Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia; UNSW Centre for Transformational Environmental Technologies (CTET), Yixing, Jiangsu Province 214206, PR China.
J Hazard Mater. 2022 Feb 5;423(Pt B):127255. doi: 10.1016/j.jhazmat.2021.127255. Epub 2021 Sep 17.
The heterogeneous catalytic ozonation process is a promising treatment option for high salinity reverse osmosis concentrate (ROC) however the influence of salts on the catalyst performance is not well understood. In this work, we investigate the effect of salts on the performance of the catalytic ozonation process for treatment of synthetic ROC using a commercially available Fe-loaded AlO catalyst. Our results show that the presence of salts influences the rate and extent of degradation of organic compounds present in the synthetic ROC when subjected to the heterogeneous catalytic ozonation process. Scavenging of aqueous O by chloride ions and/or transformation of organics (particularly humics) to more hydrophobic form as a result of charge shielding between adjacent functional groups and/or intramolecular binding by cations inhibits the bulk oxidation of organics to a measurable extent. While the scavenging of aqueous hydroxyl radicals at the salt concentrations investigated here was minimal, the accumulation of chloride ions in the electric double layer near the catalyst surface, particularly when pH< pH, results in more significant scavenging of surface associated hydroxyl radicals. Overall, the presence of salts (particularly chloride ions) has a significant influence on the performance of both conventional and catalytic ozonation processes with some scope to mitigate this effect through appropriate choice of catalyst.
多相催化臭氧氧化工艺是一种很有前途的高盐反渗透浓缩水（ROC）处理方法，但盐对催化剂性能的影响尚不清楚。在这项工作中，我们使用市售的负载 Fe 的 AlO 催化剂，研究了盐对用于处理合成 ROC 的多相催化臭氧氧化过程性能的影响。结果表明，当合成 ROC 经历多相催化臭氧氧化过程时，盐的存在会影响其中有机物的降解速率和程度。氯离子会消耗水中的 O，或者由于相邻官能团之间的电荷屏蔽和/或阳离子的分子内结合，使有机物转化为疏水性更强的形式，从而抑制有机物的大量氧化，这种抑制在一定程度上是可测量的。尽管在研究的盐浓度下，对水合羟基自由基的消耗可以忽略不计，但在催化剂表面附近的双电层中，特别是在 pH<pH 时，氯的积累会导致表面结合的羟基自由基发生更显著的消耗。总的来说，盐（特别是氯离子）的存在对常规和催化臭氧氧化过程的性能有重大影响，通过选择合适的催化剂，可以在一定程度上减轻这种影响。
