Biodegradability enhancement of refractory pollutants by ozonation: a laboratory investigation on an azo-dyes intermediate

1998 ◽  
Vol 38 (4-5) ◽  
pp. 239-245 ◽  
Author(s):  
A. Lopez ◽  
G. Ricco ◽  
G. Mascolo ◽  
G. Tiravanti ◽  
A. C. Di Pinto ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Organic Carbon ◽  
Laboratory Investigation ◽  
Azo Dyes ◽  
Room Temperature ◽  
Carbonic Acid ◽  
Ozone Treatment ◽  
Alkaline Ph ◽  
Degradation Reactions ◽  
By Products

The effectiveness of ozone treatment for improving the biodegradability of recalcitrant pollutants has been proved by investigating the ozonation reaction of FAST-VIOLET-B (FVB) a bioresistant chemical intermediate of azo-dyes. Laboratory scale experiments have been carried out, at room temperature, by bubbling, for 90 min, ozonated air (9ppmO3/min) into 0.35 1 of an alkaline (pH=11) aqueous solution (50 ppm) of FVB. The experimental results indicate that during the ozonation, even though complete FVB degradation occurs in 10 min, ozone consumption goes on for a further 20 min after which time most degradation reactions are completed. The main ozonation by-products, identified by HPLC, IC, and GC-MS are formaldehyde, acetaldehyde, glyoxal, acetone, acetic-, formic-, oxalic- and carbonic-acid, plus six FVB derivatives scarcely biodegradable. At the end of the ozonation, i.e. after 30 min., the initial values of TOC (35 mgC/l) and COD (103 mgO2/l) are respectively 27 and 25 and correspond to a relative removal of about 23% and 76%. As for FVB solution biodegradability expressed as (BOD5)/(COD) ratio, during the first 10 min its value regularly increases from zero up to a maximum of 0.75 that corresponds to an ozone consumption of 2.4 mg per each mg of organic carbon initially present in the solution.

scholarly journals Twofold role of calcined hydrotalcites in the degradation of methyl parathion pesticide

2011 ◽  
Vol 2 ◽  
pp. 99-103 ◽  
Author(s):  
Alvaro Sampieri ◽  
Geolar Fetter ◽  
María Elena Villafuerte-Castrejon ◽  
Adriana Tejeda-Cruz ◽  
Pedro Bosch
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Methyl Parathion ◽  
Organophosphate Pesticide ◽  
Anionic Clays ◽  
Rivers And Lakes ◽  
Metal Composition ◽  
By Products ◽  
Basic Strength

Methyl parathion (MP) is a very toxic organophosphate pesticide used as a non-systematic insecticide and acaricide on many corps. As MP and its by-products are highly toxic, they have to be retained to avoid pollution of rivers and lakes. Highly efficient sorbents are hydrotalcites (HTs) (or anionic clays). We have correlated the degradation of an aqueous solution of MP at room temperature, with the basicity of the adsorbing materials. It was found that the metal composition of hydrotalcites determines both the surface electronic properties (basic or acidic) and the sorption capacity. Depending on the basic strength, some calcined hydrotalcites can catalyze the transformation of MP to p-nitrophenol (p-NP) and retain its by-products. Such a process has the advantage of being able to be carried out at room temperature and at the pH of the pesticide solution.

scholarly journals Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism and light absorptivity

2021 ◽  
Author(s):  
Bartłomiej Witkowski ◽  
Priyanka Jain ◽  
Tomasz Gierczak
Keyword(s):  
Aqueous Solution ◽  
Organic Carbon ◽  
Hydroxyl Radicals ◽  
Lower Number ◽  
Brown Carbon ◽  
Molar Yield ◽  
Reaction Solution ◽  
Open Ring ◽  
Removal Processes ◽  
By Products

