The presence of coal tars in the subsurface associated with former manufactured gas plants (MGPs) offers a remediation challenge due to their complex chemical composition, dissolution behaviour and recalcitrant characteristics. A former MGP site in Clearwater Beach, Florida was characterized and bench-scale analyses were conducted to assess the potential for in situ chemical oxidation (ISCO) using persulfate to treat MGP residuals. Completion of a conceptual site model identified a homogeneous, silty sand aquifer, with an average hydraulic conductivity of approximately 2.3x10-3 cm/s and a groundwater flow rate of 2 cm/day in the direction of S20°E. Six source zones, three near the water table and three in the deep aquifer were estimated to have a total volume of 108 m3. A multi-level well transect was installed to monitor concentrations of dissolved compounds and to estimate mass discharge downgradient of the source zones over time. On average, the morphology of the aqueous concentrations remained consistent with time. A total mass discharge across the transect of 94 mg/day was estimated for site-specific compounds. Bench-scale tests were conducted on aquifer sediments and groundwater samples. The aquifer was determined to have a low buffering capacity, low chemical oxygen demand, and low natural oxidant interaction (NOI) with persulfate. Aqueous batch experiments identified the potential for iron (II) activated persulfate to reduce concentrations of BTEX and PAHs below method detection limits (MDLs). Unactivated persulfate was able to reduce BTEX concentrations to below MDLs after 14 days; however, the concentration of PAH compounds remained above MDLs after 14 days. Higher iron doses within the system were shown to be more effective in reducing BTEX and PAH compounds. Column experiments designed to mimic site conditions were used to evaluate the feasibility of persulfate treatment on impacted sediments from the Clearwater site. Two sets of column experiments were conducted: one using unactivated persulfate followed by alkaline activated persulfate; and one using iron (II) activated persulfate. On average, unactivated persulfate was able to reduce BTEX and PAH aqueous effluent concentrations by > 75% and 40%, respectively, after a total dose of 60 g/g soil. Two additional doses of alkaline activated persulfate (total persulfate dose of ~80g/g soil) in these columns were able to further reduce effluent BTEX and PAH concentrations by > 90% and > 75%, respectively. Iron (II) activated persulfate reduced effluent BTEX concentrations by > 70% and PAHs by > 65% after a total dose of 35 g/g soil. Average reductions in mass for BTEX and PAH compounds were approximately of 48% and 26% respectively in the iron (II) activated persulfate columns, and 24% and 10%, respectively in the alkaline activated persulfate columns. The potential for the ability to use in situ chemical oxidation using persulfate for the remediation of MGP residuals in the subsurface is evaluated using field measurements and bench-scale experimentation. The reductions observed in aqueous phase compounds in MGP groundwater as observed in the laboratory indicate the potential for reductions in groundwater concentrations at this and other contaminated former MGP sites. However, column experiments, indicating the inability for activated persulfate to reduce all identified compounds in the MGP NAPL suggest source treatment with activated persulfate would not reduce concentrations to below Florida Department of Environmental Protection natural attenuation concentrations.

