Vanadium is a white bright metal that belongs to group 5 in the periodic table of elements. It can exist in different oxidation states from -2 to +5 although the forms can be found naturally in the environment are (III), (IV) and (V). As vanadium is toxic at high concentrations, and as vanadium is a common contaminant from e.g., steel slags, more detailed knowledge on the environmental behavior of this metal is required. One important property is its sorption to soils, as this will determine the bioavailability and the risk of leaching from soils. In surface soils vanadium(V) is commonly the predominating redox species. Therefore the purpose of this study was to determine vanadium(V) sorption in 7 different soils in order to investigate the factors determining vanadium(V) sorption and to estimate the capacity of the soils to bind vanadium. From laboratory adsorption experiments, vanadium sorption has been studied as a function of pH, vanadium(V) concentration, and phosphorus status. The adsorbed vanadium(V) of investigated soils was compared on the basis of the Freundlich parameters m and log Kf. The clay content of the soil and the content of oxalate soluble iron and aluminum were two important factors for the vanadium(V) sorption behavior. The higher the values of these soil properties, the stronger was vanadium(V) sorption. Among the soils investigated here the sorption strength was highest for the Kungängen A3 soil and then decreased in the following order Säby, Kungsängen D3, Pustnäs, Termunck, Guadalajara and Zwijnaarde. It is notable that the three soils with the strongest vanadium(V) sorption were clay soils, whereas the other four were sandy or silty soils. The pH dependence of vanadium sorption was also determined. The results show that the percentage sorbed vanadium(V) increases with decreasing pH. This is due probably to the anion properties of vanadium(V) (i.e. vanadate) in combination with increased positive surface charge on the soil colloids at lower pH. Moreover there is a competition between phosphate and vanadium(V) for sorption sites, which will cause less vanadium(V) sorption in soils. Therefore both the pH value and the phosphorus status are two additional factors that influence the vanadium sorption properties of soils.

The period of industrialization after the second World War in Europe released SO2 and NOx by combustion of fossil fuels and contributed the formation of S and N compounds in the forest ecosystem. The Swedish forest soil systems were influenced by emissions of SO2 followed by H2SO4 deposition, consequently the pool of SO42- had increased in the forest ecosystem. This thesis studied SO42- adsorption in a podzolic Bs horizon soils taken from a Swedish forest soil system. The soil samples from five different sampling sites were collected and the results revealed different amounts of adsorbed SO42- in response to changes in equilibrium concentration and pH. This study found that the amount of adsorbed SO42- (mmol/kg) increased with an added equilibrium concentration of SO42- (mmol/l) and with a decreasing pH. This was determined by equilibration experiments. Based on the results a Freundlich-based model was developed to predict the pool of adsorbed SO42- in the soil samples. The model predicted the pool of adsorbed SO42- (mmol/kg) as a function of pH and the equilibrium concentration of SO42- (mmol/l) in the soil solution system. The extended Freundlich model was optimized in three different ways: by use of unconstrained, constrained and simplified two-point calibration. The results showed that the adsorption of sulfate in the Kloten Bs1 and Risbergshöjden B soils was higher as compared to the Tärnsjo B, Österström B, and Risfallet B soils. The coefficient of determination (R2) determined from an unconstrained fit of the extended Freundlich model (with three adjustable parameters) for Risbergshöjden B and Kloten Bs1 were R2 =0.998 and R2=0.993. Nearly as good fits were found in a constrained fit with two adjustable parameters when it was assumed that nearly 2 protons (2 H+) are co-adsorbed with one SO42- ion (Risbergshöjden B; R2=0.997 and Kloten Bs; R2=0.992). The simplified two-point calibration with two adjustable parameters showed similar parameter values for all most soils and was considered the best optimization method of extended Freundlich model, especially as it requires only limited input data.

