Speciation of nano-copper collected in molecular sieves from chemical-mechanical planarization wastewater

Experimentally, 70-80% of copper in the chemical-mechanical planarization (CMP) wastewater was abstracted in the molecular sieve MCM-41 and zeolites Y at 298 K (for 4 h). The least-square fitted X-ray absorption near edge structural (XANES) spectra showed that mainly CuO clusters (47%) and adsorbed copper (CuO) (22%) were abstracted in MCM-41. In zeolite Y, CuO clusters (42%), Cu2+ (41%) and CuO (14%) were found. Moreover, about 20% of nano-CuO in the CMP wastewater were abstracted and formed as CuO clusters in the channels of MCM-41. The Fourier transformed extended X-ray absorption fine structural (EXAFS) data also indicated that the abstracted copper in MCM-41 or zeolite Y possessed Cu-O bond distances of 1.96-1.97 A with a coordination number (China) of 3.4