Abstract：
The presence of dyes in water stream is a major environmental problem that affects aquatic and human life negatively. Therefore, it is essential to remove dye from wastewater before its discharge into the water bodies. In this study, Banyan (Ficus benghalensis, F. benghalensis) tree leaves, a low-cost biosorbent, were used to remove brilliant green (BG), a cationic dye, from an aqueous solution. Batch model experiments were carried out by varying operational parameters, such as initial concentration of dye solution, contact time, adsorbent dose, and pH of the solution, to obtain optimum conditions for removing BG dye. Under optimum conditions, maximum percent removal of 97.3% and adsorption capacity (Qe) value of 19.5 mg/g were achieved (at pH 8, adsorbent dose 0.05 g, dye concentration 50 ppm, and 60 min contact time). The Langmuir and Freundlich adsorption isotherms were applied to the experimental data. The linear fit value, R2 of Freundlich adsorption isotherm, was 0.93, indicating its best fit to our experimental data. A kinetic study was also carried out by implementing the pseudo-first-order and pseudo-second-order kinetic models. The adsorption of BG on the selected biosorbent follows pseudo-second-order kinetics (R2 = 0.99), indicating that transfer of internal and external mass co-occurs. This study surfaces the excellent adsorption capacity of Banyan tree leaves to remove cationic BG dye from aqueous solutions, including tap water, river water, and filtered river water. Therefore, the selected biosorbent is a cost-effective and easily accessible approach for removing toxic dyes from industrial effluents and wastewater.
摘要：
水流中染料的存在是对水生和人类生活产生负面影响的主要环境问题。因此,在废水排入水体之前，必须从废水中去除染料。在这项研究中,榕树（Ficusbenghalensis，F.benghalensis)树叶，一种低成本的生物吸附剂，用于去除亮绿(BG)，阳离子染料，从水溶液。通过改变操作参数进行了批量模型实验，例如染料溶液的初始浓度，接触时间,吸附剂剂量，和溶液的pH值，以获得去除BG染料的最佳条件。在最佳条件下，达到了97.3%的最大去除率和19.5mg/g的吸附容量（Qe）值（在pH8，吸附剂剂量0.05g，染料浓度50ppm，和60分钟的接触时间)。将Langmuir和Freundlich吸附等温线应用于实验数据。线性拟合值，Freundlich吸附等温线R2,为0.93，表明它最符合我们的实验数据。还通过实施伪一阶和伪二阶动力学模型进行了动力学研究。BG在所选生物吸附剂上的吸附遵循伪二级动力学（R2=0.99），表明内部和外部质量的转移同时发生。这项研究表面榕树叶子的优异吸附能力，以去除水溶液中的阳离子BG染料，包括自来水,河水,过滤过的河水。因此,选定的生物吸附剂是一种经济有效且易于获得的方法，用于从工业废水和废水中去除有毒染料。
