This study investigated the removal of Reactive Blue 21 (RB 21) dye from aqueous solutions by adsorption, evaluating the waste fly ash (FA). The effects of the parameters, such as initial dye concentration (100-750 mg/L), initial pH (2.0-8.0), adsorbent dose (1.0-4.0 g/L), and temperature (298-323 K) on the adsorption process were investigated. The optimum initial pH value was 2.0 for the highest RB21 dye removal (75.2 mg/g). At optimized conditions (pH 2.0, an adsorbent dosage of 1.0 g/L, a dye concentration of 750 mg/L, and an equilibrium time of 72 h), the highest adsorption capacity was found to be 105.2 mg/g. Moreover, the results of the kinetic studies fitted the pseudo-second-order kinetic model. Equilibrium data were best represented by the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 103.41 mg/g at 323 K. ΔG_ads⁰ values were negative and varied from 11.64 to 9.50 kJ/mol in the temperature range of 298-323 K, the values of enthalpy (ΔH_ads^o) and entropy (ΔS_ads^o) of thermodynamics parameters were calculated as 37.62 kJ/mol and 86.67 J/mol K, respectively, indicating that this process was endothermic. Furthermore, the adsorbent costs for powdered activated carbon (PAC) and FA to remove 1 kg of RB 21 dye from aqueous solutions are calculated as 2.52 U.S. $ and 0.34 U.S. $, respectively. It is seen that the cost of FA is approximately 7.4 times lower than PAC. The results showed that FA, a low-cost industrial waste, was promising for the adsorption of RB 21 from aqueous solutions.

2023-06-01·Environmental science and pollution research international

Iron (III)-doped PbO and its application as electrocatalyst for decomposition of phthalocyanine dye

Article

作者: El Hourch, Abderrahim ; Ennouhi, Mariem ; Ennoukh, Fatima Ezzahra ; Boutakiout, Amale ; El Aggadi, Sanaa

The textile industry contributes significantly to environmental pollution through dyeing and finishing processes that release dyes into wastewater. Even small amounts of dyes can have harmful effects and cause negative impacts. These effluents have carcinogenic, toxic, and teratogenic properties and can take a long time to be naturally degraded through photo/bio-degradation processes. This work investigates degradation of Reactive Blue 21 (RB21) phthalocyanine dye using anodic oxidation process with PbO₂ anode doped with iron III (0.1 M) (marked as Ti/PbO₂-0.1Fe) and compared with pure PbO₂. Ti/PbO₂ films with and without doping were successfully prepared by electrodeposition technology on Ti substrates. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS) was used to characterize the electrode morphology. Also, linear scanning voltammetry (LSV) and cyclic voltammetry (CV) tests were conducted to investigate the electrochemical response of these electrodes. The influence of operational variables on the mineralization efficiency was studied as a function of pH, temperature, and current density. Doping Ti/PbO₂ with Fe³⁺ (0.1 M) could reduce the particle to a smaller dimension and slightly increase the oxygen evolution potential (OEP). A large anodic peak was found for both electrodes prepared in the CV test, indicating that oxidation of the RB21 dye was easily achieved on the surface of the prepared anodes. No significant effect of initial pH on the mineralization of RB21 was observed. RB21 decolorization was more rapid at room temperature and increases with increasing current density. A possible degradation pathway for the anodic oxidation of RB21 in aqueous solution is proposed based on the identified reaction products. In general, it can be said that from the findings it was observed that the Ti/PbO₂ and Ti/PbO₂-0.1Fe electrodes show good performance on RB21 degradation. However, it was noted that the Ti/PbO₂ electrode tends to deteriorate over time and exhibits poor substrate adhesion, while the Ti/PbO₂-0.1Fe electrode displays superior substrate adhesion and stability.

2019-07-01·Water Science and Technology4区 · 环境科学与生态学

Determination of the color removal efficiency of laccase enzyme depending on dye class and chromophore

4区 · 环境科学与生态学

Article

作者: Güneş, Elçin ; Çifçi, Deniz İzlen ; Atav, Rıza ; Güneş, Yalçın

AbstractThe aim of this article was to clarify which type of dye chromophores could be decolorized efficiently with the use of laccase enzyme. For this purpose, enzymatic degradation of different type of dye classes (4 reactive, 2 acid and 1 basic dye) having various chromophore groups was investigated by using commercial laccase from Cerrena unicolor. It was observed that the chromophore structure of dye is very important on enzymatic color removal efficiency. According to the experimental results, it was found that color removal efficiencies (20 mg/L initial dye) were 98.7% for RB220 (0.1 g/L enzyme after 6 h), 95.1% for RB19 (0.1 g/L enzyme after 48 h), 90.8% for AR42 (0.1 g/L enzyme after 48 h) while they were 60.9% for AR114 (0.25 g/L enzyme), 58.6% for RB21 (0.5 g/L enzyme), 39.7% for RR239 (0.25 g/L enzyme) even after seven days. As a result, it can be said that the highest decolorization rate was achieved for the reactive dye having formazan copper complex (RB220) chromophore. On the other hand, the enzymatic degradation of basic dye (BB9) was found to be rather difficult compared to the acid and reactive dyes used in this study and the maximum color removal was 42.8% after seven days.

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适应症	最高研发状态	国家/地区	公司	日期
复发性慢性淋巴细胞白血病	临床申请批准	中国	瑞阳（苏州）生物科技有限公司	2023-12-01
复发性多发性骨髓瘤	临床申请批准	中国	瑞阳（苏州）生物科技有限公司	2023-12-01