使用十六烷基溴化吡啶（CPB）改性沸石作为吸附剂从水溶液中去除硝酸盐。

Removal of nitrate from aqueous solution using cetylpyridinium bromide (CPB) modified zeolite as adsorbent.

机构信息

State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.

出版信息

J Hazard Mater. 2011 Feb 28;186(2-3):1972-8. doi: 10.1016/j.jhazmat.2010.12.090. Epub 2010 Dec 25.

DOI:10.1016/j.jhazmat.2010.12.090

Abstract

Surfactant modified zeolites (SMZ) with different coverage types were prepared by loading the cetylpyridinium bromide (CPB) onto the surface of the natural zeolites. The adsorption behavior of nitrate on SMZ was investigated. Natural zeolite and SMZ with monolayer CPB coverage were inefficient for the removal of nitrate from aqueous solution. However, SMZ with patchy bilayer or bilayer CPB coverage was efficient in nitrate removal, and the nitrate adsorption capacity of SMZ increased with its CPB loading. For typical SMZ with bilayer CPB coverage, the nitrate adsorption process was well described by the pseudo-second-order kinetic model, and the experimental isotherm data fitted well with the Langmuir, Freundlich and Dubinin-Redushkevich isotherm models. Thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were calculated and the results showed that the adsorption of nitrate on SMZ was spontaneous and exothermic in nature. The presence of competing anions such as chloride, sulfate and bicarbonate ions slightly reduced the nitrate adsorption efficiency. Anionic exchange and electrostatic interaction were proven to be the main mechanisms that govern the adsorption of nitrate on SMZ.

摘要

用不同覆盖类型的表面活性剂改性沸石（SMZ）通过将十六烷基溴化吡啶（CPB）负载在天然沸石表面来制备。研究了硝酸盐在 SMZ 上的吸附行为。天然沸石和单层 CPB 覆盖的 SMZ 对从水溶液中去除硝酸盐的效率不高。然而，具有片状双层或双层 CPB 覆盖的 SMZ 对硝酸盐去除效率较高，SMZ 的硝酸盐吸附容量随 CPB 负载量的增加而增加。对于典型的具有双层 CPB 覆盖的 SMZ，硝酸盐吸附过程很好地符合拟二级动力学模型，实验等温线数据很好地符合朗缪尔、弗伦德利希和杜宾-雷奇科夫斯基等温线模型。计算了吉布斯自由能变化、焓变和熵变等热力学参数，结果表明硝酸盐在 SMZ 上的吸附是自发的和放热的。存在竞争阴离子，如氯离子、硫酸根离子和碳酸氢根离子，会轻微降低硝酸盐的吸附效率。阴离子交换和静电相互作用被证明是控制硝酸盐在 SMZ 上吸附的主要机制。