scholarly journals Utilization ofm-Phenylenediamine-Furfural Resin for Removal of Cu(II) from Aqueous Solution-A Thermodynamic Study

2010 ◽  
Vol 7 (3) ◽  
pp. 757-762
Author(s):  
Tariq S. Najim ◽  
Israa G. Zainal ◽  
Dina A. Ali
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Free Energy ◽  
Room Temperature ◽  
Adsorption Process ◽  
Sorption Process ◽  
The Other ◽  
Weak Values ◽  
Solid Liquid Interface ◽  
Solid Liquid

m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The producedm-phenylenediamine-furfural resin was used for the removal of Cu(II) from aqueous solution. The pH for the optimum removal of Cu(II) was 6. The negative values of Gibbs free energy at low concentration of Cu(II) (20, 30 ppm) indicative of the spontaneous adsorption process, while, at higher Cu(II) concentration (40,50 ppm) the positive and weak values of ∆G° indicate that the process is feasible but non spontaneous. The values of ∆H° were positive indicating that the sorption process is endothermic. On the other hand, the values of activation energy (Ea) were inconsistent with the values of ∆H° both are positive and lie in the range of physisorption. The entropy ∆S° of the process was positive indicative of the randomness of the Cu(II) ions at the solid / liquid interface. The values of sticking probability S* were less than one which indicate a preferable adsorption process and the mechanism is physisorption.

scholarly journals Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel:Mechanistic and Thermodynamic Studies

2009 ◽  
Vol 6 (s1) ◽  
pp. S153-S158 ◽  
Author(s):  
Tariq S. Najim ◽  
Suhad A. Yassin
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Batch Process ◽  
The Other ◽  
Water Molecules ◽  
Pomegranate Peel ◽  
Solution Interface ◽  
Adsorbent Surface

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared and used as adsorbent for removal of Cr(VI) ions from aqueous solution using batch process. The temperature variation study of adsorption on both adsorbents revealed that the adsorption process is endothermic, from the positive values of ∆H˚. These values lie in the range of physisorption. The negative values of ∆G˚ show the adsorption is favorable and spontaneous. On the other hand, these negative values increases with increase in temperature on both adsorbents, which indicate that the adsorption is preferable at higher temperatures. ∆S˚ values showed that the process is accompanied by increase in disorder and randomness at the solid solution interface due to the reorientation of water molecules and Cr(VI) ions around the adsorbent surface. The endothermic nature of the adsorption was also confirmed from the positive values of activation energy, Ea, the low values of Ea confirm the physisorption mechanism of adsorption. The sticking probability, S*, of Cr(VI) ion on surface of both adsorbents showed that the adsorption is preferable due to low values of S*(0< S*< 1 ), but S*values are lower for FMPGP indicating that the adsorption on FMPGP is more preferable .

Investigation of Titania Addition into Tar Sands for Removal of Phenol from Aqueous Solutions

2006 ◽  
Vol 41 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Lua'y Zeatoun ◽  
Munjed Al-Sharif ◽  
Abeer Al-Bsoul
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Sorption Process ◽  
The Other ◽  
Solution Temperature ◽  
Equilibrium Isotherm ◽  
Activation Temperature ◽  
Tar Sands ◽  
Initial Concentration ◽  
Initial Phenol Concentration

Abstract Tar sands were found to remove significant amounts of phenol from aqueous solution in the presence of titania; about 70% at an initial concentration of 10 ppm. Batch sorption experiments showed that phenol uptake was increased with either an increase in initial phenol concentration, percentage of titania in the sorbent or pre-activation temperature. On the other hand, the presence of soft ions such as sodium, Na+, or potassium, K+, or the increase of solution temperature suppressed the uptake of phenol. Physical pre-activation of the tar sands influenced the adsorption process positively. The sorption process appears to be exothermic and relatively fast; the equilibrium isotherm data were well represented by either Langmuir or Freundlich models.

scholarly journals Performance of natural and modified smectite: kinetic and thermodynamics involving arsenic (V) adsorption

Cerâmica ◽  
2010 ◽  
Vol 56 (337) ◽  
pp. 49-56 ◽  
Author(s):  
D. L Guerra ◽  
C Airoldi ◽  
R. R Viana
Keyword(s):  
Room Temperature ◽  
Adsorption Process ◽  
Textural Analysis ◽  
Order Reaction ◽  
29Si Mas Nmr ◽  
Second Order Reaction ◽  
Calorimetric Titration ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid

