Tariq Najim | Al_Mustansiriyah - Academia.edu (original) (raw)

Papers by Tariq Najim

Research paper thumbnail of Physical and mechanical properties of polymer-gypsum composite

This paper is concern with the modification of commercial gypsum (calcium sulfate hemihydrate) wi... more This paper is concern with the modification of commercial gypsum (calcium sulfate hemihydrate) with poly(vinyl acetate) PVAc and the evaluation of physical and mechanical properties of modified and unmodified gypsum. The water-gypsum ratio was held at 45% throughout all experiments. The prepared composites show a clear improvement in impact, compression strength and modulus of elasticity while, the bending strength is reduced when the PVAc proportion in gypsum was increased from 2.5 to 10%. The other objective of this study was to evaluate the water absorption of PVAc –gypsum composite. From the experimental results it is clear that the degree of swelling was reduced when the PVAc percentage in gypsum-PVAc composite was increased.

Research paper thumbnail of Study on the removal of hexavalent chromium using a new biosorbent

Peppermint leaves (PML) have been explored as an effective and cheap adsorbent for removal of tox... more Peppermint leaves (PML) have been explored as an effective and cheap adsorbent for removal of toxic Cr(VI) ions from aqueous solutions using batch system. Adsorption of Cr (VI) ions onto PML was found to be pH dependent and maximum removal of Cr(VI) ions was obtained at pH 2. It was also found that after 180 min of PML contact with chromium solution at the concentration of 0.3846 mmol/L, more than 95% of Cr(VI) ions can be removed. The equilibrium data were fitted with the Langmuir and Freundlich models. The adsorption kinetic data were best fitted with the pseudo-second-order. The activation energy E a of the adsorption process was determined as 23 kJ mol À1 , which may indicate a physisorption process. The Gibbs free energy, enthalpy, and entropy of the process were also determined, and their values revealed that the process is spontaneous and endothermic accompanied with randomness at the solid/solution interface.

Research paper thumbnail of Adsorption of Copper and Iron Using Low Cost Material as Adsorbent

Journal of Chemistry, 2009

In this study, pine fruit was used as solid adsorbent for removal of ferrous and copper ions from... more In this study, pine fruit was used as solid adsorbent for removal of ferrous and copper ions from aqueous solutions through batch equilibrium technique. The influence of contact time, pH of the solution and initial concentration of metal ions on adsorbed amount of metal ions were investigated. 90 minutes of adsorption time was found sufficient to reach equilibrium for ferrous ion and 120 minutes for copper ion. Adsorption of metal ions were pH dependent and the results indicate the optimum pH for the removal of Fe +2 was found to be 5.0 and that of Cu +2 was 7.0, the highest adsorption capacity was found to be 4.8 and 14.1 mg of metal ion per gram of adsorbent at initial concentration of 22.22 mg/L and 57.6 mg/L of ferrous and copper ions respectively and would be higher with higher initial concentration. Ferrous ion was removed by 96.3 -97.3% and copper ion by 94.1-96% along the whole range of initial concentrations. Isotherm studies showed that the data were best fitted to the Freundlich isotherm model. The kinetic data corresponded well with the pseudo-second order equation, suggesting that the adsorption process is presumably a chemisorption.

Research paper thumbnail of Removal of Cr(VI) from Aqueous Solution Using Modified Pomegranate Peel: Equilibrium and Kinetic Studies

Journal of Chemistry, 2009

The present investigation deals with the utilization of modified pomegrenate peel (MPGP) and form... more The present investigation deals with the utilization of modified pomegrenate peel (MPGP) and formaldehyde modified pomegrenate peel (FMPGP) as adsorbents for the removal of chromium Cr(VI) from aqueous solution. A series of experiments were conducted in a batch system to evaluate the effect of system variables. The effect of pH, initial Cr(VI) concentration, contact time, adsorbent dosage and temperature were considered. The optimal pH values of Cr(VI) removal by MPGP and FMPGP were 2.0 and 3.0 respectively. The time required for equilibrium was found to be about 100 minutes. The initial Cr(VI) concentration and adsorbent dosage was found to have large effect on the adsorption of Cr(VI). The maximum uptake capacities were 13.01 and 22.28 mg of Cr(VI) per gram of MPGP and FMPGP respectively. Adsorption kinetic data were tested using pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo second order reaction due to the high correlation coefficient and the agreement between the experimental and calculated values of q e .The adsorption may follow intraparticle diffusion as well, due to the highest values of rate constants for the surface adsorption and intraparticle diffusion kinetic models, the higher values of rate constants are related to an improved bonding between Cr(VI) ions and adsorbent particle.The Dubinin-radushkevich, Freundlich and Tempkin models were the closest fit for the equilibrium data of MPGP and FMPGP.

