An-Najah Staff

In this study we examined the adsorption, kinetics and thermodynamics of heavy metals of used engine oil that come during engine operation and forsaw the possibility of polluting soil and ground water. the effect of temperature on
adsorption was investigated in the range (15 – 45o C) and results showed that maximum removal occurred at 45C. Effect of pH indicated that maximum removal of both Zn and Pb was at pH =13. Increasing adsorbent (soil) dosage from 0.5 to 3g showed that maximum adsorption of both Zn and Pb onto soil occurred with 3 g of soil. Equilibrium concentration happened at 90 minutes. Lanqmuir and Freiundlich models were used to study adsorption process at equilibrium and the
results showed that Frenundlich is better for Zn while Lanqmuir fits better with Pb. In order to investigate adsorption behavior of Zn and Pb on soil, three kinetic models applied; Pseudo-first order, Pseudo-second order and intra- particle diffusion models were applied to fit kinetics data. The rate constants and correlation coefficients were determined for the three models. Thermodynamic parameters such as Gibbs free energy, standard enthalpy and standard entropy change were calculated for both zinc and lead.

Uptake of toxic metals by plants has been of great interest to environmental scientists because this might harm the growth of plant and cause health hazard to man and animal.

In this study, the effects of two elements (lead and cadmium) which cause high concern because of their cummulative nature have been studied on broad beans. Both elements have been found to affect the growth of broad beans and this effect increased with the increase of concentration of metal in solutions used for root‐treatment or for foliar‐treatment of plant. The effect of foliar‐treatment was very much higher than the effect of root‐treatment by lead or cadmium.

Cadmium was found more toxic to plant growth than lead. The effect of cadmium treatment was more on the growth of fruits while the effect of lead treatment was more on the roots of broad beans. The least affected part by lead or cadmium was the stem of plant.

Both the concentration and the whole content of metal in plants and its varoius parts (roots, stem, leaves and fruits) increased steadily with the increase of cadmium or lead concentration in solutions used for either root‐treatment or foliar‐treatment. Concentration of metal ions was higher in roots and leaves than in fruits and stems of treated plants.

The uptake of metal to plant was calculated to be a very small part of the total amount of metal added during treatment.

Some explanations have been suggested in this study to explain the results obtained.

Decaying leaves have been proven capable of partially removing lead from polluted water. Several factors affecting the removal process have been studied. These include the concentration of lead ions, concentration of leaves, drying leaves, degree of crushing of leaves, leaf extracts, pH, agitation and presence of competing and of complexing agents. The relative capability of some common types of leaves for the removal of lead from water has been studied.
The release of lead from leaves saturated with lead ions has been studied under the effect of varying pH, addition of competing ions and the addition of complexing agents.
The results of the present work indicate that the interaction between lead ions and leaves is mainly an adsorption process and fit the Freundlich adsorption isotherm whose parameters have also been calculated. A fractional order of reaction (0.7) has been determined for the reaction between lead ions and leaves using two methods of evaluation. A mechanism in which film diffusion being the most probable limiting step has been suggested.

The effect of root‐treatment of cauliflower, spinach, and parsley plants with lead and cadmium were studied. Both metal ions showed obvious growth inhibition of treated plants with cadmium having higher toxicity on growth than lead.
Cadmium was more concentrated in the edible parts of the three treated plants whereas lead was more concentrated in the edible parts of cauliflower and spinach plants only.
Metal ion concentrations and total metal ion content of treated plants increased with the increase of concentration of cadmium or lead ions in solutions used for treatment. The uptake of metal ion per unit concentration decreased in treated plants with the increase of concentration of cadmium or lead ions in solutions used for treatment.
Metal ion concentration and metal uptake were higher in the plants treated with cadmium than those treated with lead.

Toxicity of cadmium and lead on the growth of carrot plants has been studied. Cadmium has been found to be more toxic than lead especially on the shoots of carrot plants.
Foliar treatment has been compared with root‐treatment for the two elements on carrots and on their roots and shoots.
Concentrations and total contents of lead and cadmium in whole plant in roots and in shoots have been determined for treated carrot plants and compared in root‐treatment with foliar‐treatment. Explanations have been suggested whenever possible to illucidate the results obtained.
Percentages of the metals taken by plants from the whole amounts of metal added during treatment have been calculated and related to type of metal used, concentration of metal in solutions used for treatment and the way of treatment.

Uptake of toxic metals by plants has been of great interest to environmental scientists because this might harm the growth of plant and cause health hazard to man and animal.
In this study, the effects of two elements (lead and cadmium) which cause high concern because of their cummulative nature have been studied on broad beans. Both elements have been found to affect the growth of broad beans and this effect increased with the increase of concentration of metal in solutions used for root‐treatment or for foliar‐treatment of plant. The effect of foliar‐treatment was very much higher than the effect of root‐treatment by lead or cadmium. Cadmium was found more toxic to plant growth than lead. The effect of cadmium treatment was more on the growth of fruits while the effect of lead treatment was more on the roots of broad beans. The least affected part by lead or cadmium was the stem of plant.
Both the concentration and the whole content of metal in plants and its varoius parts (roots, stem, leaves and fruits) increased steadily with the increase of cadmium or lead concentration in solutions used for either root‐treatment or foliar‐treatment. Concentration of metal ions was higher in roots and leaves than in fruits and stems of treated plants.
The uptake of metal to plant was calculated to be a very small part of the total amount of metal added during treatment.
Some explanations have been suggested in this study to explain the results obtained.

In this study the effects of root and foliar treatments of marrow plants with cadmium and lead solutions on the growth of the various parts of plant (roots, stem, leaves and fruits) have been studied. Growth inhibition of the various parts of treated plants has been compared with each other and for the two types of treatment. The toxicity of cadmium on the growth of plant has been compared with the toxicity of lead on the various parts of plants treated by root or by foliar‐treatment with metal ions.
Cadmium and lead uptake by plants and the distribution of this uptake between the various parts of treated plants have been determined and commented on.
Percentages of cadmium or lead taken by plant from the total amount of cadmium or lead added during treatment have been calculated and found to be very small. This percentage has been found to be higher in foliar‐treated plants and from dilute solutions than in root‐treated plants and from more concentrated cadmium or lead solutions.

Iron oxide nanoadsorbents are cost-effective adsorbents that provide high adsorption capacity, rapid adsorption rate and simple separation and regeneration. In this study, Fe3O4 nanoadsorbents have been employed for the removal of Pb(II) ions from aqueous solutions by a batch-adsorption technique. The effects of contact time, initial concentration of Pb(II) ions, temperature, solution pH and coexisting ions on the amount of Pb(II) adsorbed have been investigated. Pb(II) adsorption was fast, and equilibrium was achieved within 30 min. The amount of Pb(II) adsorbed increased as temperature increased, suggesting an endothermic adsorption. The optimal pH value for Pb(II) adsorption was around 5.5. Furthermore, the addition of coexisting cations such as Ca2+, Ni2+, Co2+, and Cd2+ has no remarkable influence on Pb(II) removal efficiency. The adsorption equilibrium data fitted very well to Langmuir and Freundlich adsorption isotherm models. The thermodynamics of Pb(II) adsorption onto the Fe3O4 nanoadsorbents indicated that the adsorption was spontaneous, endothermic and physical in nature. The desorption and regeneration studies have proven that Fe3O4 nanoadsorbents can be employed repeatedly without impacting its adsorption capacity.