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以1种商品腐殖酸(HA)为研究对象,以粉末活性炭(PAC)为吸附剂,测定了不同温度下HA在PAC上的吸附平衡。结果表明,在初始HA(以TOC表征)的质量浓度为10～65 mg/L时,较好的符合Langmuir模型,属于均质吸附。不同初始HA含量的分段吸附表明,在10～40 mg/L的低负载条件下,吸附质首先占据少量存在的非均质高活性点位,吸附平衡更好的符合Freundlich模型;在TOC的质量浓度为30～65 mg/L的较高负载条件下,高活性点位被占据,另一类大量存在于PAC表面的均质低活性点位则被利用,吸附平衡表现为均质吸附,模拟结果更符合Langmuir模型。热力学分析表明,PAC对HA的吸附是自发的放热熵减过程,吸附后液相体系中的混乱度变小。
The adsorption equilibrium of HA on PAC was measured at different temperatures with one kind of commercial humic acid (HA) as the research object and powdered activated carbon (PAC) as the adsorbent. The results showed that when the mass concentration of initial HA (characterized by TOC) was 10-65 mg / L, it was in good agreement with the Langmuir model and was homogeneous adsorption. The segmented adsorption of different initial HA contents showed that the adsorbate occupies a small amount of heterogeneous highly active sites at low loading of 10-40 mg / L, and the adsorption equilibrium is in good agreement with the Freundlich model. At TOC Under the condition of high concentration of 30-65 mg / L, the high active sites were occupied, while the other types of homogeneous low active sites which were abundant in the PAC surface were utilized. The adsorption equilibrium showed homogeneous adsorption, The simulation results are more consistent with the Langmuir model. Thermodynamic analysis shows that adsorption of HA by PAC is a spontaneous process of exothermic entropy decrease, and the degree of confusion in the liquid-phase system after adsorption decreases.