Biocatalytic removal of perchlorate and nitrate in ion-exchange waste brine
Biocatalytic removal of perchlorate and nitrate in ion-exchange waste brine
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DOI：
10.1039/c8ew00178b
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发表时间：
2018-08-01
影响因子：
5
通讯作者：
Zilles, Julie L.
中科院分区：
文献类型：
--
作者：
Hutchison, Justin M.;Zilles, Julie L.
生物催化技术的特点是在一系列与环境有关的条件下有针对性地迅速降解污染物，这些条件以地下水为代表，但尚未被纳入饮用水处理过程。这项工作调查了混合离子交换/生物催化过程的潜力，其中生物催化用于处理离子交换废盐水，允许重复使用的盐水。在合成盐水和现实世界的废盐水中测试了受管制的阴离子高氯酸盐和硝酸盐的还原率和命运。生物催化剂作为可溶性蛋白组分从固氮螺菌的高氯酸盐还原和Paracoccus acetificans和Haloferax acetificans的硝酸盐还原。在合成的12%盐水中，生物催化剂保持活性，高氯酸盐的速率为32.3 +/-6.1 U（μ g Mo）（-1）（A.硝酸盐（P. lacticans）为16.1 +/-7.1 U（μ g Mo）（-1）。在现实世界的废盐水中，放射性略低（高氯酸盐为20.3 +/-6.5 U（μ g Mo）（-1），硝酸盐为14.3 +/-3.8 U（μ g Mo）（-1））。高氯酸盐还原的差异是由于废盐水中硝酸盐、碳酸氢盐和硫酸盐的浓度较高。硝酸盐还原的主要最终产物是一氧化二氮或二氮气体，这取决于生物催化剂的来源和盐浓度。这些结果表明，在现实世界的废盐水，这可以促进盐水再利用离子交换技术的再生，并防止这些阴离子和它们的中间体重新引入到环境中的受管制的阴离子的生物催化还原。
Biocatalytic technologies are characterized by targeted, rapid degradation of contaminants over a range of environmentally relevant conditions representative of groundwater, but have not yet been integrated into drinking water treatment processes. This work investigated the potential for a hybrid ion-exchange/biocatalytic process, where biocatalysis is used to treat ion-exchange waste brine, allowing reuse of the brine. The reduction rates and the fate of the regulated anions perchlorate and nitrate were tested in synthetic brines and a real-world waste brine. Biocatalysts were applied as soluble protein fractions from Azospira oryzae for perchlorate reduction and Paracoccus denitrificans and Haloferax denitrificans for nitrate reduction. In synthetic 12% brine, the biocatalysts retained activity, with rates of 32.3 +/- 6.1 U (mu g Mo)(-1) for perchlorate (A. oryzae) and 16.1 +/- 7.1 U (mu g Mo)(-1) for nitrate (P. denitrificans). In real-world waste brine, activities were slightly lower (20.3 +/- 6.5 U (mu g Mo)(-1) for perchlorate and 14.3 +/- 3.8 U (mu g Mo)(-1) for nitrate). The difference in perchlorate reduction was due to higher concentrations of nitrate, bicarbonate, and sulfate in the waste brine. The predominant end products of nitrate reduction were nitrous oxide or dinitrogen gas, depending on the source of the biocatalysts and the salt concentration. These results demonstrate biocatalytic reduction of regulated anions in a real-world waste brine, which could facilitate brine reuse for the regeneration of ion-exchange technologies and prevent reintroduction of these anions and their intermediates into the environment.