Effect of draw solution concentration and operating conditions on forward osmosis and pressure retarded osmosis performance in a spiral wound module
Effect of draw solution concentration and operating conditions on forward osmosis and pressure retarded osmosis performance in a spiral wound module
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DOI：
10.1016/j.memsci.2009.11.013
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发表时间：
2010-02-15
影响因子：
9.5
通讯作者：
Nie, Shengzhe
中科院分区：
文献类型：
--
作者：
Xu, Yuan;Peng, Xiaoyu;Nie, Shengzhe
正向渗透（FO）和压力延迟渗透（PRO）是浓度驱动的膜过程。虽然它们可以潜在地用于水、废水和能源应用中，但这些过程遭受多孔膜支撑体内部的浓差极化，导致严重的通量降低，这种现象被称为内部浓差极化（ICP）。研究人员在理论和实验研究中研究了ICP的影响。目前的研究扩展了现有的ICP模型，以包括在螺旋缠绕FO模块（SWFO）中膜渗透流对汲取溶液稀释的影响。在浸没和错流条件下使用SWFO进行FO和PRO实验。系统地研究了驱动液浓度、驱动液流速、给水流速和膜取向对FO和PRO水通量性能的影响。在FO和PRO模式下，渗透液流量随着汲取溶液浓度的增加而增加。发现ICP在浓度驱动的膜过程中极大地限制了可用的膜通量，并且其不利影响在更大的汲取溶液浓度下更严重。当渗透液流速与提取液流速相当或大于提取液流速时，提取液稀释也会影响膜通量。浸没式FO配置的性能几乎与具有在膜包封外部循环的给水的错流配置一样好（较短的流动路径）。在这种情况下，进料水流速对膜通量的影响有限，可能是由于其低传质阻力。相反，当给水在膜包封内部循环时，在低给水流速下膜通量可能受到不利影响（较长的流动路径）。(C)2009爱思唯尔有限公司版权所有。
Forward osmosis (FO) and pressure retarded osmosis (PRO) are concentration-driven membrane processes. While they can be potentially used in water, wastewater, and energy applications, these processes suffer from the concentration polarization inside the porous membrane support resulting in severe flux decrease, a phenomenon known as internal concentration polarization (ICP). Researchers have investigated the effect of ICP both in theoretical and experimental studies. The current study extends the existing ICP model to include the effect ofdraw solution dilution by membrane permeate flow in a spiral wound FO module (SWFO). FO and PRO experiments were performed using a Hydrowell (R) SWFO under both submerged and cross-flow conditions. The effect ofdraw solution concentration, draw solution flow rate, feed water flow rate, and membrane orientation on FO and PRO water flux performance was systematically investigated. Permeate flow increased with greater draw solution concentration in both FO and PRO modes. ICP was found to drastically limit the available membrane flux in the concentration-driven membrane processes, and its adverse effect was more severe at greater draw solution concentration. Membrane flux was also affected by the dilution ofdraw solution when the permeate flow rate was comparable or greater than the draw solution flow rate. The submerged FO configuration performed nearly as good as the cross-flow configuration with feed water circulating outside of the membrane envelope (shorter flow path). In this case, the feed water flow rate only had limited effect on membrane flux likely due to its low mass transfer resistance. In contrary, the membrane flux can be adversely affected at low feed water flow rate when it was circulated inside of the membrane envelope (longer flow path). (C) 2009 Elsevier B.V. All rights reserved.