Recently, metal nanoparticles have attracted the attention of researchers in several fields of study due to their high surface area and other unique properties. Using metal nanoparticles as a component of an in situ chemical oxidation (ISCO) system is emerging and hence very little information is available. In this research, nano zero valent iron (nZVI) particles and iron-based bimetallic zero valent nanoparticles (BZVNs) were employed to activate some common peroxygens (hydrogen peroxide (H2O2), persulfate (S2O82-), and peroxymonosulfate (HSO5-)) to degrade hazardous organic compounds. Aqueous and soil slurry batch systems were used along with a one-dimensional physical model. The results from the aqueous batch systems showed that nZVI is a promising activator for S2O82- compared to other conventional iron activators (e.g., granular-ZVI and Fe2+). For example, the initial trichloroethylene (TCE) reaction rate by nZVI activated S2O82- was 1.11 x 10-4 M L-1 min-1 compared to an initial reaction rate of 6.25 x 10-5 M L-1 min-1, 5.18 x 10-6 M L-1 min-1, and 1.8 x 10-7 M L-1 min-1 for Fe2+ activated S2O82-, granular-ZVI activated S2O82-, and non-activated S2O82-, respectively. However, the surfaces of nZVI particles were passivated quickly following exposure to S2O82-, causing the reaction rate to reduce to a magnitude representative of an un-activated S2O82- system. An iron-sulfate (FeSO4) complex was formed on the surfaces of the nZVI particles following exposure to S2O82- compared to the iron oxyhydroxide (FeOOH) layer that was present on fresh nZVI surfaces. BZVNs showed better treatment effectiveness than nZVI particles as activators for H2O2, S2O82-, and HSO5-. For example, the TCE reaction rate constant for nano-Ag-Fe0 activated H2O2 was 9 to 18 fold higher than that for nZVI activated H2O2. Of the nine different BZVNs investigated as activators, the greatest TCE degradation was achieved by nano-Pd-Fe0 and nano-Zn-Fe0 activated S2O82- system, nano-Co-Fe0 activated HSO5- system, and nano-Ag-Fe0 activated H2O2 system. For all of these systems, an increase in the dosage of nanoparticles and peroxygens increased TCE degradation. The activated H2O2 system showed a lower TCE degradation rate compared to either the activated S2O82- or the activated HSO5- systems, suggesting that a bridged group complex is formed between the activators and H2O2. The dissolved TCE concentration remaining in the soil slurry batch systems after using the nano-Pd-Fe0 activated S2O82- system was two to three fold higher than that in an aqueous batch system. Furthermore, for five different aquifer materials used, the higher mass of aquifer materials the lower the TCE degradation, indicating that the aquifer materials compete with a target organic compound in the presence of activated S2O82-. A linear relationship was observed between the organic carbon (OC) content and the initial TCE decomposition rate. Although there is no direct evidence of the effect of OC on the treatment system, it is suggested that the OC may result in scavenging the generated free radicals or by directly consuming persulfate. In the one-dimensional physical model systems, bimetallic nanoparticles were mobile in a non-geological porous medium and relatively immobile in a geological porous medium. In the non-geological porous medium, we found that adding a second metal (e.g., Pd) to nano-Fe0 particles significantly improved their functionality and performance (e.g., mobility and suspension). For example, the results from mobility experiments using columns packed with glass beads showed that the effluent iron concentration was <6 % of the influent iron concentration for the nano-Fe0 particles, while it was ~100 % for the nano-Pd-Fe0 particles. In the geological porous medium, based on visual inspection, nano-Pd-Fe0 particles could not travel more than a few centimeters into columns packed with CFB Borden sand, and no iron was detected in the effluent. To overcome the delivery issue in porous media, nano-Pd-Fe0 particles were injected to create a zone of activation to activate S2O82- for the treatment of TCE source zone. However, we found that the TCE mass destruction was only 9 % higher in the nano-Pd-Fe0 activated S2O82- system compared to the non-activated S2O82- system as revealed by the effluent chloride concentration. In addition, the activation zone composed of nano-Pd-Fe0 particles was rapidly deactivated after exposure to persulfate as visually observed by color change, indicating that the longevity of the activation zone is limited. This research effort provides a contribution to the field of ISCO by evaluating the potential utility and applicability of a new class of activators for some common peroxygens.

