滤料表面活性滤膜对水中锰的吸附特性与机理研究

STUDY ON ADSORPTION CHARACTERISTICS AND MECHANISMS OF MANGANESE BY ACTIVE FILTER MEMBRANES IN SOLUTION

以中试滤柱中石英砂表面充分覆盖的复合氧化物活性滤膜为对象,通过研究活性滤膜对水中Mn2+的吸附特性,探讨其吸附水中Mn2+的机理;结合光电子显微镜对滤膜比表面积及孔道测定结果,对滤膜形貌与物理结构进行了表征;通过X射线光电子能谱(XPS)对Mn2+在滤膜表面的吸附活性位进行了初步研究。结果表明,Mn2+吸附过程符合Lagergren拟1级动力学方程(R2>0.95);随着水中Mn2+初始质量浓度ρ0的增加,平衡吸附量Se逐渐增大;活性滤膜对Mn2+吸附等温曲线符合Langmuir方程(R2=0.943 4),满足单分子层化学吸附的模型;滤膜成熟后,滤料比表面积、总孔容和孔径显著增加,吸附Mn2+的能力明显加强;当水中Mn2+的质量浓度为0～5 mg/L时,可用Se/(mg.g-1)=[0.02781ρ0/(mg.L-1)]+0.027 12测算活性滤膜对Mn2+的吸附量。通过XPS测定活性滤膜吸附Mn2+前后表面元素原子结合能的变化,确定了活性滤膜表面Mn2+吸附活性位为复合氧化物中Fe-O和Mn-O的O原子。

The adsorption characteristics and mechanisms of active filter membranes for Mn2＋in solution were studied by using composite oxide active filter membranes,which fully covered on the quartz sand surface of pilot filter column,as a research object.The channel,specific surface area,physical structure and morphology of the filter membranes were characterized by SEM.The adsorption activity sites of Mn2＋on filter membranes surface were confirmed by X-ray photoelectron spectroscopy（XPS）.The results showed that the Mn2＋adsorption process on active filter membranes fitted well with the Lagergren pseudo first-order kinetics（R2＆gt;0.95）.With increasing the initial Mn2＋concentration（ρ0）,equilibrium adsorption capacity of oxide coatings for Mn2＋increased.Mn2＋adsorption isotherm curve was also fitted well with Langmuir equation（R2=0.943 4）,and the absorption process was corresponded with monolayer chemical absorption model.With the increase of specific surface area、total pore volume and average pore diameter,the adsorption capacity for Mn2＋on co-oxidize membrane was enhanced.In the range of Mn2＋concentration from 0～5 mg/L,the adsorption capacity for Mn2＋with oxide coatings could be calculated by the relationship ofSe/（mg.g-1）=[0.0278 1ρ0/（mg.L-1）]＋0.027 12.The change of the binding energies of atoms on the surface before and after adsorption Mn2＋were determined by XPS,the adsorption activity sites of Mn2＋on filter membranes surface are the oxygen atoms in Fe-O and Mn-O.