Department of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.; Zhejiang Provincial Key Laboratory of Water Science and Technology, Zhejiang 314006, China.
Department of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
J Environ Sci (China). 2016 Jul;45:191-9. doi: 10.1016/j.jes.2016.01.010. Epub 2016 Feb 26.
Phosphate is one of the most predominant pollutants in natural waters. Laboratory experiments were conducted to investigate the phosphate adsorption performance of a (NFS) made from drinking water treatment residuals. The adsorption of phosphate on the NFS fitted well with the Freundlich isotherm and pseudo second-order kinetic models. At pH7.0, the maximum adsorption capacity of 1.03mg/g was achieved at 15°C corresponding to the wastewater temperature in cold months, and increased notably to 1.31mg/g at 35°C. Under both acidic conditions (part of the adsorption sites was consumed) and basic conditions (negative charges formed on the surface of NFS, which led to a static repulsion of PO4(3-) and HPO4(2-)), the adsorption of phosphate was slightly inhibited. Further study showed that part of the adsorption sites could be recovered by 0.25mol/L NaOH. The activation energy was calculated to be above 8.0kJ/mol, indicating that the adsorption of phosphate on NFS was probably a chemical process. Considering the strong phosphate adsorption capacity and recoverability, NFS showed great promise on enhancing phosphate removal from the secondary treated wastewater in the filtration process.
磷酸盐是天然水中最主要的污染物之一。本研究采用饮用水处理厂剩余污泥制备的 (NFS) 作为吸附剂，通过实验室试验考察了其对磷酸盐的吸附性能。结果表明，磷酸盐在 NFS 上的吸附较好地符合 Freundlich 等温吸附模型和准二级动力学模型。在 pH7.0、15°C 条件下，NFS 对磷酸盐的最大吸附容量为 1.03mg/g，这一值接近寒冷月份污水的温度，而在 35°C 条件下，最大吸附容量显著增加至 1.31mg/g。在酸性条件（部分吸附点位被消耗）和碱性条件（NFS 表面形成负电荷，导致 PO4(3-)和 HPO4(2-)静电排斥）下，磷酸盐的吸附均受到一定程度的抑制。进一步的研究表明，部分吸附点位可通过 0.25mol/L NaOH 溶液得到恢复。计算得到磷酸盐在 NFS 上的吸附过程的活化能大于 8.0kJ/mol，表明该吸附过程可能为化学吸附过程。NFS 对磷酸盐具有较强的吸附容量和可恢复性，有望在过滤过程中增强对二级处理废水中磷酸盐的去除效果。
