Zimmermann Karl, Wright Jaycee, Bérubé Pierre, Barbeau Benoit, Mohseni Madjid
University of British Columbia, Department of Chemical and Biological Engineering, Vancouver, BC, V6T 1Z3, Canada.
University of British Columbia, Department of Civil Engineering, Vancouver, BC, V6T 1Z4, Canada.
Water Res. 2021 May 15;196:117036. doi: 10.1016/j.watres.2021.117036. Epub 2021 Mar 12.
Biological ion exchange (BIEX) offers removal of dissolved organic carbon (DOC) with greatly reduced regeneration frequency. In the present work, a strong base anionic exchange resin was operated without regeneration and using inlet water with either Low (12 mg L) or High (60 mg L) sulphate and DOC of 2.75 or 5.0 mg L. Filters operated continuously for 226 days (16,500 bed volumes) and achieved DOC removal varying from 32% to 50%. Initially, sulphate and DOC were retained by the resin with chloride being released. During this period, DOC removal occurred due to traditional mechanisms, referred to as primary ion exchange. Following this initial period, DOC removal continued even though the conventionally defined resin capacity was exhausted (based on chloride loading). During the later period, no chloride release was observed, but instead sulphate was released. Although suggested by others, the present study is the first to confirm the direct exchange in charge equivalence of anions removed (DOC and nitrate) to released (sulphate) during the secondary ion exchange mechanism. Further, increasing inlet sulphate from 12 to 60 mg L resulted in a 19% decrease in DOC removal. Finally, percent DOC removal was affected only by an increase of inlet DOC but not changes to the counter ion or after DOC loading on the resin increased to 1/3 of total capacity. This work promotes BIEX as a viable alternative to biological activated carbon and a leading solution for low-maintenance DOC removal.
生物离子交换（BIEX）能够去除溶解有机碳（DOC），且再生频率大幅降低。在本研究中，一种强碱性阴离子交换树脂在不进行再生的情况下运行，使用的进水硫酸盐含量低（12毫克/升）或高（60毫克/升），DOC含量为2.75或5.0毫克/升。过滤器连续运行226天（16,500床体积），DOC去除率在32%至50%之间变化。起初，硫酸盐和DOC被树脂保留，同时释放出氯离子。在此期间，DOC的去除是由于传统机制，即所谓的一次离子交换。在这个初始阶段之后，即使按照传统定义树脂容量已耗尽（基于氯离子负载量），DOC去除仍在继续。在后期，未观察到氯离子释放，而是释放出了硫酸盐。尽管其他人曾提出过，但本研究首次证实了在二次离子交换机制中，被去除的阴离子（DOC和硝酸盐）与释放出的阴离子（硫酸盐）在电荷当量上的直接交换。此外，将进水硫酸盐含量从12毫克/升提高到60毫克/升导致DOC去除率下降了19%。最后，DOC去除百分比仅受进水DOC增加的影响，而不受抗衡离子变化的影响，也不受树脂上DOC负载量增加到总容量的1/3之后的影响。这项工作推动了BIEX成为生物活性炭的可行替代方案以及低维护DOC去除的领先解决方案。
