήθηκε για την απομόνωση των χουμικών οξέων βασίστηκε στην τροποποιημένη μεθοδολογία, που προτείνεται από την IHSS (International Humic Substances Society). Για τη μελέτη της ρόφησης φαινανθρενίου κατασκευάστηκαν οι ισόθερμες καμπύλες ρόφησης, ύστερα από την πραγματοποίηση πειραμάτων ρόφησης με συγκεντρώσεις φαινανθρενίου σε υδατικά διαλύματα 30, 50, 100, 300 και 500 μg/l. Τα αποτελέσματα δείχνουν ότι η ρόφηση στα περισσότερα δείγματα των χουμικών οξέων είναι μεγαλύτερη από ό,τι στα αντίστοιχα δείγματα των μητρικών τους γαιανθράκων. Επίσης στα δείγματα των γαιανθράκων παρατηρείται μεγαλύτερη ρόφηση στις χαμηλές συγκεντρώσεις φαινανθρενίου από ό,τι στις υψηλές, με αποτέλεσμα η ρόφηση να μην είναι γραμμική. Σχετικά με τη χρήση τους ως ροφητικά υλικά για απορρύπανση για δυο δείγματα λιγνίτη προτείνεται η χημική τους επεξεργασία, προκειμένου να χρησιμοποιηθούν ως ροφητικά υλικά, ενώ για τα υπόλοιπα δείγματα η διαφορά στη ροφητική ικανότητα μεταξύ των μητρικών γαιανθράκων και των παραγόμενων χουμικών οξέων δεν είναι τόσο σημαντική, με αποτέλεσμα να μπορεί να χρησιμοποιηθεί απευθείας το μητρικό υλικό / The scope of this study is the determination of the phenanthrene sorption mechanism for some Greek lignite and peat samples, as well as for their extracted humic acids. The scope is to assess their suitability for application in remediation of fresh water environments from polycyclic aromatic hydrocarbons (PAHs) For the extraction of the humic acids, the methodology provided by the IHHS (International Humic Substances Society) with some alterations, was applied. The sorption experiments were conducted by mixing 0,004 g of the sorbent within water solutions of phenanthrene at different concentrations of 30, 50, 100, 300 and 500 μg/l. The results show that phenanthrene sorption is higher in the humic acid samples rather than in the original lignite and peat. The original samples display higher sorption at low phenanthere concentration solutions (30 μg/l) than at the denser phenanthrene concentration solution (500 μg/l). Thus, the sorption in these samples is non-linear. In order to use these materials as sorbents, the TH4 and MT6 samples might have to be treated, because sorption is higher in the humic acid fraction than in the source material. The rest of the samples display lower variation in the sorption capacity between the humic acid samples and the original samples, thus there is no need for chemical treatment.

Vatten är en förutsättning för allt liv, men det är inte bara vatten som krävs, utan även att vattnet är rent och går att dricka. Det finns goda tillgångar till vatten på vår jord, men bara en bråkdel av detta vatten är av tillräckligt god kvalité för att det ska kunna drickas. Idag saknar fler än 700 miljoner människor i världen tillgång till tjänligt dricksvatten. Uganda är ett av många länder som berörs av detta och många dricksvattenkällor i Ugandas urbana miljöer riskerar dessutom att förorenas av metaller, såsom bly och mangan. Landet är i en kraftig utvecklingsfas, men de ekonomiska resurserna är begränsade. Det är därför viktigt att försöka lösa dricksvattenförsörjningen både snabbt och på ett ekonomiskt fördelaktigt sett. Till följd av att Uganda är ett land rikt på naturresurser så har det börjat undersökas kring möjligheterna att använda biomassa från resterna av vissa jordbruksprodukter för att rena vattnet. I denna studie fokuseras det på två av de största jordbruksprodukterna i Uganda, Coffea canephora och Musa spp, vilka är en sorts kaffeplanta respektive bananplantor. Biomassa från dessa produkter har i tidigare studier visat sig vara teoretiskt lämpade för att rena vatten från metaller. Syftet med denna studie är att fastställa sorptionsförmågan av bly hos biomassa från Coffea canephora och Musa spp för att bidra med ny data och information för praktiskt tillämpning av dessa biomassor vid rening av dricksvatten i Uganda. Detta har genomförts med laboration. I laborationen konstruerades sex olika vattenprover innehållande olika sammansättningar av metallerna bly, mangan och kalcium. Halterna av mangan och kalcium varierades för att fastställa hur deras förekomst påverkade biomassornas sorptionsförmåga av bly. Resultaten visade att både Coffea canephora och Musa spp kan rena vatten, med en ursprunglig blykoncentration av 50 μg/L, så pass bra att blyhalten hamnar under WHOs gränsvärde