Lin Jian-wei, Wang Hong, Zhan Yan-hui, Chen Dong-mei
Huan Jing Ke Xue. 2016 Jan 15;37(1):208-19.
A series of composites of lanthanum hydroxide/natural zeolite ( La( OH) 3/NZ composites) were prepared by co-precipitation method, and these composites were used as adsorbents to remove phosphate from aqueous solution. The phosphate adsorption capacities of different composites prepared with different precipitated pH values were compared in batch mode. The adsorption characteristics of phosphate from aqueous solution on the La(OH)3/NZ composite prepared with the precipitated pH value of 11 was investigated using batch experiments. The results showed that the La(OH)3/NZ composite prepared with the precipitated pH values of 5-7 and 13 had a low adsorption capacity for phosphate in aqueous solution, while the La( OH) 3/NZ composites prepared with the precipitated pH values of 9-12 exhibited much higher phosphate adsorption capacity. The phosphate adsorption capacity of the La (OH)3/NZ composite increased with the increase of the precipitated pH value from 9 to 11, but remained basically unchanged with the increase of the precipitated pH value from 11 to 12. The equilibrium adsorption data of phosphate from aqueous solution on the La ( OH ) 3/NZ composite prepared with the precipitated pH value of 11 could be described by the Langmuir isotherm model with the predicted maximum phosphate adsorption of 44 mg x g(-1) (phosphate solution pH 7 and 30 degrees C). The kinetic data of phosphate adsorption from low concentration phosphate solution on the La(OH)3/NZ composite prepared with the precipitated pH value of 11 well followed a pseudo-second-order model. The presence of Cl- and SO4(2-) in low concentration phosphate solution had no negative effect on phosphate adsorption onto the La(OH)3/NZ composite prepared with the precipitated pH value of 11, while the presence of HCO3- slightly inhibited the adsorption of phosphate. Coexisting humic acid had a negative effect on the adsorption of phosphate at low concentration on the La(OH)3/NZ composite prepared with the precipitated pH value of 11. The mechanism for phosphate adsorption onto the La(OH)3/NZ composite prepared with the precipitated pH value of 11 was explained by the ligand exchange process. Results of this work indicate that the La(OH)3/NZ composite prepared with the precipitated pH value of 11 is a promising adsorbent material for the removal of low concentration phosphate from water/wastewater.
采用共沉淀法制备了一系列氢氧化镧/天然沸石复合材料（La(OH)₃/NZ复合材料），并将这些复合材料用作吸附剂以去除水溶液中的磷酸盐。以分批模式比较了在不同沉淀pH值下制备的不同复合材料对磷酸盐的吸附容量。通过分批实验研究了在沉淀pH值为11时制备的La(OH)₃/NZ复合材料对水溶液中磷酸盐的吸附特性。结果表明，在沉淀pH值为5 - 7和13时制备的La(OH)₃/NZ复合材料对水溶液中磷酸盐的吸附容量较低，而在沉淀pH值为9 - 12时制备的La(OH)₃/NZ复合材料表现出更高的磷酸盐吸附容量。La(OH)₃/NZ复合材料的磷酸盐吸附容量随着沉淀pH值从9增加到11而增加，但随着沉淀pH值从11增加到12基本保持不变。在沉淀pH值为11时制备的La(OH)₃/NZ复合材料对水溶液中磷酸盐的平衡吸附数据可用Langmuir等温线模型描述，预测的最大磷酸盐吸附量为44 mg·g⁻¹（磷酸盐溶液pH值为7且温度为30℃）。在低浓度磷酸盐溶液中，沉淀pH值为11时制备的La(OH)₃/NZ复合材料对磷酸盐的吸附动力学数据很好地符合准二级模型。低浓度磷酸盐溶液中Cl⁻和SO₄²⁻的存在对沉淀pH值为11时制备的La(OH)₃/NZ复合材料对磷酸盐的吸附没有负面影响，而HCO₃⁻的存在略微抑制了磷酸盐的吸附。共存的腐殖酸对沉淀pH值为11时制备的La(OH)₃/NZ复合材料对低浓度磷酸盐的吸附有负面影响。通过配体交换过程解释了沉淀pH值为11时制备的La(OH)₃/NZ复合材料对磷酸盐的吸附机理。这项工作的结果表明，沉淀pH值为11时制备的La(OH)₃/NZ复合材料是一种有前景的吸附材料，可用于从水/废水中去除低浓度磷酸盐。
