基于铁锰泥的除砷吸附剂性能比较及吸附机理

为解决反冲洗铁锰泥粉末吸附剂（BSPA）使用后难以泥水分离问题，将除铁锰水厂生物滤池产生的反冲洗泥制成颗粒吸附剂（GA）和磁性粉末吸附剂（MPA），并对BSPA、GA和MPA的除砷性能进行了比较，通过SEM、TED、XRD、BET、FTIR等技术对3种材料进行了表征，寻找3种吸附剂之间除砷性能差异的根源.结果表明，BSPA、GA和MPA对As （V）的最大吸附容量分别为40.980，5.048，8.694mg/g，改性后的吸附材料GA和MPA对砷的吸附能力下降.BSPA是一种以纤铁矿为主的无定形结构混合物，并混有针铁矿和结晶度差的水铁矿，GA的XRD图谱中出现石英晶体和少量赤铁矿晶体的衍射峰，而MPA的主要成分为结晶程度较高的磁赤铁矿.3种材料中均存在有利于吸附的含羟基官能团.BSPA、MPA和GA的比表面积分别为253.150，238.660，43.803m²/g.物相改变且结晶程度增加、表面羟基减少和比表面积降低是导致GA和MPA的砷吸附容量比BSPA低的主要因素.

Performance comparison and adsorption mechanism of arsenic removal adsorbents made of backwashing sludge from biofilter for iron and manganese removal

The backwashing residuals from iron and manganese removal biological filter of underground waters was made into granular adsorbent (GA) and magnetic powder adsorbent (MPA) to solve the problem that it is difficult to separate the exhausted backwashing sludge powder adsorbent (BSPA) and treated water. The arsenic removal capability of BSPA、GA and MPA were compared. And their structure and surface feature were compared by SEM, TED, XRD, BET and FTIR to find the cause of difference in arsenic removal capability among these three adsorbents. Results showed that the maximum As (V) adsorption capacity of BSPA, GA and MPA were 40.980, 5.048 and 8.694mg/g respectively. As it suggested, the As (V) adsorption capacity of GA and MPA decreased compared to BSPA. BSPA was a mixture with amorphous structure, lepidocrocite was the main ingredient, goethite and poor crystallized ferrihydrite also mixed in it. The XRD spectrum of GA appeared crystal diffraction peaks of quartz crystal and a small amount of hematite, while the main component of MPA was maghemite with high crystallinity. There are hydroxyl functional groups that are conducive to adsorption in all three materials. The specific surface areas of BSPA, MPA and GA were 253.150, 238.660 and 43.803m²/g respectively. Phase changes and increase of crystallinity, reduction of surface hydroxyl group and decrease of specific surface area may be the main factors lower the adsorption capacity of GA and MPA compared with BSPA.