Recently, metal nanoparticles have attracted the attention of researchers in several fields of study due to their high surface area and other unique properties. Using metal nanoparticles as a component of an in situ chemical oxidation (ISCO) system is emerging and hence very little information is available. In this research, nano zero valent iron (nZVI) particles and iron-based bimetallic zero valent nanoparticles (BZVNs) were employed to activate some common peroxygens (hydrogen peroxide (H2O2), persulfate (S2O82-), and peroxymonosulfate (HSO5-)) to degrade hazardous organic compounds. Aqueous and soil slurry batch systems were used along with a one-dimensional physical model. The results from the aqueous batch systems showed that nZVI is a promising activator for S2O82- compared to other conventional iron activators (e.g., granular-ZVI and Fe2+). For example, the initial trichloroethylene (TCE) reaction rate by nZVI activated S2O82- was 1.11 x 10-4 M L-1 min-1 compared to an initial reaction rate of 6.25 x 10-5 M L-1 min-1, 5.18 x 10-6 M L-1 min-1, and 1.8 x 10-7 M L-1 min-1 for Fe2+ activated S2O82-, granular-ZVI activated S2O82-, and non-activated S2O82-, respectively. However, the surfaces of nZVI particles were passivated quickly following exposure to S2O82-, causing the reaction rate to reduce to a magnitude representative of an un-activated S2O82- system. An iron-sulfate (FeSO4) complex was formed on the surfaces of the nZVI particles following exposure to S2O82- compared to the iron oxyhydroxide (FeOOH) layer that was present on fresh nZVI surfaces. BZVNs showed better treatment effectiveness than nZVI particles as activators for H2O2, S2O82-, and HSO5-. For example, the TCE reaction rate constant for nano-Ag-Fe0 activated H2O2 was 9 to 18 fold higher than that for nZVI activated H2O2. Of the nine different BZVNs investigated as activators, the greatest TCE degradation was achieved by nano-Pd-Fe0 and nano-Zn-Fe0 activated S2O82- system, nano-Co-Fe0 activated HSO5- system, and nano-Ag-Fe0 activated H2O2 system. For all of these systems, an increase in the dosage of nanoparticles and peroxygens increased TCE degradation. The activated H2O2 system showed a lower TCE degradation rate compared to either the activated S2O82- or the activated HSO5- systems, suggesting that a bridged group complex is formed between the activators and H2O2. The dissolved TCE concentration remaining in the soil slurry batch systems after using the nano-Pd-Fe0 activated S2O82- system was two to three fold higher than that in an aqueous batch system. Furthermore, for five different aquifer materials used, the higher mass of aquifer materials the lower the TCE degradation, indicating that the aquifer materials compete with a target organic compound in the presence of activated S2O82-. A linear relationship was observed between the organic carbon (OC) content and the initial TCE decomposition rate. Although there is no direct evidence of the effect of OC on the treatment system, it is suggested that the OC may result in scavenging the generated free radicals or by directly consuming persulfate. In the one-dimensional physical model systems, bimetallic nanoparticles were mobile in a non-geological porous medium and relatively immobile in a geological porous medium. In the non-geological porous medium, we found that adding a second metal (e.g., Pd) to nano-Fe0 particles significantly improved their functionality and performance (e.g., mobility and suspension). For example, the results from mobility experiments using columns packed with glass beads showed that the effluent iron concentration was <6 % of the influent iron concentration for the nano-Fe0 particles, while it was ~100 % for the nano-Pd-Fe0 particles. In the geological porous medium, based on visual inspection, nano-Pd-Fe0 particles could not travel more than a few centimeters into columns packed with CFB Borden sand, and no iron was detected in the effluent. To overcome the delivery issue in porous media, nano-Pd-Fe0 particles were injected to create a zone of activation to activate S2O82- for the treatment of TCE source zone. However, we found that the TCE mass destruction was only 9 % higher in the nano-Pd-Fe0 activated S2O82- system compared to the non-activated S2O82- system as revealed by the effluent chloride concentration. In addition, the activation zone composed of nano-Pd-Fe0 particles was rapidly deactivated after exposure to persulfate as visually observed by color change, indicating that the longevity of the activation zone is limited. This research effort provides a contribution to the field of ISCO by evaluating the potential utility and applicability of a new class of activators for some common peroxygens.

