Kirkendall Effect Boosts Phosphorylated nZVI for Efficient Heavy Metal Wastewater Treatment

Angew Chem Int Ed Engl. 2021 May 15. doi: 10.1002/anie.202104586. Online ahead of print.ABSTRACTRemoval of non-biodegradable heavy metals has been the top priority in wastewater treatment; the development of green technologies remains a significant challenge. Here we show the phosphorylated nanoscale zero-valent iron (nZVI) is promising for heavy metals (Ni(II), Cu(II), Cr(VI), Hg(II)) removal via boosted Kirkendall effect. Phosphorylation confines tensile hoop stress on the nZVI particles and "breaks" the structurally-dense spherical nZVI to produce numerous radial nanocracks. Exemplified by Ni(II) removal, the radial nanocracks favor the facile inward diffusion of Ni(II) and the rapid outward transport of electrons and ferrous ions through the oxide shell for surface (Ni(II)/electron) and boundary (Ni(II)/Fe0) galvanic exchange. Accompanied by a pronounced hollow-out phenomenon, phosphorylated nZVI can instantly reduce and immobilize Ni(II) throughout the inherent oxide shell with a high capacity (258 mg Ni/g Fe). For real electroplating factory wastewater treatment, this novel nZVI performs simultaneous Ni(II) and Cu(II) removal, producing effluent of stable quality that meets local discharge regulation.PMID:33991384 | DOI:10.1002/anie.202104586
Source: Angewandte Chemie - Category: Chemistry Authors: Source Type: research