Dissolved organic carbon retention by coprecipitation during the oxidation of ferrous iron

Sodano, Marcella; Lerda, Cristina; Nisticò, Roberto; Martín, María; Magnacca, Giuliana; Celi, Luisella; Said-Pullicino, Daniel

doi:10.1016/j.geoderma.2017.07.022

Cited by 97 publications

(39 citation statements)

References 53 publications

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“…LC‐DAD‐ESI‐MS results showed similar trends of a loss of aromatic species upon aeration of anoxic water, and corresponded closely to previous studies showing loss of low H:C species, such as unsaturated polyphenols and highly condensed aromatic forms that are prone to associate with Fe (III) (Dadi et al, 2017; Riedel et al, 2013; Sodano et al, 2017). Unsaturated polyphenols and some aliphatic forms were dominant in the treatment with peat‐particles, while condensed aromatic forms were more dominant in the filtered treatment.…”

Section: Discussionsupporting

confidence: 88%

Particles and Aeration at Mire‐Stream Interfaces Cause Selective Removal and Modification of Dissolved Organic Matter

et al. 2020

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Peatlands are dominant sources of dissolved organic matter (DOM) to boreal inland waters and play important roles in the aquatic carbon cycle. Yet before peat-derived DOM enters aquatic networks, it needs to pass through peat-stream interfaces that are often characterized by transitions from anoxic or hypoxic to oxic conditions. Aeration at these interfaces may trigger processes that impact the DOM pool, and its fate downstream. Here we experimentally assessed how the aeration of iron-and organic-rich mire-waters influences biodegradation, particle-formation, and modification of DOM. In addition, we investigated how suspended peat-derived particles from mires may influence these processes. We found that within 5 days of aeration, 20% of the DOM transformed into particulate organic matter (POM). This removal was likely due to combination of mechanisms including coprecipitation with oxidized iron, aggregation, and DOM-adsorption onto peat-derived particles. Peat-derived particles promoted microbial activity, but biodegradation was a minor loss mechanism of DOM removal. Interestingly, microbial respiration accounted for only half of the oxygen loss, suggesting substantial nonrespiratory oxygen consumption. The differences observed in DOM characteristics between anoxic and aerated treatments suggest that hydrophilic, aromatic DOM coprecipitated with iron oxides in aerated samples, and the corresponding C:N analysis of generated POM revealed that these organic species were nitrogen-poor. Meanwhile, POM formed via adsorption onto peat-derived particles generated from nonaromatic DOM and more nitrogen-rich species. Hence, selective removal of DOM, dissolved iron, and thus oxygen may be important and overlooked processes in mire-dominated headwater systems. Plain Language Summary Substantial amounts of dissolved organic matter are discharged from boreal peatlands into small streams and delivered to downstream rivers and lakes, impacting water quality, freshwater ecology, and the aquatic carbon cycle. About half of this dissolved organic matter is processed and removed during downstream transport, mainly via degradation and CO 2 emission, but also through particle formation and sedimentation. Less is known about the processing in upstream systems, where peat-water emerges into small streams. These peat-stream interfaces are characterized by rapid transitions from anoxic to oxic conditions. Since oxygen exposure may promote both microbial activity and chemical reactions, e.g., coprecipitation with iron, these interfaces might be critical locations for dissolved organic matter transformations. Here we experimentally study microbial and nonbiological processing of dissolved organic matter when anoxic mire-waters are aerated. We also assess how particles found in the peat-water may stimulate these processes. Our results suggest significant nonbiological particle formation and modification of the dissolved organic matter pool when anoxic waters from peatlands are first delivered to streams. In addition, we find that natural pa...

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Section: Discussionsupporting

confidence: 88%

Particles and Aeration at Mire‐Stream Interfaces Cause Selective Removal and Modification of Dissolved Organic Matter

et al. 2020

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“…The quantification was realized by means of an external calibration (i.e., Fe(II) standards concentration 0.1, 0.5, 1.0, and 5.0 mg·L −1 ). Additionally, in order to evaluate the total iron amount (i.e., Fe(II) + Fe(III)), a spatula tip of ascorbic acid was added to the supernatant prior to the colorimetric test; this way also Fe(III) was reduced to Fe(II) [ 40 ], allowing the determination of the total iron concentration.…”