The presence of coal tars in the subsurface associated with former manufactured gas plants (MGPs) offers a remediation challenge due to their complex chemical composition, dissolution behaviour and recalcitrant characteristics. A former MGP site in Clearwater Beach, Florida was characterized and bench-scale analyses were conducted to assess the potential for in situ chemical oxidation (ISCO) using persulfate to treat MGP residuals. Completion of a conceptual site model identified a homogeneous, silty sand aquifer, with an average hydraulic conductivity of approximately 2.3x10-3 cm/s and a groundwater flow rate of 2 cm/day in the direction of S20°E. Six source zones, three near the water table and three in the deep aquifer were estimated to have a total volume of 108 m3. A multi-level well transect was installed to monitor concentrations of dissolved compounds and to estimate mass discharge downgradient of the source zones over time. On average, the morphology of the aqueous concentrations remained consistent with time. A total mass discharge across the transect of 94 mg/day was estimated for site-specific compounds. Bench-scale tests were conducted on aquifer sediments and groundwater samples. The aquifer was determined to have a low buffering capacity, low chemical oxygen demand, and low natural oxidant interaction (NOI) with persulfate. Aqueous batch experiments identified the potential for iron (II) activated persulfate to reduce concentrations of BTEX and PAHs below method detection limits (MDLs). Unactivated persulfate was able to reduce BTEX concentrations to below MDLs after 14 days; however, the concentration of PAH compounds remained above MDLs after 14 days. Higher iron doses within the system were shown to be more effective in reducing BTEX and PAH compounds. Column experiments designed to mimic site conditions were used to evaluate the feasibility of persulfate treatment on impacted sediments from the Clearwater site. Two sets of column experiments were conducted: one using unactivated persulfate followed by alkaline activated persulfate; and one using iron (II) activated persulfate. On average, unactivated persulfate was able to reduce BTEX and PAH aqueous effluent concentrations by > 75% and 40%, respectively, after a total dose of 60 g/g soil. Two additional doses of alkaline activated persulfate (total persulfate dose of ~80g/g soil) in these columns were able to further reduce effluent BTEX and PAH concentrations by > 90% and > 75%, respectively. Iron (II) activated persulfate reduced effluent BTEX concentrations by > 70% and PAHs by > 65% after a total dose of 35 g/g soil. Average reductions in mass for BTEX and PAH compounds were approximately of 48% and 26% respectively in the iron (II) activated persulfate columns, and 24% and 10%, respectively in the alkaline activated persulfate columns. The potential for the ability to use in situ chemical oxidation using persulfate for the remediation of MGP residuals in the subsurface is evaluated using field measurements and bench-scale experimentation. The reductions observed in aqueous phase compounds in MGP groundwater as observed in the laboratory indicate the potential for reductions in groundwater concentrations at this and other contaminated former MGP sites. However, column experiments, indicating the inability for activated persulfate to reduce all identified compounds in the MGP NAPL suggest source treatment with activated persulfate would not reduce concentrations to below Florida Department of Environmental Protection natural attenuation concentrations.

Abstract This work investigates the kinetics of the emulsion polymerization of vinyl acetate. Several aspects of this system have been clarified, including the induced decomposition of persulfate, retardation by oxygen and entry by, and analysis of, the aqueous phase oligomeric radicals. It has been shown that the retardation period observed in the emulsion polymerization of VAc can be explained by the effect of traces of oxygen (< 10-6 M) on the entry efficiency of the initiator-derived aqueous-phase oligomeric radicals. Comparison of rates of polymerization in V and persulfate -initiated polymerizations together with electrospray mass spectrometry of aqueous phase oligomers, has shown that the mechanism for the induced decomposition of persulfate by vinyl acetate is chain transfer to initiator from aqueous-phase oligomeric radicals. A value has been determined for the rate coefficient for transfer to initiator, by fitting literature data to a model based on this mechanism. The reported independence of the rate of polymerization from the monomer concentration in the emulsion polymerization of vinyl acetate has been investigated. Possible explanations for this behaviour have been proposed and tested in this work, by measuring radical-loss rates directly with y-relaxation techniques. Although the Y relaxations were found to be affected by experimental artefacts, it has been demonstrated that rapid exit is not responsible for the high radical-loss rates in this system. The major artefact identified in the y relaxations was the significant effect of relatively small exotherms on relaxation behaviour, Methodologies were developed for correcting affected data and for avoiding exotherms under certain conditions. Arrhenius parameters were determined for the rate coefficient for chain transfer to monomer using the In^M method, which utilises the whole MWD. This section of the work is incomplete, for reasons detailed in chapter 5. However, as a preliminary indication it was found that the frequency factor was 106.38 M-1 s-1 and the activation energy was 38.8 kJ mol-1.

PFAS are a group of relatively newly discovered man-made pollutants. PFAS contains a C-F bond which is one of the strongest bonds in organic chemistry. Therefore, PFAS are not easily degradable and, once release into nature, are very persistent. PFAS are also labile in natural environments and therefore, they can sometimes be found far from the source of pollution. Their persistent and labile nature, in combination with their bioaccumulation ability and human health effects make of this compounds an important contaminant to take care of. Currently there are not stablish, wellfunctioning methods to treat contaminated soils and waters. A lot of research is performed at the moment to find good treatment options. In this work a test to chemically degraded spiked samples of PFOA, PFOS and PFBA was performed. By means of experimental design tools, we aim to evaluate which operational factors are relevant for this treatment. Best results when using hydrogen peroxide as a reactant was 70% degradation for PFOS and 42% degradation for PFOA. When persulfate was used as a reactant, a 57% degradation of PFOS, 99% degradation of PFOA and 99% degradation of PFBA was achieved.

