Degradation of Congo red by UV photolysis of nitrate: Kinetics and degradation mechanism

2021 ◽  
Vol 262 ◽  
pp. 118276
Author(s):  
Shishun Wang ◽  
Congwei Luo ◽  
Fengxun Tan ◽  
Xiaoxiang Cheng ◽  
Qiao Ma ◽  
...  
Keyword(s):  
Congo Red ◽  
Degradation Mechanism ◽  
Uv Photolysis

scholarly journals Synthesis of Magnetic Targeted Cellulose Composite Decorated with Poly(AA-DMC) for Synergistic Adsorption Degradation of Congo Red from Organic Wastewater

2021 ◽  
Author(s):  
Chen Ling ◽  
Dai Yimin ◽  
Lu Qi ◽  
Fang Chengqian ◽  
Wang Zhiheng ◽  
...  
Keyword(s):  
Congo Red ◽  
Magnetic Particles ◽  
Degradation Mechanism ◽  
Degradation Of Dyes ◽  
Cellulose Composites ◽  
Natural Cellulose ◽  
The Stability ◽  
Adsorption Desorption ◽  
Cr Removal ◽  
Organic Wastewater

Abstract A brand-new environmental-friendly magnetic cellulosic adsorbent MnFe2O4@Cel-g-p(AA-DMC) was synthesized by natural cellulose and easy-recovered magnetic particles MnFe2O4. Magnetic cellulose composites were characterized by SEM, TEM, XPS, XRD, BET, VSM, TGA and FTIR. The MnFe2O4NPs could activate the peroxymonosulfate (PMS) to produce various reactive oxygen species (ROS). Accordingly, magnetic cellulose composites can synergistic adsorption degradation of dyes from organic wastewater. The Congo red (CR) removal efficiency by MnFe2O4@Cel-g-p(AA-DMC) via PMS activated by MnFe2O4 reached a maximum of 96.9% and only 9% reduction after four adsorption-desorption cycles, indicating the stability and recoverability of adsorbent. It is worth noting that adsorbents can be quickly recovered from aqueous solution by external magnet owing to superior saturation magnetization (35.44 emu·g-1). A possible degradation mechanism of CR on the MnFe2O4@Cel-g-p(AA-DMC) composite was proposed. The results suggest that adsorbent display strong potential for the removal of CR dyes from organic wastewater.

scholarly journals Photo fenton like process Fe3+/(NH4)2S2O8/UV for the degradation of Di azo dye congo red using low iron concentration

2009 ◽  
Vol 7 (3) ◽  
pp. 468-477 ◽  
Author(s):  
L. Devi ◽  
S. Kumar ◽  
K. Reddy
Keyword(s):  
Congo Red ◽  
Azo Dye ◽  
Degradation Mechanism ◽  
Iron Concentration ◽  
Catalytic Efficiency ◽  
Ammonium Persulfate ◽  
Process Efficiency ◽  
Radical Scavenger ◽  
Hydroxyl Radical Scavenger ◽  
Acidic Conditions

AbstractDegradation of Congo Red (CR) a di azo dye in aqueous solution is investigated by a Photo Fenton like process using Fe3+ ions as the catalyst and peroxy disulfate as the oxidant. The influence of various reaction parameters like, concentration of Fe3+ ions, concentration of the dye, concentration of ammonium persulfate, pH of the solution and the presence of hydroxyl radical scavenger are studied and optimal conditions are reported. The degradation rate decreased at higher dye concentration and at higher pH. The rate constant (k), catalytic efficiency (kc) and process efficiency (Φ) are evaluated for different concentration of Fe3+ ions. The degradation of CR by the photo Fenton like process leads to the formation of 4-Amino, 3-azo naphthalene sulphonic acid, dihydroxy substituted naphthalene, dihydroxy substituted biphenyl, phenol, quinol etc., as intermediates, based on which probable degradation mechanism is proposed. These results show that a photo Fenton like process could be useful technology for the mineralization of di azo dyes under lower concentration of iron in acidic conditions. The present process is advantageous as it lowers the sludge production resulting from the iron comple

scholarly journals Radiation induced degradation of Congo red dye: a mechanistic study

Nukleonika ◽  
2019 ◽  
Vol 64 (2) ◽  
pp. 49-53 ◽  
Author(s):  
Majid Muneer ◽  
Muhammad Saeed ◽  
Ijaz Ahmad Bhatti ◽  
Atta-ul Haq ◽  
Muhammad Kaleem Khosa ◽  
...  
Keyword(s):  
Congo Red ◽  
Gamma Ray ◽  
Advanced Oxidation Process ◽  
Degradation Mechanism ◽  
Degradation Pathway ◽  
Mechanistic Study ◽  
Synthetic Dyes ◽  
Experimental Conditions ◽  
Congo Red Dye ◽  
Red Dye

Abstract Synthetic dyes are persistent pollutants with poor biodegradability. The present study is about the degradation of direct Congo red dye in aqueous media using the Co-60 gamma radiation source. The experimental conditions such as gamma-ray absorbed doses, amount of oxidant (H2O2) and pH conditions were evaluated. The λmax of dye solution was noted as 498 nm, and then, decrease in absorbance and reduction in chemical oxygen demand (COD) were examined. The complete colour removal of dye was observed at 5 kGy, while a significant COD removal was observed at 15 kGy gamma-ray absorbed dose in conjunction with oxidant for 50 mg/L concentration. It was found that pH has no influence on degradation efficiency. A possible degradation pathway was proposed. The radiolytic end products were monitored by Fourier transform infrared (FTIR) and gas chromatography coupled with mass spectrometry (GC-MS) to explore the degradation mechanism. It was imperative to study the oxidative degradation pathway to provide directions for potential applicability of advanced oxidation process (AOP) in industrial wastewater treatment.

