凝灰岩石粉对聚羧酸减水剂（PCs）有一定的吸附性, 使得“有效减水剂”比例降低, 导致PCs性能大大降低。 PCs抗吸附特性具有重要的设计参考意义, 与PCs组成、 结构密切相关。 紫外可见分光光度法（UV）是用于吸附量检测的常用方法, 但对PCs测试还存在较多的不确定性, 给测试带来了困难。 为此, 采用紫外分光度技术及导数光谱处理的方法定量分析凝灰岩石粉对不同侧链长度聚羧酸减水剂的吸附量, 并对试验参数进行了分析与优化。 结果显示, PCs吸收光谱图中无明显紫外特征峰, 增大浓度、 降低溶液pH值时可在190~200 nm波长范围出现假峰, 并通过乙酸分析试剂光谱试验得到证实; 对光谱数据进行二阶导数处理后, 可获得PCs特征峰207 nm, 此特征峰对应的样品吸光度与其浓度间存在良好的线性关系, 相关系数r均大于099; 为了进一步论证紫外吸收光谱法的准确性, 与TOC测定法进行比较, 两者之间呈良好的线性关系, 相关系数r为0997, 这表明UV二阶导数光谱法可为PCs吸附性分析提供一种简单、 快速、 准确、 便宜且无需显色剂的定量测试方法; 从样品测试分析可看出, 凝灰岩石粉对聚羧酸减水剂的吸附随着PCs侧链长度减小而减弱。 研究成果为紫外可见分光光度技术快速检测弱紫外吸收有机物含量提供了新的途径。

The tuff powder has certain adsorption to the polycarboxylic acid water reducing agent（PCs）, which makes the number of “effective water reducing agent” decrease, resulting in greatly reduced performance of PCs. The anti-adsorption characteristics of PCs have important design reference significance, and it is closely related to the composition and structure of PCs. The UV spectrophotometry is a common method for the detection of adsorption quantity, but there are still many uncertainties in the PCs test. So, UV spectrophotometry and derivative spectrometry were used to quantitatively analyze the adsorption capacity of tuff powder on PCs with different side chain lengths, and the experimental parameters were analyzed and optimized. The results show that there is no obvious ultraviolet characteristic peak in the absorption spectrum of PCs. When test solution concentration is increased and its pH value is lowered, the pseudo peak can be seen in the wavelength range of 190~200 nm, which is confirmed by the spectral test of acetic acid analysis reagent. After the derivative treatmentof the PCs spectral data, the characteristic peak of PCs can be obtained. There is a good linear relationship between the test solution absorbance and its concentration under this characteristic peak, and the correlation coefficient r is greater than 099. Further, the accuracy of UV absorption spectroscopy is demonstrated, compared with the TOC method. There is a good linear relationship between the above two methods, and the correlation coefficient r is 0997, which indicates that second derivative UV spectrum can provide a simple, fast, accurate, inexpensive and non-developing agent quantitative test method for PCs adsorption analysis; The adsorption of the PCs by the tuff rock powder decreases as the length of its side chain decreases. The research results will help to provide a new way for UV detection of organic matter with weak ultraviolet absorption.