Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : kinetics


Experimental Investigation of Thermodynamics, Kinetics, and Equilibrium of Nickel Ion Removal from Wastewater Using Zinc Oxide Nanoparticles as the Adsorbent

Shurooq T. Remedhan

Engineering and Technology Journal, 2020, Volume 38, Issue 7, Pages 1047-1061
DOI: 10.30684/etj.v38i7A.608

In the present study commercial zinc oxide (ZnO) nanoparticles in the size of 30 nm were utilized as an adsorbent for the removal of Ni (II) ion from synthetic waste aqueous solution. Adsorption capacity of ZnO for removing Ni (II) ions from aqueous solutions was measured at different pH, adsorbent dose, contact time, temperature and metal ion concentration. Moreover,  adsorption isotherms, kinetics and thermodynamics were studied to understand  the  nature  and  mechanism  of  adsorption. ZnO nanoparticles were characterized by X-Ray diffract analysis(XRD),Fourier Transform Infrared Spectroscopy(FT-IR), scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy(EDS) and Brunauer-Emmett-Teller (BET). The maximum amount of Ni (II) removal were found to be (98.71%) from its aqueous solutions by ZnO nanoparticles which was achieved at the evaluated optimum conditions. The experimental kinetic data were examined using the pseudo-second-order rate model with a high regression coefficient. The adsorption isotherm was well described to the equilibrium data by Langmuir isotherm model (R2=0.990). In addition, the calculated thermodynamic parameters, the standard Gibbs free energy ΔGo, the change in standard enthalpy ∆Ho and the standard entropy change ∆So showed that the adsorption of Ni (II) onto ZnO nanoparticles was feasible, endothermic and spontaneous respectively. The experimental results suggest that ZnO nanoparticles can be used as a potential adsorbent for the efficient removal of heavy metals from aqueous solutions than any other adsorbent because an economical and low- consumption energy due to its ambient operation conditions.

Textile Dye Removal by Activated Date Seeds

Seroor A. Khaleef; Huda T. Hamad

Engineering and Technology Journal, 2019, Volume 37, Issue 2C, Pages 242-247
DOI: 10.30684/etj.37.2C.7

The objective of the study was to prepare activated carbon from date seeds (ADS) and use it as a medium for textile dye adsorption. Batch adsorption of reactive green dye showed that dye adsorption depends on the contact time, the dye concentration, and the pH equilibrium. Different concentrations of the prepared activated carbon were used with different dye concentrations and evaluated for dye removal efficiency. The maximum dye adsorption in this study was achieved after 270 min at a pH range of 5-9. In this study, the functional groups in the prepared ADS were identified using Fourier transform infrared (FTIR) while the crystal size was determined using an X-ray diffractometer (XRD). The Langmuir and Freundlich isotherm equation were used to study the adsorption kinetics, isotherms, and dye desorption while the pseudo-second-order kinetics was used to analyze the equilibrium adsorption data of the reactive green dye on the prepared ADS. The dyes’ adsorption kinetics followed pseudo-second-order kinetics, which is adjudged as the best in adsorption studies. The equilibrium data were best fitted with the Freundlich isotherm model. Conclusively, the adsorption of dye onto the prepared ADS was observed to be an endothermic physical adsorption process.

Thermodynamic and Kinetic Investigation of Desalination by Refrigerant Clathrate Hydrate Formation

Shurooq T. AL-Hemeri; Riyadh S. AL-Mukhtar; Lina W. Mahmood

Engineering and Technology Journal, 2019, Volume 37, Issue 1C, Pages 29-44
DOI: 10.30684/etj.37.1C.6