Il existe en France des centaines de friches industrielles polluées par du goudron de houille, un mélange récalcitrant de composés tels que les hydrocarbures aromatiques polycycliques. Lorsque la zone non saturée des sols est fortement contaminée, elle est usuellement excavée et remblayée. Cette thèse porte sur un traitement alternatif permettant une valorisation potentielle des sols sur site : l’oxydation chimique in situ, qui a déjà montré des résultats encourageants au laboratoire mais n’a que très peu été testée en grandeurs réelles. Les recherches ont donc été menées autour de trois échelles – bibliographie, laboratoire et pilote – afin de déterminer s’il existait un traitement oxydant répondant à des critères techniques, économiques et environnementaux acceptables pour être appliquée à l’échelle de la friche. La phase laboratoire a montré que l’ajout d’un soutien thermique augmentait significativement l’efficacité du traitement, i) par augmentation de la disponibilité de la pollution par préchauffage de la terre dans le cas du permanganate, ou ii) par activation thermique de l’oxydant dans le cas du persulfate. A l’échelle du pilote, une mise en contact homogène entre l’oxydant et la pollution n’a été possible que par noyage partiel de la terre avec les solutions oxydantes concentrées. L’activation du persulfate s’est révélée délicate à mettre en œuvre, le chauffage de solutions concentrées ayant mené à une décomposition parasite de l’oxydant. Au contraire, l’utilisation de solutions concentrées de permanganate a conduit à une dégradation des polluants encore plus élevée qu’au laboratoire grâce à la forte exothermicité de la réaction / In France, hundreds of brownfields are currently polluted with coal tar, a complex and recalcitrant mixture of organic compounds such as polycyclic aromatic hydrocarbons. When the unsaturated zone of soils is highly contaminated, it is commonly excavated and backfilled. This work deals with an alternative treatment, in situ chemical oxidation, that allows a potential reuse of soils directly on site. This technique has already provided encouraging results at the lab scale but has rarely been tested in the field. Research was made around three scales – bibliography, laboratory and pilot – in order to respond to the main problem: is there an oxidative treatment able to meet technical, economic and environmental criteria quite acceptable to be applied at brownfield level? The laboratory research phase showed that the addition of a moderate thermal support significantly increased treatment effectiveness, by i) an increase in pollutant availability by soil preheating in the case of permanganate, or ii) a thermal activation of the oxidant in the case of persulfate. At the pilot scale, a homogeneous contact between the oxidant and the pollutants was possible only by a partial flooding of the soil with the concentrated oxidizing solutions. The persulfate activation turned out to be difficult to implement because heating concentrated solutions led to a parasite decomposition of the oxidant. On the contrary, the use of concentrated solutions of permanganate led to an even higher degradation than in the laboratory, as a result of the strong exothermicity of the reaction

In this Thesis either advanced oxidation or reductive processes are investigated for the degradation of two pesticides considered persistent in the environment: amicarbazone (AMZ) and chlorpyrifos (CP). In chapter I, different advanced oxidation processes (AOPs) driven by sulfate (SO4o-) and hydroxyl radicals (oOH) were applied to the degradation of AMZ. In the first study, several persulfate (PS) activated reactions were explored for AMZ degradation, namely activation with UVA radiation, Fe(II) and H2O2, as well as the combination of UVA radiation with Fe(II), Fe(III) and Fe(III)-complexes. Here, the influence of different reaction variables, such as solution pH, reactants and pesticide initial concentrations, addition of a second oxidant (H2O2) and the addition of different iron catalysts were also investigated. Control experiments regarding the photolysis of iron species in the absence of PS captured our interest and, with the aim of exploring more deeply this process on AMZ degradation, a second investigation was carried out. In this second study, a Doehlert experimental design was applied to investigate the simultaneous effects of two variables on AMZ degradation: pH and Fe(III):carboxylate ratio, where the carboxylate could be oxalate, citrate or tartrate. A response surface model for the observed degradation rate (kobs) as a function of pH and Fe(III):carboxylate ratio was obtained. The processes explored in both aforementioned studies revealed to be effective for AMZ removal, although nothing is known yet about their effectiveness regarding toxicity