scholarly journals Quantification and Degradation of 2,2-Dibromo-3-Nitrilopropionamide (DBNPA) in Bioethanol Fermentation Coproducts

2021 ◽  
Author(s):  
John V. Simpson ◽  
Christopher Louis Wiatr
Keyword(s):  
Analytical Chemistry ◽  
Degradation Rate ◽  
Degradation Products ◽  
Field Trials ◽  
Measured Signal ◽  
Industrial Water ◽  
First Order ◽  
First Order Kinetics ◽  
Whole Stillage ◽  
Potential Alternative

Abstract 2,2-Dibromo-3-Nitrilopropionamide (DBNPA) has been used as a biocide in industrial water applications due to its instantaneous antimicrobial activity and rapid chemical breakdown. In this study DBNPA is considered as a potential alternative for antibiotics used for bacterial control during corn to ethanol fermentation. A method using LC/MS/MS was developed to accurately quantify DBNPA in water. When this method was applied to quantify DBNPA concentration in a fermentation matrix, DBNPA was found to be unstable and to decay rapidly, preventing validation of the method or quantitation. This method was then used to evaluate the degradation rate of DBNPA in whole stillage, which is the nonvolatile residue produced by removal of ethanol from corn-based fermentation beer by distillation through the relative decrease in measured signal. In addition, a method was developed and validated to quantify bromide, one of the degradation products of DBNPA, in whole stillage using LC/MS/MS. The degradation rate of DBNPA in whole stillage was found to display first order kinetics with a calculated half-life of 85 min. Laboratory analytical chemistry results on DBNPA degradation were confirmed in field trials.

Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
Author(s):  
Xin Tong ◽  
Jiao Li ◽  
Jun Ma ◽  
Xiaoquan Chen ◽  
Wenhao Shen
Keyword(s):  
Degradation Rate ◽  
Southern China ◽  
Catalytic Degradation ◽  
Pulp And Paper ◽  
Gaseous Pollutants ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

New insights on the UV/TiO2 photocatalytic treatment of thiomersal and its 2-sulfobenzoic acid product

2021 ◽  
Vol 02 ◽  
Author(s):  
Emmanuel M. de la Fournière ◽  
Jorge M. Meichtry ◽  
Graciela S. Custo ◽  
Eduardo A. Gautier ◽  
Marta I. Litter
Keyword(s):  
Degradation Products ◽  
Acidic Ph ◽  
Cosmetic Products ◽  
Acid Product ◽  
First Order ◽  
First Order Kinetics ◽  
Photocatalytic Destruction ◽  
Pseudo First Order ◽  
Mineralization Degree ◽  
Suitable Technique

Background: Thiomersal (TM), a complex between 2-mercaptobenzoic acid (2-MBA) and ethylmercury (C2H5Hg+), is an antimicrobial preservative used in immunological, ophthalmic, cosmetic products, and vaccines. Objective: TM has been treated by UV/TiO2 photocatalysis in the presence or absence of oxygen at acidic pH. C2H5Hg+, 2-MBA, and 2-sulfobenzoic acid (2-SBA) were found as products. A 2-SBA photocatalytic treatment was undertaken to study sulfur evolution. Methods: Photocatalytic runs were performed using a UVA lamp (λmax = 352 nm), open to the air or under N2. A suspension of the corresponding TM or 2-SBA salt and TiO2 was prepared, and pH was adjusted. Suspensions were stirred in the dark for 30 min and then irradiated. TM, 2-MBA, 2-SBA, and C2H5Hg+ were quantified by HPLC, sulfur by TXRF, and the deposits on the photocatalyst were analyzed by chemical reactions. The mineralization degree was followed by TOC. Sulfate was determined using BaCl2 at 580 nm. Results: Photocatalytic destruction of TM and total C2H5Hg+ was complete under N2 and air, but TM degradation was much faster in air. The evolution of TM and the products followed a pseudo-first-order kinetics. Conclusion: TiO2-photocatalytic degradation is a suitable technique for the treatment of TM and its degradation products. In contrast to other organomercurial compounds, TM degradation is faster in the presence of O2, indicating that the oxidative mechanism is the preferred pathway. A significant TM mineralization (> 60%, NPOC and total S) was obtained. TM was more easily degraded than 2-SBA. Sulfate was the final product.

Residue analysis of fosthiazate in cucumber and soil by QuEChERS and GC-MS

2014 ◽  
Vol 68 (10) ◽  
Author(s):  
Min Wu ◽  
Jiye Hu
Keyword(s):  
Solid Phase ◽  
Residue Analysis ◽  
Field Trials ◽  
Residue Level ◽  
Gas Chromatography Mass Spectrometry ◽  
Dispersive Solid Phase Extraction ◽  
First Order ◽  
First Order Kinetics ◽  
Maximum Residue Level ◽  
Relative Standard

