Acid Red 73

Carbon nanotube/Chitosan hydrogel for adsorption of acid red 73 in aqueous and soil environments.[Pubmed:37620928]

BMC Chem. 2023 Aug 24;17(1):104.

Acid Red 73 is an azo dye, and its residue can pollute the environment and seriously threaten human health and life. In this study, glutaraldehyde was used as the crosslinking agent, chitosan and polyvinyl alcohol were crosslinked under appropriate conditions to obtain a chitosan hydrogel film, and carbon nanotubes were dispersed in the chitosan hydrogel film. The FTIR, XRD, BET, SEM were applied to chatacterize the structure and the morphology of the absorbent and results showed that when the mass fraction of the carbon nanotubes was 1%, the structure was a three-dimensional network with microporous, and the water absorption reached to the maximum value of 266.07% and the elongation at break reached to a maximum of 98.87%. The ability to remove Acid Red 73 from aqueous and soil environments was evaluated by UV. In the aqueous samples, 70 mg of the adsorbent reached a saturated adsorption capacity of 101.07 mg/g and a removal rate of 92.23% at pH = 5. The thermodynamics conformed with the Langmuir adsorption isotherm and pseudo second-order adsorption kinetic models. In the soil samples, 100 mg of the adsorbent reached an adsorption capacity of 24.73 mg/g and removal rate of 49.45%. When the pH of the soil is between 4 and 7, the removal rate and adsorption capacity do not change much; hence, the pH should be maintained between 5.2 and 6.8, which is extremely suitable for the growth of general plants. Moreover, the experimental results demonstrated that the adsorbent maintained a good removal rate of Acid Red 73 over six adsorption cycles.

Transcriptome analysis reveals self-redox mineralization mechanism of azo dyes and novel decolorizing hydrolases in Aspergillus tabacinus LZ-M.[Pubmed:36934962]

Environ Pollut. 2023 May 15;325:121459.

Bio-degradation is the most affordable method of azo dye decontamination, while its drawbacks such as aromatic amines accumulation and low degradation efficiency must be overcome. In this study, a novel mechanism of azo dye degradation by a fungus was discovered. At a concentration of 400 mg/L, the decolorization efficiency of Acid Red 73 (AR73) by Aspergillus tabacinus LZ-M was 90.28%. Metabolite analysis and transcriptome sequencing analysis revealed a self-redox process of AR73 degradation, where the electrons generated in carbon oxidation were transferred to the reduction of -C-N = and -NN. The metabolites, 2-hydroxynaphthalene and N-phenylnitrous amide were mineralized into CO(2) through catechol pathway and a glycolytic process. Furthermore, the mineralization ratio of dye was computed to be 31.8% by the carbon balance and electron balance. By using comparative transcriptome, a novel decoloring enzyme Ord95 was discovered in unknown genes through gene cloning. It hydrolyzed AR73 into 2-hydroxynaphthalene and N-phenylnitrous amide, containing a glutathione S-transferase domain with three arginines as key active sites. Here the new mechanism of azo dye degradation was discovered with identification of a novel enzyme in Aspergillus tabacinus LZ-M.

Synergistic and efficient degradation of acid red 73 by UV/O(3)/PDS: Kinetic studies, free radical contributions and degradation pathways.[Pubmed:36270531]

Environ Res. 2023 Jan 1;216(Pt 3):114449.

Acid Red 73 (AR73) is a representative dye pollutant that poses a threat to the environment and human health. Effectively removing this type of pollutant by conventional processes is difficult. However, this study found that compared with UV/PDS, UV/O(3), and PDS/O(3), UV/O(3)/PDS composite system had the highest degradation effect on AR73. The degradation efficiency in the composite system reached 97.61% within 30 min, and the synergistic coefficients in the composite system were all greater than 1. In the UV/O(3)/PDS system, .OH was the main free radical that mainly degrades AR73. The increase of PDS dosage promoted the degradation of AR73, but the increase of O(3) dosage was difficult to greatly improve the degradation of AR73 effect. The kinetic model of the apparent reaction rate was determined. The UV/O(3)/PDS system can efficiently degrade AR73 in a wide range of substrate concentrations and pH levels, and at the same time showed good adaptability to various concentrations of anions (Cl(-), CO(3)(2-), SO(3)(2-), and C(2)O(4)(2-)). Under raw water quality, the degradation effect of AR73 was still as high as approximately 90%. The theoretical attack site was obtained by DFT calculation, and the possible degradation pathway of AR73 was proposed based on the GC-MS spectrum and UV-Vis absorption spectrum. The attack of -NN- by .OH, SO(4)(-), and O(3) was proposed to be the main possible degradation pathway for AR73. Therefore, this study further improves the understanding of the UV/O(3)/PDS system and shows the potential applicability of this system in the treatment of dye wastewater.