Kinetics and degradation mechanism of clofibric acid and diclofenac in UV photolysis and UV/H2O2reaction

2013 ◽  
Vol 52 (31-33) ◽  
pp. 6211-6218 ◽  
Author(s):  
In-Young Kim ◽  
Moon-Kyung Kim ◽  
Yeomin Yoon ◽  
Jong-Kwon Im ◽  
Kyung-Duk Zoh
Keyword(s):  
Degradation Mechanism ◽  
Clofibric Acid ◽  
Uv Photolysis

Structures of c-di-GMP/cGAMP degrading phosphodiesterase VcEAL: identification of a novel conformational switch and its implication

2019 ◽  
Vol 476 (21) ◽  
pp. 3333-3353 ◽  
Author(s):  
Malti Yadav ◽  
Kamalendu Pal ◽  
Udayaditya Sen
Keyword(s):  
Active Site ◽  
Metal Binding ◽  
Metal Ion ◽  
Triosephosphate Isomerase ◽  
Catalytic Mechanism ◽  
Degradation Mechanism ◽  
Structural Basis ◽  
Conserved Residues ◽  
Phosphodiester Bond ◽  
Cyclic Dinucleotides

Cyclic dinucleotides (CDNs) have emerged as the central molecules that aid bacteria to adapt and thrive in changing environmental conditions. Therefore, tight regulation of intracellular CDN concentration by counteracting the action of dinucleotide cyclases and phosphodiesterases (PDEs) is critical. Here, we demonstrate that a putative stand-alone EAL domain PDE from Vibrio cholerae (VcEAL) is capable to degrade both the second messenger c-di-GMP and hybrid 3′3′-cyclic GMP–AMP (cGAMP). To unveil their degradation mechanism, we have determined high-resolution crystal structures of VcEAL with Ca2+, c-di-GMP-Ca2+, 5′-pGpG-Ca2+ and cGAMP-Ca2+, the latter provides the first structural basis of cGAMP hydrolysis. Structural studies reveal a typical triosephosphate isomerase barrel-fold with substrate c-di-GMP/cGAMP bound in an extended conformation. Highly conserved residues specifically bind the guanine base of c-di-GMP/cGAMP in the G2 site while the semi-conserved nature of residues at the G1 site could act as a specificity determinant. Two metal ions, co-ordinated with six stubbornly conserved residues and two non-bridging scissile phosphate oxygens of c-di-GMP/cGAMP, activate a water molecule for an in-line attack on the phosphodiester bond, supporting two-metal ion-based catalytic mechanism. PDE activity and biofilm assays of several prudently designed mutants collectively demonstrate that VcEAL active site is charge and size optimized. Intriguingly, in VcEAL-5′-pGpG-Ca2+ structure, β5–α5 loop adopts a novel conformation that along with conserved E131 creates a new metal-binding site. This novel conformation along with several subtle changes in the active site designate VcEAL-5′-pGpG-Ca2+ structure quite different from other 5′-pGpG bound structures reported earlier.

The Use of Radioiodinated Congo Red in the Study of Amyloidosis

1963 ◽  
Vol 03 (01) ◽  
pp. 25-38
Author(s):  
Manuel Tubis ◽  
William Blahd ◽  
John Endow
Keyword(s):  
Rheumatoid Arthritis ◽  
Multiple Myeloma ◽  
Comparative Studies ◽  
Congo Red ◽  
Half Time ◽  
Positive Correlation ◽  
Autopsy Findings ◽  
Percentage Removal

SummaryA study of the removal of I131-labeled Congo red from the blood of amyloid, non-amyloid, multiple myeloma, rheumatoid arthritis and other patients is presented. The percentage removal of the labeled dye shows the same variation reported by many other workers using Bennhold’s test and its modifications.However, there seems to be a positive correlation between the percentage removal of the labeled dye and the presence of amyloid as revealed by biopsy and autopsy. The half-time of disappearance is also correlated with the amyloidosis.The availability of the I131-labeled dye permits the use of very small weights of the dye thereby drastically reducing the possibility of toxic and sometimes fatal reactions encountered with the unlabeled dye. The I131 present permits easy quantitation of the dye in the blood without separation of plasma and obviates the need of fasting. It also permits external counting and scanning of deposits in the organs containing the dye.The availability and use of the labeled dye may stimulate more comparative studies of the removal of the dye from the blood correlated with biopsy and autopsy findings.

Effect of Congo Red on Blood Platelets and Leucocytes of Rabbits and Cats

1971 ◽  
Vol 26 (03) ◽  
pp. 488-492 ◽  
Author(s):  
Th B. Tschopp ◽  
H.-R Baumgartner ◽  
A Studer
Keyword(s):  
Fatty Acids ◽  
Congo Red ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Severe Thrombocytopenia ◽  
Ultrastructural Alterations ◽  
Indirect Mechanism

SummaryIn rabbits and cats Congo red administered intravenously causes severe thrombocytopenia and ultrastructural alterations of platelets and leucocytes, similar to those produced by some fatty acids and endotoxin. Transient leucopenia is followed by leucocytosis. In contrast, incubation of Congo red in citrated blood or platelet rich plasma has no effect. Therefore, an indirect mechanism is postulated to explain the in vivo effect of Congo red.

An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 157-164 ◽  
Author(s):  
Shengdan Wang ◽  
Wenhua Gao ◽  
Kefu Chen ◽  
Jinsong Zeng ◽  
Jun Xu ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Congo Red ◽  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Standard Curve ◽  
Congo Red Dye ◽  
Mechanical Disintegration ◽  
Softwood Kraft Pulp ◽  
White Water ◽  
Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

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