Sonochemical decomposition of phenol: evidence for a synergistic effect of ozone and ultrasound for the elimination of total organic carbon

2006 ◽  
Vol 6 (3) ◽  
pp. 71-78
Author(s):  
T. Lesko ◽  
A.J. Colussi ◽  
M.R. Hoffmann
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Synergistic Effects ◽  
Phenol Degradation ◽  
Ultrasonic Power ◽  
Intermediate Species ◽  
Oxidation Processes ◽  
The Individual

The degradation of phenol (C6H5OH) was investigated under sonication, ozonation, and the combination of sonication and ozonation. The coupling of these two oxidation processes yielded phenol degradation kinetics that are similar to those predicted from the linear combination of the individual sonication and ozonation experiments. However, synergistic effects of sonolytic ozonation were observed for the reduction of the total organic carbon (TOC) in these systems. The rate of TOC decomposition was found to be proportional to both the aqueous steady-state ozone concentration and the ultrasonic power density. At 358 kHz, sonication combined with ozonation enhanced TOC loss rates by 43% over the sum of the rates obtained by the separate treatments. Intermediate species detected during the degradation of phenol indicate that while the primary degradation products are efficiently degraded by simple ozonolysis, the simultaneous addition of ultrasonic irradiation is necessary to degrade the more recalcitrant unsaturated daughter products.

Evaluation of the total organic carbon of source rocks in lacustrine basins using the variable-coefficient ΔLgR technique — A case study of the Xujiaweizi Fault Depression in the Songliao Basin

2019 ◽  
Vol 7 (4) ◽  
pp. SJ67-SJ75
Author(s):  
Chao Liu ◽  
Lidong Sun ◽  
Jijun Li ◽  
Shuangfang Lu ◽  
Lei Tian ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Variable Coefficient ◽  
Prediction Equation ◽  
Songliao Basin ◽  
Source Rocks ◽  
High Quality ◽  
Natural Gamma ◽  
The Individual ◽  
Fourth Member

To lay the foundation for the exploration of shale gas, we calculated the total organic carbon (TOC) of Shahezi Formation source rocks in the Xujiaweizi Fault Depression in the Songliao Basin by using the measuring data and the logging curves. Because the source rocks in the study area were formed in a lacustrine basin, they are characterized by strong organic heterogeneity, making it difficult to objectively characterize any changes in the TOC of the underground source rocks based on discrete and limited sampling. In addition, because the source rock is relatively rich in shale and poor in organic matter, the logging response features of high natural gamma, medium-high interval transit time, and medium-low resistivity, making it easily identified. However, because the logging parameters to predict the TOC of source rocks are not universal, it is impossible to establish a prediction equation that is universally applicable. To solve the above problems, we used the variable-coefficient [Formula: see text] technique to predict the TOC of the source rocks in the study area. We defined the two key parameters that affect the TOC prediction in the classic [Formula: see text] technique as the undetermined coefficients, and the coefficients were determined according to the logging and geologic data of the individual wells. The application results indicate that the variable-coefficient [Formula: see text] technique has an average relative error of 17.5% in the prediction of the TOC, which is 16.1% lower than that of the classic [Formula: see text] technique. Thus, the prediction results can effectively reflect the vertical variation in the TOC of source rocks. Based on the logging evaluation results for the TOC of source rocks in 35 wells throughout the study area, the thickness of the high-quality source rocks in the fourth member of the Shahezi Formation was mapped. The thickness of the high-quality source rocks in the fourth member of the Shahezi Formation is generally [Formula: see text]. There are two centers of greater thickness in the plane, with the maximum thickness of more than 70 m.

scholarly journals Oxidación electroquímica para la degradación de ciprofloxacíno asistida con radiación ultravioleta utilizando ánodos dimensionalmente estables

2020 ◽  
Author(s):  
◽  
Angel Eduardo Yañez Rios
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
High Performance ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Visible Spectroscopy ◽  
Oxidation Processes ◽  
Dimensionally Stable Anode

