Abstract: In this study a neural network (NN) was proposed to
predict the sorption of binary mixture of copper-cobalt ions into
clinoptilolite as ion-exchanger. The configuration of the
backpropagation neural network giving the smallest mean square
error was three-layer NN with tangent sigmoid transfer function at
hidden layer with 10 neurons, linear transfer function at output layer
and Levenberg-Marquardt backpropagation training algorithm.
Experiments have been carried out in the batch reactor to obtain
equilibrium data of the individual sorption and the mixture of coppercobalt
ions. The obtained modeling results have shown that the used
of neural network has better adjusted the equilibrium data of the
binary system when compared with the conventional sorption
isotherm models.
Abstract: The remediation of water resources pollution in
developing countries requires the application of alternative
sustainable cheaper and efficient end-of-pipe wastewater treatment
technologies. The feasibility of use of South African cheap and
abundant pine tree (Pinus patula) sawdust for development of lowcost
AC of comparable quality to expensive commercial ACs in the
abatement of water pollution was investigated. AC was developed at
optimized two-stage N2-superheated steam activation conditions in a
fixed bed reactor, and characterized for proximate and ultimate
properties, N2-BET surface area, pore size distribution, SEM, pHPZC
and FTIR. The sawdust pyrolysis activation energy was evaluated by
TGA. Results indicated that the chars prepared at 800oC and 2hrs
were suitable for development of better quality AC at 800oC and 47%
burn-off having BET surface area (1086m2/g), micropore volume
(0.26cm3/g), and mesopore volume (0.43cm3/g) comparable to
expensive commercial ACs, and suitable for water contaminants
removal. The developed AC showed basic surface functionality at
pHPZC at 10.3, and a phenol adsorption capacity that was higher than
that of commercial Norit (RO 0.8) AC. Thus, it is feasible to develop
better quality low-cost AC from (Pinus patula) sawdust using twostage
N2-steam activation in fixed-bed reactor.
Abstract: The effects of equilibrium time, solution pH, and
sorption temperature of cationic methylene blue (MB) adsorption on nanoporous metallosilicoaluminophosphate ZnAPSO-34 was studied
using a batch equilibration method. UV–VIS spectroscopy was used
to obtain the adsorption isotherms at 20° C. The optimum period for
adsorption was 300 min. However, MB removal increased from
81,82 % to 94,81 %. The equilibrium adsorption data was analyzed
by using Langmuir, Freundlich and Temkin isotherm models.
Langmuir isotherm was found to be the better-fitting model and the process followed pseudo second–order kinetics. The results showed
that ZnAPSO-34 could be employed as an effective material and could be an attractive alternative for the removal of dyes and colors
from aqueous solutions.
Abstract: This paper present a new way to find the aerodynamic
characteristic equation of missile for the numerical trajectories
prediction more accurate. The goal is to obtain the polynomial
equation based on two missile characteristic parameters, angle of
attack (α ) and flight speed (ν ). First, the understudied missile is
modeled and used for flow computational model to compute
aerodynamic force and moment. Assume that performance range of
understudied missile where range -10< α
Abstract: The adsorption of simulated aqueous solution containing textile remazol reactive dye, namely Red 3BS by palm shell activated carbon (PSAC) as adsorbent was carried out using Response Surface Methodology (RSM). A Box-Behnken design in three most important operating variables; initial dye concentration, dosage of adsorbent and speed of impeller was employed for experimental design and optimization of results. The significance of independent variables and their interactions were tested by means of the analysis of variance (ANOVA) with 95% confidence limits. Model indicated that with the increasing of dosage and speed give the result of removal up to 90% with the capacity uptake more than 7 mg/g. High regression coefficient between the variables and the response (R-Sq = 93.9%) showed of good evaluation of experimental data by polynomial regression model.
