The present study aims to investigate the potential of Oedogonium subplagiostomum AP1 in the removal of methyl orange from aqueous solution. The effects of process parameters, namely, dye concentration, biosorbent concentration, pH and contact time on adsorption were optimised using RSM. The predictions of the model output specified that process parameters influenced responses at a confidence level of 95% (P < 0.05). Optimum conditions for methyl orange removal (97%) was obtained at pH 6.5, contact time of 5.5 days, algal dose of 400 mg/L and dye concentration of 500 mg/L. Adsorption isotherm, kinetics and thermodynamic studies were conducted to assess the decolourisation efficiency. The results indicated that Langmuir isotherm and pseudo-second-order kinetic models best fitted the experimental data. The thermodynamic parameters indicated that methyl orange biosorption onto alga is spontaneous, favourable and exothermic in nature. The biosorbent-adsorbate interactions were characterised using UV-Vis, FT IR, SEM with EDX and XRD. The reuse potential of treated dye solution was assessed by dyeing fabrics. The physical properties of fabrics dyed using algae-treated water are comparable with that of tap water–dyed fabric proving the reuse potential of treated water in textile industries. The algal biomass subjected to composting diminishes the level of pollution. In silico study was performed to observe the interaction between methyl orange (ligand) and receptor protein (azoreductase) which plays an important role in the biodegradation of textile dyes. Thus, the results showed that Oedogonium subplagiostomum AP1 could be employed as an efficient and eco-friendly biosorbent for the removal of methyl orange.

Graphical Abstract

中文翻译：

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使用耻骨孔亚目AP1去除水溶液中甲基橙的体外和计算机模拟研究

本研究的目的是调查臭毛线虫亚纲AP1在从水溶液中去除甲基橙的潜力。使用RSM优化了工艺参数，即染料浓度，生物吸附剂浓度，pH和接触时间对吸附的影响。模型输出的预测指定过程参数以95％的置信度（P <0.05）。在pH 6.5，接触时间为5.5天，藻类剂量为400 mg / L和染料浓度为500 mg / L的条件下，可获得最佳的甲基橙去除条件（97％）。进行吸附等温线，动力学和热力学研究以评估脱色效率。结果表明，Langmuir等温线和拟二级动力学模型最适合实验数据。热力学参数表明甲基橙在藻类上的生物吸附是自然的，有利的和放热的。使用UV-Vis，FT IR，具有EDX和XRD的SEM表征了生物吸附剂-被吸附物的相互作用。通过染色织物评估处理过的染料溶液的再利用潜力。用藻类处理过的水染色的织物的物理性能与用自来水染色过的织物的物理性能相当，证明了处理后的水在纺织工业中的再利用潜力。经受堆肥处理的藻类生物质降低了污染水平。在计算机上进行了研究，以观察甲基橙（配体）与受体蛋白（偶氮还原酶）之间的相互作用，该相互作用在纺织品染料的生物降解中起着重要作用。因此，结果表明耻骨毛孔亚目（Oedogonium subplagiostomum） AP1可作为一种高效，环保的生物吸附剂用于去除甲基橙。

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