Potential Environmental Contaminants: Exploring Hydrolyzed Dyes in Household Washing Sources and Electrochemical Degradation.

Reactive dyes are often released into the environment during the washing process due to their susceptibility to hydrolysis. The hydrolysis experiment of a pure reactive dye, red 195 (RR 195), and the washing experiment of RR 195-colored fabrics (CFSCs) were carried out successively to explore the sources of hydrolyzed dyes in the washing microenvironment. Reversed-phase high-performance liquid chromatography (RP-HPLC) was used for the analysis of hydrolysis intermediates and final products of reactive red 195. The experimental results indicated that the structure of the dye washing shed is consistent with the final hydrolysate of reactive red 195, which is the main colored contaminant in washing wastewater. To eliminate the hydrolyzed dyes from the source, an electrochemical degradation device was designed. The degradation parameters, including voltage, electrolyte concentration, and dye shedding concentration are discussed in the electrochemical degradation experiment. The electrochemical degradation device was also successfully implemented and verified in a home washing machine.

Systematic Structural Tuning Yields Hydrazonyl Sultones for Faster Bioorthogonal Protein Modification.

We report the synthesis of a series of hydrazonyl sultones (HS) containing an ortho-CF3 group, a five- or six-membered sultone ring, and a varying N-aryl substituent, and characterization of their aqueous stability and reactivity toward bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN) in a 1,3-dipolar cycloaddition reaction. To avoid purification of highly polar intermediates, we employed two protecting groups in our synthetic schemes. Most HS were obtained in moderate to good yields under optimized reaction conditions. The X-ray crystal structure analysis of two HS revealed that the partially negative-charged fluorine atoms in CF3 electrostatically shield the electrophilic nitrile imine (NI) center from a nucleophilic attack, underpinning their extraordinary aqueous stability. In addition, the N-aryl substituents further modulate HS reactivity and stability, with the electron-rich six-membered HS displaying excellent aqueous stability and increased cycloaddition reactivity. The utility of these improved HS reagents was demonstrated through fast and selective modification of a BCNK-encoded nanobody with second-order rate constants as high as 1500 M-1 s-1 in phosphate-buffered saline-ethanol (9 : 1), representing the fastest HS-BCN ligation reported in the literature.

Advancement in electrochemical strategies for quantification of Brown HT and Carmoisine (Acid Red 14) From Azo Dyestuff class.

Brown HT and carmoisine, which are the most used dyestuffs in pharmaceuticals, textiles, cosmetics and foods, are important components of the Azo family. Although the Azo group is not toxic or carcinogenic under normal conditions, these dyestuffs require great care due to the reduction of the Azo functional group to amines. In particular, fast, reliable, easy, on-site and precise determinations of these substances are extremely necessary and important. In this review, the properties, applications, and electrochemical determinations of brown HT and carmoisine, which are used as synthetic food colorants, are discussed in detail. Up to now, sensor types, detection limits (LOD and LOQ), and analytical applications in the developed electrochemical strategies for both substances were compared. In addition, the validation parameters such as the variety of the sensors, sensitivity, selectivity and electrochemical technique in these studies were clarified one by one. While the electrochemical techniques recommended for brown HT were mostly used for the removal of dyestuff, for carmoisine they included fully quantitative centered studies. The percentiles of voltammetric techniques, which are the most widely used among these electroanalytical methods, were determined. The benefits of a robust electrochemical strategy for the determination of both food colors are summed up in this review. Finally, the brown HT and carmoisine suggestions for future perspectives in electrochemical strategy are given according to all their applications.

The protective effect of natural phenolic compound on the functional and structural responses of inhibited catalase by a common azo food dye.

In this research retrieval effects of natural yellow (NY) on the performance of carmoisine (CAR) inhibited bovine liver catalase (BLC) was studied using multispectral and theoretical methods. Kinetic studies showed that CAR inhibited BLC through competitive inhibition (IC50 value of 2.24 × 10-6 M) while the addition of NY recover the activity of CAR-BLC up to 82% in comparison with the control enzyme. Circular dichroism data revealed that NY can repair the structural changes of BLC, affected by CAR. Furthermore, an equilibrium dialysis study indicated that NY could reduce the stability of the CAR-catalase complex. The surface plasmon resonance (SPR) data analysis indicated a high affinity of NY to BLC compared to CAR and the binding of NY led to a decrease in the affinity of the enzyme to the inhibitor. On the other hand, fluorescence and molecular docking studies showed that the quenching mechanism of BLC by CAR occurs through a static quenching process, and van der Waals forces and hydrogen bonding play a crucial role in the binding of CAR to BLC. MLSD data demonstrated that NY could increase the binding energy of CAR-BLC complex from -7.72 kJ mol-1 to -5.9 kJ mol-1, leading to complex instability and catalase activity salvage.

