Search Results (3)

To fully harness the potential of laccase in the efficient decolorization and detoxification of single and mixed dyes with diverse chemical structures, we carried out a systematic study on the decolorization and detoxification of single and mixed dyes using a crude laccase preparation obtained from a white-rot fungus strain, Pleurotus eryngii. The crude laccase preparation showed efficient decolorization of azo, anthraquinone, triphenylmethane, and indigo dyes, and the reaction rate constants followed the order Remazol Brilliant Blue R > Bromophenol blue > Indigo carmine > New Coccine > Reactive Blue 4 > Reactive Black 5 > Acid Orange 7 > Methyl green. This laccase preparation exhibited notable tolerance to SO₄²⁻ salts such as MnSO₄, MgSO₄, ZnSO₄, Na₂SO₄, K₂SO₄, and CdSO₄ during the decolorization of various types of dyes, but was significantly inhibited by Cl⁻ salts. Additionally, this laccase preparation demonstrated strong tolerance to some organic solvents such as glycerol, ethylene glycol, propanediol, and butanediol. The crude laccase preparation demonstrated the efficient decolorization of dye mixtures, including azo + azo, azo + anthraquinone, azo + triphenylmethane, anthraquinone + indigo, anthraquinone + triphenylmethane, and indigo + triphenylmethane dyes. The decolorization kinetics of mixed dyes provided preliminary insight into the interactions between dyes in the decolorization process of mixed dyes, and the underlying reasons and mechanisms were discussed. Importantly, the crude laccase from Pleurotus eryngii showed efficient repeated-batch decolorization of single-, two-, and four-dye mixtures. This crude laccase demonstrated high stability and reusability in repeated-batch decolorization. Furthermore, this crude laccase was efficient in the detoxification of different types of single dyes and mixed dyes containing different types of dyes, and the phytotoxicity of decolorized dyes (single and mixed dyes) was significantly reduced. The crude laccase efficiently eliminated phytotoxicity associated with single and mixed dyes. Consequently, the crude laccase from Pleurotus eryngii offers significant potential for practical applications in the efficient decolorization and management of single and mixed dye pollutants with different chemical structures. Full article

Various synthetic dyes are artificially added to herbal medicines for the purpose of visual attraction. In order to monitor the illegal usage of synthetic dyes in herbal medication, a rapid and straightforward analysis method to determine synthetic dyes is required. The study aimed to develop and validate a high-performance liquid chromatography (HPLC) analysis to determine ten synthetic dyes in Hawthorn fruit, Cornus fruit, and Schisandra fruit. Ten synthetic dyes such as Tartrazine, Sunset yellow, Metanil yellow, Auramine O, Amaranth, Orange II, Acid red 73, Amaranth, New Coccine, Azorubine, and Erythrosine B, were extracted using 50 mM ammonium acetate in 70% MeOH; then separated by gradient elution with a mobile phase consisting of acetonitrile and 50 mM ammonium acetate in distilled water using a photodiode array detector (PDA) at 428 nm or 500 nm. In addition, this study established the LC-MS/MS method to confirm the existence of synthetic dyes in the positive sample solution. The HPLC analysis had good linearity (r² > 0.999). The recoveries of this method ranged from 74.6~132.1%, and the relative standard deviation (RSD) values were less than 6.9%. Most of the samples fulfilled the acceptance criteria of the AOAC guideline. This study demonstrates that the HPLC analysis can be applied to determine ten synthetic dyes in herbal medication. Full article

In the present work, adsorption of anionic azo dye, new coccine (NCC) on silica and silica-gel in an aquatic environment was discovered. Effective conditions such as adsorption time, pH, the influence of dosage on NCC adsorption using strong polycation, poly-diallyl-dimethylammonium chloride (PDADMAC) modified silica (PMS) and PDADMAC modified silica-gel (PMSG) were systematically studied. The removal of NCC using PMS and PMSG were much higher than that using raw silica and silica-gel without PDADMAC in all pH ranges from 3 to 10. The adsorption of NCC onto PMS and PMSG was achieved maxima at the same conditions of contact time 30 min, pH 6. The optimum adsorbent dosages of PMS and PMSG for NCC removal were 10 and 20 mg·mL⁻¹, respectively. Experimental results of NCC adsorption isotherms onto PMS and PMSG at different ionic strength were fitted by Langmuir and Freundlich models. The NCC removal efficiencies using PMS and PMSG were higher than 87%, indicating that PMS and PMSG are novel and reusable adsorbents for removal of anionic dye. Based on adsorption isotherms, and surface group changes after PDADMAC modification and NCC adsorption examined by Fourier transform infrared spectroscopy (FTIR), we demonstrate that electrostatic interaction between positively charged adsorbents’ surfaces and negative sulfonic groups of NCC are the main driving force for anionic azo dye adsorption onto PMS and PMGS adsorbents. Full article