EDTA间接滴定法快速检测CO_(2)吸收液中碳酸氢根与碳酸根总量的研究

Research on rapid determination of total bicarbonate and carbonate in CO_(2) absorption solution by EDTA indirect titration

碳捕集、利用与封存(CCUS)技术是减少二氧化碳(CO_(2))排放的有效措施之一,其中化学吸收法应用广泛且技术成熟。在化学吸收法中,用碱性溶液吸收CO_(2)后,CO_(2)吸收液中存在一定量的碳酸氢根和碳酸根,准确测定CO_(2)吸收液中碳酸氢根和碳酸根的总量,可确定CO_(2)吸收液的CO_(2)吸收量。根据脱硫废水(作为CO_(2)吸收液)的水质组分及其复杂性提出了采用EDTA间接滴定法快速测定CO_(2)吸收液中碳酸氢根和碳酸根的总量(以碳酸根计,下同)。对碳酸氢根和碳酸根系列标准溶液的测定结果表明,系列标准溶液的标准曲线线性拟合系数均大于0.9993,线性拟合范围为100~2500 mg/L,因此EDTA间接滴定法测定碳酸氢根和碳酸根总量的检测范围为100~2500 mg/L。对实际工程水样的测定结果显示,测定结果的相对标准偏差为0.92%~1.28%(n=5),准确性较好,EDTA间接滴定法测定碳酸氢根和碳酸根总量具有现实可行性。

Carbon capture,utilization and storage(CCUS)technology is one of the effective measures to reduce carbon dioxide(CO_(2))emissions,among which chemical absorption method is widely used and mature technology.In the chemical absorption method,after absorbing CO_(2) with alkaline solution,there is a certain amount of bicarbonate and carbonate in the CO_(2) absorption solution,and the total amount of bicarbonate and carbonate in the CO_(2) absorption solution can be determined accurately.According to the water quality components and complexity of desulfurization wastewater(using as CO_(2) absorption solution),EDTA indirect titration method was proposed to rapidly determine the total amount(measured in carbonate,the same as below)of bicarbonate and carbonate in CO_(2) absorption solution.The results of the determination of bicarbonate and carbonate series standard solutions show that the linear fitting coefficients of the standard curves of the series of standard solutions are greater than 0.9993,and the linear fitting range is from 100 mg/L to 2500 mg/L.Therefore,the detection range of the total amount of bicarbonate and carbonic acid by EDTA indirect titration is from 100 mg/L to 2500 mg/L.The results of actual engineering water samples show that the relative standard deviation of the measurement results is from 0.92%to 1.28%with n=5,and the accuracy is good.The EDTA indirect titration method is feasible for the determination of bicarbonate and total carbonate.