Rapid visual detection of Aeromonas salmonicida by loop-mediated isothermal amplification with hydroxynaphthol blue dye.

To make crucial prevention, reduce fish losses and minimize the economic damage of diseases on the fish farm owners, a rapid detection of fish pathogens is mandatory. In this study, a loop-mediated isothermal amplification assay combined with hydroxynaphthol blue dye (LAMP-HNB) was developed and used for the rapid detection of Aeromonas salmonicida that caused significant economic losses in fish farming. Firstly, a pair of outer and inner primers specific for conserved fragment of vapA gene in A. salmonicida were designed and synthesized. Secondly, by optimizing the reaction conditions including reaction temperature, time, Mg2+ concentration, dNTP concentration and primer ratio, a LAMP-HNB assay was successfully established for the detection of A. salmoncida. Thirdly, the assay showed good specificity with no false-positive and false-negative results, and good sensitivity with the detection limit of 3.077 × 10-6  ng/µl, which was 102 times more sensitive than the conventional PCR. Finally, the LAMP-HNB assay was validated by the fish samples inoculated with different concentrations of A. salmoncida. This is the first development of rapid visual detection of A. salmonicida based on LAMP-HNB assay, which has great application prospect and market for diagnostic testing, health certification and active surveillance programmers.

Enzymatic Degradation of Multiple Major Mycotoxins by Dye-Decolorizing Peroxidase from Bacillus subtilis.

The co-occurrence of multiple mycotoxins, including aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON), widely exists in cereal-based animal feed and food. At present, most reported mycotoxins degrading enzymes target only a certain type of mycotoxins. Therefore, it is of great significance for mining enzymes involved in the simultaneous degradation of different types of mycotoxins. In this study, a dye-decolorizing peroxidase-encoding gene BsDyP from Bacillus subtilis SCK6 was cloned and expressed in Escherichia coli BL21/pG-Tf2. The purified recombinant BsDyP was capable of oxidizing various substrates, including lignin phenolic model compounds 2,6-dimethylphenol and guaiacol, the substrate 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), anthraquinone dye reactive blue 19 and azo dye reactive black 5, as well as Mn2+. In addition, BsDyP could efficiently degrade different types of mycotoxins, including AFB1, ZEN and DON, in presence of Mn2+. More important, the toxicities of their corresponding enzymatic degradation products AFB1-diol, 15-OH-ZEN and C15H18O8 were significantly lower than AFB1, ZEN and DON. In summary, these results proved that BsDyP was a promising candidate for the simultaneous degradation of multiple mycotoxins in animal feed and food.

Quantitative urinary tract infection diagnosis of leukocyte esterase with a microfluidic paper-based device.

Leukocyte esterase (LE) is a useful marker that can be used in establishing a diagnosis of urinary tract infections (UTIs). The development of a UTI diagnostic method with quantitative determinations of biomarkers across all age groups is becoming more important. In this report, microfluidic resistance sensors based on silver ink (Ag ink) and silver ink mixed with ZnO nanoparticles (Ag-ZnO ink) were synthesized and coated on cellulose paper, namely LE-Ag-µPADs and LE-Ag-ZnO-µPADs, respectively, for the sensitive detection of LE. The microfluidic design increases the precision of data and further allows for quantitative determination and early detection of LE in human urine. The quantification of LE relies on the change in the resistance readout coating with Ag ink as well as Ag-ZnO ink in the detection zone. A mixture of 3-(N-tosyl-l-alaninyloxy)-5-phenylpyrrole (PE) and 1-diazo-2-naphthol-4-sulfonic acid (DAS) was deposited in the sample zone to selectively recognize LE, and the resulting nonconductive products, i.e., azo compounds, further reacted with the Ag ink and Ag-ZnO ink to increase resistance. The quantitative detectable LE concentrations between 2 to 32 (×5.2 U mL-1), i.e. ≈12 to 108 µg L-1, cover the commercial dipstick range of trace, +1 and +2. The minimum detectable concentration of LE in urine was 1 (×5.2 U mL-1). The lower concentrations of LE detectable by LE-Ag-µPADs (1-8 × 5.2 U mL-1) are below the value achieved with the ELISA LE kit. Urine samples from inpatients with indwelling urinary catheters were used, and the LE levels measured by the present device were highly correlated with those determined by a commercial urine analyser.

