Surface properties of SAC and its adsorption mechanisms for phenol and nitrobenzene.
Surface properties of SAC and its adsorption mechanisms for phenol and nitrobenzene.
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DOI：
10.1016/j.biortech.2012.02.130
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发表时间：
2012-06
影响因子：
11.4
通讯作者：
Daojing Li;Y. Wu;Li Feng;Liqiu Zhang
中科院分区：
文献类型：
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作者：
Daojing Li;Y. Wu;Li Feng;Liqiu Zhang
测定了从污泥中提取的活性炭（SAC）的理化性质，并与市场上的活性炭（MAC）进行了比较。以苯酚和硝基苯为目标化合物，对其在水和环己烷中的吸附行为进行了研究和比较。实验结果表明，SAC的表面积仅为MAC的1/4，SAC上的官能团均为酸性基团，而MAC上的官能团以碱性基团为主。根据活性炭的性质和两种有机污染物的吸附行为，初步推断苯酚的吸附主要受表面积的影响，而硝基苯的吸附受表面积和表面官能团的共同影响。在水中，初始浓度为0.1 ~ 10mmol/L时，SAC对苯酚和硝基苯的最大吸附量分别为0.48和1.26mmol/g，分别为MAC的1/4和1/3。在环己烷中，SAC对苯酚的吸附量高于水中，对硝基苯的吸附量低于水中；与水中相比，活性炭对苯酚的吸附量变化不大，对硝基苯的吸附量下降较多。结果进一步表明，有机污染物的疏水性和极性对其在水中的吸附有很大影响。对SAC而言，极性相互作用和疏水相互作用可能是影响其在水中吸附硝基苯的主要机制。对MAC来说，疏水相互作用和π -π相互作用可能是影响硝基苯在水中吸附的主要机制。MAC对苯酚和硝基苯的吸附能力均高于SAC。
The physicochemical properties of an activated carbon produced from sewage sludge (SAC) were determined and compared with those of a market activated carbon (MAC). Phenol and nitrobenzene were selected as the target compounds and their adsorption behaviors in water and cyclohexane were studied and compared. The experimental results showed that the surface area of SAC was only 1/4 of that of the MAC. Functional groups on the SAC are all acid groups while basic groups are the dominant on the MAC. Based on the properties of the activated carbons and the adsorption behaviors of the two organic pollutants, it could be inferred preliminarily that phenol adsorption was mainly affected by surface area but nitrobenzene adsorption was affected by both surface area and surface functional groups. In water, when the initial concentration is between 0.1 and 10mmol/L, the maximum phenol and nitrobenzene adsorption capacity of SAC is 0.48 and 1.26mmol/g respectively, which is 1/4 and 1/3 of that of MAC. In cyclohexane, SAC’s phenol adsorption capacity is higher and nitrobenzene adsorption capacity is lower than that in water; but MAC’s phenol adsorption capacity does not change much and nitrobenzene adsorption capacity decreases a lot compared that in water. The results further indicate that the hydrophobicity and the polarity of the organic pollutants can greatly affect their adsorption in water. For SAC, polar interaction and hydrophobic interaction may be the main mechanisms affecting the sorption of nitrobenzene in water. For MAC, hydrophobic interaction and π–π interaction may be the main mechanisms affecting the sorption of nitrobenzene in water. For both phenol and nitrobenzene, the adsorption capacities of MAC are higher than that of SAC.