Abstract: Adsorption of Toluidine blue dye from aqueous solutions onto Neem Leaf Powder (NLP) has been investigated. The surface characterization of this natural material was examined by Particle size analysis, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD). The effects of process parameters such as initial concentration, pH, temperature and contact duration on the adsorption capacities have been evaluated, in which pH has been found to be most effective parameter among all. The data were analyzed using the Langmuir and Freundlich for explaining the equilibrium characteristics of adsorption. And kinetic models like pseudo first- order, second-order model and Elovich equation were utilized to describe the kinetic data. The experimental data were well fitted with Langmuir adsorption isotherm model and pseudo second order kinetic model. The thermodynamic parameters, such as Free energy of adsorption (AG"), enthalpy change (AH') and entropy change (AS°) were also determined and evaluated.
Abstract: Palm shell obtained from coastal part of southern
India was studied for the removal for the adsorption of Hg (II) ions.
Batch adsorption experiments were carried out as a function of pH,
concentration of Hg (II) ions, time, temperature and adsorbent dose.
Maximum removal was seen in the range pH 4.0- pH 7.0. The palm
shell powder used as adsorbent was characterized for its surface area,
SEM, PXRD, FTIR, ion exchange capacity, moisture content, and
bulk density, soluble content in water and acid and pH. The
experimental results were analyzed using Langmuir I, II, III, IV and
Freundlich adsorption isotherms. The batch sorption kinetics was
studied for the first order reversible reaction, pseudo first order;
pseudo second order reaction and the intra-particle diffusion reaction.
The biomass was successfully used for removal Hg (II) from
synthetic and industrial effluents and the technique appears
industrially applicable and viable.
Abstract: Three alumina-supported Pt-Sn catalysts have been
prepared by means of co-impregnation and characterized by XRD and
N2 adsorption. The influence of catalyst composition and reaction
conditions on the conversion and selectivity were investigated in the
hydrogenation of acetic acid in an isothermal integral fixed bed
reactor. The experiments were performed on the temperature interval
468-548 K, liquid hourly space velocity (LHSV) of 0.3-0.7h-1,
pressures between 1.0 and 5.0Mpa. A good compromise of
0.75%Pt-1.5%Sn can act as an optimized acetic acid hydrogenation
catalyst, and the conversion and selectivity can be tuned through the
variation of reaction conditions.
Abstract: In this study, the effect of greywater irrigation on airwater interfacial area is investigated. Several soil column experiments were conducted for different greywater irrigation to develop the pressure-saturation curves. Surface tension was measured for different greywater concentration and fitted for Gibbs adsorption equation. Pressure-saturation curves show that the reduction of capillary rise stops when it reaches its critical micelle concentration (CMC). A simple theory is derived from pressure-saturation curves for calculating air-water interfacial area in porous medium during greywater irrigation by introducing a term 'hydraulic radius' for the pores. This term diminishes any effect of pore shapes on the air-water interfacial area. The air-water interfacial area was calculated using the pressure-saturation curves and found that it decreases with increasing moisture content. But no significant effect was observed on air-water interfacial area for different greywater irrigation. A maximum of 10% variation in interfacial area was observed at the residual saturation zone.
Abstract: Many non-conventional adsorbent have been studied
as economic alternative to commercial activated carbon and mostly
agricultural waste have been introduced such as rubber leaf powder
and hazelnut shell. Microwave Incinerated Rice Husk Ash
(MIRHA), produced from the rice husk is one of the low-cost
materials that were used as adsorbent of heavy metal. The aim of
this research was to study the feasibility of using MIRHA500 and
MIRHA800 as adsorbent for the removal of Cu(II) metal ions from
aqueous solutions by the batch studies. The adsorption of Cu(II) into
MIRHA500 and MIRH800 favors Fruendlich isotherm and imply
pseudo – kinetic second order which applied chemisorptions
Abstract: Removal of PCP by a system combining
biodegradation by biofilm and adsorption was investigated here.
Three studies were conducted employing batch tests, sequencing
batch reactor (SBR) and continuous biofilm activated carbon
column reactor (BACCOR). The combination of biofilm-GAC
batch process removed about 30% more PCP than GAC adsorption
alone. For the SBR processes, both the suspended and attached
biomass could remove more than 90% of the PCP after
acclimatisation. BACCOR was able to remove more than 98% of
PCP-Na at concentrations ranging from 10 to 100 mg/L, at empty
bed contact time (EBCT) ranging from 0.75 to 4 hours. Pure and
mixed cultures from BACCOR were tested for use of PCP as sole
carbon and energy source under aerobic conditions. The isolates
were able to degrade up to 42% of PCP under aerobic conditions in
pure cultures. However, mixed cultures were found able to degrade
more than 99% PCP indicating interdependence of species.