Novel Pyridine-Containing Sultones: Structure-Activity Relationship and Biological Evaluation as Selective AChE Inhibitors for the Treatment of Alzheimer's disease.

Novel pyridine-containing sultones were synthesized and evaluated for their cholinesterase (ChE) inhibitory activity. Most of compounds showed selective acetylcholinesterase (AChE) inhibitory activity. The structure-activity relationship (SAR) showed: (i) the fused pyridine-containing sultones increase AChE inhibition, series B>series A; (ii) for series A, the effect of the 4-substituent on AChE activity, p->m- or o-; (iii) for series B, a halophenyl group increase activity. Compound B4 (4-(4-chlorophenyl)-2,2-dioxide-3,4,5,6-tetrahydro-1,2-oxathiino[5,6-h]quinoline) was identified as a selective AChE inhibitor (IC50 =8.93 µM), and molecular docking studies revealed a good fit into TcAChE via hydrogen interactions between the δ-pyridylsultone scaffold with Asp72, Ser122, Phe288, Phe290 and Trp84. Compound B4 showed reversible and non-competitive (Ki =7.67 µM) AChE inhibition, nontoxicity and neuroprotective activity. In vivo studies confirmed that compound B4 could ameliorate the cognitive performance of scopolamine-treated C57BL/6 J mice, suggesting a significant benefit of AChE inhibition for a disease-modifying treatment of AD.

Zeolite modification with cellulose nanofiber/magnetic nanoparticles for the elimination of reactive red 198.

In this paper for the first time, a cost-effective reinforced zeolite with cellulose nanofibers and magnetic nanoparticles (MZeo/Cellulose nanofiber) was used for the elimination of reactive red 198 (RR198) dye. The fabricated sorbent was characterized by SEM, FTIR, and XRD. The effect of operational parameters, including pH, RR198 concentration, the mass ratios of zeolite to cellulose nanofiber and zeolite coated cellulose to Fe3O4 nanoparticles, contact time, agitation speed, sorbent dosage, and temperature were studied. The prepared sorbent exhibited the maximum removal efficiency of 99% for RR198 removal at 30 °C. The presence of other dyes along with the target dye did not negatively affect the adsorption process and RR198 removal efficiency from actual water samples seemed satisfactory and rational. Equilibrium studies confirmed that both Langmuir and Freundlich models described the RR198 adsorption on MZeo/Cellulose nanofiber indicating physical and chemical interactions between the sorbent and RR198 molecules. Kinetic studies demonstrated that pseudo-second-order fitted best with experimental data. Also, thermodynamic studies showed the endothermic nature of the adsorption process. Compared to zeolite, MZeo/Cellulose nanofiber represented a promising removal efficiency for the elimination of RR198 dye from contaminated water.

Synthesis of Kit-6 Magnetite Silica Nanocomposite Functionalized by Amine Group for Removal of Carmoisine Dye from Aqueous Solutions.

OBJECTIVE: In this study, amine-functionalized magnetite Kit-6 silica nanocomposite (Fe3O4@SiO2@Kit-6-NH2) was synthesized as an adsorbent for removing Carmoisine food dye from aqueous solutions. METHODS: The nanocomposite was chemically synthesized and was characterized by X-ray diffraction analysis (XRD), vibrating sample magnetometery (VSM), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Taguchi orthogonal array experimental design method was used to optimize the experimental conditions, including adsorbent amount, pH of the solution, amount of salt, the volume of sample and contact time. Pseudo first-order, pseudo second-order, intra-particle diffusion and Elovich kinetic models were investigated to study the kinetic parameters of the sorption process. RESULTS: The kinetic data corresponded to the pseudo second-order kinetic model with R2 = 0.9999. Also, adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherm models. The results indicated that the data were well fitted to the Freundlich isotherm model (R2 = 0.9984, n=1.0786). The reusability tests showed that the proposed nanocomposite could be used for more than 8 cycles with removal efficiency higher than 90%. CONCLUSION: The applicability study of the proposed nanocomposite proved its ability for efficient removal of Carmoisine dye from real aqueous samples.