A natural smectite sample has been modified by organofunctionalization process using synthetic route involved the reaction of 2-mercaptopyrimidine with 3-chloropropyltriethoxysilane. The resulting material (S MPY) was characterized by SEM, FTIR, textural analysis and 29Si MAS-NMR. The ability of this material to removed As (V) from aqueous solution was followed by series of adsorption isotherms adjusted to the Langmuir equation at room temperature and pH 2.0. The kinetic parameters analyzed by Lagergren and Elovich models gave a good fit for a pseudo-second order reaction with k2 in the 4.9 to 14.0 mmol-1 min-1 range for S MPY. The adsorption process was exothermic (ΔintH = -4.09 to -5.79 kJ.mol-1) accompanied by increase in entropy (ΔintS = 41.29 to 61.80 JK-1.mol-1) and Gibbs energy (ΔintG = -22.34 to -24.19 kJmol-1). The energetic effect caused by arsenic cation adsorption was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant.

scholarly journals Multi-variant Sorption Optimization for the Uptake Of Pb(II) Ions by Jamun Seed Waste

2013 ◽  
Vol 15 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Ali N. Siyal ◽  
Saima Q. Memon ◽  
Mahar Amanullah ◽  
Tajnees Pirzada ◽  
Sajida Parveen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Free Energy ◽  
Drinking Water ◽  
Ion Exchange ◽  
Factorial Design ◽  
Adsorption Process ◽  
Sorption Process ◽  
Ft Ir ◽  
Ir Study ◽  
Good Agreement

In the present study, jamun seed waste has been explored for the removal of Pb(II) ions from aqueous solution. The multi-variant sorption optimization was achieved by the factorial design approach. 99.91% of Pb(II) ions was removed from aqueous solution. The results predicted by the model were in good agreement with the experimental results (the values of R2 and R2adj. were found to be 99.89% and 99.95%, respectively). Langmuir and D-R isotherm studies were carried out to find adsorbent’s capacities (183.9 ± 0.31 mg/g and 184.5 ± 0.16 mg/g respectively), sorption free energy 13.17 ± 0.16 and RL values in the range of 0.05-0.77, suggested the favorable chemical and/or ion exchange nature of the sorption process. The FT-IR study was carried out for unloaded and Pb(II) ions loaded jamun seed, indicated, Pb(II) ions associated with nitrogen and oxygen of jamun seed containing moieties during the adsorption process. The proposed method was successfully validated and applied for the treatment of Pb(II) ions contaminating drinking water.

Sorption of Pb(II) by poly(hydroxamic acid) grafted oil palm empty fruit bunch

2011 ◽  
Vol 63 (8) ◽  
pp. 1788-1793
Author(s):  
M. J. Haron ◽  
M. Tiansin ◽  
N. A. Ibrahim ◽  
A. Kassim ◽  
W. M. Z. Wan Yunus ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Free Energy ◽  
Oil Palm ◽  
Hydroxamic Acid ◽  
Sorption Process ◽  
Enthalpy Change ◽  
Langmuir Model ◽  
Order Kinetic ◽  
Empty Fruit Bunch ◽  
Order Kinetic Model

This paper describes the sorption of Pb(II) from aqueous solution. Oil palm empty fruit bunch (OPEFB) fiber was first grafted with poly(methylacrylate) and then treated with hydroxylammonium chloride in alkaline medium to produce hydroxamic acid (PHA) grafted OPEFB. Sorption of Pb(II) by PHA-OPEFB was maximum at pH 5. The sorption followed the Langmuir model with maximum capacityof 125.0 mg g−1 at 25°C. The sorption process was exothermic, as shown by the negative value of enthalpy change, ΔH0. The free energy change (ΔG0) for the sorption was negative, showing that the sorption process was spontaneous. A kinetic study showed that the Pb(II) sorption followed a second order kinetic model.

scholarly journals Solid-liquid interface free energy through metadynamics simulations

2010 ◽  
Vol 81 (12) ◽  
Author(s):  
Stefano Angioletti-Uberti ◽  
Michele Ceriotti ◽  
Peter D. Lee ◽  
Mike W. Finnis
Keyword(s):  
Free Energy ◽  
Liquid Interface ◽  
Interface Free Energy ◽  
Solid Liquid Interface ◽  
Solid Liquid

Effect of storage temperature on the microbial and color stability of banana purée with addition of vanillin or potassium sorbate / Efecto de la temperatura de almacenamiento en la estabilidad microbiológica y en el color del puré de plátano con la adición de vainillina o sorbato de potasio

1999 ◽  
Vol 5 (1) ◽  
pp. 51-58 ◽  
Author(s):  
X. Castañón ◽  
A. Argaiz ◽  
A. López-Malo
Keyword(s):  
Activation Energy ◽  
Free Energy ◽  
Microbial Growth ◽  
Storage Temperature ◽  
Color Stability ◽  
The Other ◽  
Potassium Sorbate ◽  
Native Flora ◽  
Color Changes ◽  
Different Temperatures

