地表水样品中悬浮物对六价铬保存的影响探究

Exploration of Effect of Suspended Solids in Surface Water Samples on Preservation of Hexavalent Chromium

通过采集某个富营养化程度较高、悬浮物较多的湖泊水,加入六价铬模拟含有不同浓度六价铬的地表水样品,比对实验研究现场采集地表水样品时经0.45μm微孔滤膜过滤去除悬浮物可否延长六价铬样品的保存时间。实验结果表明:地表水样品经0.45μm微孔滤膜精细过滤处理,有效去除了其中的悬浮物、微生物以及其他可能存在的氧化还原物质,从而降低了保存时间对六价铬浓度影响。现场采集地表水样品时,对六价铬样品加入氢氧化钠,调节pH值为8~9,经0.45μm微孔滤膜过滤去除悬浮物后,可以稳定保存30天;经过皮尔逊(Pearson)相关系数法计算得出,样品六价铬浓度与pH值呈现高度正相关性,随着样品pH值下降,样品六价铬浓度出现下降趋势,表明地表水样品pH值对六价铬的保存时间有影响。

By collecting lake water with a high degree of eutrophication and more suspended solids,the surface water samples containing different concentrations of hexavalent chromium were simulated by adding hexavalent chromium,and whether the removal of suspended solids by 0.45μm microporous filter membrane during the field was compared to investigate whether the storage time of hexavalent chromium samples could be prolonged.The experimental results showed that the surface water samples were finely filtered by a 0.45μm microporous membrane,which effectively removed the suspended solids,microorganisms and other redox substances that may exist in them,thereby reducing the effect of storage time on the concentration of hexavalent chromium.When the surface water samples were collected in the field,sodium hydroxide was added to the hexavalent chromium sample,the pH value was adjusted to 8~9,and the suspended solids could be stably stored for 30 days after being filtered by 0.45μm microporous filter membrane.The Pearson correlation coefficient method showed that the concentration of hexavalent chromium in the sample was highly positively correlated with the pH value,and the concentration of hexavalent chromium in the sample decreased with the decrease of the pH value of the sample,indicating that the pH value of the surface water sample had an effect on the storage time of hexavalent chromium.