Abstract

This study elaborates an expeditious and efficient dye decolorization process of a widely used textile dye malachite green by green synthesized iron oxide nanoparticles (IONPs) without application of any adjuvant, catalyst and/or variation in environmental conditions. The reaction was concentration dependent, and its kinetics was of the mixed-order type. The kinetics were analyzed to show that a dye concentration of 0.1 mg/ml and IONPs at a concentration of 2.4 × 10¹¹ particles/ml were ideal to achieve 93.77 ± 0.12% decolorization almost instantaneously in 1.5 min. The IONPs were synthesized using extracellular polymeric substance (EPS) that showed biosurfactant activity and was secreted by the bacterium Alcaligenes sp. They were evident as a sharp peak obtained at 418 nm. The nanoparticles were of size 176.69 ± 5 nm as observed by transmission electron microscopy. The influence of various parameters for synthesis was optimized by response surface methodology. They were found to be as follows: pH 13, temperature 70 °C, FeCl₃ concentration 2 mM and incubation time of 2 h. The EPS was characterized biochemically and shown to display surfactant and emulsifier properties, thereby making it a useful multifunctional polymer. These results offer a viable, efficient and environment friendly solution to bio-remediate dye from textile industry effluents before its release into the environment.

Graphic abstract

中文翻译：

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使用生物表面活性剂稳定的氧化铁纳米颗粒从水溶液中脱色孔雀石绿色染料：工艺优化和反应动力学

摘要

这项研究阐述了绿色合成的氧化铁纳米粒子（IONPs）对一种广泛使用的纺织染料孔雀绿进行的快速有效的染料脱色过程，而无需应用任何助剂，催化剂和/或环境条件。该反应是浓度依赖性的，并且其动力学是混合级的。动力学分析表明，染料浓度为0.1 mg / ml和IONPs浓度为2.4×10 ¹¹ 颗粒/ ml是理想的条件，几乎可以在1.5分钟内立即实现93.77±0.12％的脱色。使用具有生物表面活性剂活性并由细菌产碱菌分泌的细胞外聚合物（EPS）合成IONP。sp。它们明显是在418 nm处获得的尖峰。通过透射电子显微镜观察，纳米颗粒的尺寸为176.69±5nm。通过响应面法优化了各种参数对合成的影响。发现它们如下：pH 13，温度70℃，FeCl ₃浓度为2mM，孵育时间为2h。EPS具有生化特性，并显示出表面活性剂和乳化剂的性能，因此使其成为有用的多功能聚合物。这些结果为纺织工业废水中的生物修复染料释放到环境中之前提供了一种可行，高效且环境友好的解决方案。

图形摘要