Abstract:

The effects of iron/carbon ratio, absorbent dosage, and acid pretreatment of urine on the synergistic adsorption of α-Fe₂O₃ and activated carbon (AC) were investigated. Its removal efficiency on urine treatment and characteristics were analyzed and discussed. The results showed that the removal rates of total organic carbon (TOC), PO{}_{\mathrm{4}}^{\mathrm{3}-}-P and TP were 39.51%, 71.03% and 76.79%, respectively, when the iron/carbon ratio was 0.6. The removal of TOC mainly depended on the adsorption of AC, while the removal of PO{}_{\mathrm{4}}^{\mathrm{3}-}-P relied on α-Fe₂O₃. Acid pretreatment of urine greatly improved the adsorption of PO{}_{\mathrm{4}}^{\mathrm{3}-}-P. The adsorption processes of TOC and PO{}_{\mathrm{4}}^{\mathrm{3}-}-P were both in accordance with the Redlich-Peterson adsorption isotherm, specifically, the synergy of monolayer adsorption and multilayer adsorption. The results of kinetic analysis showed that the adsorption of TOC and PO{}_{\mathrm{4}}^{\mathrm{3}-}-P could reach the equilibrium within 24h. The adsorption process of PO{}_{\mathrm{4}}^{\mathrm{3}-}-P can be explained by Elovich model, which is multi-layer adsorption occurred on the inhomogeneous interface. However, the adsorption of TOC is mainly controlled by the diffusion rate. Meanwhile, the removal rate of chromophoric dissolved organic matter (CDOM) was 72.16% with the best adsorption effect of humic acid. The adsorption of tyrosine, tryptophan, and soluble microbial products could be reduced by acid pretreatment. The removal of P was due to the coprecipitation between P and α-Fe₂O₃ and inorganic ions in urine. Then, it was attached to the pore of AC in the form of inorganic salt deposition.

Key words: activated carbon, α-Fe₂O₃, urine, adsorption, kinetics

摘要：

为探究α-Fe₂O₃与活性炭协同吸附对尿液的处理效果，本文考察了铁炭比、投加量及尿液酸预处理的影响，并重点分析了协同吸附特性。研究发现，铁炭比为0.6时，尿液中总有机碳（TOC）、PO{}_{\mathrm{4}}^{\mathrm{3}-}-P、总磷（TP）的去除率分别为39.51%、71.03%和76.79%，TOC的去除主要依靠活性炭的吸附作用，而PO{}_{\mathrm{4}}^{\mathrm{3}-}-P主要依靠α-Fe₂O₃的作用，尿液酸预处理可显著强化PO{}_{\mathrm{4}}^{\mathrm{3}-}-P的吸附。TOC和PO{}_{\mathrm{4}}^{\mathrm{3}-}-P的吸附过程均符合Redlich-Peterson吸附等温线模型，为单层吸附和多层吸附共同作用。动力学研究发现，TOC和PO{}_{\mathrm{4}}^{\mathrm{3}-}-P的吸附均可在24h内达到吸附平衡，PO{}_{\mathrm{4}}^{\mathrm{3}-}-P的动力学吸附过程更符合Elovich模型，即不均匀界面上的多层吸附，而TOC的动力学过程主要受扩散速率控制。同时，协同吸附对发光溶解性有机物（CDOM）的去除率可达72.16%，对腐殖酸类的吸附效果最佳，酸预处理主要减少酪氨酸类、色氨酸类和可溶性微生物代谢产物的吸附。P的去除主要依靠其与α-Fe₂O₃和尿液中无机盐的共沉淀作用，并以无机盐沉积的形式附着于活性炭孔道内。

关键词: 活性炭, α-Fe₂O₃, 尿液, 吸附, 动力学