荷叶活性炭吸附铍的效果及机理研究

Study on the Effect and Mechanism of Beryllium Adsorption by Activated Carbon from Lotus Leaves

含铍废水有重大环境危害,为了找到低成本且有效的解决办法,采用水热预处理方式制备了荷叶活性炭,并将其用于含Be(Ⅱ)废水的处理。结果表明,荷叶活性炭的吸附效果优异,可以有效去除废水中的铍。最后,结合SEM、FTIR和XRD表征手段,探讨了荷叶活性炭对铍的吸附机理。结果表明:在pH=3.0、铍初始浓度10 mg/L、荷叶活性炭投加量为3 g/L、吸附温度为25℃、吸附平衡时间30 min的条件下,荷叶活性炭对铍的最佳吸附效率为99%;荷叶活性炭对铍的吸附符合准一级动力学模型和Langmuir等温吸附模型;荷叶活性炭的Langmuir单层吸附量为30.26 mg/g。荷叶活性炭对铍的吸附机理主要为表面吸附及颗粒内扩散。通过傅里叶变换红外光谱图(FT-IR)、X射线衍射(XRD)等表征手段可知,在吸附过程中,铍与荷叶活性炭上的羟基反应生成了氢氧化铍沉淀。本研究为水相铍污染的可持续修复绿色材料开发作出了贡献。

Beryllium-containing wastewater has serious environmental hazards.In order to find a low-cost and effective solution,lotus leaf activated carbon was prepared by hydrothermal pretreatment and used for the treatment of Be(Ⅱ)-containing wastewater.The results showed that lotus biochar had excellent adsorption effect and could effectively remove beryllium from wastewater.Finally,the adsorption mechanism of activated carbon on beryllium from lotus leaf was studied by means of SEM,FTIR and XRD.The results showed that under the conditions of pH=3.0,initial beryllium concentration of 10 mg/L,activated carbon dosage of 3 g/L,adsorption temperature of 25℃ and adsorption equilibrium time of 30 min,the optimal adsorption efficiency of activated carbon of lotus leaf to beryllium was 99%.The adsorption of beryllium by activated carbon conforms to the quasi-first-order kinetic model and the Langmuir isothermal adsorption model.The Langmuir monolayer adsorption capacity of lotus leaf biochar was 30.26 mg/g.The adsorption mechanism of activated carbon to beryllium is mainly surface adsorption and intra particle diffusion.By means of Fourier transform infrared spectroscopy(FT-IR)and X-ray diffraction(XRD),it can be seen that beryllium hydroxide precipitate was formed in the adsorption process of beryllium and the hydroxyl group on activated carbon.This study can contribute to the development of green materials for sustainable remediation of hydroberyllium pollution.