A novel annulated dinuclear dizinc phthalocyanine cross-linked h-BN polyamides for efficient photocatalytic levofloxacin removal from real pharmaceutical wastewater

Abstract

The alignment of the strong visible-light harvesting phthalocyanine and its metal derivatives onto wide-gap semiconductors has been recognized as a bright approach to fabricate highly effective photocatalysts for energy conversation and environmental restoration. However, the practical application of phthalocyanine-sensitized photocatalysts depends on their incorporation mode between phthalocyanine and basic materials. In this work, a novel high-effective dinuclear zinc (II) phthalocyanine-sensitized photocatalyst is fabricated via covalent immobilization of (Bis(82,112,152-tri-(6-oxyl-2-carboxyl)-naphthaoxytribenzo)[g,l,q]-5,10,15,20-tetraazaporphrinno[b,e]benzene) dizinc (II), (ZnTcPc)2 onto the amino functionalized hexagonal boron nitride (–NH2-h-BN) nanosheets for the first time by a facile condensation strategy. The optimized 9%(ZnTcPc)2/h-BN polymer displays remarkably improved photocatalytic activity in levofloxacin degradation from different aqueous solutions with long-term stability under visible-light illumination. Its decomposition rates reach 81.4%, 71.7% and 90.8% in deionized water, tap water and real pharmaceutical wastewater, respectively. It is approximately 7 times than that of bare h-BN nanosheets in deionized water. The detailed experimental data indicate that the critical role of for improving visible-light harvesting and photoinduced electron transfer capability of h-BN acted by the strongly chemical bond constructed between (ZnTcPc)2 and –NH2-h-BN. The improved photocatalytic mechanism for levofloxacin removal over 9%(ZnTcPc)2/h-BN polymer is proposed according to the results of ESR, UV–vis and fluorescence measurements. Therefore, this unique combination approach affords a carefully designed molecular photocatalyst with great potential application in environmental remediation.