Photocatalytic Reduction and In Situ Superstable Mineralization of Cr VI to PW 12 @ZnCr-LDH and Its Application for Efficient PET Glycolysis

作者：Haoran Wang, Xiaofeng Pang, Dongyuan Cui, Menghan Huang, Sai An, Yu‐Fei Song · 发表于：Industrial & Engineering Chemistry Research · 年份：2025 · DOI：10.1021/acs.iecr.5c03461 · 被引用次数：4 · 研究领域：Advanced Photocatalysis Techniques、Advanced Nanomaterials in Catalysis、Covalent Organic Framework Applications

The removal of toxic, highly soluble, and nonbiodegradable hexavalent chromium (Cr VI ) has been a major challenge for wastewater purification technologies. Herein, the in situ superstable mineralization strategy was applied for the complete removal of Cr (including Cr VI and Cr III ) in aquatic systems. Detailed quasi in situ X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed that under visible-light irradiation, Cr VI can be in situ superstably mineralized in the form of PW 12 @ZnCr-LDH (K sp ≈ 10 –60 ) by using PW 12 @ZIF-8 (PW 12 = H 3 PW 12 O 40 ·nH 2 O). The removal efficiencies of total Cr can reach > 99.9% in 24 h, and the maximum mineralization capacities of PW 12 @ZIF-8 toward Cr VI can achieve 224.6 mg g –1, surpassing most Cr mineralizers reported so far. On the basis of the results of X-ray absorption fine structure (XAFS), electron spin resonance (ESR), etc., the removal mechanism was proposed as follows: the Cr VI can be reduced to Cr III by the intermediate ·O 2 – and ·OH generated by PW 12 @ZIF-8 under visible-light irradiation, and the Cr III in the presence of slowly released Zn 2+ from PW 12 @ZIF-8, leading to in situ formation of PW 12 @ZnCr-LDH. Furthermore, the mineralized product PW 12 @ZnCr-LDH was used for polyethylene terephthalate (PET) glycolysis, which demonstrated a high BHET yield of 83.12% and excellent applicability to various postconsumer PET. This work provides a new pathway for the Cr VI -containing wastewater trea...