Powerful Reactive Sorption of Silver(I) and Mercury(II) onto Poly(o-phenylenediamine) Microparticles

Abstract

The strong adsorbability of Ag(I) and Hg(II) ions onto fine poly(o-phenylenediamine) (PoPD) microparticles synthesized through a chemically oxidative polymerization of o-phenylenediamine was systematically examined and PoPD/Ag nanocomposites were facilely prepared through the reactive sorption method. The effect of the (NH4)2S2O8 oxidant/o-phenylenediamine monomer ratio on the polymerization yield, macromolecular structure, conductivity, and insolubility of the PoPD microparticles was studied. The Ag(I) adsorbability of the microparticles was significantly optimized by varying the oxidant/monomer ratio, doping state, Ag(I) concentration, sorption time, and solution pH. The Ag(I) adsorbance steadily increases with changing oxidant/monomer molar ratio from 3/1 to 1/1, reaching up to the highest Ag(I) adsorbance of 533 mg.g(-1) at the oxidant/monomer ratio of 1/1. The sorption process fits the pseudosecond-order kinetics. The sorption is rapid because both the adsorbance and adsorptivity within 30 min reach up to 76% of the final values. The initial sorption rate of silver ions obtained from the pseudosecond-order equation is 12.9 mg.g(-1).min(-1). The highest adsorptivity of silver ions is up to 99.1%. The optimal solution pH for Ag(I) sorption is around 5.0. The sorption mechanism may include the chelation and redox reaction between Ag(I) ions and amine/imine groups on the PoPD chains. Similarly, the microparticles also have powerful Hg(II) adsorbability with 96.7% adsorptivity at an initial Hg(II) concentration of 4 mM. Competitive sorption between Ag(I) and Hg(II) in their mixture solution onto the microparticles was studied, exhibiting a preferential sorption toward Ag(I). The microparticles as a cost-effective sorbent demonstrate a promising application in the removal and even recovery of heavy-metal ions from wastewater. The PoPD/Ag nanocomposites possess (1) high Ag content of 34.8 wt %, (2) small diameter of Ag nanoparticles of around 10-20 nm, (3) narrow size distribution, (4) intrinsic electrical conductivity that is much higher than that of original PoPD microparticles without Ag.

Morphology, Electrical, and Rheological Properties of Silane‐Modified Silver Nanowire/Polymer Composites

“…Figure 3(a) presents XPS spectra of the ex situ and in situ silane-modified AgNw/epoxy composites which appeared at 103 (Si 2p), 154 (Si 2s), 285 (C 1s), 368 (Ag 3d), 400 (N1s), and 531 eV(O 1s), respectively. [49] Figure 3(b) presents the Ag 3d peaks appeared the same locations at 367.8 and 373.8 eV for both in situ and ex situ method, hence AgNws are metallic state (Ag 0 ) [50,51] without chemical bonding. Figure 3(c) presents the N1s peaks at 398.9 (in situ) and 399.9.0 eV (ex situ) respond respectively to ÀNHÀ and ÀNH 2 groups.…”

Amorphous and ordered organosilicas functionalized with amine groups as sorbents of platinum (II) ions

“…Fig. 7 Adsorption isotherms of Pt(II) for the samples studied Additionally, it was stated that for unloaded M4 the XPS spectra of N1s region are characterized by two peaks at 399.1 and 401.4 eV, which corresponds to -NH-and -NH 2 groups (Li et al 2009). On the other hand, for Pt loaded M4 (Fig.…”

Redox Sorption and Recovery of Silver Ions as Silver Nanocrystals on Poly(aniline‐co‐5‐sulfo‐2‐anisidine) Nanosorbents

“…Evidence from cross-polarizing microscopy: Considering that a great difference between the crystalline ordered structures of Ag nanocrystals and the non-crystalline copolymer nanograins revealed by X-ray diffraction in Figure 9, crosspolarizing microscopy is more suitable to observe the ordered Ag nanocrystals in the amorphous unordered copolymer nanograins than scanning and transmission electron microscopy. [20] As shown in Figure 10, compared with wholly black view of the pure nanograins without adsorbing Ag I ions, the views of the Ag-loaded nanograins become brighter with increasing Ag I concentration or sorption time. Apparently, the bright points and zones imply the presence of anisotropically ordered Ag nanocrystals and their thin aggregates in the almost optically isotropic nanograins because, although the Ag reduced by the copolymer nanograins is in the form of anisotropically ordered crystals, [20] the crystals would not transmit the cross-polarized light if their size and thickness were much larger than 100 nm.…”

“…poly(o-phenylenediamine) 50 100 5.4 540 10 400 7.4 285 k = 0.119 [20] poly www.chemeurj.org pseudo-first-order model with a correlation coefficient of 0.9897. The pseudo-second-order model is based on the assumption that the chemical sorption behavior between adsorbent and adsorbate over the whole range of sorption mechanism is a rate-controlling step, [25] which means that the sorption mechanism of Ag I on the grainy nanosorbents is chemically reactive sorption including redox, chelation, and ion exchange.…”

“…The amino and imino groups on the polyaniline chains have strong chelating ability with various metal ions, [20][21][22][23] and chelation sorption is one of the most important sorption mechanisms. Such chelation sorption between AN/SA copolymer nanograins and Ag I ions is depicted in Scheme 1.…”