Study of congo red adsorption on the polyaniline and polypyrrole

Polyaniline (PANI) and polypyrrole (PPY) were synthesized via in situ chemical oxidative polymerization and are used as adsorbents for removal of Congo Red (CR) dye from aqueous solution. The effects of various experimental parameters including pH of the solution, contact time, initial concentration, adsorbent dosage, and temperature on adsorption of CR by PANI and PPY were systematically investigated. The experimental results showed that the adsorption efficiency was increased with contact time and adsorbent dosage. The maximum removal efficiency was found after 45 minutes of solid/liquid contact with adsorbent doses of 0.4 and 1.73?g/L for PANI and PPY, respectively. The kinetic data were best fitted by the pseudo-second-order model. The adsorption equilibrium results were well fitted by the Langmuir isotherm model. These results suggest that the PANI and PPY can be used as alternative adsorbents for the treatment of wastewaters containing dyes.     

Optimization of Polypyrrole Chemical Synthesis by Heat Flow Reaction Calorimetry

Chemical polymerization of pyrrole (Py) was carried out in a reaction calorimeter by using FeCl₃ or CuCl₂ as an oxidant in an acetonitrile medium. The formation heat of polypyrrole (PPy), determined under a wide range of reactant concentrations and reaction temperatures, is directly related to the PPy yields and to the degree of polymerization. Due to the negative values of both the entropy and enthalpy of the reaction the gravimetric yield is inversely related to the temperature and directly to the Py concentration. The yields to the PPy and the related reaction heats, are close to zero when the ceiling temperatures are reached (T_ceil=348 K for Fe-doped and T_ceil=313 K for Cu-doped PPys). It was observed that a ceiling concentration corresponds to each ceiling temperature and only light oligomers are formed if Py concentration is too low. The electric conductivity values of the products were also determined and a direct relationship to the yields was found as well. The highest electric conductivity value (C=0.6 S cm^–1) was related to the PPy fresh synthesized from a 0.017 M Py solution.This revised version was published online in November 2005 with corrections to the Cover Date.     

Polypyrrole core/polyacrolein shell latex for protein immobilization

The redox polymerization of pyrrole, with ferric chloride as oxidant, carried out in the presence of polyvinylpyrrolidone (PVP), yielded polypyrrole latex particles. The polypyrrole latex was used, as seed, for the radical polymerization of acrolein. The resulting polypyrrole core/polyacrolein shell latex (poly(P/A)) was suitable for immobilization of up to 11 mg of human serum albumin (HSA) and/or 33 mg of human gamma globulin (G) per 1 g of latex particles.The work was supported by the KBN Grant 2 0624 91 01     

A Two-Dimensional Mesoporous Polypyrrole–Graphene Oxide Heterostructure as a Dual-Functional Ion Redistributor for Dendrite-Free Lithium Metal Anodes

Guiding the lithium ion (Li-ion) transport for homogeneous, dispersive distribution is crucial for dendrite-free Li anodes with high current density and long-term cyclability, but remains challenging for the unavailable well-designed nanostructures. Herein, we propose a two-dimensional (2D) heterostructure composed of defective graphene oxide (GO) clipped on mesoporous polypyrrole (mPPy) as a dual-functional Li-ion redistributor to regulate the stepwise Li-ion distribution and Li deposition for extremely stable, dendrite-free Li anodes. Owing to the synergy between the Li-ion transport nanochannels of mPPy and the Li-ion nanosieves of defective GO, the 2D mPPy-GO heterostructure achieves ultralong cycling stability (1000 cycles), even tests at 0 and 50 °C, and an ultralow overpotential of 70 mV at a high current density of 10.0 mA cm⁻², outperforming most reported Li anodes. Furthermore, mPPy-GO-Li/LiCoO₂ full batteries demonstrate remarkably enhanced performance with a capacity retention of >90 % after 450 cycles. Therefore, this work opens many opportunities for creating 2D heterostructures for high-energy-density Li metal batteries.     