Research paper thumbnail of Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel: Mechanistic and Thermodynamic Studies

Journal of Chemistry, 2009

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared... more 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.

Research paper thumbnail of Thermal and Ablative Properties of Ipns and Composites of High Ortho Resole Resin and Difurfurylidene Acetone

Leonardo Electronic Journal of …, 2008

High ortho resole resin was prepared by condensation of phenol with excess of formaldehyde in the... more High ortho resole resin was prepared by condensation of phenol with excess of formaldehyde in the presence of magnesium oxide as catalyst. Reaction of furfuraldehyde with acetone in basic medium led to difurfurylidene acetone (DFA).

Research paper thumbnail of Poly (Furfural-Acetone) as New Adsorbent for Removal of Cu (II) from Aqueous Solution: Thermodynamic and Kinetic Studies

International Journal of Chemistry, 2010

Poly(furfural-acetone) was prepared and used for the removal of Cu(II) from aqueous solution. The... more Poly(furfural-acetone) was prepared and used for the removal of Cu(II) from aqueous solution. The optimum pH for the removal was found to be 6. The adsorption kinetic of Cu(II) was studied, and the rates of sorption were found to conform to Pseudo-Second-order kinetic with a correlation coefficient (R 2 =1), results indicate that the pH 6 of the system supported the adsorption of Cu(II) on PFA, which involve higher negative value of ∆G o . On the other hand, the degree of spontaneity of the reaction increases with increasing temperature for all concentrations of Cu(ІІ). The positive values of ∆H° reveals, the endothermic nature of the process and its value lie in the range of physisorption. It was also observed that the randomness increases at the solid-solution interface from the positive values of ∆S°. Estimation of sticking probability S* values reveal that the process is favorable due to low value of S*(S*<1). Activation energy Ea values were consistent with values of ∆H° both are positive and their values lie in the range of physisorption.

Research paper thumbnail of Poly (furfural-acetone) as New Adsorbent for Removal of Cu(II) from Aqueous Solution: Equilibrium Study

Journal of Chemistry, 2010

The batch removal of Cu(II) from aqueous solution using poly (furfural-acetone), (PFA) as adsorbe... more The batch removal of Cu(II) from aqueous solution using poly (furfural-acetone), (PFA) as adsorbent was investigated in this study. The influences of initial Cu(II) ion concentration (10 to 120 ppm), pH (4-8) and contact time have been reported. Adsorption of Cu(II) is highly pH-dependent and the result indicate that the optimum pH for the removal was found to be 6. At this pH a small amount of PFA, 2 g/L, could remove as much as 97% of Cu(II) from a solution of initial concentration 10 ppm. It was observed that an increase in initial concentration of Cu(II) leads to decrease in percent removal of Cu(II) and increase in amount of Cu(II) adsorbed per unit mass of PFA. The adsorption process of Cu(II) is tested with four isotherm models, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R). It was found that all models were applicable and the maximum adsorption capacity was found to be 13.66 mg/g. From the isotherm constants it was confirmed that, the sorption process was physisorption.

Research paper thumbnail of Optical properties modification of poly (vinyl chloride) using complexes of 2-amino acetate benzothiazole

… of Engineering and …, 2006

The optical properties of PVC in the region from (200-600 nm) were studied by preparing the compo... more The optical properties of PVC in the region from (200-600 nm) were studied by preparing the composites with 2amino acetate benzothiazole complexes. The optical data analyzed and interpreted in term of the theory of phonon assisted direct electronic transition; it is observed that the energy is affected by doping type of inorganic complexes used.

Research paper thumbnail of Utilization of m-Phenylenediamine-Furfural Resin for Removal of Cu (II) from Aqueous Solution-A Thermodynamic Study

Journal of Chemistry, 2010

m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The pr... more m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The produced m-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 o 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.