AbstractA convenient method was developed for the determination and validation of fosthiazate in cucumber and soil. The procedure is based on liquid partitioning with acetonitrile followed by dispersive solid phase extraction as the clean-up step, after which samples were analysed by gas chromatography-mass spectrometry (GC-MS). The average recoveries ranged from 91.2 % to 99.0 % with relative standard deviations (RSDs) of less than 6.05 %, at three fortification levels (0.02 mg kg−1, 0.1 mg kg−1, 0.5 mg kg−1) in cucumber and soil, and the limits of quantification (LOQs) for fosthiazate were all established at 0.02 mg kg−1. The proposed method was applied successfully to analyses of the dissipation and residue of fosthiazate in field trials. The dissipation rate of fosthiazate was described using pseudo-first-order kinetics with a half-life of 4.33 days and 4.08 days in soil in Beijing and Shandong, respectively. In the terminal residue experiment, fosthiazate residues in cucumber and soil were clearly below the maximum residue level (MRL, 0.2 mg kg−1) set in China.

scholarly journals Pharmacokinetics and Toxicity Evaluation of a PLGA and Chitosan-Based Micro-Implant for Sustained Release of Methotrexate in Rabbit Vitreous

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1227
Author(s):  
Soumyarwit Manna ◽  
Anna M. Donnell ◽  
Rafaela Q. Caixeta Faraj ◽  
Blanca I. Riemann ◽  
Christopher D. Riemann ◽  
...  
Keyword(s):  
Current Treatment ◽  
Invasive Procedures ◽  
Toxicity Evaluation ◽  
Therapeutic Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Histopathologic Evaluation ◽  
Potential Alternative ◽  
The Right ◽  
Micro Implants

The present research investigates the pharmacokinetics and toxicity of a chitosan (CS) and poly(lactic-co-glycolic) acid (PLGA)-based methotrexate (MTX) intravitreal micro-implant in normal rabbit eyes. PLGA and CS-based micro-implants containing 400 µg of MTX were surgically inserted in the vitreous of twenty-four New Zealand rabbits using minimally invasive procedures. The PLGA-coated CS-MTX micro-implant and the placebo micro-implant were inserted in the right eye and in the left eye, respectively, of each rabbit. The intravitreal MTX concentration was evaluated on Days 1, 3, 7, 14, 28 and 56. A therapeutic concentration of MTX (0.1–1.0 µM) in the rabbit vitreous was observed for 56 days. The release of MTX in the therapeutic release phase followed first-order kinetics. Histopathologic evaluation on Days 14, 28 and 56 of the enucleated eyes demonstrated no signs of toxicity or any anatomical irregularity in the vitreoretinal domain. Additionally, the micro-implants were stationary at the position of their implantation throughout the duration of the study. The PLGA-coated CS-MTX micro-implant can serve as a potential alternative to the current treatment modality of intravitreal MTX injections based on its performance, thereby avoiding associated complications and the treatment burden of multiple injections.

Effect of Ultrasonic Frequency on Chlorpyrifos Degradation in Sonolytic Ozonolysis

2014 ◽  
Vol 587-589 ◽  
pp. 578-581
Author(s):  
Jin Zhu ◽  
Chang Ping Zhu ◽  
Bin Wang ◽  
Run Hang Gong ◽  
Qing Gong Ren ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Degradation Pathway ◽  
Frequency Effect ◽  
Ultrasonic Frequency ◽  
Kinetics Parameters ◽  
First Order ◽  
First Order Kinetics ◽  
Degradation Reaction

The degradation of chlorpyrifos is investigated with the treatments of sonolysis, ozonolysis, and sonolytic ozonolysis at various frequencies. Results show that there exists frequency effect in sonolytic ozonolysis. In sonolytic ozonolysis, the maximum degradation rate is obtained at 495 kHz, and the degradation kinetics is fitted to the first-order kinetics model well. However, the most significant synergistic effect between ultrasonic and ozone is at 124 kHz. The kinetics parameters indicate that chlorpyrifos is much more labile to ultrasonic at 495 kHz, while ozone is much more soluble at 124 kHz. The hydrolysis and oxidation are deduced to contribute to the degradation reaction and the degradation pathway for chlorpyrifos degradation is proposed.

scholarly journals Photodegradation of levofloxacin in aqueous and organic solvents: A kinetic study

2013 ◽  
Vol 63 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Iqbal Ahmad ◽  
Raheela Bano ◽  
Muhammad Ali Sheraz ◽  
Sofia Ahmed ◽  
Tania Mirza ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Degradation Rate ◽  
Hplc Method ◽  
Ph Profile ◽  
Degree Of Ionization ◽  
First Order ◽  
First Order Kinetics ◽  
Anionic Species ◽  
Ph Range ◽  
Kinetics Of

The kinetics of photodegradation of levofloxacin in solution on UV irradiation in the pH range 2.0-12.0 has been studied using a HPLC method. Levofloxacin undergoes first-order kinetics in the initial stages of the reaction and the apparent first-order rate constants are of the order of 0.167 to 1.807×10-3 min-1. The rate-pH profile is represented by a curve indicating the presence of cationic, dipolar and anionic species during the reaction. The singly ionized form of the molecule is non-fluorescent and is less susceptible to photodegradation. The increase in the degradation rate in the pH range 5.0-9.0 may be due to greater reactivity of the ionized species existing in that range. The rate appears to vary with a change in the degree of ionization of the species present in a particular pH range and their susceptibility to photodegradation. Above pH 9, the decrease in the rate of photodegradation may be a result of deprotonation of the piperazinyl group. The levofloxacin molecule is more stable in the pH range around 7, which is then suitable for formulation purposes. The photodegradation of levofloxacin was found to be affected by the dielectric constant and viscosity of the medium

scholarly journals A multivariate study of the rGO/g-C3N4 composite for the photocatalytic degradation of bisphenol A: Characterization, degradation kinetics, products identification, and ecotoxicity

