磷酸盐功能化生物炭高效吸附U(Ⅵ)的研究

Research on the efficient adsorption of phosphate functional biochar for U (Ⅵ)

高温厌氧制备玉米芯生物炭,并利用植酸对其改性,获得富含官能团且孔隙率高的高效功能化生物炭复合材料磷酸盐功能化生物炭(IPCB)。以水中U(Ⅵ)为处理对象,探究IPCB对U(Ⅵ)的吸附能力和机制。实验结果表明,U(Ⅵ)初始浓度为10mg/L时,最佳吸附条件为30℃,pH=4,材料投加量0.8mg/L,120min后吸附达到平衡,此时U(Ⅵ)去除率达到95.9%。IPCB对U(Ⅵ)的吸附过程符合准二级动力学模型和Langmiur等温模型,以化学吸附为主;且4次吸附-解析实验后,U(Ⅵ)去除率仍然达到91.2%,说明IPCB可以重复利用。EDS和XPS等表征方法证明,植酸改性增加了玉米芯生物炭表面的磷酸基团;IPCB对U(Ⅵ)的吸附机制主要是配位作用和离子交换。

Corncob biochar was prepared by high-temperature anaerobic method, and modified by phytic acid to obtain highly functional biochar composites phosphate functional biochar(IPCB)rich in functional groups and with high porosity.Taking U(Ⅵ) in water as the treatment object, the adsorption capacity, and the mechanism of the IPCB on U(Ⅵ) were investigated.The experimental results showed that when the initial concentration of U(Ⅵ) was 10 mg/L,the optimal adsorption condition was 30℃,pH=4,the material dosage was 0.8 mg/L,and the adsorption reached equilibrium after 120 min.At this time, the removal rate of U(Ⅵ) reached 95.9%.The adsorption process of IPCB on U(Ⅵ) was in line with the quasi-second-order kinetic model and Langmuir isothermal model, with chemical adsorption as the main method.Also, the removal rate of U(Ⅵ) still reached 91.2% after 4 adsorption-analytical tests, indicating that IPCB could be reused.EDS and XPS characterization methods proved that phytic acid modification increased phosphate groups on the surface of corncob biochar.The adsorption mechanism of IPCB on U(Ⅵ) was mainly coordination action and ion exchange.