Poly(butylene adipate-co-terephthalate) (PBAT), a promising biodegradable aliphatic-aromatic copolyester material, can be applied as an alternative material to reduce the adverse effects of conventional plastics. However, the degradation of PBAT plastics in soil is time-consuming, and effective PBAT-degrading microorganisms have rarely been reported. In this study, the biodegradation properties of PBAT by an elite fungal strain and related mechanisms were elucidated. Four PBAT-degrading fungal strains were isolated from farmland soils, and Purpureocillium lilacinum strain BA1S showed a prominent degradation rate. It decomposed approximately 15 wt.

Plastic films are widely used in current agricultural practices; however, most mulch films used are discarded and buried in the land after harvest, having adverse environmental impacts. To solve this environmental problem, the demand for biodegradable mulch has been increasing in recent years. Polybutylene succinate-co-adipate (PBSA) is a biodegradable polymer with good ductility and can be used for packaging and mulching. In this study, we isolated two elite fungal strains for PBSA degradation from farmlands, i.e., Aspergillus fumigatus L30 and Aspergillus terreus HC, and the latter showed better degradation ability than the former. It is noteworthy that biodegradation of PBSA by A. terreus is reported for the first time, which revealed unique characteristics. In the soil burial test, even the soil with relatively poor degradation ability could be improved by the addition of elite fungal mycelia. In substrate specificity analyses of soil samples, PBSA could induce the synthesis of lipolytic enzymes of indigenous microbes to degrade substrates with medium and long carbon chains in soil. Furthermore, PBSA residues or fungal mycelia supplementation in soils had no adverse effect on the seed germination rate, seedling growth, or mature plant weight of the test green leafy vegetable. Taken together, the results of this study not only advance our understanding of the biodegradation of PBSA films by filamentous fungi but also provide insight into improving the efficiency of biodegradation in soil environments.

Reduced graphene oxides have been prepared via controllably thermal and chemical reduction processes. The structure, surface chemistry and electrochemical behaviors of reduced graphene oxides are investigated by Raman spectroscopy, N-2 adsorption, temperature-programmed desorption, Fourier-transform Infrared spectroscopy, X-ray photoelectron spectroscopy, as well as charge/discharge measurements. The enhanced reversible capacity of reduced graphene oxides is attributed to specific functionalities rather than to exceptional large specific surface area or structure defect. The contributed capacities at potential higher than 1.5 V and in region of 0.8-1.5 V are attributed dominantly to phenol groups and cyclic edge ether groups, respectively. These findings may be beneficial to the material design of graphene-based anode materials with high energy density. (C) 2013 Elsevier B.V. All rights reserved.

Reduced graphene materials were prepared by different reducing approaches of graphite oxide, including chemical reduction and thermal reduction. In this study, the characteristics of reduced graphene and the lithium storage behavior of graphene-based anodes were investigated by SEM, BET, TPD, FTIR as well as C/D tests and Raman measurements. The electrochemical behaviors of reduced graphene materials were sensitive to reduction process, of which the capacity varying from 717 to 230 mAh/g. The enhanced capacity should not be predominantly attributed to exceptional high surface area and enlarged d-spacing, but rather more possible for existence of functional groups along with structure defects.

In this study, we investigate the characteristics and electrochemical properties of graphene nanosheets derived from chemical-thermal exfoliation processes of SFG44 synthetic graphite (SFG44-GNS). The characterizations and electrochemical measurements were carried out by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, BET, Raman, rate capability as well as cycling tests and AC impedance. The as-synthesized SFG44-GNS with larger d-spacing of 0.3407 nm exhibits reversible capacity of 626 mAh/g and good rate capability of ~ 300 mAh/g at 2C rate, which are superior to those of graphite anode. The enhanced electrochemical performance of GNS anode was resulted from larger d-spacing, lower impedance in the interface and enhanced pore volume. The results indicate that graphene-based material is a good candidate for HEV/EV application.

Unpurified carbon nanotubes exhibit enhanced electromagnetic absorption at radiofrequencies and the underlying mechanism involves the polarization of odd alternate p-radicals encapsulated in carbonaceous impurities. The intertube junctions behave as capacitive elements and are found capable of absorbing radiation in the low frequency domain.

NH3·H2O treated carbon nanotubes form an electric double layer in the presence of an electric field and tube wetting is therefore improved. Proton concentration on tube surfaces can be further modulated by a Lorentz force and is verified by multi-transition of an hydrophobic into an hydrophilic phase.

MnFe2O4 nanocrystallites have been found to exhibit capacitive characteristics in organic electrolyte containing 1 M LiPF6 in a mixture of ethyl carbonate + ethylene methyl carbonate up to 4.5 V vs Li/Li+. The ferrite exhibits a capacitance of 126 F/g-MnFe2O4, and the symmetric-cell demonstrated a stable working voltage window of 2.5 V. In situ synchrotron spectroscopic analysis identified valence change at Mn-ion sites and a very small (< 1%) extent of lattice variation, in response to Li-ion insertion/extraction. Compared with other pseudocapacitive oxides with Li-ion electrolytes, the present ferrite system has demonstrated superior cycling stability under high-rate cycling. (c) 2007 The Electrochemical Society.