på 10 μg/L efter sorptionsprocessen. Detta gällde för samtliga vattenprover, trots olika metallinnehåll. Sorptionskapaciteten var för Musa spp från 6,64 μg/g till 7,17 μg/g och för Coffea canephora var den från 5,94 μg/g till 6,40 μg/g. Biomassa från Musa spp hade bättre sorptionsförmågan i jämförelsen mellan de båda biomassorna, oberoende av vattenprovernas olika sammansättningar. Sorptionskapaciteten visade sig dock minska för Musa spp då det fanns mangan men inget kalcium i vattnet. Soprtionskapaciteten för Coffea canephora försämrades då vattenproverna innehöll andra metaller än bly. Utöver detta fanns inget tydligt samband över hur koncentrationen av mangan och kalcium förhöll sig till sorptionsförmågan av bly. Studien har varit begränsad vad gäller tid och resurser. Ytterligare studier behövs för att få en bättre helhetsuppfattning av hur användning av biomassor kan bidra till dricksvatten av god kvalité. Trots detta visade resultaten på bra sorptionsförmåga hos de båda biomassorna, vilket är ett bra underlag för att fortsätta arbeta mot en verklig implementering av biomassornas användning vid dricksvattenrening i Uganda. / Water is the source of all life, but water itself is not the only requirement, the water also needs to be clean and potable. There are good assets to water on our Earth, but only a fraction of this water is of a quality good enough for it to be potable. As of today, more than 700 million people worldwide lack access to drinking water of good quality. Uganda is one out of many countries that are affected by this and many sources of drinking water in Uganda's urban environments also risk to be contaminated by metals such as lead and manganese. The country is undergoing a significant development, but the financial resources are limited. It is therefore important to try to solve the drinking water supply both quickly and economically advantageous. Uganda is a country that is rich in natural resources, and as a result of that, the feasibility of using biomass from the remains of some agricultural products for water purification water has begun to being examined. This study focuses on two of the biggest agricultural products in Uganda, Coffea canephora and Musa spp, which are sorts of coffee plant and banana plants. Biomasses from these products have previously been shown to be theoretically suitable for purifying water from metals. The purpose of this study is to determine the sorption capacity of lead for the biomasses of Coffea canephora and Musa spp. This new data and information can then help with the development of practical application of these biosorbents in drinking water treatment in Uganda. This has been carried out by laboration. In the lab, six different water samples were constructed, all with different compositions of the metals lead, manganese and calcium. The levels of manganese and calcium were varied to determine how their presence affected the sorption capacity of lead for both biomasses. The results showed that both Coffea canephora and Musa spp can purify water, with an initial lead concentration of 50 μg/L, so good that the lead concentration falls below the WHO’s threshold of 10 μg/L after the sorption process. This was true for all water samples, despite of difference in metal content. The Sorption capacity showed to be for Musa spp from 6.64 μg/g to 7.17 μg/g and for Coffea canephora from 5.94 μg/g to 6.40 μg/g. Biomass from Musa spp had better sorption capacity in comparison between the two biomasses, regardless of the different compositions of the water. However, the sorption capacity for Musa spp was reduced when there was manganese but no calcium in the water. The sorption capacity for Coffea canephora deteriorated when there were more metals than lead in the water. Apart from this, there was no clear correlation of how the concentration of manganese and calcium were related to the sorption capacity of lead. This study has been limited in terms of time and resources, therefore further studies will be needed to get a better overall understanding of how the use of biosorbents can contribute to drinking water of good quality. In spite of this, the results prove that both biomasses have a good sorption capacity of lead, which is a good basis for further studies towards a real implementation of biomass use in purification of drinking water in Uganda.