生物炭和碳纳米管固定化漆酶去除水体雌二醇

Removal of β-estradiol in wastewater using laccase immobilized by biochar and carbon nano tube

漆酶是一类具有高效的催化氧化能力的含铜多酚的氧化酶,而固定化漆酶技术在有机废水处理领域受到了越来越多的关注。通过比较吸附法和包埋法利用木炭(WB)、竹炭(BB)和碳纳米管(CNT)固定游离漆酶去除水体雌二醇(E2)。在25℃、pH=5条件下,固定化漆酶经120 h贮存仍保留80%的活性。经过5次循环研究,固载的漆酶仍保留了27%~58%的剩余活性。结合扫描电子显微镜和傅里叶变换红外光谱,证实了漆酶成功地负载在碳基材料上。仅在8 h内,50 mg·L^(-1)E2通过吸附法制备的WB、BB、CNT固定化漆酶去除了42.92%、47.66%、43.92%,而包埋法制备的WB、BB、CNT固定化漆酶分别去除84.08%、87.20%、87.86%。结果表明,包埋法固定化漆酶对E2的去除效率更优,这是由于包埋固载在生物炭和CNT的漆酶更为稳定。此外,K^(+)和Mn^(2+)离子可能通过干扰漆酶的电子传递过程影响漆酶的活性,从而抑制E2的去除。本研究旨在为固定化漆酶在有机废水处理的实际应用提供指导。

Laccase is a class of Cu-containing polyphenol oxidase with high catalytic oxidation ability.The immobilized laccase technique has attracted an increasing attention in organic wastewater treatment.In this study,wood-and bamboo-derived biochars(WB and BB)or carbon nano tube(CNT)were used to immobilize laccase by the adsorption and embedding methods for the removal of β-estradiol(E2)in aqueous environment.At 25℃ and pH=5,80%activity of the immobilized laccase on WB,BB,and CNT was preserved after 120 h storage.After 5 cycles,the residual activity of the immobilized laccase was 27%~58%.Combined with scanning electron microscopy and Fourier transform infrared spectroscopy,it was confirmed that laccase was successfully loaded on carbon-based materials.Within only 8 h,42.92%,47.66%,and 43.92% of 50 mg·L^(-1) E2 were removed by WB-,BB-,and CNT-immobilized laccases using the adsorption method,while 84.08%,87.2%,and 87.86%of 50 mg·L^(-1) E2 were removed by WB-,BB-,and CNT-immobilized laccases using the embedding method.The results showed that the immobilized laccase using the embedding method had a better removal efficiency for E2 due to its stronger stability onto biochars and CNT.In addition,K^(+)and Mn^(2+)ions could interfere with electron transfer of laccases,then affect the activity of laccases,diminish E2 removal.The aim of this work can provide a guidance for designing immobilized laccase for organic wastewater treatment.