Structural characterization and in vitro lipid binding studies of non-specific lipid transfer protein 1 (nsLTP1) from fennel (Foeniculum vulgare) seeds.

Non-specific lipid transfer proteins (nsLTPs) are cationic proteins involved in intracellular lipid shuttling in growth and reproduction, as well as in defense against pathogenic microbes. Even though the primary and spatial structures of some nsLTPs from different plants indicate their similar features, they exhibit distinct lipid-binding specificities signifying their various biological roles that dictate further structural study. The present study determined the complete amino acid sequence, in silico 3D structure modeling, and the antiproliferative activity of nsLTP1 from fennel (Foeniculum vulgare) seeds. Fennel is a member of the family Umbelliferae (Apiaceae) native to southern Europe and the Mediterranean region. It is used as a spice medicine and fresh vegetable. Fennel nsLTP1 was purified using the combination of gel filtration and reverse-phase high-performance liquid chromatography (RP-HPLC). Its homogeneity was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. The purified nsLTP1 was treated with 4-vinyl pyridine, and the modified protein was then digested with trypsin. The complete amino acid sequence of nsLTP1 established by intact protein sequence up to 28 residues, overlapping tryptic peptides, and cyanogen bromide (CNBr) peptides. Hence, it is confirmed that fennel nsLTP1 is a 9433 Da single polypeptide chain consisting of 91 amino acids with eight conserved cysteines. Moreover, the 3D structure is predicted to have four α-helices interlinked by three loops and a long C-terminal tail. The lipid-binding property of fennel nsLTP1 is examined in vitro using fluorescent 2-p-toluidinonaphthalene-6-sulfonate (TNS) and validated using a molecular docking study with AutoDock Vina. Both of the binding studies confirmed the order of binding efficiency among the four studied fatty acids linoleic acid > linolenic acid > Stearic acid > Palmitic acid. A preliminary screening of fennel nsLTP1 suppressed the growth of MCF-7 human breast cancer cells in a dose-dependent manner with an IC50 value of 6.98 µM after 48 h treatment.

The interaction of Naphthol Yellow S (NYS) with pepsin: Insights from spectroscopic to molecular dynamics studies.

The effects of Naphthol Yellow S (NYS) on the structure and activity of pepsin were carried out using ultraviolet-visible (UV-Vis) spectroscopy, intrinsic fluorescence spectroscopy, circular dichroism (CD), thermal stability, kinetic techniques, as well as molecular docking, and Molecular dynamic simulations (MD) technique. The experimental results from fluorescence spectroscopy showed that the changes in pepsin's tertiary structure were caused by NYS binding. The apparent binding constant Ka, the number of the binding sites, and thermodynamic parameters were computed at three different temperatures. Thermodynamic results revealed that NYS interacts with pepsin spontaneously by hydrogen bond and Van der Waals forces. The result of the circular dichroism spectral suggests the secondary structural changes. An increase in the content of the ß-sheet and ß-turn structure was shown. Kinetic parameters revealed that NYS inhibited the activity of pepsin by the mixed model. The Molecular dynamic (MD) and docking simulations supported experimental findings. The main interactions between NYS and pepsin are hydrogen bonds and Van der Waals Forces. As a result, NYS could be considered as an inhibitor with adverse effects on pepsin structure and function.

Rapid UV/Vis Spectroscopic Dye Authentication Assay for the Determination and Classification of Reactive Dyes, Monascus Pigments, and Natural Dyes in Coloring Foodstuff.

Food authenticity in the field of food dyes can be interpreted as the correctness of the coloring ingredients indicated. The Rapid UV/vis Spectroscopic Dye Authentication Assay (RaSDAY) presented in this work was used to verify the authenticity of water-soluble reddish colorings for food use. RaSDAY includes the processing of samples under different experimental conditions with pH variations and heat exposure. The absorbances measured are analyzed by principal component analysis and a k-nearest neighbors algorithm. As a result, classification of anthocyanins, betalains, and carmine and the detection of Monascus pigments, undeclared artificial food dyes, and reactive textile azo dyes can be performed by utilizing a rapid screening method. In 17 out of 20 samples of coloring food additives that were included in this work, reactive dyes, unpermitted Monascus pigments, and artificial food dyes were detected using the developed method. "Reactive Red 120", "Reactive Red 195", and "Reactive Red 198" were identified by subsequent 1H NMR spectroscopy in eight of those samples.