removal. Given that, a third study was carried out, where the toxicity of AMZ solutions, before and after submission to the processes studied was evaluated towards five microorganisms: Vibrio fischeri (acute toxicity), Tetrahymena thermophile, Chlorella vulgaris (chronic toxicity), Escherichia coli and Bacilus subtilis (antimicrobial activity). The last investigation detailed in chapter I is related with the application of zero-valent-metals on PS activation, which is a subject that links this chapter with the following one. For that, zero-valent-iron (ZVI) was investigated as a PS activator and the influence of variables that help to assess the environmental applicability of this process. In general, organochlorine pesticides reveal a higher resistance to oxidation than reduction, the latter process preferred when the aim is to degrade that important class of contaminants. Therefore, in chapter II the reductive degradation of CP by means of zero-valent-metals and bimetallic particles was investigated. ZVI has been extensively applied for that purpose. However, besides iron, other zero-valent metals can be potential reactive materials for reductive degradation and hence, in this study, the effectiveness of Zn0 and Cu0 was also explored in comparison to that widely reported for ZVI. Furthermore, two different ways of enhancing metals reactivity were here explored: i) by coating ZVI or Zn0 with a more noble metal (Cu), in order to analyze the copper catalytic effect on the bimetallic system; ii) by different surface pretreatments. / Na presente Tese de Doutorado foram abordados tanto processos oxidativos avançados (POA), como processos redutivos por metais de valência zero, na degradação de dois pesticidas considerados persistentes no meio ambiente: amicarbazona (AMZ) e clorpirifós (CP). No capítulo I são apresentados os estudos realizados com diversos POA, mediados por radicais sulfato (SO4o-) e hidroxila (oOH), aplicados da AMZ. Num primeiro estudo foi explorada a ativação do oxidante persulfato (PS), de diferentes formas, tais como radiação UVA, H2O2 e Fe(II), assim como a combinação de radiação UVA com Fe(II), Fe(III) e complexos de Fe(III). Aqui também foram investigados os efeitos de diversas variáveis reacionais, tais como pH, concentração inicial de reagentes e de pesticida, adição de um segundo oxidante (H2O2) e adição de diferentes espécies de ferro. Os testes realizados, para efeito de controle, referentes à irradiação das espécies de Fe(III) na ausência de PS, despertaram o interesse para um estudo mais aprofundado sobre o efeito da fotólise destas espécies na degradação da AMZ, surgindo assim o segundo trabalho. Neste utilizou-se um projeto experimental de Doehlert, para avaliar o efeito de duas variáveis em simultâneo quanto à degradação da AMZ: pH e proporção Fe(III): ligante, sendo o ligante um dos seguintes carboxilatos: oxalato, citrato ou tartarato. Um modelo de superfície de resposta, que correlaciona a taxa de degradação observada (kobs) em função do pH e proporção Fe(III):ligante foi obtido para cada um dos complexos de Fe(III) estudados. Os processos explorados, tanto no primeiro como no segundo estudo, se mostraram eficazes na remoção da AMZ, porém nada se sabe acerca da remoção da toxicidade. Para tal, foi desenvolvido um terceiro estudo dedicado à avaliação da toxicidade da solução de AMZ, antes e após a aplicação de cada um dos processos anteriormente abordados, contra cinco micro-organismos: Vibrio fischeri (toxicidade aguda); Tetrahymena thermophila, Chlorella vulgaris (toxicidade crônica); Escherichia coli e Bacilus subtilis (atividade antimicrobiana). O último estudo abordado no capitulo I é referente à aplicação de metais de valência zero também nos POA, correlacionado assim o capítulo I e o capítulo II. Como tal, foi feito um estudo de ativação de PS por meio de ferro de valência zero (Fe0), em que se investigou a influência de diversas variáveis por forma a inferir sobre a aplicabilidade prática deste processo. Pesticidas organoclorados apresentam maior resistência à degradação por processos oxidativos do que redutivos, sendo preferível o último na degradação desta importante classe de contaminantes. Como tal, o capítulo II se refere à degradação redutiva, por meio de diferentes metais de valência zero e partículas bimetálicas, do pesticida organoclorado CP. Além do amplamente explorado Fe0, outros metais podem ser aplicados neste processo, pelo que, neste estudo, explorou-se a potencialidade de Zn0 e Cu0 comparativamente ao primeiro. Ainda neste estudo foram investigadas duas formas de aumentar a reatividade dos metais: i) no caso do Fe0 e Zn0, revestindo com um metal mais nobre (Cu), por forma a observar o efeito catalisador do último no sistema bimetálico; ii) realizando um pré-tratamento à superfície dos metais.

