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Novel Process for Simultaneous Removal of NOx and SO2 from Simulated Flue Gas by Using a Sustainable Ag(I)/Ag(II) Redox Mediator
No full textThe objective of this work is to develop a sustainable process
for simultaneous removal of waste gases such as NO, NO2,
and SO2 by an electrochemically generated Ag(I)/Ag(II) redox
mediator system. High removal efficiency was achieved for NO
and SO2 by the wet scrubbing method at room temperature
and atmospheric pressure. This removal is achieved through
oxidation and absorption by contacting the gaseous stream with
redox mediator ions that offer specific or selective solubility
for the solute gases to be recovered in a wet scrubber. The
process parameters such as gas velocity, liquid velocity, Ag(I)
concentration, and HNO3 concentration were investigated to
explore the possibility of complete removal of waste gases. The
Ag(I)/Ag(II)-based mediated electrochemical oxidation
process proved to be quite effective for simultaneous removal
of NO, NOx, and SO2 from the simulated flue gas mixtures
containing NO and SO2 over a wide concentration range of
100-400 ppm. Studies were carried out with individual
gas components for the mixture, and the effect of input NO
and input SO2 concentrations on the NOx and SO2 removal
efficiencies at 20 °C was examined. Complete oxidation of NO
to NO2 with 100% NO removal efficiency and 92% NOx
removal efficiency was achieved along with 100% SO2 removal
efficiency, highlighting a potentially far greater efficiency of
the Ag(I)/Ag(II)-based system in functionality and selectivity.
Active research work in this direction is anticipated in the near
future
PEDOT/Palladium composite material: synthesis, characterization and application to simultaneous determination of dopamine and uric acid
No full textPalladium (Pd) incorporated poly (3,4-ethylenedioxythiophene)
(PEDOT) films were synthesized
through an electrochemical route and characterized using
scanning electron microscopy (SEM) and atomic force
microscopy (AFM). The electrochemical study showed
catalytic oxidation of dopamine (DA) with optimum
loading of Pd. DA and uric acid (UA) were detected using
differential pulse voltammetry (DPV). In the presence of
ascorbic acid (AA), DA-AA showed peak potential separation
of 0.19 V while 0.32 V between UA-AA on Pdincorporated
PEDOT. These peak separations are large
enough for sensing DA and UA in the presence of AA. DA
and UA exhibited linear calibration plots and the minimum
detection limits are 0.5 and 7 lM respectively. On Pd-
PEDOT, the reversibility of DA oxidation was found to
increase compared to bare glassy carbon electrode (GCE)
and PEDOT modified GCE. Fouling effects were also
found to be minimal making Pd-PEDOT composite suitable
for electroanalysis
Studies on chromium/aluminium-doped manganese spinel as cathode materials for lithium-ion batteries—A novel chelated sol–gel synthesis
No full textNanoparticles of LiMn2O4, LiCrxMn2−xO4 and LiAlxMn2−xO4 (x = 0.0–0.4) have been synthesized
using either phthalic acid or fumaric acid as chelating agents, for the first time, through
sol–gel method. These materials were characterized by thermo gravimetric analysis (TGA),
Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron
microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical performance
of these materials was assessed to use as cathode material for lithium-ion batteries.
XRD patterns ascertain the formation of the phase pure compounds. SEM images indicate
the nanosized nature of the particles with uniform morphology and texture. Doping of Cr/Al
with the spinel resulted to increased agglomeration. Cr-doped spinel delivers 138mAh/g
while Al-doped spinel exhibit 139mAh/g at the first cycle reversible capacity. Doping of 0.1
Al spinel cells shows superior performance over the tested 10 cycles in terms of low capacity
fading. Co-doped Li3−xCoxN (x = 0.40) has also been synthesized by solid-state method to
use as anode material for lithium-ion batteries. Cells were assembled with the synthesized
spinel cathodes and these cells delivered stable specific capacity with high columbic efficiency.
