探究生活饮用水测定总硬度的影响条件

Investigate the Conditions that Influence the Total Hardness of Drinking Water

生活饮用水是否达标直接影响人体健康,《生活饮用水卫生标准》中明确规定了各项指标卫生要求,其中要求总硬度(以CaCO3计,mg/L)限值为450 mg/L,但测量生活饮用水的总硬度时往往存在诸多影响因素,导致测量结果存在误差。因此,本文通过研究水样的pH值、水样温度、缓冲溶液加入量、反应时间的快慢、滴定速度、干扰物质等因素对测定水中总硬度结果准确度的影响,探究出生活饮用水测定总硬度的最佳条件为:pH=7左右的中性水溶液,测定温度为25~30℃,缓冲溶液的加入量为2.00 mL,加入缓冲溶液后1 min内进行测定。通过该条件对生活饮用水的总硬度进行测定,极大地提高了水中总硬度测定的准确性。

Whether drinking water meets the standards directly affects human health,the sanitary requirements for various indicators are clearly defined in the Sanitary Standards for Drinking Water,where the total hardness(calculated as CaCO3,mg/L)is 450 mg/L,but the measurement is There are often many influencing factors in the total hardness of drinking water,resulting in errors in the measurement results.Therefore,this paper explores the influence of the pH value of the water sample,the temperature of the water sample,the amount of the buffer solution,the reaction time,the titration rate,the interfering substances and other factors on the accuracy of the determination of the total hardness of the water.The optimum conditions for the hardness are:a neutral aqueous solution having a pH of about 7,a measurement temperature of 25 to 30℃,a buffer solution addition amount of 1.5 mL,and measurement immediately after the addition of the buffer solution.The total hardness of drinking water is measured by this condition,which greatly improves the accuracy of the determination of total hardness in water.