中文关键词钛酸盐铌酸盐Cd(Ⅱ)吸附离子交换回用 英文关键词titanateniobateCd(Ⅱ)adsorptionion-exchangereuse

作者	单位	E-mail
康丽	太原科技大学环境与安全学院, 太原 030024	kl199047@163.com
刘文	北京大学环境科学与工程学院, 北京 100871 北京大学深圳研究生院环境与能源学院, 深圳 518055
刘晓娜	太原科技大学环境与安全学院, 太原 030024	liuxiaona82168@sina.com
刘宏芳	太原科技大学环境与安全学院, 太原 030024
李一菲	太原科技大学环境与安全学院, 太原 030024

中文摘要 采用温和水热法合成了负载铌酸盐纳米粒子的钛酸纳米片（Nb-TNS），并应用于水体中重金属离子Cd（Ⅱ）的吸附去除.XRD、TEM和SEM等多种表征证实了新合成的复合材料为未卷曲成管的纳米片状结构.Nb-TNS对Cd（Ⅱ）的吸附机制为Cd（Ⅱ）阳离子与层间Na⁺的离子交换.Nb-TNS对Cd（Ⅱ）的吸附动力学过程很快，60 min内即可达到吸附平衡，且符合准二级动力学方程.吸附等温线符合Langmuir模型，且对Cd（Ⅱ）的理论最大吸附量高达287.9 mg·g^-1.高pH利于Nb-TNS对Cd（Ⅱ）的吸附，原因是带负电的材料表面易于通过静电作用捕集Cd（Ⅱ）阳离子进而发生离子交换，而酸性环境会抑制Cd（Ⅱ）吸附.共存离子Na⁺和Ca²⁺抑制Cd（Ⅱ）在Nb-TNS上的吸附，主要因为共存离子与Cd²⁺竞争吸附位点所致.腐殖酸（HA）对Nb-TNS吸附Cd（Ⅱ）抑制作用较小.经HNO₃处理，Cd（Ⅱ）离子易从Nb-TNS上解吸，NaOH再生后，Nb-TNS的-ONa位点恢复.由于Nb-TNS简易的合成方法、对金属阳离子的高效去除效果及可再生性能，在重金属废水修复领域具有很好的应用前景. 英文摘要 Niobate-modified titanate nanosheets (Nb-TNS) were synthesized through a hydrothermal method and used to remove Cd(Ⅱ) from water. TEM and SEM characterizations indicated that the new nanocomposites were non-curled nanosheets. XRD showed that the material was composed of sodium tri-titanate and niobate, and titanate was the primary component. Ion exchange between Cd²⁺ and Na⁺ in the interlayers of the Nb-TNSs was the dominant mechanism for Cd(Ⅱ) adsorption, leading to good adsorption performance. The material exhibited rapid adsorption kinetics for Cd(Ⅱ), reaching equilibrium within 60 min, and the data fit well with the pseudo-second order model (R²=1). The maximum adsorption capacity of Cd(Ⅱ) was 287.9 mg·g^-1, according to the Langmuir isotherm model, which was larger than that of most of traditional adsorbents. Higher pH promoted adsorption because the negatively charged material could capture Cd(Ⅱ) cations more easily. Co-existing inorganic ions (Na⁺and Ca²⁺) were unfavorable to the adsorption of Cd(Ⅱ) by Nb-TNS owing to the competition for adsorption sites. In addition, a slight inhibition effect on the adsorption in the presence of humic acid (HA) was found. Cd(Ⅱ) was efficiently desorbed from Nb-TNS after HNO₃ treatment, and -ONa sites were restored with NaOH treatment. Considering its simple synthesis method, high removal efficiency for heavy metals, and good reusability, Nb-TNS is a promising material for remediation of areas contaminated by heavy metals.

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