Abstract. The reaction of hydroxyl radicals (OH) with 4-nitrophenol (4-NP) in the aqueous solution was investigated at pH = 2 and 9. As a result, the molar yield of the phenolic products was measured to be 0.20 ± 0.05 at pH = 2 and 0.40 ± 0.1 at pH = 9. The yield of 4-nitrocatechol (4-NC) was higher at pH = 9; at the same time, a lower number of phenolic products was observed due to the hydrolysis and other irreversible reactions at pH > 7. Mineralization investigated with total organic carbon (TOC) technique showed that after 4-NP was completely consumed approx. 85 % of the organic carbon remained in the aqueous solution. Hence, up to 65 % of the organic carbon that remained in the aqueous solution accounted for the open-ring non-phenolic products. The light absorptivity of the reaction solution between 250 and 600 nm decreased as a result of OH reaction with 4-NP. At the same time, 4-NP solution showed some resistance to chemical bleaching due to the formation of the light-absorbing by-products. This phenomenon effectively prolongs the time-scale of chemical bleaching or 4-NP via reaction with OH by a factor of 3–1.5 at pH 2 and 9, respectively. The experimental data acquired indicated that both photolysis and reaction with OH can be important removal processes of the atmospheric brown-carbon from the aqueous particles containing 4-NP.

scholarly journals Synthesis of Highly Stable Cobalt Nanomaterial Using Gallic Acid and Its Application in Catalysis

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Saba Naz ◽  
Abdul Rauf Khaskheli ◽  
Abdalaziz Aljabour ◽  
Huseyin Kara ◽  
Farah Naz Talpur ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Methyl Orange ◽  
Green Synthesis ◽  
Aqueous Medium ◽  
Gallic Acid ◽  
Azo Dyes ◽  
Room Temperature ◽  
Model Compound ◽  
Characterization Studies

We report the room temperature (25–30°C) green synthesis of cobalt nanomaterial (CoNM) in an aqueous medium using gallic acid as a reducing and stabilizing agent. pH 9.5 was found to favour the formation of well dispersed flower shaped CoNM. The optimization of various parameters in preparation of nanoscale was studied. The AFM, SEM, EDX, and XRD characterization studies provide detailed information about synthesized CoNM which were of 4–9 nm in dimensions. The highly stable CoNM were used to study their catalytic activity for removal of azo dyes by selecting methyl orange as a model compound. The results revealed that 0.4 mg of CoNM has shown 100% removal of dye from 50 μM aqueous solution of methyl orange. The synthesized CoNM can be easily recovered and recycled several times without decrease in their efficiency.

scholarly journals Reduction of aflatoxin B1 during tortilla production and identification of degradation by-products by direct-injection electrospray mass spectrometry

2015 ◽  
Vol 57 (1) ◽  
pp. 50 ◽  
Author(s):  
Abigail Moreno-Pedraza ◽  
Laura Valdés-Santiago ◽  
Laura Josefina Hernández-Valadez ◽  
Alicia Rodríguez-Sixtos Higuera ◽  
Robert Winkler ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aflatoxin B1 ◽  
Room Temperature ◽  
Electrospray Mass Spectrometry ◽  
Direct Injection ◽  
Alkaline Ph ◽  
Principal Factors ◽  
Mass Spectometry ◽  
Kinetics Of ◽  
By Products

Objective. To determine the effect of pH, and exposure time over the inactivation of aflatoxin B1 (AFB1) during the tortilla making process as well as the degradative molecules generated. Materials and methods. Inactivation of AFB1 in maize-dough with alkaline pH and in alkaline methanolic solutions was determined by HPLC. Kinetics of time exposure of AFB1 in methanolic solution and the degradative products were analyzed by direct injection electrospray mass spectometry (DIESI-MS). Results. The alkaline pH of the maize-dough after nixtamalización between 10.2, and 30-40 minutes of resting at room temperature allows the 100% reduction of AFB1. DIESI-MS analysis of the extracts indicated the presence of two degradation molecules from AFB1.Conclusion. The alkaline pH of maize-dough and resting time are the principal factors involved in diminishing AFB1 levels in tortillas. A procedure to the tortilla making process is proposed, which allows the reduction of remnant AFB1, avoiding the accumulative effect over consumers.

