Mandarin biochar-CO-TETA was utilized for Acid Red 73 dye adsorption from water, and its isotherm and kinetic studies were investigated.

Environmental pollution is a major issue today due to the release of dyestuff waste into the environment through industrial wastewater. There is a need for affordable and effective adsorbents to remove harmful dyes from industrial waste. In this study, Mandarin biochar-CO-TETA (MBCOT) adsorbent was prepared and used to remove Acid Red 73 (AR73) dye from aqueous solutions. The efficiency of dye removal was influenced by various factors such as solution pH, contact time, initial AR73 dye concentration, and MBCOT dosage. All experiments were conducted at 25 ± 2 °C, and the optimal pH was determined to be 1.5. The optimal conditions for dye removal were found to be an AR73 dye concentration of 100 mg/L, an MBCOT dosage of 1.5 g/L, and a contact time of 150 min, resulting in a 98.08% removal rate. Various models such as pseudo-first-order (PFO), pseudo-second-order (PSO), film diffusion (FD), and intraparticle diffusion (IPD) were used to determine the adsorption kinetics of AR73 dye onto MBCOT. The results showed that the PSO model best explains the AR73 dye adsorption. Furthermore, Langmuir and Freundlich's isotherm models were studied to explain the adsorption mechanism using experimental data. The adsorption capacities at equilibrium (qe) in eliminating AR73 dye varied from 92.05 to 32.15, 128.9 to 65.39, 129.25 to 91.69, 123.73 to 111.77, and 130.54 to 125.01 mg/g. The maximum adsorption capacity (Qm) was found to be 140.85 mg/g. In conclusion, this study demonstrates that biochar produced from mandarin peels has the potential to be an effective and promising adsorbent for removing AR73 dye from water.

Synergistic and efficient degradation of acid red 73 by UV/O3/PDS: Kinetic studies, free radical contributions and degradation pathways.

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/O3, and PDS/O3, UV/O3/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/O3/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 O3 dosage was difficult to greatly improve the degradation of AR73 effect. The kinetic model of the apparent reaction rate was determined. The UV/O3/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-, CO32-, SO32-, and C2O42-). 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, SO4-, and O3 was proposed to be the main possible degradation pathway for AR73. Therefore, this study further improves the understanding of the UV/O3/PDS system and shows the potential applicability of this system in the treatment of dye wastewater.

Synthesis of coal fly ash supported MnO2 for the enhanced degradation of Acid Red 73 in the presence of peroxymonosulfate.

In this study, coal fly ash supported MnO2 (CFA@MnO2) 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@MnO2 possesses a large surface area of 74.59 m2/g. In the catalytic experiment, CFA@MnO2 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 MnO2. The operating parameters of CFA@MnO2-based fenton catalytic system were discussed, including MnO2 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 SO4 ·- are considered as the main active radicals in the degradation process. The composite of CFA@MnO2 provides a low-cost and efficient alternative for the catalytic oxidation of organic pollutants.

EDTA modified ß-cyclodextrin/chitosan for rapid removal of Pb(II) and acid red from aqueous solution.

EDTA modified ß-cyclodextrin/chitosan (CDCS-EDTA) was fabricated successfully by a two-step method and applied to remove Pb(II) and anionic dye acid red 73 (AR). CDCS-EDTA was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and zeta potential analysis. The effects of experimental parameters including adsorbent dose, contact time and pH value on the adsorption efficiency of CDCS-EDTA for the pollutants were investigated. The maximum adsorption capacities were 114.8 mg g-1 for Pb(II) and 754.6 mg g-1 for AR under the optimal conditions. 93.4% of Pb(II) and 92.1% of AR could be adsorbed within 5 min, and the adsorptions reached equilibrium rapidly within 20 min and 10 min for Pb(II) and AR, respectively. A possible adsorption mechanism had been proposed that chelation of EDTA and electrostatic attraction of hydroxyl and amino groups dominated the adsorption of Pb(II), while the adsorption of AR mainly by the formation of inclusion complex with cyclodextrin cavities and electrostatic attraction with functional groups. For these two pollutants, the adsorption kinetic and isotherm data fitted well with the pseudo-second-order model and the Langmuir model, respectively. Thermodynamic studies implied that the adsorption process of Pb(II) and AR were spontaneous. Furthermore, the excellent regeneration performance indicated that CDCS-EDTA has a promising application in water treatment.