Degradation of acid red 73 wastewater by hydrodynamic cavitation combined with ozone and its mechanism.[Pubmed:35183517]

Environ Res. 2022 Jul;210:112954.

Many azo dyes are consumed in the textile and dyeing industry, which makes the wastewater recalcitrant and toxic to the aquatic environment. Dye degradation by the combination of hydrodynamic cavitation and ozone (HC + O(3)) has caused extensive interest. The degradation mechanism of the hybrid system needs further investigation. This study investigated the degradation of Acid Red 73 (AR73) by HC + O(3). Meanwhile, the degradation pathways and mechanisms were present. The optimal operation parameters were: inlet pressure of 0.15 MPa, O(3) dosage of 45 mg/min, initial dye concentration of 10 mg/L, and initial pH at 7.5. As a result, the decolorization rate, removal of UV(254) and NH(3)-N were 100%, 71.28%, and 87.36% in 30 min, respectively. Humic acid and most of the co-existing anions (HCO(3)(-), SO(4)(2-), Cl(-), PO(4)(3-), NO(3)(-)) played a positive role in the degradation of AR73, while NO(2)(-) restrained. The reactive species of singlet oxygen ((1)O(2)), hydroxyl radicals (.OH) and super oxygen radicals (.O(2)(-)) showed synergism in the hybrid system, and the decolorization was attributed to the fracture of azo bonds by (1)O(2). Meanwhile, aromatic amines were generated and further degraded into small molecule compounds. The research certificated that the HC + O(3) can be an effective technology for azo dye degradation.

Synthesis of a functional biomass lignin-based hydrogel with high swelling and adsorption capability towards Acid Red 73.[Pubmed:33978948]

Environ Sci Pollut Res Int. 2021 Oct;28(37):51306-51320.

In this study, sodium lignosulfonate (LS) was used as raw material. Acrylamide (AM) and acryloxyethyltrimethylammonium chloride (DAC) were grafted onto LS through the free radical graft copolymerisation to synthesise a functional biomass terpolymer lignin-based hydrogel adsorbent (LAD). The effects of different factors on the LAD adsorption of Acid Red (AR 73) were investigated through the static adsorption method. LAD adsorbed AR 73 (C(0)=100mg.L(-1)) for 2 h to reach equilibrium, and the equilibrium adsorption capacity and removal rate were 47.59 mg.g(-1) and 95.18%, respectively. The prepared LAD hydrogel swelling ratio for 2 h was 25 g.g(-1), and the water loss rate in ethanol solvent in 120 min was 93.51%. The adsorption of AR 73 by LAD was consistent with the Langmuir isotherm adsorption model. This adsorption was a single-molecule adsorption with a maximum adsorption capacity of 409.84 mg.g(-1). The adsorption was a process of spontaneous heat release and entropy reduction. The adsorption kinetic was in accordance with the pseudo-second-order model, and the adsorption activation energy was 2.501 kJ.moL(-1). Moreover, the mechanism of adsorption was electrostatic attraction, and comprehensive effects of physical, and chemical adsorption and hydrogen bond. The LAD hydrogel adsorbent has a remarkable adsorption effect on AR 73, and can be used as an efficient and recyclable biomass adsorbent for the treatment of anionic dye wastewater.

Ternary metal oxide embedded carbon derived from metal organic frameworks for adsorption of methylene blue and acid red 73.[Pubmed:33945901]

Chemosphere. 2021 Oct;280:130567.

Organic dyes can enter water bodies through industrial wastes and may pose a threat to the health of aquatic organisms and human. Metal organic framework derived carbon materials (CMOFs) have shown excellent performance for aqueous dye adsorption. However, few have studied multimetallic CMOFs for dye removal. Herein, a ternary metal oxide embedded carbon derived from amino-modified metal organic framework (CMOF(Fe/Al/Ni 8/7/5)-NH(2)) has been developed as an efficient adsorbent to remove aqueous methylene blue (MB) and Acid Red 73 (AR-73). CMOF(Fe/Al/Ni 8/7/5)-NH(2) reached adsorption equilibrium for both MB and AR-73 within 30 min at neutral pH condition. It also achieved 18 and 24 times higher adsorption than commercial activated carbon (AC) in 10 min for MB and AR-73, respectively. Compared to other CMOFs-NH(2), CMOF(Fe/Al/Ni 8/7/5)-NH(2) had the highest adsorption capacity for both cationic MB and anionic AR-73. In addition, CMOF(Fe/Al/Ni 8/7/5)-NH(2) had < 0.15% metal leaching in 90 min in the pH range of 4-10, and it also maintained 89% and 95% adsorption capacity for MB and AR-73 in five consecutive adsorption batches, respectively. Electrostatic interaction was identified as the primary interaction between CMOFs-NH(2) and the dyes, and the embedded crystalline metal oxides with different points of zero charge (PZCs) were identified to be the key adsorption sites. A uniformly distributed surface charge model was proposed to explain the exceptional adsorption capacity of CMOF(Fe/Al/Ni 8/7/5)-NH(2.) With fast kinetics, high adsorption capacity, wide applicability and good stability, CMOF(Fe/Al/Ni 8/7/5)-NH(2) may be an effective adsorbent for many other ionic organic pollutants.