Numerosos reportes han descrito un aumento de los productos farmacéuticos y de cuidado personal, detectados en diversos cuerpos de agua durante los últimos años. Su continua detección es un riesgo, ya que puede significar una afectación directa hacia el ecosistema. La presencia de este tipo de contaminantes en efluentes de plantas de tratamiento de aguas residuales, demuestran las bajas eficiencias de degradación por los métodos convencionales. Debido a lo anterior, alternativas como los procesos de oxidación avanzada (AOPs, Advanced Oxidation Processes) han ganado interés, por la producción de especies oxidantes capaces de degradar compuestos altamente recalcitrantes. El acoplar dos o más AOPs, puede favorecer el aumento en la producción de agentes oxidantes (HOCl, .OH), así como incrementar la eficiencia de degradación y mineralización de contaminantes. Con este último propósito, se realizó la degradación de ciprofloxacino (20 ppm) al implementar un sistema electroquímico foto-asistido, donde se utilizó un electrodo de RuO2 como ánodo dimensionalmente estable (DSA, Dimensionally Stable Anode), sintetizado mediante el método de Pechini, en conjunto con una fuente de radiación de 254 nm y soluciones de 0.05M de NaCl como fuente de cloruros. Además, se estudió el comportamiento del sistema foto-electrocatalítico en condiciones de pH 3, 6 y 9, con ayuda de la imposición de densidades de corriente de 5 y 10 mA cm−2, ocurriendo entonces, la electrogeneración de especies de cloro activo, así como reacciones de homólisis de las mismas para la degradación del ciprofloxacino. Los productos de los sistemas se evaluaron por medio de espectroscopía UV (UV-Vis, Ultraviolet-Visible Spectroscopy), cromatografía de líquidos de alta resolución (HPLC, High Performance Liquid Chromatography) y carbono orgánico total (TOC, Total Organic Carbon). Los resultados indicaron mayor eficiencia durante el proceso a condiciones de pH 6 e imposición de 10 mA cm-2, obteniendo una mineralización promedio del 69.4±5.6%, del contaminante a 60 minutos, mientras que la degradación del contaminante ocurrió durante los primeros 5 minutos del proceso.

Photochemical Degradation of Organics in Water

1992 ◽  
Vol 27 (1) ◽  
pp. 123-138 ◽  
Author(s):  
P. L. Yue ◽  
O. Legrini
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Power Law ◽  
Advanced Oxidation Processes ◽  
Threshold Value ◽  
Photochemical Degradation ◽  
Mercury Lamp ◽  
Oxidation Processes ◽  
Uv Ozone

Abstract Trichloroethylene, phenol, 4-cholorophenol, catechol and a pesticide were degraded by two advanced oxidation processes: photolytic oxidation with hydrogen peroxide, andphotolytic oxidation with ozone. The reactions were studied in a batch photoreactor with a low pressure mercury lamp as the radiation source. The variation of the concentration of total organic carbon with time was measured. For the organics studied, the reaction kinetics for the reduction of total organic carbon (TOC) were found to follow a power law. The exponent of the power law varies with the initial TOC concentration. Results show that TOC can be very effectively reduced provided the concentration of hydrogen peroxide used exceeds a certain threshold value. The UV/Ozone process yielded a more rapid rate of degradation and a greater degree of mineralisation.

scholarly journals Intermolecular Interactions in the Membrane Filtration of Highly Alkaline Steeping Lye

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 88
Author(s):  
Klaus Schlackl ◽  
Richard Herchl ◽  
Lukas Almhofer ◽  
Robert H. Bischof ◽  
Karin Fackler ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Organic Acids ◽  
Total Organic Carbon ◽  
Intermolecular Interactions ◽  
Membrane Filtration ◽  
Degradation Products ◽  
Hydroxy Acids ◽  
Retention Efficiency ◽  
Organic Carbon Concentration ◽  
The Impact

