Dyes and pigments have been used in many industries for colorization purpose but they pose hazards to the environment and end users of water. Therefore, it is important to remove this pollutant from waste water before their final disposal. This study aimed to investigate the removal of methylene blue by cost effective, ecofriendly, high-efficiency bio-sorbent from activated coffee husk. The process was carried out using chemical activation (H3PO4) process. Fourier transform infrared spectroscopy and surface analyzer (Brunauer-Emmett-Teller) were used to characterize the adsorbent. The specific surface area adsorbent was obtained as 28.54 m2/g. The maximum removal efficiency was obtained as 96.9% at pH of 5, initial dye concentration of 20 mg/L, adsorbent dosage of 0.8 g/50 mL, for contact time of 50 min and 30°C temperature on the activation surface of coffee husk. Langmuir model was found to fit the equilibrium data for methylene blue adsorption with 6.82 mg/g at 30°C. The adsorption process follows the pseudo-second-order model. Thermodynamics analysis showed that the adsorption of methylene blue on to the activated coffee husk was a spontaneous and endothermic process. The experimental data obtained in the present study proved that coffee husk is a suitable bio-sorbent in removal of cationic dyes.

中文翻译：

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利用处理过的咖啡壳作为低成本生物吸附剂吸附亚甲基蓝

染料和颜料已在许多行业中用于着色目的，但它们对环境和水的最终用户构成危害。因此，重要的是在最终处置之前从废水中去除这种污染物。本研究旨在研究通过经济、环保、高效的生物吸附剂从活化的咖啡壳中去除亚甲基蓝。该过程使用化学活化（H3PO4）过程进行。傅里叶变换红外光谱和表面分析仪（Brunauer-Emmett-Teller）用于表征吸附剂。获得的比表面积吸附剂为 28.54 m2/g。在 pH 为 5、初始染料浓度为 20 mg/L、吸附剂用量为 0.8 g/50 mL 时获得的最大去除效率为 96.9%，在咖啡壳的活化表面上接触时间为 50 分钟，温度为 30°C。发现 Langmuir 模型在 30°C 下以 6.82 mg/g 拟合亚甲基蓝吸附的平衡数据。吸附过程遵循拟二级模型。热力学分析表明，亚甲蓝吸附到活化的咖啡皮上是一个自发的吸热过程。本研究中获得的实验数据证明，咖啡壳是去除阳离子染料的合适生物吸附剂。热力学分析表明，亚甲蓝吸附到活化的咖啡皮上是一个自发的吸热过程。本研究中获得的实验数据证明，咖啡壳是去除阳离子染料的合适生物吸附剂。热力学分析表明，亚甲蓝吸附到活化的咖啡皮上是一个自发的吸热过程。本研究中获得的实验数据证明，咖啡壳是去除阳离子染料的合适生物吸附剂。