Degradation of Acid Red 73 by Activated Persulfate in a Heat/Fe(3)O(4)@AC System with Ultrasound Intensification.[Pubmed:32566839]

ACS Omega. 2020 Jun 2;5(23):13739-13750.

This work aimed to investigate the degradation efficiency of waste water with an azo dye, Acid Red 73 (AR73), by persulfate/heat/Fe(3)O(4)@AC/ultrasound (US). The introduction of ultrasound into the persulfate/heat/Fe(3)O(4)@AC system greatly enhanced the reaction rate because of the physical and chemical effects induced by cavitation. Various parameters such as temperature, initial pH, sodium persulfate dosage, catalyst dosage, initial concentration of AR73, ultrasonic frequency and power, and free-radical quenching agents were investigated. The optimal conditions were determined to be AR73 50 mg/L, PS 7.5 mmol/L, catalyst dosage 2 g/L, ultrasound frequency 80 kHz, acoustic density 5.4 W/L, temperature 50 degrees C, and pH not adjusted. Nearly, 100% decolorization was achieved within 10 min under optimal conditions. Different from some other similar research studies, the reaction did not follow a radical-dominating way but rather had (1)O(2) as the main reactive species. The recycling and reusability test confirmed the superiority of the prepared Fe(3)O(4)@AC catalyst. The research achieved a rapid decolorization method not only using waste heat of textile water as a persulfate activator but also applicable to a complex environment where common radical scavengers such as ethanol exist.

Enhanced degradation of Acid Red 73 by using cellulose-based hydrogel coated Fe(3)O(4) nanocomposite as a Fenton-like catalyst.[Pubmed:32087222]

Int J Biol Macromol. 2020 Jun 1;152:242-249.

Carboxymethyl cellulose-based hydrogel coated Fe(3)O(4) 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, H(2)O(2) 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 H(2)O(2) to produce reactive radicals for dye degradation, achieving complete decomposition under optimal conditions of 300 min at 25 degrees C and pH 3.5 with 100 mM H(2)O(2) and 200 mg.L(-1) catalyst. The complexing hydrogel-Fe(2+)/Fe(3+) were the key factors that speed up the redox cycling between Fe(2+) and Fe(3+) 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.

Preparation of a SnO(2)-Sb electrode on a novel TiO(2) network structure with long service lifetime for degradation of dye wastewater.[Pubmed:35540643]

RSC Adv. 2019 Nov 29;9(67):39242-39251.

Developing effective electrodes with long service lifetime for electrochemical degradation of dyes is of paramount importance for their practical industrial applications. We constructed a novel SnO(2)-Sb electrode (Ti/TiO(2)-NW/SnO(2)-Sb electrode) based on a uniform TiO(2) network structure decorated Ti plate (Ti/TiO(2)-NW) for a long-term electrocatalytic performance. The SnO(2)-Sb coating layer on this electrode was grown on the Ti/TiO(2)-NW by pulse electrodeposition. The introduction of the three-dimensional TiO(2)-NW enhances the bonding strength between the Ti substrate and the SnO(2)-Sb surface coating. An accelerated life test shows that the service life of Ti/TiO(2)-NW/SnO(2)-Sb electrode is 11.15 times longer than that of the traditional Ti/SnO(2)-Sb electrode. The physicochemical properties of the electrodes were characterized through SEM, EDS, XRD and HRTEM. In addition, through LSV, EIS, CV and voltammetric charge analysis, it is found that compared with the traditional electrode, the Ti/TiO(2)-NW/SnO(2)-Sb electrode possesses a higher oxygen evolution potential, a lower charge transfer resistance and a larger electrochemical active surface area. Besides, this novel electrode also exhibits an outstanding electrocatalytic oxidation ability for degradation of Acid Red 73 in simulated sewage. After a 5 hours' test, the removal efficiency of Acid Red 73 and the COD reached 98.6% and 71.8%, respectively, which were superior to those of Ti/SnO(2)-Sb electrode (89.1% and 58.8%). This study highlights the excellent stability of the Ti/TiO(2)-NW/SnO(2)-Sb electrode and provides an energy-efficient strategy for dye degradation.

