• 关键词：竹炭  PCB1  Tenax  吸附  解吸

• 基金项目：国家自然科学基金项目（No.41877463）；浙江省自然科学基金重点项目（No.LZ19D030001）

• 施珂珂
• 浙江大学环境与资源学院, 杭州 310058

• 徐伟健
• 浙江大学环境与资源学院, 杭州 310058

• 胡昕怡
• 浙江大学环境与资源学院, 杭州 310058

• 童彦宁
• 浙江大学环境与资源学院, 杭州 310058

• 楼轶玲
• 浙江大学环境与资源学院, 杭州 310058

• 沈超峰
• 1. 浙江大学环境与资源学院, 杭州 310058;2. 浙江省水体污染控制与环境安全技术重点实验室, 杭州 310058

• 楼莉萍
• 1. 浙江大学环境与资源学院, 杭州 310058;2. 浙江省水体污染控制与环境安全技术重点实验室, 杭州 310058

• 摘要：利用Tenax（聚2，6-二苯基对苯醚）解吸技术能够较好地模拟水环境中疏水性有机物（HOCs）在生物炭上解吸的行为，不仅可以用于筛选对HOCs有较好固定效果的吸附材料，还可以分析污染物在不同吸附点位上的吸附强度，深入探讨吸附-解吸机理.本文运用Tenax解吸技术研究了2-氯联苯（PCB1）在6种不同温度制备的竹炭（BC）上的解吸动力学，并通过吸附-解吸参数之间的相关性分析，以及这两类参数与竹炭理化性质之间的相关性分析，深入探讨PCB1的吸附-解吸机制.吸附等温线的结果表明，高温竹炭（≥700℃）对PCB1的吸附性能远好于低温竹炭（<700℃），900℃竹炭的吸附容量为400℃的27.1倍.随着热解温度的升高，竹炭对PCB1的分配作用和表面吸附均增强，但后者增加得更快.Tenax解吸动力学结果表明：高温竹炭上PCB1的解吸"快而短"，9 h后就进入慢速解吸阶段，不可逆解吸比例高于0.7；而低温竹炭则"慢而长"，快速解吸阶段长达30 h，不可逆解吸比例低于0.6.与700℃竹炭相比，900℃竹炭的吸附系数K_f高30%左右，但两者的不可逆解吸比例非常接近，说明一定污染物浓度范围内，700℃和900℃竹炭具有相近的吸附固定HOCs的功能.机理分析表明，以"相似相溶作用"为机制的分配作用吸附的PCB1固定效果差，在快速解吸和慢速解吸过程均发生解吸，以孔隙填充作用和π-π电子供体受体作用为机制的表面吸附对PCB1的固定效果好，仅在慢速解吸过程少量释放.这项研究说明Tenax解吸技术可为实际工程中生物炭的选型提供科学依据.

• Abstract：Tenax (poly(2,6-diphenyl-p-phenylene oxide)) desorption technology can simulate the desorption behavior of hydrophobic organic compounds (HOCs) on biochar in water environment, which can be used not only to select adsorbent materials, but also to analyze the adsorption strength of contaminants at different sites of the adsorbent and to explain the mechanism of adsorption-desorption in-depth. In this paper, the desorption kinetics of 2-chlorobiphenyl (PCB1) on bamboo charcoal (BC) prepared under six different pyrolysis temperatures were studied by Tenax desorption technology. The correlation analysis between the adsorption and desorption parameters, and between these parameters and the properties of bamboo charcoal, were used to explore the adsorption-desorption mechanism. The results of adsorption isotherms showed that With increased pyrolysis temperature, the distribution and surface adsorption of PCB1 by bamboo charcoal were enhanced. The adsorption performance of PCB1 by high-temperature bamboo charcoal (≥700 ℃) was much better than low-temperature bamboo charcoal (<700 ℃), and the adsorption capacity of bamboo charcoal at 900 ℃ BC was 27.1 times higher than that of 400 ℃ BC. The results of Tenax desorption kinetics showed that the desorption of PCB1 on high temperature bamboo charcoal was "fast". the desorption rate began to drop after 9 h, and the irreversible desorption ratio was higher than 0.7. The desorption of PCB1 on low temperature bamboo charcoal was "slow", and rapid desorption stage was up to 30 h, and the irreversible desorption ratio was less than 0.6. Compared to 700 ℃ BC, the adsorption coefficient K_f of 900 ℃ BC was about 30% higher, but their irreversible desorption ratios were very close, indicating that 700 ℃ BC and 900 ℃ BC had similar adsorption capacity for HOCs. Results also showed that, based on "similar compatibility", the distribution of PCB1 was poor, and the desorption of PCB1 occurred in both rapid and slow desorption processes. The surface adsorption based on the pore filling and π-π electron donor acceptor had a good fixation effect of PCB1, which released only in a small amount during the slow desorption process. This study demonstrated that Tenax desorption technology can provide a scientific basis for the selection of biochar in practical engineering.

• Key words：bamboo charcoal  PCB1  Tenax  adsorption  desorption

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