The electrochemical mechanism leading to the pseudocapacitance of MnFe2O4 in aqueous electrolyte solutions has been investigated by, in addition to electrochemical characterization, synchrotron X- ray absorption near-edge spectroscopy (XANES) and X- ray diffraction (XRD) analyses using KCl solution as the model electrolyte. The ferrite crystallites, prepared by a solution method, contain Mn and Fe ions randomly distributed over the tetrahedral and octahedral sites of the spinel structure and exhibit an average capacitance exceeding 100 F/g- ferrite. Based on the data from the in situ XANES and XRD measurements and open-circuit- potential dependence on solution pH, it is concluded that the pseudocapacitance of MnFe2O4 involves charge transfer at both the Mn- and Fe- ion sites, balanced by insertion/ extraction of proton into/ from the lattice. In addition, compared with MnO2 . nH(2)O electrode, the ferrite exhibits a far reduced, by similar to 90%, lattice expansion upon cycling. (c) 2006 The Electrochemical Society.

MnFe2O4–carbon black (CB) composite powders synthesized by a co-precipitation method have been characterized and optimized for their electrochemical properties for supercapacitor applications. The composite shows pseudocapacitance in electrolyte solutions of alkali and alkaline chlorides, sulfates and sulfites. For the chlorides and sulfates electrolytes, the pseudocapacitance has been identified, by in situ X-ray absorption near-edge spectroscopy study, to involve charge-transfer at both the Mn and Fe sites of the ferrite. In 1M NaCl(aq), the composite electrode exhibits an operating potential window of 1.0V with a maximum leakage current of 0.3mAF−1, and it exhibits far superior cycling stability to amorphous MnO2 electrode. Both the specific capacitance and self-discharge behavior of the composite electrode depend strongly on the composite composition. The optimum capacitance occurs at ferrite:CB weight ratio of 7:3, which gives reduced self-discharge rate as compared with CB. The composite electrode also demonstrates capability of high-power delivery.

Pseudocapacitive charge-storage reaction of MnO(2)(.)nH(2)O in several aqueous alkali and alkaline salts solutions, including LiCl, NaCl, KCl, CsCl, and CaCl2, has been studied on fine-grained MnO(2)(.)nH(2)O thin films and particles which possess the epsilon-MnO2-type crystal structure. In situ synchrotron X-ray diffraction analysis shows that charge transfer at Mn sites upon reduction/oxidation of MnO(2.)nH(2)O is balanced by bulk insertion/extraction of the solution cations into/from the oxide structure, which causes reversible expansion and shrinkage in lattice spacing of the oxide during charge/discharge cycles. Electrochemical quartz-crystal microbalance and X-ray photoelectron spectroscopy data further indicate that H3O+ plays the predominant (> 60%) role in all cases, while the extent of participation of alkali cations first decreases and then increases with ionic size. The charge-storage reaction can be summarized as: Mn (IV)O(2)(.)nH(2)O + delta e(-) + delta(1 - f ) H3O+ + delta fM(+) reversible arrow (H3O)(delta(1-f))M-delta f [Mn (III)(delta)Mn(IV)(1-delta)]O(2)(.)nH(2)O, where M+ is alkali cation.

Ferrites including MFe2O4 where M = Mn, Fe, Co, or Ni have been synthesized by solution methods and tested for their capacitive behaviors in aqueous NaCl solution. MnFe2O4 has been found to exhibit unusually large capacitances, while the other ferrites do not. The results indicate unique pseudocapacitive property associated with the Mn+2 ions at the tetrahedral sites in the spinel structure. The pseudocapacitance was observed only for crystalline, rather than amorphous, MnFe2O4 phase, which has exhibited specific capacitances of > 100 F/g and high-power delivering capabilities of > 10 kW/ kg. (c) 2005 The Electrochemical Society.

The capacitance mechanisms of magnetite (Fe3O4) electrochemical capacitor in Na2SO3, Na2SO4, and KOH aqueous solutions have been investigated by electrochemical quartz-crystal microbalance analysis, along with cyclic voltammetry and X-ray photoelectron spectroscopy. The oxide thin-film electrode was prepared by an electroplating method, and exhibits a capacitance of similar to 170, 25, and 3 F/g in 1.0 M Na2SO3 (aq), Na2SO4 (aq), and KOH (aq), respectively. Strong specific adsorption of the anion species was evidenced in all solutions. Experimental results indicate that, in Na2SO3 (aq), the capacitive current of magnetite electrode originates from the combination of electric double-layer capacitance (EDLC) and the pseudocapacitance that involves successive reduction of the specifically adsorbed sulfite anions, from SO32- through, e. g., S2-, and vice versa. In Na2SO4 (aq), the current is due entirely to EDLC. Furthermore, due to the specific adsorption behavior, magnetite exhibits high EDLC, > 30 mu F/cm(2), in both Na2SO3 and Na2SO4 solutions. The lowest capacitance of magnetite was observed in KOH, which is attributed to the formation of an insulating layer on the magnetite surface. (c) 2005 The Electrochemical Society. [DOI: 10.1149/1.2131820] All rights reserved.