A multifunctional gelatine-quaternary ammonium copolymer: An efficient material for reducing dye emission in leather tanning process by superior anionic dye adsorption.[Pubmed:31639610]

J Hazard Mater. 2020 Feb 5;383:121142.

Leather wastewater is one of the most polluting industrial emissions. The efficiency of wastewater remediation is limited by its complex composition. Herein, a novel strategy for designing modified gelatine with higher degree of quaternization (MG-2) is presented. The higher degree of quaternization allows sufficient adsorption of dyes in the tanning process. It is an in situ, environmentally friendly, and innovative strategy to limit dye emissions and can circumvent the subsequent waste management. Dyes such as Direct Purple N and Acid Black 24 could be adsorbed completely within 5 min by the MG-2 film formed from MG-2 solution. In addition, a remarkable efficiency in removing Acid Red 73, Golden Orange G, and Acid Orange II (>96.1% removal rates) was achieved within 30 min. The adsorption equilibrium data suggested that the adsorption capacity was positively correlated to the concentration of MG-2. When Acid Orange II and MG-2 were used in the industrial re-tanning process, the residual dye concentration in wastewater was only 23.1 mg L(-1), indicating that MG-2 is a promising re-tanning agent for adsorbing dyes in the leather tanning process.

Synthesis of coal fly ash supported MnO(2) for the enhanced degradation of Acid Red 73 in the presence of peroxymonosulfate.[Pubmed:31116650]

Environ Technol. 2021 Jan;42(1):81-92.

In this study, coal fly ash supported MnO(2) (CFA@MnO(2)) was synthesized as heterocatalyst for the activation of peroxymonosulfate to degrade Acid Red 73 (AR73). The synthesized catalyst was characterized by X-Ray Fluorescence Spectrometer (XRF), X-ray powder diffraction (XRD), Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). The composite of CFA@MnO(2) possesses a large surface area of 74.59 m(2)/g. In the catalytic experiment, CFA@MnO(2) exhibits excellent catalytic performance with 99.13% AR73 removed within 40 min with a high kinetic rate constant of 0.124 min(-1), 5.49 times higher than that of pure MnO(2). The operating parameters of CFA@MnO(2)-based fenton catalytic system were discussed, including MnO(2) loading, solution pH, PMS dosage and temperature. The catalyst maintained a relatively high removal rate (>85%) over 5 cycles and degradation intermediates are detected on the catalyst surface after cycled via XPS analysis. The degradation mechanism was investigated by quenching experiments and Electron Paramagnetic Resonance technology. The surface-bound (.)OH and SO(4) (.-) are considered as the main active radicals in the degradation process. The composite of CFA@MnO(2) provides a low-cost and efficient alternative for the catalytic oxidation of organic pollutants.

[Determination of common dyes in dyed safflower by near infrared spectroscopy].[Pubmed:31090316]

Zhongguo Zhong Yao Za Zhi. 2019 Apr;44(8):1537-1544.

Because the red and bright color of corolla is the main indicator for the quality assessment of good safflower,the dyed safflower is sometimes found at the herbal market,what is influence on this herb quality and efficacy. A total of 127 safflower samples was therefore collected from different cultivating areas and herbal markets in China to develop a rapid method to identify the dyed safflower. Near-infrared spectroscopy(NIRS) combined with characteristic identification,high performance liquid chromatography(HPLC),principal component analysis(PCA) and partial least squares regression analysis(PLS) were employed to differentiate safflower from dyed safflower samples,and further quantify the levels of the 6 dyes,i.e. tartrazine,carmine,sunset yellow,azorubine,Acid Red 73 and orange Ⅱ in the dyed safflower. The results indicated that the 50 safflower samples and 77 dyed safflower samples were located at different regions in PCA cluster diagram by NIR spectra. Tartrazine,carmineand and sunset yellow were found in the 77 dyed safflower samples with the amounts of 0. 60-3. 66,0. 11-1. 37,0. 10-0. 71 mg.g-1,respectively. It indicated that the three dyes were the common and main dyes in the dyed safflower. However,azorubine,Acid Red 73 and orange Ⅱ were not detected in all herb samples. A total of 62 dyed safflower samples were chosen as calibration samples to develop the model for estimating the amount of dyes in dyed safflower. The estimating accuracy was verified by another 15 dyed safflower samples. The values of tartrazine,carmine and sunset yellow in dyed safflower samples were compared between the NIRS and HPLC methods. Each value of mean absolute difference(MAD) was less than 5%. The correlation coefficients of tartrazine,carmineand and sunset yellow were 0. 970,0. 975,0. 971,respectively. It indicated the data quantified by NIRS and HPLC were consistence. It is concluded that NIRS can not only differentiate safflower from dyed safflower,but also quantify the amount of the dyes. NIRS is suitable for rapidly identify the quality of safflower.