2021 ◽  
Author(s):  
Chubraider Xavier ◽  
Bianca Rebelo Lopes ◽  
Caue Ribeiro ◽  
Eduardo Bessa Azevedo
Keyword(s):  
Bisphenol A ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Surface Response Methodology ◽  
First Order ◽  
Surface Areas ◽  
First Order Kinetics ◽  
Reduced Graphene ◽  
Endocrine Disrupting ◽  
Oxidation Agent

Abstract Bisphenol A (BPA), a common polymer plasticizer, is a contaminant of emerging concern with endocrine disrupting activity. Among existing abatement methods, photodegradation demands easily fabricated, inexpensive, high photoactive catalysts, leading to non-toxic byproducts after degradation. It is proposed an optimized (surface response methodology) catalyst for those goals: graphitic carbon nitride impregnated with reduced graphene oxide. The method was based on the sonication of preformed particles followed by reduction with hydrazine in reflux, a methodology that allows for better reproducibility and larger specific surface areas. The catalyst removed 90% of BPA (100 mL, 100 µg L− 1) in 90 min under UV irradiation (365 nm, 26 W) compared to 50% with pure g-C3N4 (pseudo-first-order kinetics). Tests with radicals scavengers revealed that superoxide radical was the main oxidation agent in the system. By mass spectrometry, two major degradation products were identified, which were less ecotoxic than BPA towards a series of organisms, according to in silico estimations performed with the ECOSAR 2.0 software.

scholarly journals ESTUDO DE ESTABILIDADE DO FOSFATO DISSÓDICO DE PREDNISOLONA EM CONDIÇÕES DE ESTRESSE OXIDATIVO E TÉRMICO, EM FORMULAÇÃO ORAL

2018 ◽  
Vol 35 (4) ◽  
pp. 09
Author(s):  
Cleber Antonio Lindino ◽  
Marcia Lina Mitsui ◽  
Rodolfo Ortiguara ◽  
Daiane Felin ◽  
Mauricio Ferreira Da Rosa ◽  
...  
Keyword(s):  
High Performance ◽  
Dosage Form ◽  
Degradation Products ◽  
Degradation Process ◽  
Oral Solution ◽  
Form Solution ◽  
Oral Dosage ◽  
First Order ◽  
First Order Kinetics

This work was to investigate the process of degradation of the drug Prednisolone Sodium Phosphate (FSP) in oral solution dosage form through the degradation experiments, evaluating the parameters in accordance with Resolution 899/2003 ANVISA and the degradation process of the drug. The method by high performance liquid chromatography (HPLC) developed for the determination of the drug was validated to demonstrate its applicability as an indicator of stability, ensuring reliability. After the method be validated to study the degradation of the drug, it was shown that drastic conditions of oxidative stress (H O 30%) and 2 2 temperature 60°C, the degradation of the drug is dependent on its concentration (first order kinetics). The results were  satisfactory, showing that this method is suitable to investigate the formation of degradation products in oral dosage form solution

scholarly journals Degradation kinetics and in vitro digestive stability of selected bioactive compounds from a beverage formulated with butterfly pea flowers

2022 ◽  
Vol 52 (5) ◽  
Author(s):  
Renata Oliveira Santos ◽  
Laura Monteiro Keller ◽  
Vanessa Sales de Oliveira ◽  
Carlos Alberto Bucher ◽  
José Lucena Barbosa Junior ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Model Systems ◽  
First Order ◽  
Ph Values ◽  
First Order Kinetics ◽  
Butterfly Pea ◽  
Effects Of Temperature

ABSTRACT: This study evaluated the effects of temperature on the pH of extracts of ascorbic acid and anthocyanins from petals of butterfly pea, as well as their in vitro digestive stability in model systems at 60, 70, and 80 °C. The pH values significantly decreased with an increase in the temperature (P < 0.05). The findings were similar for the degradation of anthocyanins and ascorbic acid, which followed first-order kinetics in all the systems. The samples heated at 80 °C presented the highest degradation rate (kobs), as well as higher percentages of degradation at the end of digestive stability in vitro.

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts

2013 ◽  
Vol 69 (6) ◽  
pp. 1219-1226
Author(s):  
C. Chen ◽  
Q. Xie ◽  
B. Q. Hu ◽  
X. L. Zhao
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Degradation Rate ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Solution Ph ◽  
First Order ◽  
First Order Kinetics ◽  
Catalyst Dosage ◽  
H2o2 Addition

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol–gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

Sign in / Sign up

Export Citation Format

Share Document