As técnicas de remediação para solos contaminados como os processos de oxidação avançados \"in situ\" visam essencialmente a mineralização dos contaminantes, reduzindo-os, em última instância, a CO2 e H2O. O objetivo deste estudo é apresentar os resultados de experimentos conduzidos para investigar como as características do solo, tais como a granulação, o teor e a natureza dos minerais argilosos, e o teor da matéria orgânica influem no desempenho da mineralização do contaminante linar alquilbenzeno no solo. Em várias partes da cidade de São Paulo há locais contaminados por esse e outros tipos de vazamentos e os responsáveis e as autoridades estão interessadas em possíveis soluções. Uma possível solução seria o tratamento in situ através dos processos de oxidação avançada. Porém, não há como decidir a priori sobre a melhor técnica, pois ela dependerá tanto do reagente empregado como do tipo de solo contaminado. Essa resposta poderá ser cientificamente fundamentada a partir de ensaios no laboratório desenhados para investigar os fatores que controlam a eficácia do processo. Os experimentos em laboratório foram conduzidos com dois tipos de solo da região metropolitana de São Paulo contaminados com linear alquilbenzeno, composto utilizado como óleo térmico em revestimentos de cabos subterrâneos de alta voltagem. Os desempenhos da mineralização com o Reagente de Fenton e Persulfato de Sódio foram avaliados na oxidação do composto linear alquilbenzeno com uma concentração inicial de 10 mg/grama de solo contaminado. Os resultados mostram uma redução considerável em massa de 82% a 85% do contaminante nos dois solos com a utilização de Persulfato de Sódio ativado termicamente e através de metal de transição \'Fe POT.2+\' disponível naturalmente no solo . O reagente de Fenton nas mesmas condições do experimento mostrou um desempenho mais limitado entre 10 % a 30% de redução em massa do contaminante. O conhecimento prévio das características do solo como o teor de argila , teor de carbono orgânico que influem fortemente os fenômenos de sorção e desorção e a composição mineralógica são variáveis importantes na definição dos reagentes e nas condições de reação de oxidação dos poluentes e contribuem na escolha mais acertada da tecnologia de remediação \'in situ\". / The remediation techniques used in contaminated soils such as \"in situ\" chemical oxidation aim essentially the mineralization of contaminants, reducing it to CO2 and H2O. The objective of this study is pointing out the results of experiments conducted to investigate how the soil characteristics such as granulometry, assay and nature of clay minerals as well as organic matter can influence in the mineralization performance of linear alkylbenzene in the soil. In some areas of São Paulo city there are contaminated sites by leakage of linear alkylbenzene and many other chemical leakages and site\'s responsible and local authorities are interested in possible technical solutions to clean it. One possible solution would be in situ treatment through advanced oxidation process; however there is no way how to decide about the best technique because it depends on contaminant substance, reagents used as well as the contaminated soil characteristics. The answer could be scientifically based on bench laboratory experiments properly designed to investigate the factors that control the process performance. The bench lab experiments were conducted with two soils sampled from metropolitan region of São Paulo and contaminated with linear alkyl benzene, used in high and medium voltage underground electrical cables. The mineralization performance was evaluated in soils contaminated with an initial concentration of 10 mg / gr of contaminated soil by oxidation of linear alkyl benzene with Fenton reagent and sodium persulfate. The final results pointed out a considerable mass reduction from 82% to 85% in both soils tested with sodium persulfate thermally activated and by naturally available transition metal \'Fe pot.2+\' in the soil. The Fenton reagent in the same experiment conditions pointed out a more limited mass reduction performance between 10% and 30%. The previous knowledge of soil characteristics such as clay assay , natural carbon content in the soil which influence the sorption / desorption phenomenon as well as the mineral composition of the soil are the key variables to define reagents and the oxidation reaction conditions which contribute to select a proper in situ chemical oxidation technology.

