论文部分内容阅读
在水厂和供水管网中,加氯消毒副产物(DBPs)的生成浓度会随着季节转换和水温变化而出现明显波动.为了探究不同温度条件下DBP生成浓度的变化规律,本研究利用腐殖酸(HA)作为有机前体物进行加氯消毒,参照DBP统一生成条件(uniform formation condition,UFC),在不同水温下监测DBP[包括三卤甲烷(THM)和卤乙酸(HAA)]的生成浓度,并从动力学角度对该生成反应的机制做出分析,进而建立初步的浓度预测模型.结果表明,对于检测到的3种典型DBPs[三氯甲烷(CHCl3)、二氯乙酸(DCAA)和三氯乙酸(TCAA)],水温升高均能够明显提高其生成速率和最大生成浓度,其中后者随着温度的升高近似呈指数增长(R2>0.90).根据一级反应动力学模型对各组温度条件下的DBP实测值进行拟合,得到了较好的相关性(R2>0.94).为了进一步验证该动力学模型的准确性和可靠性,在20℃和30℃条件下分别采用该模型对DBP的实际生成浓度进行预测,并与实测值进行比较,均得到了良好的预测结果.为定量研究温度对DBP生成速率的影响规律,利用阿伦尼乌斯公式计算得到CHCl3、DCAA和TCAA的表观反应活化能分别为22.3、25.5和40.8 kJ.mol-1.
In waterworks and water distribution networks, the concentrations of DBPs generated fluctuate significantly with seasonal changes and water temperature changes.In order to explore the variation of DBP production concentration under different temperature conditions, (HA) was chlorinated as an organic precursor and DBP [including trihalomethane (THM) and haloacetic acid (HAA)] was monitored at different water temperatures with reference to DBP uniform formation condition (UFC) (CHCl3) and dichloroacetic acid (DCAA) were used to analyze the mechanism of the formation reaction from the kinetic point of view, and then the initial concentration prediction model was established.The results showed that for the three typical DBPs detected [CHCl3, ) And trichloroacetic acid (TCAA)], the water temperature can significantly increase the formation rate and the maximum generation concentration, which the latter exponential growth with temperature (R2> 0.90) .According to the first-order reaction kinetics In order to further verify the accuracy and reliability of the kinetic model, the correlation between the measured DBP values and the measured DBP values under various temperature conditions (R2> 0.94) Under the model were used to the actual DBP students The concentration of CHCl3, DCAA and TCAA were calculated by using the Arrhenius equation, and the results were compared with the measured values to obtain good predictions.In order to quantitatively study the effect of temperature on the rate of DBP formation, Activation energies were 22.3, 25.5 and 40.8 kJ · mol-1, respectively.