Zinc nanozymes for hydrolytic degradation of di(2-ethylhexyl) phthalate (DEHP).

Phthalate esters (PAEs) are persistent plasticizers of environmental concern, and di(2-ethylhexyl) phthalate (DEHP) is especially difficult to hydrolyze because of its steric bulk, branching, and hydrophobicity. Here we report zinc-containing molecularly imprinted nanozymes designed as synthetic mimics of zinc hydrolases for the hydrolytic degradation of DEHP and related unactivated esters. The nanozymes were prepared in cross-linked surfactant micelles using an acylthiourea template that simultaneously coordinates a polymerizable zinc complex and hydrogen-bonds to an acidic functional monomer, thereby installing a Lewis acidic metal center and a proximal base within a substrate-shaped active site. Template variation allowed systematic tuning of active-site shape, leading first to improved hydrolysis of model unactivated esters bearing 2-ethylhexyl-like steric features and ultimately to a DEHP-imprinted catalyst that operates in aqueous methanol at elevated temperature, conditions that typically denature enzymes. The nanozyme also hydrolyzes other phthalate esters under strongly enzyme-denaturing conditions, and its surface alkynes enable covalent immobilization onto azide-functionalized magnetic nanoparticles to afford a magnetically recoverable catalyst that retains substantial activity over repeated cycles. These results establish molecular imprinting as a practical strategy for constructing robust esterase-mimicking nanozymes for hydrolysis of sterically hindered, hydrophobic plasticizers.