摘要:
为提高层状双金属氢氧化物(MgAl-LDH)对水中Hg(Ⅱ)的吸附效果,利用水热法合成了MgAl-LDO-L-Cys复合吸附剂。利用SEM、FTIR、XPS、Zeta电位等对复合吸附剂进行了表征,并探讨了其对水溶液中Hg(Ⅱ)的吸附效果。结果表明,煅烧后的层状双金属氢氧化物(MgAl-LDO)被L-半胱氨酸(L-Cys)包裹,L-Cys分子通过与MgAl-LDO表面氧化物基团或金属离子形成配位键实现稳定插层。MgAl-LDO-L-Cys对Hg(Ⅱ)的吸附行为遵循Langmuir吸附等温模型和准二级反应动力学模型,在25 ℃下Hg(Ⅱ)的理论最大吸附量为397.92 mg/g,且该吸附过程是一个自发的吸热过程。MgAl-LDO-L-Cys在10次循环使用后,对Hg(Ⅱ)的吸附量依然可达到初始吸附量的71.9%,且在其他离子的存在下,MgAl-LDO-L-Cys对Hg(Ⅱ)依然具有较好的去除效果。MgAl-LDO-L-Cys主要通过巯基、羟基、氨基和羧基等基团与Hg(Ⅱ)发生络合作用去除水中的Hg(Ⅱ)。
关键词:
层状双金属氢氧化物,
L-半胱氨酸,
Hg(Ⅱ),
吸附
Abstract:
To improve the adsorption effect of layered bimetallic hydroxide(MgAl-LDH) towards Hg(Ⅱ) in water, hydrothermal method was used to synthesize the MgAl-LDO-L-Cys composite adsorbent. The composite adsorbent was characterized by SEM, FTIR, XPS, and Zeta potential determination. The adsorption of Hg(Ⅱ) from aqueous solution by the composite adsorbent was investigated. The results indicated that the calcined layered bimetallic hydroxide (MgAl-LDO) was encapsulated by L-cysteine(L-Cys), and L-Cys molecules achieved stable intercalation by forming coordination bonds with oxide groups or metal ions on the surface of MgAl-LDO. The adsorption behavior of MgAl-LDO-L-Cys towards Hg(Ⅱ) followed the Langmuir adsorption isotherm model and pseudo-second-order reaction kinetic model. The theoretical optimal adsorption capacity of Hg(Ⅱ) at 25 ℃ was 397.92 mg/g, and the adsorption process was a spontaneous endothermic process. After 10 cycles of use, MgAl-LDO-L-Cys still achieved an adsorption capacity of 71.9% of the initial adsorption capacity for Hg(Ⅱ), and it still had a good removal effect on Hg (Ⅱ) in the presence of other ions. The MgAl-LDO-L-Cys mainly removed Hg(Ⅱ) from water by chelating with Hg(Ⅱ) through thiol, hydroxyl, amino, and carboxyl groups.
Key words:
layered bimetallic hydroxide,
L-cysteine,
Hg(Ⅱ),
adsorption
中图分类号:
徐胡娟, 马楫, 林振锋, 盛铭军, 朱国营, 王红专, 王晓梁, 郭永福. 层状双金属氢氧化物MgAl-LDO-L-Cys对水中Hg(Ⅱ)的去除[J]. 工业水处理, 2025, 45(5): 127-134.
Hujuan XU, Ji MA, Zhenfeng LIN, Mingjun SHENG, Guoying ZHU, Hongzhuan WANG, Xiaoliang WANG, Yongfu GUO. Highly efficient removal of Hg(Ⅱ) from water by layered bimetallic hydroxide MgAl-LDO-L-Cys[J]. Industrial Water Treatment, 2025, 45(5): 127-134.