Preliminary investigation of phosphorus adsorption onto two types of iron oxide-organic matter complexes
Preliminary investigation of phosphorus adsorption onto two types of iron oxide-organic matter complexes
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两类氧化铁-有机物复合物对磷吸附的初步研究
DOI：
10.1016/j.jes.2015.08.008
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发表时间：
2016
影响因子：
6.9
通讯作者：
Wei Shiqiang
中科院分区：
文献类型：
--
作者：
Yan Jinlong;Jiang Tao;Yao Ying;Lu Song;Wang Qilei;Wei Shiqiang
天然有机物包裹的氧化铁（FeO）是普遍存在的。矿物质与有机物（OM）的结合显著改变了它们的表面性质和反应性，从而影响了污染物的环境命运，包括营养物质（例如，磷（P））。制备了水铁矿/针铁矿-腐殖酸（FH/GE-HA）复合物，研究了其在不同pH和离子强度下对磷的吸附特性。结果表明，FeO-OM复合物对磷的吸附能力较未复合的FeO有所降低。最大吸附量（Qmax）为FH（22.17 mg/g）> FH-HA（5.43 mg/g）> GE（4.67 mg/g）> GE-HA（3.27 mg/g）。无定形FH-HA复合物经HA包覆后，仍表现出比结晶GE-HA复合物更高的磷吸附。P吸附量的减少可能是由于OM缔合作用引起的FeO表面电荷的变化。P吸附量与吸附剂比表面积的相关性表明，复合物中的FeO组分仍然是吸附表面的主要贡献者。FeO-HA复合物对磷的吸附量随初始pH的升高或初始离子强度的降低而降低。磷吸附对离子强度和pH值的强烈依赖性可能表明，外球之间的OM组分的表面和P可能共存的FeO组分和P之间的内球表面络合物。因此，以前过分强调的贡献，原始矿物的磷固定可能高估了土壤的磷负载能力，特别是在富含腐殖酸的地区。
Iron oxide (FeO) coated by natural organic matter (NOM) is ubiquitous. The associations of minerals with organic matter (OM) significantly changes their surface properties and reactivity, and thus affect the environmental fate of pollutants, including nutrients (e.g., phosphorus (P)). In this study, ferrihydrite/goethite-humic acid (FH/GE–HA) complexes were prepared and their adsorption characteristics on P at various pH and ionic strength were investigated. The results indicated that the FeO–OM complexes showed a decreased P adsorption capacity in comparison with bare FeO. The maximum adsorption capacity (Qmax) decreased in the order of FH (22.17 mg/g) > FH-HA (5.43 mg/g) > GE (4.67 mg/g) > GE-HA (3.27 mg/g). After coating with HA, the amorphous FH–HA complex still showed higher P adsorption than the crystalline GE–HA complex. The decreased P adsorption observed might be attributed to changes of the FeO surface charges caused by OM association. The dependence of P adsorption on the specific surface area of adsorbents suggests that the FeO component in the complexes is still the main contributor for the adsorption surfaces. The P adsorptions on FeO–HA complexes decreased with increasing initial pH or decreasing initial ionic strength. A strong dependence of P adsorption on ionic strength and pH may demonstrate that outer-sphere complexes between the OM component on the surface and P possibly coexist with inner-sphere surface complexes between the FeO component and P. Therefore, previous over-emphasis on the contributions of original minerals to P immobilization possibly over-estimates the P loading capacity of soils, especially in humic-rich areas.