Gas hydrate is a crystalline solid compound form of water with hydrophobic gas at certain conditions (pressure and temperature). The hydrogen bond in water molecules constructs a framework as a host that entraps gas molecules (gust). Gas hydrate can be applied to many industries such as gas separation, cool storage, food concentration and desalination. Hydrate route looks a promising alternative technology compared to the conventional process, by utilizing a proper gas host, which can be held within water cavities composed by hydrogen-bonded water molecules. In this study the selected host gas was Refrigerant R134a, the work consists of an experimental and theoretical investigation dealing with hydrate formation for the ternary system (water, refrigerant gas, salt) at different initial pressures, the salts were NaCl, KBr and NaF. Method of isochoric pressure search method was used to measure the pressure and temperature for hydrate formation and conduction the three phases of (hydrate-liquid-vapour). The measurements were performed with pressure range (0.1 - 0.4) MPa and the temperatures about (275.2 – 283)K at the concentrations of (0.09,0.17 and 0.26)mol/kg for each salt. The kinetics of R134a clathrate formation for ternary systems (R134a, water and salt) at various types and concentrations of salts. Many objective functions were obtained from the kinetic model for hydrate formation, such as the amount of gas consumed, the growth rate, and the conversion of the water to hydrate. The results showed the effect of the initial pressure on the gas consumed, the rate of growth and water to hydrate conversion, that when the initial pressure increase the moles of R134a gas consumed was increased due to the increased driving force of hydrate formation, also other functions were increased. While the increasing in the concentration of salt for all types will be decreased gas consumed, whereas water to hydrate conversion, the growth rate is slightly decreased. And from the results noticed the presence of different salts in the ternary systems have an effect on the thermodynamics inhibition of refrigerant hydrates and the inhibition increases with the presence of NaCl salt in the ternary system more than other types of salt and also increases with increase the concentration of salt.

Simple Method For Control of Phosphate Level of Manure Using Magnesium Oxide

Mahmood M. Barbooti

Engineering and Technology Journal, 2015, Volume 33, Issue 4, Pages 677-689

A simple method is described for the reduction of available phosphate released from soaking manure in water. The method involves the indirect contact of magnesium oxide, MgO, with manure soaked in water for pre-specified time. Preliminary study indicated that phosphate could be removed effectively by MgO addition and the precipitation is accelerated by NH4Cl addition. Thus, and for economic reasons, the study was continued using only MgO. Two sets of experiments were carried out. Water was used for the extraction of manure by shaking for 2 h followed by press filtration. The aqueous phase was used for phosphate removal experiments. The weighed amount of MgO was placed in a cotton bag fixed to the stirring bar of a jar tester. The concentration of phosphate was monitored after equilibration for 0, 7, 30, 50, 89, 100, 120, 150 and 192 hours. In the other set of experiments, weighed amount of manure powder (Less than 2 mm diameter particles) was placed in 50-mL capacity capped plastic bottles (50 bottles) with various amounts of MgO: 0, 0.4, 0.8, 1.4 and 2.0% (by weight MgO:Manure) in 9 bottles each. Water was added to the bottles to make 40 mL. The bottles were shaken on a rotary shaker at 250 rpm. One set of bottles containing the different amounts of MgO was removed from the shaker after 2 hours. The other sets were removed after 7, 10, 25, 24, 36, 48, 72 and 120 hours. Phosphate was determined in the filtered aqueous samples. The first seven hours was enough to cause a removal of 65-70% of phosphate from solution. The removal of the remaining part of phosphate required as long as 9 days. It was concluded that MgO in clothing bags may be suspended and moved inside manure-water suspension for 10 hours to extract the majority of the phosphate. The remaining manure may be used for fertilization with harmless phosphate content that may not result in the growth of undesirable water environment plants. The reacted oxide in the bags can then be used later as a slowly released phosphate source (Struvite) for plant application a matter that increase the economy of the method.

A Deactivation Correlation for Platinum Y-Zeolite in n-Hexane Isomerization

Haiyam Mohammed A. Al-Raheem

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1451-1462

The objective of the present work is to realize the kinetic modeling regarding
deactivation of Pt-HY zeolite and monitor the isomerization reaction of n-hexane. The
catalyst has been prepared with o.4% Pt and evaluated during the isomerization reaction
of n-hexane. Based on the results of catalytic investigation, a kinetic model was proposed
to deactivate the catalyst by coke formation. The present method provides information on
apparent overall kinetics as well as deactivation parameters and would seem to provide a
rapid method for screening of reaction/deactivation behavior. Accordingly the
deactivation order was found to be 3.72. The obtained correlation of deactivation predicts
the activity pattern under the applied reaction conditions, closely mimics those observed
experimentally, and spans those obtained from empirical correlations.