Simultaneous Determination of 9 Illegal Dyes in Carthamus tinctorius by HPLC-MS/MS / 中国药房

OBJECTIVE:To establish the method for the determination of 9 illegal dyes in Carthamus tinctorius.METHODS:HPLC-MS/MS was adopted.The determination was performed on SB-C18 column with mobile phase consisted of 10 mmol/L ammonium formate-acetonitrile (gradient elution) at the flow rate of 0.2 mL/min.The column temperature was 30 ℃,and the sample size was 10 μL.Mass spectrometry condition:electrospray ion source,negative ion multi-ion reaction monitoring mode,ion spray voltage of 3 500 V,drying gas temperature of 350 ℃,drying gas flow rate of 10 L/min,colliding gas of high pure nitrogen gas,scanning range of m/z 50～ 1 000.RESULTS:The linear ranges of ponceau,acid red 73,lemon yellow,azorubin,allura red,gold orange Ⅱ,sunset yellow,pyrosine and golden orange G were 5.313 5～531.35 ng/mL(r=0.987 0),1.312 0～1 312.00 ng/mL(r=0.994 8),124.480 0～2 824.00 ng/mL(r=0.983 2),6.300 0～630.00 ng/mL(r=0.964 8),1.035 8～517.92 ng/mL(r=0.996 4),0.552 0～1 104.00 ng/mL(r=0.909 0),5.046 3～2 018.52 ng/mL(r=0.996 2),5.046 3～2 018.52 ng/mL(r=0.997 6),1.079 5～2 159.00 ng/mL(r=0.990 0),respectively.The limits of quantitation were 10.418 7,1.131 0,68.401 0,13.695 7,1.670 7,0.238 0,3.973 3,1.064 7,1.285 0 ng/kg.The limits of detection were 3.125 6,0.339 3,20.520 3,4.108 7,0.501 2,0.071 4,1.192 0,0.319 4,0.385 5 ng/kg,respectively.RSDs of precision,stability and reproducibility tests were all lower than 3.0％.The recoveries were 91.2％-99.1％ (RSD=0.7％-2.2％,n=6).CONCLUSIONS:The established method is specific,sensitive,simple and rapid,and can be used for the detection of 9 illegal dyes in C.tinctorius.

Simultaneous Determination of 9 Illegal Dyes in Carthamus tinctorius by HPLC-MS/MS / 中国药房

OBJECTIVE:To establish the method for the determination of 9 illegal dyes in Carthamus tinctorius.METHODS:HPLC-MS/MS was adopted.The determination was performed on SB-C18 column with mobile phase consisted of 10 mmol/L ammonium formate-acetonitrile (gradient elution) at the flow rate of 0.2 mL/min.The column temperature was 30 ℃,and the sample size was 10 μL.Mass spectrometry condition:electrospray ion source,negative ion multi-ion reaction monitoring mode,ion spray voltage of 3 500 V,drying gas temperature of 350 ℃,drying gas flow rate of 10 L/min,colliding gas of high pure nitrogen gas,scanning range of m/z 50～ 1 000.RESULTS:The linear ranges of ponceau,acid red 73,lemon yellow,azorubin,allura red,gold orange Ⅱ,sunset yellow,pyrosine and golden orange G were 5.313 5～531.35 ng/mL(r=0.987 0),1.312 0～1 312.00 ng/mL(r=0.994 8),124.480 0～2 824.00 ng/mL(r=0.983 2),6.300 0～630.00 ng/mL(r=0.964 8),1.035 8～517.92 ng/mL(r=0.996 4),0.552 0～1 104.00 ng/mL(r=0.909 0),5.046 3～2 018.52 ng/mL(r=0.996 2),5.046 3～2 018.52 ng/mL(r=0.997 6),1.079 5～2 159.00 ng/mL(r=0.990 0),respectively.The limits of quantitation were 10.418 7,1.131 0,68.401 0,13.695 7,1.670 7,0.238 0,3.973 3,1.064 7,1.285 0 ng/kg.The limits of detection were 3.125 6,0.339 3,20.520 3,4.108 7,0.501 2,0.071 4,1.192 0,0.319 4,0.385 5 ng/kg,respectively.RSDs of precision,stability and reproducibility tests were all lower than 3.0％.The recoveries were 91.2％-99.1％ (RSD=0.7％-2.2％,n=6).CONCLUSIONS:The established method is specific,sensitive,simple and rapid,and can be used for the detection of 9 illegal dyes in C.tinctorius.

Enhanced coagulation-photocatalytic treatment of Acid red 73 dye and real textile wastewater using UVA/synthesized MgO nanoparticles.

Sequencing coagulation - photocatalytic degradation using UVA/MgO nanoparticles process was investigated for Acid red 73dye removal and then treatment of a real textile wastewater. Effective operational parameters including pH and coagulant and photocatalyst dosage were studied in synthetic wastewater and then the process was applied for real wastewater. Both coagulation and photocatalytic processes were pH dependent. At coagulant dosage of 200 mg/L and initial pH of 6, the dye concentration decreased from 200 to 31 mg/L. Complete removal of AR73 was observed with MgO nanoparticles of 0.8 g/L, initial pH of 5 and reaction time of 60 min. Langmuir-Hinshelwood model was well fitted with removal results (R(2): 0.939-0.988 for different initial dye concentration). In the case of real textile wastewater, the sequence coagulation-UVA/MgO nanoparticles photocatalytic degradation yielded considerable total COD and TOC removal 98.3% and 86.9%respectively, after 300 min.