Abstract: In this work, we incorporated a quartic bond potential
into a coarse-grained bead-spring model to study lubricant adsorption
on a solid surface as well as depletion instability. The surface tension
density and the number density profiles were examined to verify the
solid-liquid and liquid-vapor interfaces during heat treatment. It was
found that both the liquid-vapor interfacial thickness and the
solid-vapor separation increase with the temperatureT* when T*is
below the phase transition temperature Tc
*. At high temperatures
(T*>Tc
*), the solid-vapor separation decreases gradually as the
temperature increases. In addition, we evaluated the lubricant weight
and bond loss profiles at different temperatures. It was observed that
the lubricant desorption is favored over decomposition and is the main
cause of the lubricant failure at the head disk interface in our
simulations.
Abstract: In the present work, we have developed a symmetric electrochemical capacitor based on the nanostructured iron oxide (Fe3O4)-activated carbon (AC) nanocomposite materials. The physical properties of the nanocomposites were characterized by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances of the composite electrode in 1.0 M Na2SO3 and 1.0 M Na2SO4 aqueous solutions were evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The composite electrode with 4 wt% of iron oxide nanomaterials exhibits the highest capacitance of 86 F/g. The experimental results clearly indicate that the incorporation of iron oxide nanomaterials at low concentration to the composite can improve the capacitive performance, mainly attributed to the contribution of the pseudocapacitance charge storage mechanism and the enhancement on the effective surface area of the electrode. Nevertheless, there is an optimum threshold on the amount of iron oxide that needs to be incorporated into the composite system. When this optimum threshold is exceeded, the capacitive performance of the electrode starts to deteriorate, as a result of the undesired particle aggregation, which is clearly indicated in the SEM analysis. The electrochemical performance of the composite electrode is found to be superior when Na2SO3 is used as the electrolyte, if compared to the Na2SO4 solution. It is believed that Fe3O4 nanoparticles can provide favourable surface adsorption sites for sulphite (SO3 2-) anions which act as catalysts for subsequent redox and intercalation reactions.
Abstract: Empirical force fields and density functional theory
(DFT) was used to study the binding energies and structures of
methylamine on the surface of activated carbons (ACs). This is a first
step in studying the adsorption of alkyl amines on the surface of
functionalized ACs. The force fields used were Dreiding (DFF),
Universal (UFF) and Compass (CFF) models. The generalized
gradient approximation with Perdew Wang 91 (PW91) functional
was used for DFT calculations. In addition to obtaining the aminecarboxylic
acid adsorption energies, the results were used to establish
reliability of the empirical models for these systems. CFF predicted a
binding energy of -9.227 (kcal/mol) which agreed with PW91 at -
13.17 (kcal/mol), compared to DFF 0 (kcal/mol) and UFF -0.72
(kcal/mol). However, the CFF binding energies for the amine to ester
and ketone disagreed with PW91 results. The structures obtained
from all models agreed with PW91 results.
Abstract: The lubricating properties of commercially available
mucins originating from different animal organs, namely bovine
submaxillary mucin (BSM) and porcine gastric mucin (PGM), have
been characterized at polymeric surfaces for biomedical applications.
Atomic force microscopy (AFM) and pin-on-disk tribometry have
been employed for tribological studies at nanoscale and macroscale
contacts, respectively. Polystyrene (PS) was employed to represent
‘rigid’ contacts, whereas poly(dimethylsiloxane) (PDMS) was
employed to represent ‘soft contacts’. To understand the lubricating
properties of mucins in correlation with the coverage on surfaces,
adsorption properties of mucins onto the polymeric substrates have
been characterized by means of optical waveguide light-mode
spectroscopy (OWLS). Both mucins showed facile adsorption onto
both polymeric substrates, but the lubricity was highly dependent
upon the pH change between 2 and 7.