The microbial and color changes during storage at different temperatures (15, 25 and 35 °C) of ba nana purée preserved by the combination of a blanching, reduced pH (3.4) and water activity ( aw, 0.97) and the addition of 1000 or 3000 ppm of vanillin (VA) or 1000 ppm potassium sorbate (PS) were evaluated and compared. The use of 3000 ppm VA or 1000 ppm PS inhibited for at least 60 days of storage the native flora of the banana purée at any of the temperatures studied. The addition of 1000 ppm VA was not enough to stop the microbial growth. However, at 15 °C the growth was delayed 16 days. In the presence of 3000 ppm VA or 1000 ppm PS the banana purée stored at 15, 25 and 35 °C presented several color changes that contributed to browning. The rate of browning was greater in samples with VA than in those formulated with PS, but the activation energy was 10% lower in the former systems. An analysis of the transition state parameters revealed that Gibbs free energy was similar, indicating that the mechanism of browning did not change in the presence of one antimicro bial or the other.

Room temperature on-surface synthesis of two-dimensional imine polymers at the solid/liquid interface: concentration takes control

2016 ◽  
Vol 52 (39) ◽  
pp. 6609-6612 ◽  
Author(s):  
Yanxia Yu ◽  
Jianbin Lin ◽  
Yan Wang ◽  
Qingdao Zeng ◽  
Shengbin Lei
Keyword(s):  
Room Temperature ◽  
Monomer Concentration ◽  
Liquid Interface ◽  
Two Dimensional ◽  
Interface Concentration ◽  
Solid Liquid Interface ◽  
Solid Liquid

With delicate control of the monomer concentration, imine surface COFs can be synthesized at the solid/liquid interface at room temperature.

Removal of fluoride from aqueous solution by adsorption onto Kanuma mud

2010 ◽  
Vol 62 (8) ◽  
pp. 1888-1897 ◽  
Author(s):  
Nan Chen ◽  
Zhenya Zhang ◽  
Chuanping Feng ◽  
Miao Li ◽  
Rongzhi Chen ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Fluoride Concentration ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Solution Ph ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid

Kanuma mud, a geomaterial, is used as an adsorbent for the removal of fluoride from water. The influences of contact time, solution pH, adsorbent dosage, initial fluoride concentration and co-existing ions were investigated by batch equilibration studies. The rate of adsorption was rapid with equilibrium being attained after about 2 h, and the maximum removal of fluoride was obtained at pH 5.0–8.0. The Freundlich isotherm model was found to represent the measured adsorption data well. The negative value of the thermodynamic parameter ΔG suggests the adsorption of fluoride by Kanuma mud was spontaneous, the endothermic nature of adsorption was confirmed by the positive ΔH value. The negative ΔS value for adsorbent denoted decreased randomness at the solid/liquid interface. The adsorption process using Kanuma mud followed the pseudo-second-order kinetic model. Fluoride uptake by the Kanuma mud was a complex process and intra-particle diffusion played a major role in the adsorption process. It was found that adsorbed fluoride could be easily desorbed by washing the adsorbent with a solution of pH 12. This indicates the material could be easily recycled.

scholarly journals Snapshots of Ce70 Toroid Assembly from Solids and Solution

2021 ◽  
Author(s):  
Ian Colliard ◽  
Jessica C. Brown ◽  
Dylan B. Fast ◽  
Ashleigh Sockwell ◽  
Amy Hixon ◽  
...  
Keyword(s):  
Room Temperature ◽  
X Ray Diffraction ◽  
Modular Assembly ◽  
X Ray ◽  
Energy Applications ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Show Evidence ◽  
Solid Liquid Interface ◽  
Solid Liquid

Crystallization at the solid-liquid interface is difficult to spectroscopically observe and therefore challenging to understand and ultimately control at the molecular level. The Ce70-torroid formulated [CeIV70(OH)36(O)64(SO4)60(H2O)10] 4- , part of a larger emerging family of MIV70- materials (M=Zr, U, Ce), presents such an opportunity. We have elucidated assembly mechanisms by X-ray scattering (small-angle scattering and total scattering) of solutions and solids, as well as crystallizing and identifying fragments of Ce70 by single-crystal X-ray diffraction. Fragments show evidence for templated growth (Ce5, [Ce5(O)3(SO4)12] 10- ) and modular assembly from hexamer (Ce6) building units (Ce13, [Ce13(OH)6(O)12(SO4)14(Η2Ο)14] 6- and Ce62, [Ce62(OH)30(O)58(SO4)58] 14- ). Ce62, an almost complete ring, precipitates instantaneously in the presence of ammonium cations as two torqued arcs that interlock by hydrogen boding through NH4 +, which can also be replaced by other cations, demonstrated with CeIII. Room temperature rapid assembly of both Ce70 and Ce62, respectively, by addition of Li+ and NH4 +, along with ion?exchange and redox behavior, invite exploitation of this emerging material family in environmental and energy applications.

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