Biodegradability of Danube bank filtrate and its enhancement by ozonation

2007 ◽  
Vol 7 (3) ◽  
pp. 139-144
Author(s):  
V.Z. Cukic ◽  
V.L. Knezic
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Distribution Networks ◽  
Organic Content ◽  
Low Risk ◽  
Danube River ◽  
Source Water ◽  
Transformation Processes ◽  
By Products

The reduction of organic content through transformation processes in the Danube aquifer along a studied area, biodegradability of Danube bank filtrate and its enhancement by ozonation have all been examined in a study carried out in order to assess amenability of Danube bank filtrate for bio-filtration. As determined during the study period Dissolved Organic Carbon (DOC) varied from 4.6–6.5 mgC/L and from 2.8–3.7 mgC/L in Danube River and Danube bank filtrate respectively. As determined 11.2% of Danube bank filtrate DOC was bio-degradable. A substantial enhancement of biodegradability has been observed after the application of Ozone dosages ranging from 0.45 to 0.9 mgO3/ mgC. It was concluded that Danube bank filtrate itself is not amenable for bio-filtration but an enhancement of its bio-degradability by ozonation could make bio-filtration a reasonable and economical option for reducing of DOC content to the levels that provide low risk of excessive disinfection by-products formation and prevent bacterial re-growth in distribution networks of cities using Danube bank filtrate as the source water.

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.

Pattern Formation in the Methylene Blue-Fructose-Oxygen System in Aqueous Solution and in Gel Systems

2000 ◽  
Vol 65 (9) ◽  
pp. 1394-1402 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Mária Hupková ◽  
Peter Ševčík
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Pattern Formation ◽  
Alkaline Ph ◽  
Initial Reactant ◽  
Nonlinear Reaction ◽  
Oxygen System ◽  
Hydrodynamic Processes ◽  
Liquid Layer Thickness ◽  
Catalyzed Oxidation

Spatial patterns in methylene blue-catalyzed oxidation of fructose at alkaline pH were found in aqueous solution and in gel systems. In a thin liquid layer (thickness >2.4 mm) a mixture of spots and stripes was formed by interaction of a nonlinear reaction and the Rayleigh or Maragoni instabilities. The pattern formation was affected by initial reactant concentrations and by the thickness of the reaction mixture layer. Long-lasting structures were formed in gel systems (polyacrylamide, agar, gelatin). These patterns also arise primarily from hydrodynamic processes.

scholarly journals Practical Synthesis of 2-Iodosobenzoic Acid (IBA) without Contamination by Hazardous 2-Iodoxybenzoic Acid (IBX) under Mild Conditions

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1897
Author(s):  
Hideyasu China ◽  
Nami Kageyama ◽  
Hotaka Yatabe ◽  
Naoko Takenaga ◽  
Toshifumi Dohi
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Practical Method ◽  
Hypervalent Iodine ◽  
Mild Conditions ◽  
Sequential Procedures ◽  
Iodine Compounds ◽  
Practical Synthesis ◽  
Iodosobenzoic Acid ◽  
Lower Temperature

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.

scholarly journals Self-assembly induced luminescence of Eu3+-complexes and application in bioimaging

2021 ◽  
Author(s):  
Ping-Ru Su ◽  
Tao Wang ◽  
Pan-Pan Zhou ◽  
Xiao-Xi Yang ◽  
Xiao-Xia Feng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Luminescence Intensity ◽  
Self Assembly ◽  
Room Temperature ◽  
Molecular Motion ◽  
Proof Of Concept ◽  
Room Temperature Phosphorescence ◽  
New Strategy ◽  
Size Controlled

Abstract Design and engineering of highly efficient emitting materials with assembly-induced luminescence, such as room temperature phosphorescence (RTP) and aggregation-induced emission (AIE), have stimulated extensive efforts. Here, we propose a new strategy to obtain size-controlled Eu3+-complex nanoparticles (Eu-NPs) with self-assembly induced luminescence (SAIL) characteristics without encapsulation or hybridization. Compared with previous RTP or AIE materials, the SAIL phenomena of increased luminescence intensity and lifetime in aqueous solution for the proposed Eu-NPs are due to the combined effect of self-assembly in confining the molecular motion and shielding the water quenching. As a proof of concept, we also show that this system can be further applied in bioimaging, temperature measurement and HClO sensing. The SAIL activity of the rare-earth (RE) system proposed here offers a further step forward on the roadmap for the development of RE light conversion systems and their integration in bioimaging and therapy applications.

Kinetics process of room temperature phosphorescence and fluorescence of gadolinium porphyrin in aqueous solution☆

2020 ◽  
Author(s):  
Ting Liu ◽  
Xiyu Zhang ◽  
Honglin Zhang ◽  
Hua Zhao ◽  
Zhiguo Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Room Temperature Phosphorescence
Sign in / Sign up

Export Citation Format

Share Document