Removal of silver nanoparticles by mussel-inspired Fe3O4@ polydopamine core-shell microspheres and its use as efficient catalyst for methylene blue reduction

Abstract

The removal of silver nanoparticles (AgNPs) from water is highly needed because of their increasing use and potential risk to the environment due to their toxic effects. Catalysis over AgNPs has received significant attention because of their highly catalytic performance. However, their use in practical applications is limited due to high cost and limited resources. Here, we present for the first time that the mussel-inspired Fe3O4@polydopamine (Fe3O4@PDA) nanocomposite can be used for efficient removal and recovery of AgNPs. Adsorption of AgNPs over Fe3O4@PDA was confirmed by TEM, FT-IR, XRD, TGA and magnetic property. The adsorption efficiency of AgNPs by Fe3O4@PDA was investigated as a function of pH, contact time, ionic strength and concentration of AgNPs. The kinetic data were well fitted to a pseudo-second order kinetic model. The isotherm data were well described by Langmuir model with a maximum adsorption capacity of 169.5 mg/g, which was higher than those by other adsorbents. Notably, the obtained AgNPs-Fe3O4@PDA exhibited highly catalytic activity for methylene blue reduction by NaBH4 with a rate constant of 1.44 × 10−3/s, which was much higher than those by other AgNPs catalysts. The AgNPs-Fe3O4@PDA promised good recyclability for at least 8 cycles and acid resistant with good stability.

Mussel-Inspired Magnetic Nanoflowers as an Effective Nanozyme and Antimicrobial Agent for Biosensing and Catalytic Reduction of Organic Dyes

“…Diminishing the color of the MB solution by NaBH 4 + MNPs PDA–Cu NFs leads to the reduction behavior of specific peak intensity of MB, which demonstrated the conversion of whole MB to leucomethylene blue (LMB) for less than 5 min by a catalytic reduction reaction. 22 , 34 , 35 The essential catalytic reduction is the electron transfer from a donor to an acceptor. 36 In the process, MNPs PDA–Cu NFs plays the role of an electron relay center so that MB and NaBH 4 were absorbed on their surface.…”

“…Accordingly, the concentrations of MNPs PDA–Cu NFs and MB were measured in the 50–300 and 100–400 mg/L ranges, respectively. The reduction catalytic rate constant ( K app , min –1 ) of MB was determined by matching the experimental data with pseudo-first-order kinetics equation ( eq 1 ) 22 where C 0 and C t denote the MB concentrations at the initial step and time t , respectively. The percent degradation efficiency ( E d ) of MB at any moment can be calculated by eq 2 ( 9 ) where C 0 is the initial step and C t belongs to time t .…”

Mussel-Inspired Surface Engineering for Water-Remediation Materials

“…Magnetically recyclable nanocatalysts can also be prepared via capture of Ag NPs from solution with the Fe 3 O 4 @PDA. 172 Another effective strategy to solve the recycling problem is to immobilize catalysts on a block support, as the supported complexes can be easily removed from the reaction mixture, realizing the recovery of catalysts and avoiding metal contamination of the treated water. [173][174][175] Compared with magnetic nanocatalysts, the block-supported metal catalysts can be easily recycled without a magnetic field.…”

High-Level Extraction of Recyclable Nanocatalysts by Using Polyphosphazene Microparticles

“…Recently, adsorption treatments have attracted ever more attention because of their facile operation and high efficiency, while maintaining the original morphology and chemical activity of the target NPs. Nanofiber networks, 27 functionalized carbon microspheres, 28 and dopamine derivatives 29 have been designed to address the issue of pollution by metal NPs. It is notable that the majority of previously reported adsorbents required functionalization with amino/ catechol groups to improve their adsorption capacities.…”