Cyclic voltammograms of both spinels exhibit good oxidation and reduction peaks
for Mn3+/Mn4+, Cr3+/Cr4+ and Al+/Al3+
Preparation of iron-deposited graphite surface for application as cathode material during electrochemical vat-dyeing process
No full textIron-deposited graphite surfaces were prepared, characterized and employed as cathode materials for
electrochemical vat-dyeing process containing very low concentration of sodium dithionite. The electrodeposition,
in presence of ammonium thiocyanate and gelatin or animal glue as binding additives,
were found to give finer iron deposits for improved electrochemical dyeing application. The electrodepositswere
characterized using scanning electron microscopy, electron-dispersiveX-ray spectroscopy and
X-ray diffraction methods, before and after electrochemical dyeing process. The electrochemical activity
of the iron-deposited graphite electrodes always stored in water seems to depend on the surface-bound
Fe3+/Fe2+ redox species. Vat dyes like C.I. Vat Violet 1, C.I. Vat Green 1 and C.I. Vat Blue 4 could be efficiently
dyed employing these above electrode materials. The colour intensity and washing fastness of the dyed
fabrics were found to be equal with conventionally dyed fabrics. The electrodes could also be reused for
the dyeing process
Ruthenium(II)-mediated synthesis of conducting polyaniline (PAni): A novel route for PAni–RuO2 composite
No full textIn this communication we describe the unprecedented ruthenium(II)-mediated synthesis of polyaniline.
The synthesis enroutes via formation of a simple ruthenium(II)–tetraaniline complex which on
chemical oxidation with hydrogen peroxide in the presence of hydrochloric acid gives conducting
polyaniline–RuO2 composite. The reaction is novel in the way that both the metal center Ru(II) and the
coordinated aniline molecules of the intermediate complex 1 take part in the oxidation reaction to yield
polyaniline–ruthenium oxide hybrid
A new composite anode, Fe–Cu–Si/C for lithium ion battery
No full textA new anode composite material comprising Fe, Cu and Si in conjunction with graphite has been obtained through high energy ball milling
(HEBM) technique. The X-ray diffraction (XRD) analysis predicts that the milled composite particles remain in the elemental state and the scanning
electron microscope (SEM) pictures show that the electrode annealed at 200 ◦C consists of well-defined aggregate particulates with interspaces.
The composite electrode exhibits high initial discharge and charge capacity of 809 and 464 mAh g−1, respectively with a sustainable reversible
capacity >385 mAh g−1 at 30th cycle and maintains high coulombic efficiency >95% after 4th cycle. As the annealing temperature is changed from
110 to >150 ◦C, the irreversible capacity increased from 158 to 340 mAh g−1
Heavy metal removal from copper smelting effluent using electrochemical cylindrical flow reactor
No full textThe purpose of this study is mainly to evaluate the performance of the continuous recirculation flow cell at low current density and pH (the
pH at which the effluents are available) in removing heavy metals from copper smelting effluent by cathodic reduction. During the electrolysis at
different pH, % removal of heavy metals removal, energy consumption and heterogeneous reaction rate constants were investigated at given flow
rate and current density on the selected industrial effluent. The overall specific energy consumption at the pH 0.64 was observed to be lowest,
which is 10.99 kWh/kg of heavy metal removal
Template synthesized high conducting silver chloride nanoplates
No full textSilver chloride was synthesized using a water-soluble polyelectrolyte as a capping agent. X-ray diffraction (XRD), scanning electron
microscopy (SEM), atomic force microscopy (AFM) and differential scanning calorimetry (DSC) were employed to characterize morphology,
structure and phase transition of as-prepared silver chloride. XRD, SEM and AFM confirms the formation of nanoplates of AgCl with a polygonal
edge of diameter ∼250–300 nm. These nanoplates are found to be thermally stable up to its melting temperature (∼455 °C) with smaller value of
melting enthalpy and higher room temperature conductivity values compared to pristine silver chloride (σNanoplate /σPristine≈104)
Catastrophic corrosion failures and corrosion management
No full textNatural calamities like cyclones and earthquakes have a sudden and devastating impact. On the other hand, the losses caused by corrosion often have a tantamount but inconspicuous impact. Several catastrophic failures are discussed, and sound corrosion management practices are outline
Short communication On microalgal settlements and the sluggish development of marine biofouling in Port Blair waters,Andamans.
No full textSettlement of microalgae was investigated on Perspex1, aluminium and zinc coupons immersed in Port Blair Bay waters
for over 3 months. Commencement of fouling was exceptionally slow, and few microalgae were found until 14 days.
Settlement occurred thereafter, and 47 microalgal species contributed to the fouling. The dominant forms belonged to
the genera Navicula and Nitzschia, whereas Coscinodiscus eccentricus, Gyrosigma balticum and Trichodesmium
erythraeum also accounted for high proportions of the settlements. The dominance of Nitzschia sigma was particularly
marked on zinc coupons, suggesting an ability by the organism to resist toxicity. Settlement of both centric and pennate
diatoms was observed in the early and mid periods, and absolute dominance of the pennate diatoms subsequently. The
foulingmass was low even after 103 days, and it is speculated that strong ultraviolet radiation might be the prime reason
for the sluggish development of marine biofouling in these oceanic island waters