Abstract：
The extensive use and discharge of toluidine blue have caused serious problems to the water environment. As a green biocatalyst, laccase has the ability to decolorize the dyes, but it is limited by poor reusability and low stability. Metal-organic frameworks (MOFs) are a good platform for enzyme immobilization. However, due to the weak dispersion of MOFs, the enzyme activity is inevitably inhibited. Herein, we proposed to use graphene oxide (GO) as the dispersion medium of mesoporous ZIF-8 to construct MZIF-8/GO bi-carrier for laccase (FL) immobilization. On account of the narrower bandgap energy of FL@MZIF-8/GO (4.07 eV) than that of FL@MZIF-8 (4.69 eV), electron transport was enhanced which later increased the catalytic activity of the immobilized enzyme. Meanwhile, the improved hydrophilicity characterized by contact angle and full infiltration time further promoted the efficiency of the enzymatic reaction. Benefiting from such regulatory effects of GO, the composite showed excellent storage stability and reusability, as well as multifaceted enhancements including pH, thermal, and solvent adaptation. On the basis of the characterized synergistic effect of adsorption and degradation, FL@MZIF-8/GO was successfully applied to the degradation of toluidine blue (TB) with a removal rate of 94.8%. Even in actual treated wastewater, the highest removal rate still reached more than 80%. Based on the inner mechanism analysis and the universality study, this material is expected to be widely used in the degradation of pollutants in real water under complex environmental conditions.
摘要：
甲苯胺蓝的广泛使用和排放给水环境带来了严重的问题。作为一种绿色生物催化剂，漆酶具有使染料脱色的能力，但它受限于较差的可重用性和较低的稳定性。金属有机骨架(MOFs)是酶固定化的良好平台。然而,由于MOFs的弱分散性，酶活性不可避免地被抑制。在这里，我们建议使用氧化石墨烯（GO）作为介孔ZIF-8的分散介质来构建MZIF-8/GO双载体，以固定漆酶（FL）。由于FL@MZIF-8/GO的带隙能量（4.07eV）比FL@MZIF-8的带隙能量（4.69eV）窄，电子传递增强，后来提高了固定化酶的催化活性。同时,以接触角和完全渗透时间为特征的改善的亲水性进一步促进了酶促反应的效率。受益于GO的这种调节作用，该复合材料表现出优异的储存稳定性和可重复使用性，以及包括pH值在内的多方面增强，热,和溶剂适应。在表征吸附和降解协同作用的基础上,成功应用FL@MZIF-8/GO降解甲苯胺蓝(TB),去除率达94.8%。即使在实际处理过的废水中，最高去除率仍达到80%以上。基于内在机理分析和普遍性研究,该材料有望广泛用于复杂环境条件下实际水体中污染物的降解。
