地表水中悬浮物含量和粒径对磷测定的影响  

Effects of Suspended Solid Content and Particle Size on Phosphorus Determination in Surface Water Body

作　　者：韩超南 孙宁宁 戴岩 秦延文[2] HAN Chaonan;SUN Ningning;DAI Yan;QIN Yanwen(School of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China)

机构地区：[1]南京林业大学土木工程学院,江苏南京210037 [2]中国环境科学研究院,北京100012

出　　处：《中国环境监测》2022年第5期161-167,共7页Environmental Monitoring in China

基　　金：国家自然科学基金项目(42007346);江苏省自然科学基金项目(BK20190763)。

摘　　要：我国地表水体悬浮物含量和颗粒粒径组成的时空分异明显。该研究筛分3种粒径颗粒,研究不同粒径颗粒中赋存的磷形态及其解吸-吸附磷的能力特性差异,探讨不同悬浮物含量引起水体总磷(TP)测定结果偏差情况及改进建议。结果表明,粒径d<30μm颗粒所赋存总磷、生物有效态磷含量明显高于50~150μm、30~50μm颗粒,水空白环境下粒径<30μm颗粒所释放磷量也最高,等温吸附条件下粒径<30μm颗粒具有更高的磷吸附能力。通过Freundlich交叉型吸附曲线拟合,粒径50~150μm、30~50μm、<30μm颗粒的磷解吸-吸附平衡质量浓度分别为0.84、0.63、0.58 mg/L,粒径<30μm颗粒在地表Ⅰ~Ⅴ类水体(TP≤0.4 mg/L)中更易达到磷解吸-吸附平衡状态。我国地表一般水体中悬浮物含量大多在零至几千mg/L范围,而使用“静沉30min-消解”国标前处理方法无法保证统一的沉降效果,使得水体TP含量测定结果偏低或偏高。针对地表一般水体,建议同时增加“混匀-消解-过滤”前处理方法测定水体TP含量作为参考。Suspended solid content and particle size composition in surface water bodies in China have obvious spatial and temporal variations.This study focused on the differences of phosphorus components and phosphorus desorption-adsorption capacity of three size particles, discussed the deviation of water total phosphorus(TP) content measurement results caused by different suspended solid contents and made suggestions for improvement.The results showed that particulate phosphorus and bioavailable phosphorus in particles with particle size of ‘<30 μm’ were significantly higher than those in particles with particle size of ‘30-50 μm’ and ‘50-150 μm’.Fine particles(‘<30 μm’) released the highest amount of phosphorus into blank water among three size particles, and they also presented the strongest phosphorus adsorption capacity under isothermal adsorption conditions.Based on Freundlich cross-type adsorption curves fitting, the equilibrium concentration of phosphorus desorption-adsorption for three size particles(‘<30 μm’,‘30-50 μm’,‘50-150 μm’) were 0.84,0.63,0.58 mg/L,respectively.These indicated that fine particles(‘<30 μm’) were more likely to reach equilibrium state of phosphorus desorption-adsorption in I-Ⅴ class surface water bodies where TP contents were under 0.4 mg/L.Most of suspended solid contents in general surface water bodies in China are in the range of zero to several thousand mg/L.The national standard pretreatment method using ‘sedimentation 30 min and digestion’ can′t guarantee the unified settlement effect, which can cause large measuring errors of water TP contents.For the general surface water body, the pretreatment method of ‘mixing-digestion-filtration’ was recommended to determine additionally water TP content as a reference.

关 键 词：总磷 悬浮物含量 粒径 吸附-解吸 地表水 

分 类 号：X832[环境科学与工程—环境工程]