ZIF-8-derived N-doped hierarchical porous carbon coated with imprinted polymer as magnetic absorbent for phenol selective removal from wastewater.

Producing a desirable adsorbent with strong affinity adsorption sites, excellent selectivity properties, and the ability to easily separate solid from liquid for the removal of phenol to a permissible level remains a great challenge in wastewater treatment. Herein, an N-doped magnetic carbon skeleton is presented as a porous adsorbent matrix. Importantly, the pore volume and specific surface area of the adsorbent matrix can be meticulously tuned by adjusting the thermal treatment condition, while dispersing and immobilizing the N fraction. This would ultimately result in an N-rich matrix structure with flexible mass transfer channel. The imprinted modification generates a large number of phenol-shaped geometrical cavities on the matrix. This helps to activate the phenol recognition "awareness" of N-active sites and greatly endows the adsorbent with selective adsorption property. Due to the advantageous balance between the hierarchical porous adsorbent matrix with uniformly distributed N-active sites and the imprinted polymer, the adsorbent has a superior adsorption capacity of 995.2 mg g-1 and selective recognition (Kd = 3.92, 3.78; HQ, PTBP) towards phenol. It outperforms previously reported adsorbents. In addition, its easy magnetic separation property makes the adsorbent to have excellent reusability. The adsorbent presents a promising potential for separating pollutants from wastewater and it sheds light on the design of an efficient comprehensive adsorbent.

Reasonable design and sifting of microporous carbon nanosphere-based surface molecularly imprinted polymer for selective removal of phenol from wastewater.

Highly selective surface molecularly imprinted polymer (SMIP) was prepared on glucose-derived microporous carbon nanospheres (GMCNs) by surface molecular imprinting technology for the removal of phenol from wastewater. GMCNs with rich pore structure and surface oxygenic functional groups were adopted as support materials, on which the active layers were constructed by grafting silane coupling agent 3-(methacryloyloxy) propyltrimethoxysilane. Then with phenol as template molecule, different types and amounts of functional monomer (including methacrylic acid and 4-vinylpyridine (4-VP)) were screened for optimizing imprinting conditions suitable for phenol adsorption, and a series of SMIP was obtained through crosslinking polymerization. The adsorption behaviors of SMIP were evaluated by UV spectrophotometry. The results show that, when 4-VP is used as functional monomer, the resultant 4-VP/SMIP exhibites an excellent adsorption capacity of 85.72 mg g-1. The relative selectivity factor for phenol against hydroquinone, p-nitrophenol and p-tert-butylphenol is 8.38, 7.96 and 6.67, respectively, indicating outstanding adsorption capacity and selectivity of 4-VP/SMIP. The pseudo-second-order model and Langmuir‒Freundlich model fit better than other models for the adsorption of phenol. 4-VP/SMIP is promising for selective removal and enrichment recovery towards phenol in wastewater.

The structures and antibacterial properties of nano-SiO2 supported silver/zinc-silver materials.

OBJECTIVES: The aims of this study were to investigate the structures and antibacterial properties of two kinds of sterilizing nano-SiO(2) specimens. METHODS: The specimens were synthesized by adsorption methodology. One of them was synthesized by adsorbing silver cation onto nano-SiO(2) carrier (silver-loading nano-SiO(2) specimen (SLS)), and the other one by co-adsorbing zinc and silver cations onto the same kind of carrier (zinc-silver-loading nano-SiO(2) specimen (SLZS)). Chemical compositions of these specimens were estimated. The structure and morphology of the specimens were determined by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Also, the antibacterial properties of the specimens were examined. RESULTS: The amount of silver loaded in SLZS was approximate to that of SLS. Consequently, it can be proved that the amount of nano-SiO(2) adsorbed silver cation did not change with the addition of zinc cation. The obvious differences were not observed among the XRD patterns for each specimen. So it was possible to confirm no formation of new phase(s) after Ag(+)/Zn(2+) absorption. The loaded silver and zinc existed as nano-particles, as observed by HRTEM. Antibacterial properties of SLS and SLZS were excellent against Escherichia coli and S. faecalis. The antibacterial effect of the same antibacterial agent against E. coli or S. faecalis was different. In addition, the antibacterial effect of SLZS was better than that of SLS. SIGNIFICANCE: These results suggested SLS and SLZS can be effectively incorporated in dental resin-based materials to provide antibacterial activity against bacteria.

Magnesium hydroxide nanoparticles synthesized in water-in-oil microemulsions.

Well-dispersed magnesium hydroxide nanoplatelets were synthesized by a simple water-in-oil (w/o) microemulsion process, blowing gaseous ammonia (NH(3)) into microemulsion zones solubilized by magnesium chloride solution (MgCl(2)). Typical quaternary microemulsions of Triton X-100/cyclohexane/n-hexanol/water were used as space-confining microreactors for the nucleation, growth, and crystallization of magnesium hydroxide nanoparticles. The obtained magnesium hydroxide was characterized by field-emission scanning electron microscopy (FESEM), high-resolution transmission election microscopy (HRTEM), X-ray powder diffraction (XRD), laser light scattering, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC). The mole ratio of water to surfactant (omega(0)) played an important role in the sizes of micelles and nanoparticles, increasing with the increase of omega(0). The compatibility and dispersibility of nanoparticles obtained from reverse micelles were improved in the organic phase.