Made available in DSpace on 2017-05-12T14:47:13Z (GMT). No. of bitstreams: 1 Thaisa _Pegoraro.pdf: 1491826 bytes, checksum: 1b9380fd12ae09c6e6128b1816c0215e (MD5) Previous issue date: 2015-02-23 / Biochar, also known as terra preta do índio, is a highly porous material and is a result of biomass pyrolysis in oxygen-controlled conditions and low temperatures (up to 600 oC). Due to the viable manufacturing process and the wide variety of applications, it is a promising material for various uses. Among the main uses of biochar, studies indicate its potential in improving soil quality, besides being a way of contributing to carbon sequestration from the atmosphere and used in the retention of organic and inorganic contaminants in the environment. This work aimed to present a review of the concepts and current studies on biochar, for a better understanding of the subject (Paper 1). The objective was to also investigate the adsorption of pharmaceuticals carbamazepine (CBZ) and lincomycin (LMC) by six biochars under the influence of surface characteristics of biochar (produced from Brazilian pepper and sugarcane bagasse, in temperatures of 300 o, 400 o and 600o C) and environmental factors (pH and adsorption competition between CBZ and LMC) (Paper 2). The latest study aimed to understand the effects of exposure of dissolved organic matter (DOM) in the surface properties of three biochars produced from sugarcane bagasse, in the CBZ adsorption (Paper 3). Batch equilibrium tests were performed in constant temperature, varying pH, and the data were adjusted in Freundlich isotherms. For the DOM test, the biochars were previously loaded with humic acid, tannic acid, gallic acid, and catechol in concentrations equivalent to those found in soils. The values of Kd, n and KF were reported and analyzed. As a result, it was found that biochars produced from sugarcane bagasse and high pyrolysis temperature were more effective in CBZ and LMC adsorption. In the biochar produced from bagasse at 300° C, the adsorption of CBZ was not affected by the presence of functional groups on the surface of biochar. LMC, which is ionized at pH 7.6, is more easily binded to negatively charged biochars when pH is acidic (pH<pKa). Furthermore, it was found that the CBZ and LMC compete for the same adsorption sites, regardless the variation of pH solution. In general, DOM affected adsorptive properties of biochars and attenuated CBZ adsorption, especially for biochars produced in higher temperatures because of the greater complexity of its structure, when DOM enters or blocks the biochar micro and mesoporous. It was concluded that the use of biochar as a product of sustainable feature looks promising, but there are still some gaps in the current literature about the positive and negative impacts of its use. Laboratory results indicate a possible use of biochar in removing organic compounds from water, which can replace less effective existing treatment technologies. There is to be considered, however, several factors that influence this process and more studies are needed to corroborate such evidence. / O biocarvão, também conhecido como terra preta do índio, é um material de alta porosidade e é resultado da pirólise da biomassa em condições de oxigênio controlado e baixas temperaturas (até 600 oC). Devido ao viável processo de produção e à ampla variedade de aplicações, trata-se de um material promissor para diversos usos. Dentre as principais utilidades do biocarvão, estudos indicam seu potencial na melhoria da qualidade do solo, além de ser uma forma de contribuir para o sequestro de carbono da atmosfera e ser utilizado na retenção de contaminantes orgânicos e inorgânicos no ambiente. Nesse trabalho, objetivou-se realizar uma revisão sobre os conceitos e estudos atuais sobre biocarvão, para uma melhor compreensão do tema (Artigo 1). Objetivou-se também investigar o processo de adsorção dos fármacos carbamazepina (CBZ) e lincomicina (LMC) por seis biocarvões, sob a influência de características superficiais do biocarvão (produzidos a partir de pimenta brasileira e bagaço de cana-de-açúcar, a 300o, 400o e 600o C) e fatores