The reuse of steeping lye is crucial for the sustainable production of viscose fibers. Steeping lye contains hemicellulose and many alkaline degradation products, such as organic acids, so that its purification can be evaluated in terms of total organic carbon removal. When considering purification by membrane filtration, intermolecular interactions between hemicellulose and organic acids can strongly affect their retention efficiency. Herein, we give more insights into the ultrafiltration and nanofiltration of steeping lye and corresponding model solutions. Furthermore, we studied the impact of total organic carbon concentration, hemicellulose concentration and sodium hydroxide concentration on the membrane performance. Hydrogen bonds between hemicellulose and certain types of hydroxy acids increased the retention of the latter. In contrast, charge based repulsion forces led to a decreased retention of a certain type of hydroxy acids. It can be clearly shown that taking intermolecular interactions into account is highly important for the description of complex multicomponent mixtures. In addition, the results can be extended to other, highly alkaline process streams with organic content, such as Kraft pulping liquors.

CHARACTERISATION OF DISSOLVED ORGANIC CARBON (DOC) LEACHED FROM LEAVES IN WATER

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Markus Heryanto Langsa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry ◽  
Pinus Radiate

<p>Penelitian ini bertujuan untuk menentukan senyawa organik khususnya organic karbon terlarut (DOC) dari dua spesies daun tumbuhan (<em>wandoo eucalyptus </em>and <em>pinus radiate, conifer</em>) yang larut dalam air selama periode 5 bulan leaching eksperimen. Kecepatan melarutnya senyawa organic ditentukan secara kuantitatif dan kualitatif menggunakan kombinasi dari beberapa teknik diantaranya Total Organic Carbon (TOC) analyser, Ultraviolet-Visible (UV-VIS) spektrokopi dan pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).</p><p>Hasil analisis DOC dan UV menunjukkan peningkatan yang tajam dari kelarutan senyawa organic di awal periode pengamatan yang selanjutnya berkurang seiring dengan waktu secara eksponensial. Jumlah relatif senyawa organic yang terlarut tergantung pada luas permukaan, aktifitas mikrobiologi dan jenis sampel tumbuhan (segar atau kering) yang digunakan. Fluktuasi profil DOC dan UV<sub>254</sub> disebabkan oleh aktifitas mikrobiologi. Diperoleh bahwa daun kering lebih mudah terdegradasi menghasilkan senyawa organic dalam air dibandingkan dengan daun segar. Hasil pyrolysis secara umum menunjukkan bahwa senyawa hidrokarbon aromatic dan fenol (dan turunannya) lebih banyak ditemukan pada residue sampel setelah proses leaching kemungkinan karena adanya senyawa lignin atau aktifitas humifikasi mikrobiologi membuktikan bahwa senyawa-senyawa tersebut merupakan komponen penting dalam proses karakterisasi DOC.</p>

Stabilization of Organic Carbon and Nitrogen in Consolidating Benthal Deposits

1985 ◽  
Vol 17 (6-7) ◽  
pp. 929-940 ◽  
Author(s):  
C. W. Bryant ◽  
L. G. Rich
Keyword(s):  
Organic Carbon ◽  
Model Verification ◽  
Volatile Acid ◽  
Free Energies ◽  
Organic Loading ◽  
Carbon And Nitrogen ◽  
Loading Rates ◽  
Degradation Reactions ◽  
The Individual ◽  
Organic Deposits

The objective of this research was to develop and validate a predictive model of the benthal stabilization of organic carbon and nitrogen in deposits of waste activated sludge solids formed at the bottom of an aerated water column, under conditions of continual deposition. A benthal model was developed from a one-dimensional, generalized transport equation and a set of first-order biological reactions. For model verification, depth profiles of the major interstitial carbon and nitrogen components were measured from a set of deposits formed in the laboratory at 20°C and a controlled loading rate. The observed sequence of volatile acid utilization in each benthal deposit was that which would be predicted by the Gibbs free energies of the individual degradation reactions and would be controlled by the reduction in interstitial hydrogen partial pressure with time. Biodegradable solids were solubilized rapidly during the first three weeks of benthal retention, but subsequent solubilization occurred much more slowly. The benthal simulation effectively predicted the dynamics of consolidating, organic deposits. Simulation of organic loading rates up to 250 g BVSS/(m2 day) indicated that the stabilization capacity of benthal deposits was far above the range of organic loading rates currently used in lagoon design.

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