Response of Trametes hirsuta to hexavalent chromium promotes laccase-mediated decolorization of reactive black 5.

The recalcitrant azo dyes combined with heavy metals constitute a major challenge for the bioremediation of industrial effluents. This study aimed to investigate the effect and mechanism of action of a white-rot fungus Trametes hirsuta TH315 on the simultaneous removal of hexavalent chromium [Cr(VI)] and azo dye (Reactive Black 5, RB5). Here, this study discovered that toxic Cr(VI) (1 mM) greatly promoted RB5 decolorization (from 57.15% to 83.65%) by white-rot fungus Trametes hirsuta with high Cr(VI)-reducing ability (>96%), resulting in the simultaneous removal of co-contaminants. On the basis of transcriptomic and biochemical analysis, our study revealed that the oxidative stress in co-contaminants mainly caused by Cr(VI), and a number of dehydrogenases and oxidases showed up-regulation in response to Cr(VI) stress. It was noteworthy that the oxidative stress caused by Cr(VI) in co-contaminants can both significantly induce glutathione S-transferase and laccase expression. Glutathione S-transferase potentially involved in antioxidation against Cr(VI) stress. Laccase was found to play a key role in RB5 decolorization by T. hirsuta. These results suggested that the simultaneous removal of co-contaminants by T. hirsuta could be achieved with Cr(VI) exposure. Overall, the elucidation of the molecular basis in details will help to advance the general knowledge about the fungus by facing harsh environments, and put forward a further possible application of fungi on environmental remediation.

Comparative Evaluation and Quantitative Analysis of Loop-Mediated Isothermal Amplification Indicators.

Loop-mediated isothermal amplification (LAMP) as a diagnostic tool is rapidly gaining recognition and maturity. Among various advantages over traditional polymerase chain reaction, the ability to visually detect amplification by the incorporation of colorimetric indicators is one of its most unique features. There is an overwhelming variety of LAMP indicators in the literature, yet a comprehensive comparative study is lacking. This study evaluates the use of hydroxynaphthol blue, phenol red, calcein, leuco crystal violet, malachite green, and a fluorescent dye for visual detection. A method for objective quantitative analysis using ImageJ is described that is readily implemented in standard and microfluidic workflows. The work here also includes the largest inter-reader variability study involving 24 participants to evaluate these indicators. We found inaccuracies in visual assessment as bias and/or individual-based perception can exist, solidifying the need for objective analysis. There was not a "universal" indicator, although considerations in sample preparation, storage, and applicability are discussed in length.

Environment responsive Al3+ networked chitosan-gelatin spherical beads for the effective removal of organic pollutants from aqueous solutions.

In order to remove noxious Congo Red (CR), Acid Red 1 (AR1) and Reactive Red 2 (RR2) dye molecules from water, an environment responsive and biodegradable spherical chitosan-gelatin biopolymeric beads were designed and embedded with Al3+ ions. The surface morphology, specific surface area, crystalline phases, elemental composition and thermal properties of the CAG spherical beads had examined. Adsorption experiments were explored to investigate the adsorption properties of dye molecules on CAG spherical beads. The adsorption parameters like solution pH, contact time, co-existing ions, adsorbent dosage and regeneration studies were optimized using batch experiment method. The maximum adsorption efficiency of CR, AR1, and RR2 dye molecules on CAG spherical beads were 34.89, 32.36 and 33.63 mg/g, respectively. The adsorption system fits well with pseudo-second-order kinetics and Freundlich isotherm model. The molecular interactions followed in the adsorption mechanisms were the electrostatic force of attraction, surface complexation and hydrogen bondings that exist between dye molecules and the CAG spherical beads. The CAG spherical beads could be regenerated up to six consecutive cycles using an aqueous 0.1 M NaOH solution. The study emphasizes that the fabricated CAG spherical beads could act as a potential adsorbent in the water/wastewater treatment process.

Identification of benzofused five-membered sultams, potent dual NOD1/NOD2 antagonists in vitro and in vivo.

