用改性斜发沸石从水介质中去除多环芳烃。

Removal of polycyclic aromatic hydrocarbons from aqueous media using modified clinoptilolite.

机构信息

Department of Civil Engineering, University of British Columbia, 6250, Applied Science Lane, Vancouver, BC V6T 1Z4, Canada.

出版信息

J Environ Manage. 2020 Nov 1;273:111113. doi: 10.1016/j.jenvman.2020.111113. Epub 2020 Jul 29.

DOI:10.1016/j.jenvman.2020.111113

PMID:32734893

Abstract

Carcinogenic polycyclic aromatic hydrocarbons (PAHs) are widespread in the environment. In this study, the removal of PAHs from aqueous media was assessed using samples of clinoptilolite, a natural zeolite, pre-treated with 1 mol/L of NaCl, (Na pre-treated clinoptilolite, NC). Samples (10 g) of NC were separately modified with 5, 2, 2, and 20-mmol/L solutions of cetylpyridinium chloride (CPC), didodecyldimethyl ammonium bromide (DDAB), hexadecyltrimethylammonium bromide (HDTMA), and tetramethyl ammonium chloride (TMA) surfactants as potential cost-effective adsorbents. The kinetics, optimal sorbent dosage, and competitive effects were evaluated through batch adsorption tests using deionised water spiked with five PAHs (anthracene (50 μg/L), fluoranthene (100 μg/L), fluorene (100 μg/L), phenanthrene (100 μg/L), and pyrene (100 μg/L)). The surfactant non-modified (NC) and TMA-MC (modified clinoptilolite) exhibited PAH removal of <66% from the spiked concentration in aqueous solution, while CPC-MC, DDAB-MC, and HDTMA-MC achieved removal rates of >93% for the five PAHs after 24 h at a solid:liquid ratio of 1:100. The remaining concentrations of anthracene and fluoranthene were below 3 μg/L, and that of fluorene was <6 μg/L, lower than the water quality criteria of British Columbia, Canada, for protecting aquatic life. However, HDTMA-MC retained >83% of the fluorene. Over 80% of all PAHs were absorbed within 15 min for the CPC-MC and DDAB-MC, and the maximum adsorption was reached in <2 h. Three kinetic models were applied assuming pseudo-first-order, pseudo-second-order, and intra-particle equations, and the results were well-represented by the pseudo-second-order equation. The PAH sorption results indicated that the adsorption mechanism is based on PAH hydrophobicity, and π-π electron-donor-acceptor interaction with surfactant. CPC and DDAB with two long chain hydrocarbons had more PAH adsorption than HDTMA with one, and TMA with no long chain hydrocarbons (DDAB-MC > CPC-MC > HDTMA-MC ≫ TMA-MC > NC). With a solid:liquid ratio of 1:200, over 90%, 80%, and 70% of the anthracene, fluoranthene, and pyrene were adsorbed by the CPC-MC, DDAB-MC, and HDTMA-MC, respectively.

摘要

致癌多环芳烃（PAHs）广泛存在于环境中。在这项研究中，使用经过 1 mol/L NaCl 预处理的天然沸石斜发沸石（Na 预处理斜发沸石，NC）样品评估了从水介质中去除 PAHs 的情况。将 5、2、2 和 20 mmol/L 的十六烷基氯化吡啶（CPC）、双十二烷基二甲基溴化铵（DDAB）、十六烷基三甲基溴化铵（HDTMA）和四甲基氯化铵（TMA）表面活性剂溶液分别改性 10 g NC，用作潜在的具有成本效益的吸附剂。通过使用去离子水对 5 种 PAHs（蒽（50μg/L）、荧蒽（100μg/L）、芴（100μg/L）、菲（100μg/L）和芘（100μg/L））进行批吸附试验，评估了动力学、最佳吸附剂剂量和竞争效应。未改性的表面活性剂（NC）和 TMA-MC（改性斜发沸石）在水溶液中从加标浓度去除的 PAH 去除率<66%，而 CPC-MC、DDAB-MC 和 HDTMA-MC 在 24 小时后以固液比为 1:100 实现了 5 种 PAH 的去除率>93%。剩余的蒽和荧蒽浓度均低于 3μg/L，芴的浓度低于 6μg/L，低于加拿大不列颠哥伦比亚省保护水生生物的水质标准。然而，HDTMA-MC 保留了超过 83%的芴。CPC-MC 和 DDAB-MC 在 15 分钟内吸收了超过 80%的所有 PAHs，2 小时内达到最大吸附量。三种动力学模型（假设为伪一级、伪二级和内粒子方程）都适用于假设，结果与伪二级方程很好地吻合。PAH 吸附结果表明，吸附机制基于 PAH 的疏水性和与表面活性剂的π-π电子供体-受体相互作用。与具有一个长链烃的 HDTMA 相比，具有两个长链烃的 CPC 和 DDAB 具有更多的 PAH 吸附，而没有长链烃的 TMA（DDAB-MC>CPC-MC>HDTMA-MC≫TMA-MC>NC）。在固液比为 1:200 时，CPC-MC、DDAB-MC 和 HDTMA-MC 分别吸附了超过 90%、80%和 70%的蒽、荧蒽和芘。