As técnicas de remediação para solos contaminados como os processos de oxidação avançados \"in situ\" visam essencialmente a mineralização dos contaminantes, reduzindo-os, em última instância, a CO2 e H2O. O objetivo deste estudo é apresentar os resultados de experimentos conduzidos para investigar como as características do solo, tais como a granulação, o teor e a natureza dos minerais argilosos, e o teor da matéria orgânica influem no desempenho da mineralização do contaminante linar alquilbenzeno no solo. Em várias partes da cidade de São Paulo há locais contaminados por esse e outros tipos de vazamentos e os responsáveis e as autoridades estão interessadas em possíveis soluções. Uma possível solução seria o tratamento in situ através dos processos de oxidação avançada. Porém, não há como decidir a priori sobre a melhor técnica, pois ela dependerá tanto do reagente empregado como do tipo de solo contaminado. Essa resposta poderá ser cientificamente fundamentada a partir de ensaios no laboratório desenhados para investigar os fatores que controlam a eficácia do processo. Os experimentos em laboratório foram conduzidos com dois tipos de solo da região metropolitana de São Paulo contaminados com linear alquilbenzeno, composto utilizado como óleo térmico em revestimentos de cabos subterrâneos de alta voltagem. Os desempenhos da mineralização com o Reagente de Fenton e Persulfato de Sódio foram avaliados na oxidação do composto linear alquilbenzeno com uma concentração inicial de 10 mg/grama de solo contaminado. Os resultados mostram uma redução considerável em massa de 82% a 85% do contaminante nos dois solos com a utilização de Persulfato de Sódio ativado termicamente e através de metal de transição \'Fe POT.2+\' disponível naturalmente no solo . O reagente de Fenton nas mesmas condições do experimento mostrou um desempenho mais limitado entre 10 % a 30% de redução em massa do contaminante. O conhecimento prévio das características do solo como o teor de argila , teor de carbono orgânico que influem fortemente os fenômenos de sorção e desorção e a composição mineralógica são variáveis importantes na definição dos reagentes e nas condições de reação de oxidação dos poluentes e contribuem na escolha mais acertada da tecnologia de remediação \'in situ\". / The remediation techniques used in contaminated soils such as \"in situ\" chemical oxidation aim essentially the mineralization of contaminants, reducing it to CO2 and H2O. The objective of this study is pointing out the results of experiments conducted to investigate how the soil characteristics such as granulometry, assay and nature of clay minerals as well as organic matter can influence in the mineralization performance of linear alkylbenzene in the soil. In some areas of São Paulo city there are contaminated sites by leakage of linear alkylbenzene and many other chemical leakages and site\'s responsible and local authorities are interested in possible technical solutions to clean it. One possible solution would be in situ treatment through advanced oxidation process; however there is no way how to decide about the best technique because it depends on contaminant substance, reagents used as well as the contaminated soil characteristics. The answer could be scientifically based on bench laboratory experiments properly designed to investigate the factors that control the process performance. The bench lab experiments were conducted with two soils sampled from metropolitan region of São Paulo and contaminated with linear alkyl benzene, used in high and medium voltage underground electrical cables. The mineralization performance was evaluated in soils contaminated with an initial concentration of 10 mg / gr of contaminated soil by oxidation of linear alkyl benzene with Fenton reagent and sodium persulfate. The final results pointed out a considerable mass reduction from 82% to 85% in both soils tested with sodium persulfate thermally activated and by naturally available transition metal \'Fe pot.2+\' in the soil. The Fenton reagent in the same experiment conditions pointed out a more limited mass reduction performance between 10% and 30%. The previous knowledge of soil characteristics such as clay assay , natural carbon content in the soil which influence the sorption / desorption phenomenon as well as the mineral composition of the soil are the key variables to define reagents and the oxidation reaction conditions which contribute to select a proper in situ chemical oxidation technology.