To discharge the colored effluents from industries there needs to be effective and affordable treatment options. Adsorption using reduced graphene oxide (rGO) as an adsorbent is a prominent one. In this study, green coffee bean extract (GCBE) is utilized as a safe reducing agent for the reduction of graphene oxide (GO) to synthesize rGO. The formation of rGO is confirmed by a new peak in the UV–vis spectra at 275 nm and a diffraction peak in the XRD patterns at 22°. The effective formation of rGO is further substantiated by a change in the GO peak's properties in the FTIR, EDX, and Raman spectra and a weight loss change in TGA. The SEM and TEM analyses demonstrate the effective production of the nano-sheets of rGO having exfoliated and segregated in a few layers. Furthermore, the obtained rGO exhibited outstanding efficacy in wastewater cleanup, effectively adsorbing MB as a prototype organic dye. The kinetics and isotherm study suggested that the adsorption leads by the chemisorption and monolayer formation on the homogeneous surface of rGO. The maximum adsorption capacity is found to be 89.3 mg g⁻¹. This process offers a fresh opportunity for the economical and safe production of rGO for wastewater treatment.

中文翻译：

---

绿咖啡豆提取物辅助还原氧化石墨烯的简易合成及其染料去除活性

为了排放工业中的有色废水，需要有效且负担得起的处理方案。使用还原氧化石墨烯（rGO）作为吸附剂的吸附是一种突出的吸附方法。在这项研究中，绿咖啡豆提取物（GCBE）被用作还原氧化石墨烯（GO）以合成rGO的安全还原剂。rGO 的形成通过 UV-vis 光谱中 275 nm 处的新峰和 XRD 图中 22° 处的衍射峰得到证实。FTIR、EDX 和拉曼光谱中 GO 峰性质的变化以及 TGA 中失重的变化进一步证实了 rGO 的有效形成。SEM 和 TEM 分析证明了 rGO 纳米片的有效生产，该纳米片在几层中剥离和偏析。此外，所获得的 rGO 在废水净化方面表现出出色的功效，可有效吸附作为原型有机染料的 MB。动力学和等温线研究表明，吸附是由rGO均匀表面上的化学吸附和单分子层形成引起的。发现最大吸附容量为89.3 mg g ^-1。该工艺为经济、安全地生产用于废水处理的 rGO 提供了新的机会。