Eco-friendly polyvinyl alcohol/carboxymethyl cellulose (isolated from pineapple peel) hydrogels reinforced with graphene oxide and bentonite were prepared as efficient adsorbents for methylene blue (MB). The structure and morphology of the prepared hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). Introducing graphene oxide and bentonite into the hydrogels evidently enhanced the thermal stability, swelling ability and MB adsorption capacity. The effects of initial concentration of MB, pH, contact time and temperature on MB adsorption capacity of the prepared hydrogels were investigated. Adsorption kinetics and equilibrium adsorption isotherm fitted pseudo-second-order kinetic model and Langmuir isotherm model well, respectively. After introducing graphene oxide and bentonite into the hydrogels, the maximum adsorption capacity calculated from the Langmuir isotherm model reached 172.14 mg/g at 30 °C, obviously higher than the hydrogels prepared without these additions (83.33 mg/g). Furthermore, all the prepared hydrogels also displayed good reusability for the efficient removal of MB. Consequently, the prepared hydrogels could be served as eco-friendly, stable, efficient and reusable adsorbents for anionic dyes in wastewater treatment.

制备了用氧化石墨烯和膨润土增强的环保型聚乙烯醇/羧甲基纤维素（从菠萝皮中分离）水凝胶作为亚甲基蓝（MB）的有效吸附剂。通过傅立叶变换红外光谱（FTIR），扫描电子显微镜（SEM），X射线衍射（XRD），热重分析（TG）和差示扫描量热法（DSC）表征了所制备水凝胶的结构和形态。在水凝胶中引入氧化石墨烯和膨润土明显增强了热稳定性，溶胀能力和MB吸附能力。研究了MB的初始浓度，pH，接触时间和温度对制备的水凝胶的MB吸附能力的影响。吸附动力学和平衡吸附等温线分别拟合拟二阶动力学模型和Langmuir等温线模型。将氧化石墨烯和膨润土引入水凝胶后，根据Langmuir等温线模型计算得出的最大吸附容量在30°C时达到172.14 mg / g，明显高于未添加这些水凝胶的水凝胶（83.33 mg / g）。此外，所有制备的水凝胶还显示出良好的可重用性，可有效去除MB。因此，制备的水凝胶可作为废水处理中阴离子染料的环保，稳定，高效和可重复使用的吸附剂。在30°C下为14 mg / g，明显高于未添加这些水凝胶而制备的水凝胶（83.33 mg / g）。此外，所有制备的水凝胶还显示出良好的可重用性，可有效去除MB。因此，制备的水凝胶可作为废水处理中阴离子染料的环保，稳定，高效和可重复使用的吸附剂。在30°C下为14 mg / g，明显高于未添加这些水凝胶而制备的水凝胶（83.33 mg / g）。此外，所有制备的水凝胶还显示出良好的可重用性，可有效去除MB。因此，制备的水凝胶可作为废水处理中阴离子染料的环保，稳定，高效和可重复使用的吸附剂。