ambientais (pH e competição sortiva entre CBZ e LMC) (Artigo 2). No último estudo, objetivou-se compreender os efeitos da exposição da matéria orgânica dissolvida (MOD) nas propriedades superficiais de três biocarvões produzidos a partir de bagaço de cana-de-açúcar, na adsorção de CBZ (Artigo 3). Ensaios de equilíbrio de adsorção foram realizados em batelada e temperatura constante, variando o pH, e os dados foram ajustados em isotermas de Freundlich. Para o ensaio com MOD, os biocarvões foram previamente carregados com ácido húmico, ácido tânico, ácido gálico e catecol em concentrações equivalentes às de matéria orgânica encontrada em solos. Os valores de Kd, KF e n foram reportados e analisados. Como resultado, verificou-se que biocarvões produzidos a partir da biomassa de bagaço de cana-de-açúcar e altas temperaturas de pirólise foram mais efetivos na adsorção de CBZ e LMC. Em biocarvão produzido a partir de bagaço de cana-de-açúcar, a 300 oC, a adsorção de CBZ não foi afetada pela presença de grupos funcionais na superfície do biocarvão. Já a LMC, que é ionizada a pH 7,6, liga-se mais facilmente a biocarvões carregados negativamente quando o pH é ácido (pH<pKa). Além disso, verificou-se que a CBZ e LMC competem entre si pelos mesmos sítios sortivos, independente da variação do pH da solução. A MOD afetou as propriedades adsortivas de biocarvões para CBZ, principalmente em biocarvões produzidos a maiores temperaturas, devido à maior complexidade de sua estrutura, entrando ou bloqueando os micro e mesoporos do biocarvão. Conclui-se que o uso do biocarvão como um produto de característica sustentável parece ser promissor, porém, lacunas ainda existem na literatura atual sobre os impactos positivos e negativos do seu uso. Os resultados laboratoriais indicam um possível uso do biocarvão na remoção de compostos orgânicos da água, o que pode substituir tecnologias de tratamento existentes menos eficazes. Há, porém, de se considerar diversos fatores de influência nesse processo e mais estudos devem ser realizados a fim de corroborar com tais evidências.

Made available in DSpace on 2017-07-10T19:23:59Z (GMT). No. of bitstreams: 1 Thaisa _Pegoraro.pdf: 1491826 bytes, checksum: 1b9380fd12ae09c6e6128b1816c0215e (MD5) Previous issue date: 2015-02-23 / Biochar, also known as terra preta do índio, is a highly porous material and is a result of biomass pyrolysis in oxygen-controlled conditions and low temperatures (up to 600 oC). Due to the viable manufacturing process and the wide variety of applications, it is a promising material for various uses. Among the main uses of biochar, studies indicate its potential in improving soil quality, besides being a way of contributing to carbon sequestration from the atmosphere and used in the retention of organic and inorganic contaminants in the environment. This work aimed to present a review of the concepts and current studies on biochar, for a better understanding of the subject (Paper 1). The objective was to also investigate the adsorption of pharmaceuticals carbamazepine (CBZ) and lincomycin (LMC) by six biochars under the influence of surface characteristics of biochar (produced from Brazilian pepper and sugarcane bagasse, in temperatures of 300 o, 400 o and 600o C) and environmental factors (pH and adsorption competition between CBZ and LMC) (Paper 2). The latest study aimed to understand the effects of exposure of dissolved organic matter (DOM) in the surface properties of three biochars produced from sugarcane bagasse, in the CBZ adsorption (Paper 3). Batch equilibrium tests were performed in constant temperature, varying pH, and the data were adjusted in Freundlich isotherms. For the DOM test, the biochars were previously loaded with humic acid, tannic acid, gallic acid, and catechol in concentrations equivalent to those found in soils. The values of Kd, n and KF were reported and analyzed. As a result, it was found that biochars produced from sugarcane bagasse and high pyrolysis temperature were more effective in CBZ and LMC adsorption. In the biochar produced from bagasse at 300° C, the adsorption of CBZ was not affected by the presence of functional