Core–shell immobilization of peroxide nanoparticles and horseradish peroxidase can be advantageous for removal of organic contaminants. In the present study, this novel technology was exploited for phenol removal from polluted water in order to prevent phenolic shock for the downstream microbial population. Since hydrogen peroxide production by calcium peroxide nanoparticles could be six times higher than magnesium peroxide (250 and 42 µmol H₂O₂ /g nanoparticles during a 10-min assay, respectively), calcium peroxide was selected as hydrogen peroxide supplier for further experiments. Regarding the immobilization matrix, diffusion properties, and mechanical strength of chitosan and alginate were compared. The mechanical strength was 3.0 ± 0.9 g for 6% of chitosan and 19.0 ± 3.3 g for 3% of alginate. According to the obtained results, the microcapsule core, embedding 1% w/v nanoparticles, was formed by cross-linking chitosan (6% w/v) with sodium tripolyphosphate. Subsequently, it was uniformly coated with an enzyme-containing alginate layer (3% w/v) cross-linked with calcium chloride. As the enzyme source, commercial horseradish peroxidase and partially purified peroxidase from horseradish roots were compared to evaluate the application of prepared microcapsules for industrial uses. The initial phenol removal rate of the optimized core–shell microcapsules was 0.0687 µmol phenol/h in a volume of reaction and gradually reduced to 50% of initial rate after 15 days in batch and column experiments. These results showed the high capacity of the proposed system for phenol removal from contaminated water streams which could be promising for various applications such as permeable reactive barriers for wastewater treatment or groundwater remediation.

Graphic abstract

中文翻译：

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辣根过氧化物酶-过氧化钙核壳微胶囊作为新型可渗透反应屏障用于苯酚污染水的生物修复

过氧化物纳米颗粒和辣根过氧化物酶的核壳固定化有利于去除有机污染物。在本研究中，这项新技术被用于从污染水中去除苯酚，以防止下游微生物种群的酚类休克。由于过氧化钙纳米颗粒产生的过氧化氢可能是过氧化镁的六倍（250 和 42 µmol H ₂ O ₂/g 纳米颗粒，分别在 10 分钟的测定中），选择过氧化钙作为过氧化氢供应商进行进一步的实验。关于固定基质，比较了壳聚糖和海藻酸盐的扩散性能和机械强度。6% 壳聚糖的机械强度为 3.0 ± 0.9 g，3% 海藻酸盐的机械强度为 19.0 ± 3.3 g。根据所得结果，通过将壳聚糖 (6% w/v) 与三聚磷酸钠交联形成嵌入 1% w/v 纳米颗粒的微胶囊核。随后，用氯化钙交联的含酶藻酸盐层（3% w/v）均匀地包被。作为酶源，商业辣根过氧化物酶和来自辣根根的部分纯化过氧化物酶进行了比较，以评估制备的微胶囊在工业上的应用。优化后的核壳微胶囊的初始苯酚去除率为 0.0687 µmol 苯酚/h，在批量和柱实验中，15 天后逐渐降低到初始速度的 50%。这些结果表明，所提出的系统从受污染的水流中去除苯酚的能力很高，可用于各种应用，例如用于废水处理或地下水修复的可渗透反应屏障。

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