Research paper thumbnail of Physical and mechanical properties of polymer-gypsum composite

This paper is concern with the modification of commercial gypsum (calcium sulfate hemihydrate) wi... more This paper is concern with the modification of commercial gypsum (calcium sulfate hemihydrate) with poly(vinyl acetate) PVAc and the evaluation of physical and mechanical properties of modified and unmodified gypsum. The water-gypsum ratio was held at 45% throughout all experiments. The prepared composites show a clear improvement in impact, compression strength and modulus of elasticity while, the bending strength is reduced when the PVAc proportion in gypsum was increased from 2.5 to 10%. The other objective of this study was to evaluate the water absorption of PVAc –gypsum composite. From the experimental results it is clear that the degree of swelling was reduced when the PVAc percentage in gypsum-PVAc composite was increased.

Research paper thumbnail of Study on the removal of hexavalent chromium using a new biosorbent

Peppermint leaves (PML) have been explored as an effective and cheap adsorbent for removal of tox... more Peppermint leaves (PML) have been explored as an effective and cheap adsorbent for removal of toxic Cr(VI) ions from aqueous solutions using batch system. Adsorption of Cr (VI) ions onto PML was found to be pH dependent and maximum removal of Cr(VI) ions was obtained at pH 2. It was also found that after 180 min of PML contact with chromium solution at the concentration of 0.3846 mmol/L, more than 95% of Cr(VI) ions can be removed. The equilibrium data were fitted with the Langmuir and Freundlich models. The adsorption kinetic data were best fitted with the pseudo-second-order. The activation energy E a of the adsorption process was determined as 23 kJ mol À1 , which may indicate a physisorption process. The Gibbs free energy, enthalpy, and entropy of the process were also determined, and their values revealed that the process is spontaneous and endothermic accompanied with randomness at the solid/solution interface.

Research paper thumbnail of Adsorption of Copper and Iron Using Low Cost Material as Adsorbent

Journal of Chemistry, 2009

In this study, pine fruit was used as solid adsorbent for removal of ferrous and copper ions from... more In this study, pine fruit was used as solid adsorbent for removal of ferrous and copper ions from aqueous solutions through batch equilibrium technique. The influence of contact time, pH of the solution and initial concentration of metal ions on adsorbed amount of metal ions were investigated. 90 minutes of adsorption time was found sufficient to reach equilibrium for ferrous ion and 120 minutes for copper ion. Adsorption of metal ions were pH dependent and the results indicate the optimum pH for the removal of Fe +2 was found to be 5.0 and that of Cu +2 was 7.0, the highest adsorption capacity was found to be 4.8 and 14.1 mg of metal ion per gram of adsorbent at initial concentration of 22.22 mg/L and 57.6 mg/L of ferrous and copper ions respectively and would be higher with higher initial concentration. Ferrous ion was removed by 96.3 -97.3% and copper ion by 94.1-96% along the whole range of initial concentrations. Isotherm studies showed that the data were best fitted to the Freundlich isotherm model. The kinetic data corresponded well with the pseudo-second order equation, suggesting that the adsorption process is presumably a chemisorption.

Research paper thumbnail of Removal of Cr(VI) from Aqueous Solution Using Modified Pomegranate Peel: Equilibrium and Kinetic Studies

Journal of Chemistry, 2009

The present investigation deals with the utilization of modified pomegrenate peel (MPGP) and form... more The present investigation deals with the utilization of modified pomegrenate peel (MPGP) and formaldehyde modified pomegrenate peel (FMPGP) as adsorbents for the removal of chromium Cr(VI) from aqueous solution. A series of experiments were conducted in a batch system to evaluate the effect of system variables. The effect of pH, initial Cr(VI) concentration, contact time, adsorbent dosage and temperature were considered. The optimal pH values of Cr(VI) removal by MPGP and FMPGP were 2.0 and 3.0 respectively. The time required for equilibrium was found to be about 100 minutes. The initial Cr(VI) concentration and adsorbent dosage was found to have large effect on the adsorption of Cr(VI). The maximum uptake capacities were 13.01 and 22.28 mg of Cr(VI) per gram of MPGP and FMPGP respectively. Adsorption kinetic data were tested using pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo second order reaction due to the high correlation coefficient and the agreement between the experimental and calculated values of q e .The adsorption may follow intraparticle diffusion as well, due to the highest values of rate constants for the surface adsorption and intraparticle diffusion kinetic models, the higher values of rate constants are related to an improved bonding between Cr(VI) ions and adsorbent particle.The Dubinin-radushkevich, Freundlich and Tempkin models were the closest fit for the equilibrium data of MPGP and FMPGP.