groups on the surface of biochar. LMC, which is ionized at pH 7.6, is more easily binded to negatively charged biochars when pH is acidic (pH<pKa). Furthermore, it was found that the CBZ and LMC compete for the same adsorption sites, regardless the variation of pH solution. In general, DOM affected adsorptive properties of biochars and attenuated CBZ adsorption, especially for biochars produced in higher temperatures because of the greater complexity of its structure, when DOM enters or blocks the biochar micro and mesoporous. It was concluded that the use of biochar as a product of sustainable feature looks promising, but there are still some gaps in the current literature about the positive and negative impacts of its use. Laboratory results indicate a possible use of biochar in removing organic compounds from water, which can replace less effective existing treatment technologies. There is to be considered, however, several factors that influence this process and more studies are needed to corroborate such evidence. / O biocarvão, também conhecido como terra preta do índio, é um material de alta porosidade e é resultado da pirólise da biomassa em condições de oxigênio controlado e baixas temperaturas (até 600 oC). Devido ao viável processo de produção e à ampla variedade de aplicações, trata-se de um material promissor para diversos usos. Dentre as principais utilidades do biocarvão, estudos indicam seu potencial na melhoria da qualidade do solo, além de ser uma forma de contribuir para o sequestro de carbono da atmosfera e ser utilizado na retenção de contaminantes orgânicos e inorgânicos no ambiente. Nesse trabalho, objetivou-se realizar uma revisão sobre os conceitos e estudos atuais sobre biocarvão, para uma melhor compreensão do tema (Artigo 1). Objetivou-se também investigar o processo de adsorção dos fármacos carbamazepina (CBZ) e lincomicina (LMC) por seis biocarvões, sob a influência de características superficiais do biocarvão (produzidos a partir de pimenta brasileira e bagaço de cana-de-açúcar, a 300o, 400o e 600o C) e fatores ambientais (pH e competição sortiva entre CBZ e LMC) (Artigo 2). No último estudo, objetivou-se compreender os efeitos da exposição da matéria orgânica dissolvida (MOD) nas propriedades superficiais de três biocarvões produzidos a partir de bagaço de cana-de-açúcar, na adsorção de CBZ (Artigo 3). Ensaios de equilíbrio de adsorção foram realizados em batelada e temperatura constante, variando o pH, e os dados foram ajustados em isotermas de Freundlich. Para o ensaio com MOD, os biocarvões foram previamente carregados com ácido húmico, ácido tânico, ácido gálico e catecol em concentrações equivalentes às de matéria orgânica encontrada em solos. Os valores de Kd, KF e n foram reportados e analisados. Como resultado, verificou-se que biocarvões produzidos a partir da biomassa de bagaço de cana-de-açúcar e altas temperaturas de pirólise foram mais efetivos na adsorção de CBZ e LMC. Em biocarvão produzido a partir de bagaço de cana-de-açúcar, a 300 oC, a adsorção de CBZ não foi afetada pela presença de grupos funcionais na superfície do biocarvão. Já a LMC, que é ionizada a pH 7,6, liga-se mais facilmente a biocarvões carregados negativamente quando o pH é ácido (pH<pKa). Além disso, verificou-se que a CBZ e LMC competem entre si pelos mesmos sítios sortivos, independente da variação do pH da solução. A MOD afetou as propriedades adsortivas de biocarvões para CBZ, principalmente em biocarvões produzidos a maiores temperaturas, devido à maior complexidade de sua estrutura, entrando ou bloqueando os micro e mesoporos do biocarvão. Conclui-se que o uso do biocarvão como um produto de característica sustentável parece ser promissor, porém, lacunas ainda existem na literatura atual sobre os impactos positivos e negativos do seu uso. Os resultados laboratoriais indicam um possível uso do biocarvão na remoção de compostos orgânicos da água, o que pode substituir tecnologias de tratamento existentes menos eficazes. Há, porém, de se considerar diversos fatores de influência nesse processo e mais estudos devem ser realizados a fim de corroborar com tais evidências.