Section: Methodsmentioning

confidence: 99%

New Insights on the Photodegradation of Caffeine in the Presence of Bio-Based Substances-Magnetic Iron Oxide Hybrid Nanomaterials

et al. 2018

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The exploitation of organic waste as a source of bio-based substances to be used in environmental applications is gaining increasing interest. In the present research, compost-derived bio-based substances (BBS-Cs) were used to prepare hybrid magnetic nanoparticles (HMNPs) to be tested as an auxiliary in advanced oxidation processes. Hybrid magnetic nanoparticles can be indeed recovered at the end of the treatment and re-used in further water purification cycles. The research aimed to give new insights on the photodegradation of caffeine, chosen as marker of anthropogenic pollution in natural waters, and representative of the contaminants of emerging concern (CECs). Hybrid magnetic nanoparticles were synthetized starting from Fe(II) and Fe(III) salts and BBS-C aqueous solution, in alkali medium, via co-precipitation. Hybrid magnetic nanoparticles were characterized via X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The effect of pH, added hydrogen peroxide, and dissolved oxygen on caffeine photodegradation in the presence of HMNPs was assessed. The results allow for the hypothesis that caffeine abatement can be obtained in the presence of HMNPs and hydrogen peroxide through a heterogeneous photo-Fenton mechanism. The role of hydroxyl radicals in the process was assessed examining the effect of a selective hydroxyl radical scavenger on the caffeine degradation kinetic.

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“…A associação com a matéria orgânica não acontece apenas com os íons de Fe(III). Diversos estudos indicam a ocorrência de um complexo Fe(II)-orgânico estável (TÓMBACZ et al 2004, JIANG et al 2014, CHEN et al 2015, BHATTACHARYYA et al 2017, SODANO et al 2017, YE et al 2017. Além desse mecanismo, há a possibilidade da própria matéria orgânica dissolvida, como ácidos húmicos e fúlvicos, ser adsorvida por minerais ricos em Fe(II) e Fe(III), como hematita, magnetita e goethita (TÓMBACZ et al 2004, YE et al 2017, USMAN et al 2018.…”

Section: Ferro(iii) X Matéria Orgânica X Cromo(vi)unclassified

Mecanismos de remoção de Cromo(VI) do solo pela interação entre matéria orgânica e Ferro(III)

et al. 2019

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A contaminação do solo e águas por cromo (Cr) tem ocorrido frequentemente em áreas industriais e em suas proximidades, muitas vezes devido a acidentes e, também, ao mal gerenciamento de seus resíduos. O cromo na forma hexavalente (Cr(VI)) é extremamente tóxico e cancerígeno, enquanto que na forma trivalente (Cr(III)) e em níveis traço é considerado benéfico aos seres humanos e animais. O presente estudo apresenta uma revisão sobre os principais mecanismos relacionados à interação do Cr(VI) com alguns componentes do solo, quando associado a um evento de contaminação do meio. Observa-se que os principais agentes responsáveis pela remoção do Cr(VI) do meio são aqueles capazes de reduzi-lo à forma trivalente (Cr(III)), como a fração orgânica do solo e o Fe(II). No entanto, minerais e compostos ricos em Fe(III) também podem auxiliar na redução do Cr(VI). Nesse caso, o Fe(III) pode ser reduzido pelo carbono orgânico à forma divalente que, por sua vez, reduz o cromo à forma trivalente, imobilizando-o no solo. Para que isso ocorra, além da presença de matéria orgânica, o pH ácido do meio também auxilia nesse processo – cujas condições são comumente encontradas em solos tropicais, como o Latossolo Vermelho. Portanto, entender como o Cr(VI) reage com os principais componentes do solo é muito importante para auxiliar nos processos de remediação de áreas contaminadas.

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Dissolved organic carbon retention by coprecipitation during the oxidation of ferrous iron

Cited by 97 publications

References 53 publications

Particles and Aeration at Mire‐Stream Interfaces Cause Selective Removal and Modification of Dissolved Organic Matter

Particles and Aeration at Mire‐Stream Interfaces Cause Selective Removal and Modification of Dissolved Organic Matter

New Insights on the Photodegradation of Caffeine in the Presence of Bio-Based Substances-Magnetic Iron Oxide Hybrid Nanomaterials

Mecanismos de remoção de Cromo(VI) do solo pela interação entre matéria orgânica e Ferro(III)

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