新型球形纤维素螯合吸附剂对Cr6+、Ni2+的吸附性能研究

Adsorption Performance of Cr6+, Ni2+ on a Novel Spherical Cellulose Chelating Adsorbent

中文关键词:  螯合吸附剂  选择性吸附  吸附等温线  动力学

Key Words:chelating adsorbent  selective adsorption  adsorption isotherm  kinetics

中文摘要:

      研究了同时含有咪唑基和羧基两种官能团的球形纤维素螯合吸附剂（SCCA）对Cr⁶⁺、Ni²⁺的静态吸附性能，并探讨了SCCA对Cr⁶⁺、Ni²⁺混合溶液的选择吸附性。结果表明，SCCA对Cr⁶⁺具有较强的吸附能力，吸附符合Langmuir吸附等温式，吸附容量随吸附温度的升高而增大，当反应温度为60℃、反应时间为2 h、溶液pH值为1时，饱和吸附容量为53.48 mg/g；SCCA对Ni²⁺的吸附能力弱，吸附符合Langmuir和Freundlich吸附等温式；吸附过程中，Cr⁶⁺和Ni²⁺扩散初期的速度控制步骤都是由表面扩散和颗粒内扩散联合控制；在Cr⁶⁺、Ni²⁺两种离子共存时，SCCA对Cr⁶⁺具有良好的吸附选择性，在30℃条件下，当溶液pH值为1时，其吸附选择系数为26.38。

Abstract:

      The selective adsorption of Cr6+, Ni2+ and static absorption of Cr6+ and Ni2+ on a novel spherical chelating cellulose adsorbent (SCCA) containing caoboxyl and imidazolyl groups were studied. The results showed that SCCA has good adsorption performance for Cr6+, and follows the relation of Langmuir adsorption isotherm formula. The adsorption capacity increases with an increase of solution temperature. The saturation adsorption capacity for Cr6+ is 53.48 mg/g under the optimum conditions (60℃ of adsorption temperature, 2 hours of adsorption time, 1 of solution pH). SCCA has bad adsorption performance for Ni2+, and it follows the relation of Langmuir and Freundlich adsorption isotherm formulas. The adsorption processes of Cr6+ and Ni2+ are controlled both by models of surface diffusion process and intraparticle diffusion process in early-time. SCCA has good adsorption selectivity for Cr6+ when Cr6+ and Ni2+ are in coexistence. The adsorption selectivity parameter is 26.38 under the solution pH value 1 and the adsorption temperature 60℃.