Abstract: The production of activated carbon from low or zero cost of agricultural by-products or wastes has received great attention from academics and practitioners due to its economic and environmental benefits. In the production of bamboo furniture, a significant amount of bamboo waste is inevitably generated. Therefore, this research aimed to prepare activated carbons from bamboo furniture waste by chemical (KOH) activation and determine their properties and adsorption capacities for water treatment. The influence of carbonization time on the properties and adsorption capacities of activated carbons was also investigated. The finding showed that the bamboo-derived activated carbons had microporous characteristics. They exhibited high tendency for the reduction of impurities present in effluent water. Their adsorption capacities were comparable to the adsorption capacity of a commercial activated carbon regarding to the reduction in COD, TDS and turbidity of the effluent water.
Abstract: Mercury adsorption on soil was investigated at
different ionic strengths using Ca(NO3)2 as a background electrolyte.
Results fitted the Langmuir equation and the adsorption isotherms
reached a plateau at higher equilibrium concentrations. Increasing
ionic strength decreased the sorption of mercury, due to the
competition of Ca ions for the sorption sites in the soils. The
influence of ionic strength was related to the mechanisms of heavy
metal sorption by the soil. These results can be of practical
importance both in the agriculture and contaminated soils since the
solubility of mercury in soils are strictly dependent on the adsorption
and release process.
Abstract: Composite of Celatom-ZeoliteY (Cel-ZY) was used to
remove cobalt ion from an aqueous solution using batch mode.
ZeoliteY has successfully superimposed on Celatom FW-14 surface
using hydrothermal treatment .The product was synthesized as a
novel of hierarchical porous material. It was observed from the
results that Cel-ZY has higher ability to remove cobalt ions than the
pure ZeoliteY powder (PZY) synthesized under the same conditions.
Several parameters were studied in this project to investigate the
effect of removal cobalt ion such as pH and initial cobalt
concentration. It was clearly observed that the uptake of cobalt ions
was affected with increase these parameters. The results proved that
the product can be used effectively to remove Co2+ ions from
wastewater as an environmentally friendly alternative.
Abstract: In this study, the sorption of Malachite green (MG) on Hydrilla verticillata biomass, a submerged aquatic plant, was investigated in a batch system. The effects of operating parameters such as temperature, adsorbent dosage, contact time, adsorbent size, and agitation speed on the sorption of Malachite green were analyzed using response surface methodology (RSM). The proposed quadratic model for central composite design (CCD) fitted very well to the experimental data that it could be used to navigate the design space according to ANOVA results. The optimum sorption conditions were determined as temperature - 43.5oC, adsorbent dosage - 0.26g, contact time - 200min, adsorbent size - 0.205mm (65mesh), and agitation speed - 230rpm. The Langmuir and Freundlich isotherm models were applied to the equilibrium data. The maximum monolayer coverage capacity of Hydrilla verticillata biomass for MG was found to be 91.97 mg/g at an initial pH 8.0 indicating that the optimum sorption initial pH. The external and intra particle diffusion models were also applied to sorption data of Hydrilla verticillata biomass with MG, and it was found that both the external diffusion as well as intra particle diffusion contributes to the actual sorption process. The pseudo-second order kinetic model described the MG sorption process with a good fitting.
Abstract: The aim of this study was to synthesize the single
walled carbon nanotubes (SWCNTs) and determine their hydrogen
storage capacities. SWCNTs were firstly synthesized by chemical
vapor deposition (CVD) of acetylene (C2H2) on a magnesium oxide
(MgO) powder impregnated with an iron nitrate (Fe(NO3)3·9H2O)
solution. The synthesis parameters were selected as: the synthesis
temperature of 800°C, the iron content in the precursor of 5% and the
synthesis time of 30 min. Purification process of SWCNTs was
fulfilled by microwave digestion at three different temperatures (120,
150 and 200 °C), three different acid concentrations (0.5, 1 and 1.5
M) and for three different time intervals (15, 30 and 60 min). Nitric
acid (HNO3) was used in the removal of the metal catalysts. The
hydrogen storage capacities of the purified materials were measured
using volumetric method at the liquid nitrogen temperature and gas
pressure up to 100 bar. The effects of the purification conditions such
as temperature, time and acid concentration on hydrogen adsorption
were investigated.