Nucleotide-binding oligomerization domain-containing proteins 1 and 2 play important roles in immune system activation. Recently, a shift has occurred due to the emerging knowledge that preventing nucleotide-binding oligomerization domains (NODs) signaling could facilitate the treatment of some cancers, which warrants the search for dual antagonists of NOD1 and NOD2. Herein, we undertook the synthesis and identification of a new class of derivatives of dual NOD1/NOD2 antagonists with novel benzofused five-membered sultams. Compound 14k was finally demonstrated to be the most potent molecule that inhibits both NOD1-and NOD2-stimulated NF-κB and MAPK signaling in vitro and in vivo.

Electrostatic interactions regulate the release of small molecules from supramolecular hydrogels.

Supramolecular hydrogels have great potential as biomaterials for sustained delivery of therapeutics. While peptide-based supramolecular hydrogels have been developed that show promise for drug delivery applications, the high cost of production has limited their widespread adoption. Low molecular weight (LMW) supramolecular hydrogels are emerging as attractive and inexpensive alternatives to peptide-based hydrogels. We recently reported novel cationic fluorenylmethyloxycarbonyl-modified phenylalanine (Fmoc-Phe) hydrogels for localized and sustained in vivo release of an anti-inflammatory agent for functional pain remediation. In an effort to further elucidate design principles to optimize these materials for delivery of a variety of molecular agents, we herein report a systematic examination of electrostatic effects on the release of cargo molecules from Fmoc-Phe derived hydrogels. Specifically, we interrogate the release of cationic, anionic, and neutral cargo molecules from a series of cationic and anionic Fmoc-Phe derived hydrogels. We observed that cargo was readily released from the hydrogels except when the cargo and hydrogel network had complementary charges, in which case the cargo was highly retained in the network. These results demonstrate that the electrostatic characteristics of both the hydrogel network and the specific cargo are critical design parameters in the formulation of LMW supramolecular hydrogel systems in the development of next-generation materials for drug delivery applications.

Rapid visual detection of Vibrio parahaemolyticus in seafood samples by loop-mediated isothermal amplification with hydroxynaphthol blue dye.

The detection and monitoring of Vibrio parahaemolyticus pathogen in aquatic foods have become essential for preventing outbreaks. In this study, loop-mediated isothermal amplification (LAMP) assay with the azo dye, hydroxynaphthol blue (HNB) was developed targeting species-specific tlh gene. The assay was carried out on 62 seafood samples that included clam and shrimp and compared with conventional LAMP assay performed with the commonly used fluorescent dye, conventional PCR, and real-time PCR (RT-PCR). Of 62 samples studied for tlh gene, 32 (51.61%) gave positive by HNB-LAMP, which comprised 22 (70.96%) clam samples and 10 (32.25%) shrimp samples. The HNB-LAMP assay was found to be highly sensitive, specific, and superior to conventional PCR (p > 0.05). RT-PCR presented higher sensitivity than HNB-LAMP; however, it has the limitation of being cost-intensive and requiring technical expertise to perform. HNB-LAMP is affordable, rapid, simple, and easy to perform, allowing naked eye visualization.

Enhanced degradation of Acid Red 73 by using cellulose-based hydrogel coated Fe3O4 nanocomposite as a Fenton-like catalyst.

Carboxymethyl cellulose-based hydrogel coated Fe3O4 magnetic nanoparticles were prepared using a coprecipitation combining graft copolymerization method, and characterized by various techniques to study their structure-property relationships. The nanocomposite was used as a heterogeneous Fenton-like catalyst for Acid Red 73 degradation. The effects of several key parameters, solution pH, H2O2 concentration, catalyst dosage, and temperature of the reaction medium on the pseudo-first-order kinetics of dye degradation was evaluated. The results showed that the nanocomposite catalyst were highly effective in activating H2O2 to produce reactive radicals for dye degradation, achieving complete decomposition under optimal conditions of 300 min at 25 °C and pH 3.5 with 100 mM H2O2 and 200 mg·L-1 catalyst. The complexing hydrogel-Fe2+/Fe3+ were the key factors that speed up the redox cycling between Fe2+ and Fe3+ species, thus accelerate the fast degradation rate of target pollutants. Scavenging experiments and electron paramagnetic resonance analyses revealed that Acid Red 73 was decomposed mainly by the attack of •OH radicals. Besides, reusability of the prepared nanocatalyst was also tested.