针对粉末活性炭对亲水小分子有机物吸附效率低和固液分离速度慢的问题, 本研究以粉末活性炭(PAC)、腐植酸盐(HS)、聚合氯化铝(PACl)为原料, 通过融合法成功制备了粉末活性炭基复合材料PACMC (powdered activated carbon matrix composites), 将其作为含油污水的净化吸附剂. 扫描电子显微镜-X射线能量色散谱仪(SEM-EDS)和傅里叶红外光谱(FT-IR)等表征分析确认了PACMC的微观形貌和化学组成, 证实了PAC、HS和PACl是通过化学反应生成了PACMC. PACMC具有层状多孔结构和活性官能团, 有利于含油污水分子的传输扩散和化学吸附. 通过静态吸附实验研究了PACl、PAC和PACMC对含油污水中有机物的吸附性能, 结果表明: PACMC对含油污水中有机污染物的吸附能力是PAC和PACl的2~3倍(q_e=23.04 mg•g^‒1, C₀=300 mg•L^‒1); 当吸附时间达到120 min 时, PACMC上的活性位点与含油污水中有机污染物的结合已基本达到饱和(q_e=23.04 mg•g^‒1, C₀=300 mg•L^‒1). 溶液pH值对PACMC吸附去除含油污水中有机物的影响显著, pH=3时, 吸附效果最好(q_e=27.6 mg•g^‒1, C₀=300 mg•L^‒1); 伪二级动力学方程能很好地描述含油污水中有机物在PACMC上的吸附行为, 动力学拟合结果表明其吸附过程分多步进行, 化学吸附和内扩散均具有重要作用. 等温吸附数据符合Dubinin-Radushkevich模型, 证明其吸附机理为化学吸附. 因此, PACMC吸附含油污水的机理包括化学结合/螯合作用、疏水力作用和静电吸附作用.

In order to solve the problems of low adsorption efficiency and slow precipitation rate for powdered activated carbon (PAC) in the process of removing hydrophilic organics with low molecular weight, this study successfully prepare a kind of powdered activated carbon matrix composites (PACMC) by reaction of mixed powdered activated carbon (PAC), potassium humate (HS), and polyaluminium chloride (PACl) raw materials in oily sewage as the purification adsorbent. We confirmed the micro-morphology and chemical composition of PACMC by scanning electron microscopy-X-ray energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR), certifying that PACMC was synthesized by chemical reaction of PAC, HS and PACl. PACMC has layered porous structure and functional groups, which is beneficial to the transport, diffusion and chemical adsorption of oily sewage molecules. The static adsorption experiments were carried out to investigate the adsorption properties of organic pollutants in oily sewage by PACl, PAC and PACMC respectively. The results showed that the adsorption capacity of PACMC for organic pollutants in oily sewage was 2~3 times as high as that of PAC and PACl (q_e=23.04 mg•g^‒1, C₀=300 mg•L^‒1). When the adsorption time reached 120 min, the binding of the active site on PACMC and organic pollutants in oily sewage had basically reached saturation (q_e=23.04 mg•g^‒1, C₀=300 mg•L^‒1). The pH value of the solution has a significant effect on the adsorption of organic pollutants in oily sewage by PACMC, and the best adsorption effect was observed at pH=3 (q_e=27.6 mg•g^‒1, C₀=300 mg•L^‒1). The adsorption of organic pollutants in oily sewage by PACMC can be well described by the pseudo-second-order kinetics. The kinetic fitting results revealed that the adsorption process involved several steps, where the chemical adsorption and intra-particle diffusion both played the important roles. The isothermal adsorption data were in accordance with the Dubinin-Radushkevich model, which indicated that the adsorption mechanism was chemical adsorption. Therefore, the mechanism of PACMC adsorption of oily sewage included chemical binding/chelation effect, hydrophobic effect and electrostatic adsorption effect.