Research paper thumbnail of Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel: Mechanistic and Thermodynamic Studies

Journal of Chemistry, 2009

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared... more 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.

Research paper thumbnail of Thermal and Ablative Properties of Ipns and Composites of High Ortho Resole Resin and Difurfurylidene Acetone

Leonardo Electronic Journal of …, 2008

High ortho resole resin was prepared by condensation of phenol with excess of formaldehyde in the... more High ortho resole resin was prepared by condensation of phenol with excess of formaldehyde in the presence of magnesium oxide as catalyst. Reaction of furfuraldehyde with acetone in basic medium led to difurfurylidene acetone (DFA).

Research paper thumbnail of Poly (Furfural-Acetone) as New Adsorbent for Removal of Cu (II) from Aqueous Solution: Thermodynamic and Kinetic Studies

International Journal of Chemistry, 2010

Poly(furfural-acetone) was prepared and used for the removal of Cu(II) from aqueous solution. The... more Poly(furfural-acetone) was prepared and used for the removal of Cu(II) from aqueous solution. The optimum pH for the removal was found to be 6. The adsorption kinetic of Cu(II) was studied, and the rates of sorption were found to conform to Pseudo-Second-order kinetic with a correlation coefficient (R 2 =1), results indicate that the pH 6 of the system supported the adsorption of Cu(II) on PFA, which involve higher negative value of ∆G o . On the other hand, the degree of spontaneity of the reaction increases with increasing temperature for all concentrations of Cu(ІІ). The positive values of ∆H° reveals, the endothermic nature of the process and its value lie in the range of physisorption. It was also observed that the randomness increases at the solid-solution interface from the positive values of ∆S°. Estimation of sticking probability S* values reveal that the process is favorable due to low value of S*(S*<1). Activation energy Ea values were consistent with values of ∆H° both are positive and their values lie in the range of physisorption.

Research paper thumbnail of Poly (furfural-acetone) as New Adsorbent for Removal of Cu(II) from Aqueous Solution: Equilibrium Study

Journal of Chemistry, 2010

The batch removal of Cu(II) from aqueous solution using poly (furfural-acetone), (PFA) as adsorbe... more The batch removal of Cu(II) from aqueous solution using poly (furfural-acetone), (PFA) as adsorbent was investigated in this study. The influences of initial Cu(II) ion concentration (10 to 120 ppm), pH (4-8) and contact time have been reported. Adsorption of Cu(II) is highly pH-dependent and the result indicate that the optimum pH for the removal was found to be 6. At this pH a small amount of PFA, 2 g/L, could remove as much as 97% of Cu(II) from a solution of initial concentration 10 ppm. It was observed that an increase in initial concentration of Cu(II) leads to decrease in percent removal of Cu(II) and increase in amount of Cu(II) adsorbed per unit mass of PFA. The adsorption process of Cu(II) is tested with four isotherm models, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R). It was found that all models were applicable and the maximum adsorption capacity was found to be 13.66 mg/g. From the isotherm constants it was confirmed that, the sorption process was physisorption.

Research paper thumbnail of Optical properties modification of poly (vinyl chloride) using complexes of 2-amino acetate benzothiazole

… of Engineering and …, 2006

The optical properties of PVC in the region from (200-600 nm) were studied by preparing the compo... more The optical properties of PVC in the region from (200-600 nm) were studied by preparing the composites with 2amino acetate benzothiazole complexes. The optical data analyzed and interpreted in term of the theory of phonon assisted direct electronic transition; it is observed that the energy is affected by doping type of inorganic complexes used.

Research paper thumbnail of Utilization of m-Phenylenediamine-Furfural Resin for Removal of Cu (II) from Aqueous Solution-A Thermodynamic Study

Journal of Chemistry, 2010

m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The pr... more m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The produced m-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 o 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.