ACF电吸附过程动力学特性和脱盐影响因素试验研究

近年来,国家强化了对各类污水的治理力度和排放标准。其中,工业废水具有较大的节水与回用潜能,急需一种高效低成本的脱盐技术。目前电吸附技术凭借其能耗低、无需添加药剂、除盐效率高等特点在水处理领域广泛应用。采用电吸附技术实现废水快速脱盐主要从脱盐速度提高和高通量产水2个方面入手。由于动力学因素决定了离子在吸附剂内部的吸附速率,吸附容量决定除盐率,因此探究影响电吸附过程动力学特性和脱盐影响因素是该技术的关键。以活性炭纤维为电极材料,在自制的板式电吸附装置进行多组电吸附试验,研究进样浓度、外加电压、进样液pH值和温度对其除盐效率和饱和吸附容量的影响,并对不同电压、不同浓度下的电吸附动力学结果进行拟合。动力学研究表明:电压是离子吸附速率的主要因素;电压<0.8 V时,适用于准二级动力学方程,电压>0.8 V后适用一级动力学模型,电压越大离子吸附速率越快。等温吸附模型研究表明:增大电压和初始浓度可以提高电吸附容量,吸附过程适用Langmuir吸附等温模型来描述。弱酸性条件更有利于电吸附除盐性能的提高;温度升高对离子吸附有抑制作用,室温为最佳试验温度。

Experimental study on kinetic characteristics of ACF electro-sorption process and influencing factors of desalination

In recent years,the treatment intensity and discharge standards of various types of sewage have been continuously improved.Among them,industrial wastewater has greater water saving and reuse potential.An efficient and low-cost desalination technology is urgently needed.At present,electro-sorption technology is widely used in the field of water treatment by virtue of its low energy consumption,no need to add chemicals,and high salt removal efficiency.The rapid desalination of wastewater by electro-sorption technology mainly needs to start from two aspects:the increase of desalination speed and high-throughput water production.The kinetic factors determine the adsorption rate of ions inside the adsorbent,and the adsorption capacity determines the salt removal rate.Therefore,exploring the kinetic characteristics of the electro-sorption process and the influencing factors of desalination is the key to this technology.Using activated carbon fibers as electrodes,multiple sets of electro-sorption tests were carried out in a self-made plate-type electro-sorption device using activated carbon fibers as electrodes.In this paper,the effects of solution concentration,applied voltage,pH value and temperature on its salt removal efficiency and saturated adsorption capacity were studied,and the electro-sorption kinetics results under different voltages and different concentrations were fitted.The kinetic study indicates that voltage is the main factor affecting the ion adsorption rate.When the voltage is less than 0.8 V,it is suitable for pseudo-second-order kinetic equation,and when the voltage is greater than 0.8 V,pseudo-first-order kinetic model is applicable.The higher the voltage is,the faster the adsorption rate is.The adsorption isotherm research shows that electro-sorption capacity increases with the increase of voltage and initial concentration,and the adsorption process conforms with the Langmuir adsorption isotherm model.Weakly acidic condition is conducive to the improvement of electro-sorption desalination performance.The increase of temperature inhibits ion adsorption,and room temperature is best experimental temperature.