While enzymatic degradation has proven to be an effective way of remediating nanoplastic-related pollution, the practical deployment of this technique is hampered by concerns over enzyme stability, costs, and the low concentration of nanoplastics in natural settings. In this study, we unveil a facile microreactor-enhanced method that improves the effective remediation capacity of cutinase for nanoplastic-polluted water systems. Our approach leverages the self-assembly capabilities of block copolymers within microfluidic droplets to fabricate Janus microspheres with distinct dual-porosity features, which have an enzyme loading capacity of up to 103.8 mg cutinase/g microsphere. The cutinase-anchored microspheres can act as microreactors to capture and degrade nanoplastics. Despite its lower enzymatic activity, the immobilized cutinase exhibits degradation performance comparable to that of its free enzyme counterpart. Moreover, it displays good operational stability over six degradation cycles. Therefore, our findings shed some light on achieving more efficient and cost-effective enzymatic nanoplastic remediation.
Bin Wang,Wenling Guo,Tian Li,Rongmin Wang,Pengfei Song,Yufeng He,Xiaoqi Cheng
The prevention of bacterial adhesion and proliferation on substrate surfaces have been recently growing interest of scientists. Herein, hollow Janus copolymer microspheres (PSV JMs) containing hydrophilic sodium sulfonate groups (-SO 3 Na) on its outer surface and hydrophobic benzyl chloride groups (-C 6 H 5 -CH 2 Cl) on its inner surface, were first synthesized through interfacial polymerization. Furthermore, the antibacterial Janus copolymer sheets (PSVNN JSs) with contact/release-based dual-active centers were successfully synthesized by using the obtained PSV JMs for two-step quaternization with hexadecyl trimethyl ammonium bromide (CTAB) and hexadecyldimethylamine (HDMA). Notably, PSVNN JSs could be effectively obtained through reasonable control of several factors, including the ratio of hydrophilic and hydrophobic monomers , the amount of crosslinker and pore-forming agent. Moreover, the resultant PSVNN JSs exhibited higher antibacterial activity due to the quaternary ammonium salts (QASs) groups connected by ionic bond and covalent bonds , which has bright prospects in application in biomedical and environmental science.
Nanosized sorbents are widely used for uranium (VI) recovery due to their high specific surface area, but the research on the integration of micromotors with nanosorbents to establish self-locomotive composites is still worth exploring. Thus, self-locomotive composites PS@PDA@Ag/SiO 2 -AO (PPA/SA) based on asymmetric micromotors and covalently attached nanosorbents were designed for selective uranium recovery. Pickering emulsion, as an important micro-reactor, was firstly adopted to prepare Janus microspheres with chemically distinct structure (PS@PDA@Ag), on which one hemisphere was loaded with catalytic silver (Ag) nanoparticles. Then, amidoxime (AO) decorated SiO 2 nanospheres were covalently attached onto another hemisphere of PS@PDA@Ag, anisotropic configuration of as-prepared PPA/SA avoided the overlap of catalytic and binding sites. The self-propelled motion of PPA/SA induced by asymmetrical bubble evolution by H 2 O 2 was observed, and the maximum speed was about 25 μm s −1 in case of 5 % H 2 O 2 . The uranium adsorption onto PPA/SA achieved 92 % of the equilibrium amount (29.31 mg g −1 ) in the first 20 min, and this value increased to 38.71 mg g −1 under the condition of H 2 O 2 , suggesting that autonomous movement achieves rapid mixing and mass transportation. The maximum adsorption amount ( Q m ) is 114.0 mg g −1 at 298 K according to the Langmuir model. In addition, PPA/SA exhibited remarkable selectivity for uranium even in the presence of large amounts of Na + , Mg 2+ , K 2+ , Ca 2+ and other ions in the simulated seawater solution.
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