Excellent removal performance of 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer towards phenanthrene and 9-phenanthrol: Experimental, modeling and DFT calculations studies.

Phenanthrene (PTH) and 9-phenanthrol (9-PTH) exhibited severe health threats and ecological hazards, for this reason, exploring a high-efficient removing strategy for PTH and 9-PTH could be considered of great urgency. Herein the 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer (magnetic BIPH-PHEN) was successfully fabricated via Schiff base polycondensation reaction and the subsequently one-pot embedded method. The mutual aromatic nucleus of BIPH-PHEN polymer and PTH/9-PTH could form π-π interaction, thus improving the capture ability, the embedded Fe3O4 nanoparticles provided the possibility for rapid separation. The physical and chemical properties of the magnetic BIPH-PHEN were systematically characterized. The removal rate of magnetic BIPH-PHEN towards PTH and 9-PTH was 85.65 % and 98.52 %, respectively (PTH or 9-PTH: 8 mg/L; Adsorbent: 0.2 g/L). The DFT calculations including energy calculations and electrostatic potential distribution analyzed the different bonding modes and proposed the most possible bonding modes in the adsorbent/adsorbate system. Moreover, the LUMO and HOMO orbits combined with energy gaps analysis proved the existence and specific types of the π-π interaction. The monolayer adsorption occurred on the homogeneous magnetic BIPH-PHEN surface, simultaneously the chemisorption was dominant. This work not only proposed new sights on assembling magnetic Schiff base polymer for removing polycyclic aromatic hydrocarbons, but also provided a deeper understanding of intramolecular interactions.

High-efficiency adsorption of phenanthrene by Fe3O4-SiO2-dimethoxydiphenylsilane nanocomposite: Experimental and theoretical study.

Phenanthrene (PHE), as one of representative polycyclic aromatic hydrocarbons (PAHs) can cause serious adverse effects on human health, developing effective adsorbents to alleviate PHE contamination is in urgent demand. A novel Fe3O4-SiO2-Dimethoxydiphenylsilane (Fe3O4-SiO2-2DMDPS) nanocomposite was fabricated from encapsulation and grafting process. Magnetic Fe3O4 nanoparticles were served as preliminary matrix material, SiO2 was used to link the magnetic oxide and provide hydroxyl groups for proceeding the silane coupling reaction subsequently, and the aromatic rings in DMDPS could provide active sites for PHE adsorption via π-π interaction. SEM-EDS, TEM, BET, VSM, XRD, FTIR, Raman, Zeta potential, and XPS techniques were used to characterize magnetic nanocomposite. The prepared Fe3O4-SiO2-2DMDPS exhibited an excellent adsorption performance towards PHE, it could maintain 75.97% adsorption capacity after four regeneration cycles. Homogeneous adsorption acted crucial role in the whole adsorption process and film diffusion was the rate-controlling procedure. Theoretical calculations put forward the most favorable bonding modes between Fe3O4-SiO2-2DMDPS and PHE molecules, confirmed the π-π interaction was valid and it usually existed in the form of parallel-displaced. This work might aid us to develop effective modification strategy for Fe3O4 nanoparticles and expand its application in the PAHs removing field.

Preparation and Modification of Mullite Whiskers/Cordierite Porous Ceramics for Cu2+ Adsorption and Removing.

In this paper, mullite whiskers were prepared by a molten salt reaction method based on a porous cordierite ceramic substrate (MC), and the modified mullite whiskers/cordierite ceramic sample (MCK) was obtained via the silane coupling reaction with γ-aminopropyl triethoxysilane (KH550). The structural morphology and phase compositions of the MC were characterized by X-ray diffraction and scanning electron microscopy. The surface functional groups of MCK were characterized using Fourier transform infrared spectroscopy, and the result showed that the amino group (-NH2) was successfully grafted onto the surface of cordierite ceramic. X-ray photoelectron spectroscopy analysis successfully showed inclusion of the amino and Cu2+ adsorption mechanism onto MCK. The adsorption properties of MCK were investigated using Cu2+ as the target pollutant by varying the experimental conditions such as pH, time, temperature, and initial Cu2+ concentration. The adsorption was found to be spontaneous, endothermic, and feasible, as indicated by the study of thermodynamic parameters. The adsorption kinetic analysis suggested that the pseudo-second-order kinetic model was best fitted for Cu2+ adsorption. The adsorption isotherm studies showed that the results of the Freundlich model are more suitable for experimental adsorption data than the Langmuir model. The adsorption-desorption cycle indicated that MCK had good reusability and stability. A novel porous ceramic-based adsorbent with high Cu2+ adsorption and removal efficiency was fabricated and has potential applications for the metal ion removing field.

Synthesis of Cost-Effective Pomelo Peel Dimethoxydiphenylsilane-Derived Materials for Pyrene Adsorption: From Surface Properties to Adsorption Mechanisms.

This study investigated the adsorption behaviors of pyrene (PYR) on a pomelo peel adsorbent (PPA), biochar (PPB), and H3PO4-modified (HPP), NaOH-activated (NPP), and dimethoxydiphenylsilane-treated (DPDMS-NPP) pomelo peel materials. SEM, FTIR, and elemental analyses of DPDMS-NPP's surface structure showed that the material was characterized by a well-developed porous structure, a large specific surface area (698.52 m2 g-1), and an abundance of phenyl functional groups. These properties enhance the PYR adsorption performance of DPDMS-NPP. Experimental results indicated that the adsorption capacity of DPDMS-NPP was significantly affected by the amount of material used and the initial concentration of PYR. Kinetic assessments suggested that PYR adsorption on PPA, NPP, and DPDMS-NPP could be accurately described by the pseudo second-order model. The adsorption process was controlled by several mechanisms, including electron donor-acceptor (EDA), electrostatic, and π-π interactions as well as film and intraparticle diffusion. The adsorption isotherm studies showed that PYR adsorption on DPDMS-NPP and PPA was well described by the Langmuir model and the maximum Langmuir adsorption capacity of DPDMS-NPP was 531.9 µg g-1. Overall, the results presented herein suggested that the use of DPDMS-NPP adsorbents constitutes an economic and environmentally friendly approach for the mitigation of PYR contamination risks.