柚子皮生物炭负载Mg/Al-LDH对废水中U(Ⅵ)的吸附性能研究

Adsorption performance of U(Ⅵ)in wastewater by pomelo peel-based biochar loaded Mg/Al-LDH

采用液相共沉淀法制备了柚子皮生物炭负载镁铝层状双氢氧化物复合材料BC@Mg/Al-LDH,并将其用于废水中U(Ⅵ)的去除。探究了pH、温度、吸附时间、初始质量浓度、干扰离子对BC@Mg/Al-LDH吸附U(Ⅵ)的影响。结果表明,在U(Ⅵ)初始质量浓度为10 mg/L、pH=5、温度为303 K、吸附时间为5 min时,BC@Mg/Al-LDH对U(Ⅵ)的吸附量达到96 mg/g。吸附过程符合准二级动力学模型和Freundlich等温模型。FT-IR和XPS分析发现主要吸附机理为表面羟基络合和层间碳酸盐共沉淀。干扰离子试验表明,Ca^(2+)、Fe^(3+)、Mg^(2+)、Cu^(2+)等对吸附效果无影响。BC@Mg/Al-LDH经5次再生循环利用后吸附率仍可接近80%。

Pomelo peel-based biochar loaded MgAl layered double hydroxides composite(BC@Mg/Al-LDH)is synthesized via liquid phase co-precipitation method,and applied to remove U(Ⅵ)from wastewater.The effects of pH,temperature,reaction time,initial concentration and interfering ions on the adsorption of U(Ⅵ)by BC@Mg/Al-LDH are investigated.The consequence indicates that the adsorption amount of BC@Mg/Al-LDH for U(Ⅵ)has reached 96 mg·g-1in 5 minutes when the initial mass concentration of U(Ⅵ)is 10 mg·L-1,pH=5,the temperature is 303 K,and the dosage of BC@Mg/Al-LDH is 0.1 g·L-1.The adsorption process can be well described by pseudo-second-order and Freundlich models.It is shown through FT-IR and XPS analysis that main adsorption mechanisms include surface hydroxyl complexation and interlayer carbonate coprecipitation.Ca^(2+),Fe^(3+),Mg^(2+),Cu^(2+)and other interfering ions have no significant effect on the adsorption.The adsorption rate can still be closed to 80%after BC@Mg/Al-LDH has experienced for 5 cycles of regeneration.