Li Qilin, Mariñas Benito J, Snoeyink Vernon L, Campos Carlos
Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, Illinois 61801, USA.
Environ Sci Technol. 2003 Jul 1;37(13):3005-11. doi: 10.1021/es020990j.
A three-component competitive adsorption kinetic model, developed and validated in part 1 of this study, was applied to a continuous-flow PAC/membrane system to study the effects of various system and operating parameters on organic removal. The model quantitatively describes the two competitive adsorption mechanisms that occur during adsorption of trace organic compounds by powdered activated carbon (PAC) in flow-through systems where the PAC is retained in the system: pore blockage and direct competition for adsorption sites. Model simulations were conducted to investigate the effects of influent water composition, membrane cleaning water quality, PAC pore size distribution, and system operation conditions such as hydraulic retention time, membrane cleaning interval, and PAC dosing method on treatment efficiency. Effects of these factors on adsorption capacity as well as surface diffusion rate and consequent removal of the trace organic compound were discussed. It was found that optimal operating conditions for maximum trace organic compound removal must be determined on the basis of the adsorption properties and concentrations of the competing compounds in the influent. For the conditions investigated in this study, the small strongly competing compound, p-DCB, had greater impact on atrazine removal than the large pore-blocking compound, PSS-1.8k. Various process design and operating parameters had complex and interrelated effects on the impact of competitive adsorption and corresponding trace contaminant removal efficiency in hybrid PAC/membrane systems.
在本研究的第1部分中开发并验证的三组分竞争吸附动力学模型，被应用于连续流PAC/膜系统，以研究各种系统和操作参数对有机物去除的影响。该模型定量描述了在粉末活性炭（PAC）在系统中被截留的流通系统中，痕量有机化合物吸附过程中发生的两种竞争吸附机制：孔堵塞和对吸附位点的直接竞争。进行了模型模拟，以研究进水水质、膜清洗水质、PAC孔径分布以及水力停留时间、膜清洗间隔和PAC投加方式等系统运行条件对处理效率的影响。讨论了这些因素对吸附容量以及表面扩散速率和痕量有机化合物去除效果的影响。结果发现，必须根据进水的吸附特性和竞争化合物的浓度来确定最大程度去除痕量有机化合物的最佳操作条件。对于本研究中所研究的条件，小的强竞争化合物对二氯苯比对大的孔堵塞化合物PSS-1. 在混合PAC/膜系统中，各种工艺设计和操作参数对竞争吸附的影响以及相应的痕量污染物去除效率具有复杂且相互关联的作用。 8k对阿特拉津去除的影响更大。
