Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 713, CEP 60451-970 Fortaleza, CE, Brazil.
J Environ Manage. 2012 Dec 15;112:178-85. doi: 10.1016/j.jenvman.2012.07.026. Epub 2012 Aug 21.
Various technologies have been used for the treatment and remediation of areas contaminated by BTEX (benzene, toluene, ethylbenzene and xylenes), which are organic compounds that are of particular concern due to their toxicity. Potential applications of synthetic zeolites for environmental fieldwork have also been reported worldwide. In this work, a hexadecyltrimethyl ammonium (HDTMA) surfactant-modified synthetic zeolite was investigated for its efficiency in removing BTEX from aqueous solutions. Three surfactant-modified zeolites were synthesized, with amounts of surfactant corresponding to 50%, 100%, and 200% of the total cation-exchange capacity (CEC) of the synthetic zeolite Y. The results of the BTEX adsorption experiments onto both synthetic zeolite and surfactant-modified zeolites (SMZ) showed that the SMZ-100 (zeolite modified with surfactant levels at 100% of CEC) was the most efficient modified zeolite for BTEX removal. Kinetics studies indicated that the multicomponent adsorption equilibrium was reached within 6 h and followed pseudo-second-order kinetics. The Langmuir, Freundlich, Redlich-Peterson and Temkin models were used to evaluate the BTEX adsorption capacity by SMZ-100. The Temkin model was found to be suitable for all BTEX compounds in a multicomponent system. Regeneration cycles of the modified zeolite were also performed, and the results showed that the adsorbent could be used efficiently in as many as four adsorption cycles, except for benzene.
各种技术已被用于处理和修复受 BTEX（苯、甲苯、乙苯和二甲苯）污染的区域，这些有机化合物因其毒性而特别令人关注。全球范围内也有报道称合成沸石在环境领域具有潜在应用。在这项工作中，研究了十六烷基三甲基铵（HDTMA）表面活性剂改性合成沸石对从水溶液中去除 BTEX 的效率。合成了三种表面活性剂改性沸石，表面活性剂的用量分别为合成沸石 Y 的总阳离子交换容量（CEC）的 50%、100%和 200%。BTEX 吸附实验结果表明，SMZ-100（表面活性剂水平为 CEC 的 100%改性沸石）是去除 BTEX 的最有效改性沸石。动力学研究表明，多组分吸附平衡在 6 小时内达到，并遵循拟二级动力学。朗缪尔、弗伦德利希、Redlich-Peterson 和 Temkin 模型被用于评估 SMZ-100 对 BTEX 的吸附容量。结果表明，Temkin 模型适用于多组分体系中的所有 BTEX 化合物。还对改性沸石进行了再生循环实验，结果表明，除了苯之外，吸附剂可以在多达四个吸附循环中有效使用。