在水溶液中电化学反应制备大面积聚吡咯膜

以不锈钢为电极,在吡咯水溶液中,经电化学聚合制备了大面积的聚吡咯薄膜。研究了反应电流密度、反应温度、对阴离子种类和浓度等因素对成膜性能及电导率的影响。选择合适的反应条件,可得到电导率为120Scm~(-1)、抗拉强度46MPA、模量为1.75GPA的聚吡咯膜。     

A New Photoluminescent Conjugated Poly(1‐hexyl‐3,4‐dimethyl‐2,5‐pyrrolylene): Synthesis,Properties and Characterization

Oxidative coupling reaction of 1‐hexyl–3,4‐dimethylpyrrole affords a conjugated conducting poly(1‐hexyl‐3,4‐dimethyl‐2,5‐pyrrolylene) (PHDP), which is completely soluble in common organic solvents. The luminescence of PHDP is comparable to that of poly(N‐vinylcarbazole) (PVK), which has been widely used in electroluminescence devices. The quantum efficiency of PHDP is 2.5 times higher than that of PVK. A rationalization is presented relating the conductivity of PHDP to its polymer structure.     

Heteropolyacids dispersed within a polymer matrix as a new catalytic systems with controlled oxidative-reductive and acid-base active centers

Polymer support such as polypyrrole was selected as a matrix for heteropolyacid H₅PMo₁₀V₂O₄₀ in an attempt to prepare heterogeneous catalysts containing two different active centers: protons and transition metal ions. Exchanging protons from heteropolyanions dispersed in polymer matrix into ferric or ferrous ions cause the modifications of their catalytic properties. It is manifested by decrease of activity of acid-base centers and increase of activity of oxidative-reductive centers. Oxidation state of iron in all samples before and after catalytic reaction is the same (Fe(III)), but their structure is not similar. For catalysts doped with ferric ions the structural order is much more pronounced than for these doped with ferrous ions.     

Preparation of carbon-aerogel polypyrrole composite for desalination by hybrid capacitive desalination method

Capacitive Deionization (CDI) is an emerging technology with great potential applications. Most researchers view it as a viable water treatment alternative to reverse osmosis. This research reports the preparation and application of a carbon aerogel polypyrrole (CA-PPy) composite for the desalination of NaCl solution by the hybrid CDI method. The carbon aerogel (CA) was prepared from a Resorcinol / Formaldehyde precursor by the sol–gel method. The aerogel obtained from the sol–gel was then pyrolysed in a tube furnace to form CA. Polypyrrole (PPy) was prepared by the Oxidative chemical polymerisation of pyrrole, ferric chloride hexahydrate (oxidant), and sodium dodecyl sulfate (dopant). A composite of CA and PPy was then prepared and used to modify carbon electrodes. The CA-PPy composite was characterised to verify its composition, morphology, thermal properties, and functional groups. The electrochemical properties of the material were determined by Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) tests. The electrochemical tests were done using a GAMRY potentiostat electrochemical workstation, a 1.0 M KCl was used as the electrolyte, and the applied potential window was (-0.2 to + 0.6) V for the CV test. The EIS test was done with the same concentration of KCl electrolyte at an applied potential of 0.22 V and at a frequency range of (0.1 – 100, 000) Hz. The optimal specific capacitance of the CA is 115F/g, and that of the composite is 360.1F/g, they were both obtained at a scan rate of 5 mV/s. The CDI desalination study of the CA-PPy composite showed a salt adsorption capacity (SAC) of 10.10 mg/g (300 mg/L NaCl solution) – 15.7 mg/g (800 mg/L NaCl solution) at 1.2 V applied voltage. The salt recovery efficiency of the electrode material in the 300 mg/L solution is 27 %, in the 500 mg/L solution, it is 20.12 %, and in the 800 mg/L solution, it is 15.41 %. The electrode material also showed good electrochemical stability after nine cycles of ion adsorption/desorption study.