A novel fabrication of monodisperse melamine–formaldehyde resin microspheres to adsorb lead (II)

Abstract

Monodisperse melamine-formaldehyde (MF) resin microspheres were prepared by dilute solution precipitation polymerization without any surfactant and stabilizer. The optimal preparation conditions and the mechanism of microsphere formation of the microspheres were investigated by microscopy, Fourier transform infrared spectra, thermal stability, and particle size analysis. The microspheres prepared under optimal conditions had a clean surface, good thermal stability, and a narrow distribution with a mean diameter of about 2.5 μm. In addition, the microsphere had an abundance of amino and imino functional groups that could supply numerous active points for adsorption. From a study of the static and dynamic adsorption of lead (II) (Pb (II)) using MF resin microspheres as the adsorbent, it was found that the resin microspheres showed a fast adsorption and high removal efficiency of Pb (II).

Development of a High-Performance Adhesive with a Microphase, Separation Crosslinking Structure Using Wheat Flour and a Hydroxymethyl Melamine Prepolymer

“…Note that HMP shows a peak at 2950 cm −1 that is not present in the melamine spectra; this is attributed to C–H stretching vibrations. In addition, the following are also observed in the HMP spectra: An absorption peak at 3325 cm −1 , which represents amino (–NH 2 ) and amino (–NH–) vibrations [31]; a methylene C–H bending vibration at 1485 cm −1 [32]; and a secondary amine C–N stretching at 1157 cm −1 [33]. All of these findings indicate that melamine reacted with formaldehyde to develop methylol melamine and these methylol melamine further formed a prepolymer with –NH–CH 2 –NH– linkage by a self-condensation reaction (Figure 1b).…”

Optimizing Melamine Resin Microspheres with Excess Formaldehyde for the SERS Substrate

“…The MFMSs was synthesized by the polycondensation-precipitation reaction between melamine and formaldehyde [ 7 , 8 ] catalyzed by acetic acid. Acetic acid solution (pH 4.0, 90 mL), melamine (2.5 g), and a variable amount of formaldehyde solution (38 wt %) were mixed in a conical flask, and the mixture was heated to, and maintained at, 65 °C with electromagnetic stirring until the melamine was dissolved.…”

“…Melamine-formaldehyde resin (MF) from the polycondensation reaction is well-known due to its wide application in the wood and papermaking industries, as well as dinnerware manufacturing [ 5 , 6 ]. Wherein, the MF microspheres can precipitate out of the reaction solution under some special conditions [ 7 , 8 ]. MFMSs were introduced into the SERS substrate for the trace analysis of tetramethylthiuram disulfide, uric acid, and other analytes [ 9 , 10 , 11 ], in which the MFMSs were synthesized by successive catalysis of alkali and acid at a constant formaldehyde/melamine (F:M) molar ratio and the deposition of AgNPs on MF microspheres was carried out by reduction of AgNO 3 using butylamine as the reducing agent.…”

Design and preparation of magnetic mesoporous melamine–formaldehyde resin: A novel material for pre‐concentration and determination of silver

“…MF contains abundant nitrogen atoms, which can well coordinate with transition metals . However, studies of enrichment and detection of metal ions using MF are scarce . Lv et al designed and synthesized magnetic mesoporous MF nanoparticles to adsorb Cr(VI), which showed high adsorption capacity and selectivity.…”