饮用水中无机成分与氧化还原电位的关系

Relationship Between Inorganic Components and Oxidation Reduction Potential in Drinking Water

目的研究饮用水中的无机成分(如溶解氧、pH值、硬度、碱度、氯化钠以及硫酸盐和硅酸盐)与氧化还原电位(ORP)的关系。方法采用一定量的CaCl2、MgCl2、Na2CO3、NaHCO3、NaCl、Na2SO4、Na2SiO3与纯水配制成一定浓度的溶液,观察不同条件下眼pH值:2～11.15,硬度(以CaCO3计):0～600mg/L,碱度(以CaCO3计):0～300mg/L,NaCl:0～160mg/L,硫酸盐:0～350mg/L,硅酸盐:0～20mg/L演氧化还原电位的变化;将高纯氮气和氧气通入纯水,观察不同浓度的溶解氧(0.1～9.4mg/L)对氧化还原电位的影响。结果氧化还原电位与水中溶解氧浓度的对数呈正相关(r=0.9355,P<0.05),与pH值呈负相关(r=-0.9839,P<0.05),氧化还原电位随水中Ca盐和Mg盐硬度(0～100mg/LCaCO3)的增加有下降趋势。碱度(以CaCO3计)为0～50mg/L时,氧化还原电位陡降,碱度(以CaCO3计)大于50mg/L,氧化还原电位趋于平缓。氯化钠浓度为0～60mg/L时,氧化还原电位有所降低,大于60mg/L后,氧化还原电位上升,然后趋于稳定。硫酸盐浓度为0～50mg/L时,氧化还原电位呈上升趋势,随后,逐渐下降。氧化还原电位随硅酸钠浓度的升高而降低。结论在一定浓度范围内增加水中pH值、硬度、碱度、盐度、硅酸盐浓度或降低水的溶解氧都有降低氧化还原电位的作用,硫酸盐有升高氧化还原电位的作用。健康饮用水应当具有偏碱性的pH值以及适当的硬度、碱度、盐度和硅酸盐含量。

Objective The relationship between oxidation reduction potential （ORP） and inorganic components, such as DO, pH value, hardness, alkalinity, salinity, sodium sulfate and sodium silicate, was studied respectively, so that the relationship between healthy drinking water and ORP was theorized tentatively. Methods pH value（2-11.15）, hardness（0-600 mg/L CaCO3）, alkalinity （0-300 mg/L CaCO3）, salinity（0-160 mg/L）, sodium sulfate content（0-350 mg/L） and sodium silicate content （0-20 mg/L） of pure water were changed by dosing inorganic reagents respectively, and DO （0.1-9.4 mg/L） were changed by insufflating pure N2 and O2 gas, then ORP, pH value, DO and water temperature of water sample were measured. Results The better positive correlation was observed in the quantitative analysis between ORP and lgDO （r=0.935 5）. ORP showed significant negative correlation with pH value （r=-0.983 9）. Hardness, alkalinity., salinity and sodium silicate content had an effect on ORP fall. Sodium sulfate content increased ORP. Conclusion On the view of ORP, healthy drinking water should have a higher pH value, appropriate hardness, alkalinity, salinity, sodium sulfate and sodium silicate.