Removal of Iron from Aqueous Solution Using Walnut and Pomegranate Leaves

Removal of Iron from Aqueous Solution Using Walnut and Pomegranate Leaves

Anees A. Abou-Attayeb It has been suggested that life in any form would probably be ii11E1ossible without the E) rescilce of iroil, but irolt becomes toxic wlie11 its collcelltratlon becomes hlgller flail 0.3 pp111 111 drinking water. Thus finding ways of removing boll or at least reducing    its concentration is of great importance. Removal of iron from aqueous solutions by twenty different plant leaves known in Palestine was investigated. Effect of several factors on iron removal by two types of leaves, walnut and pomegranate leaves, (whic11 were found to be the most suitable types for iron removal among the types which were studied), has been thoroughly investigated. These factors included concentration of iron ions, amount of walnut or pomegranate leaves, pH, agitation, crushing and drying leaves, leaf extract, complexing agent and competing ions. Iron uptake by walnut and pomegranate leaves was found to be pH dependent. Maximum iron uptake, by the two types, was found at pH 2.50. The rate and amount of iron ion removal increased largely by increasing the initial concentration of iron ions and amount of leaves in solution . Agitation affected the removal process slightly. The rate of iron ion uptake oil walnut and pomegranate leaves has been found to be affected by the presence o1' complexing agents. Such agents have adverse effects on the iron 1011 uptake by leaves. Presence of foreign ions along with iron ion in water has different effects on the uptake of iron by pomegranate and walnut leaves. Cu, Zn, Ni and As reduced the uptake of iron by pomegranate leaves. Only As ion reduced iron uptake by walnut leaves. Some foreign ions like Ca and Mn increased the rate and amount of iron uptake by pomegranate leaves. Zn, Cu, Na and Ca ions increased iron uptake by walnut leaves, Na ions did not have any effect on the iron uptake by pomegranate leaves, Ni ion had no effect on iron uptake by walnut leaves. The most efficient form of walnut and pomegranate leaves for removing iron from aqueous solution was to use the ground form of leaves. The capacity of various forms of walnut and pomegranate leaves for removing iron ions increased in the order: nornnal leaves < crushed leaves < ground leaves. Naturally-dried walnut and pomegranate leaves had the higher capability, for iron removal from water, than both oven-dried and green-leaves. It was   found that iron removal depended on leaf type. The ability of different types of leaves to reduce the concentration of iron ions in solution followed the following decreasing order Walnut =- Ponregrancite -> Eucalyptus > Palestine Pistachio > Apple , Mpanese Allecllar - Olives - Oak = Carob > Vine > Oil-Palm - Fig tree == Sisso > Alnnoncl =Lemon > Apricot > Prickly pear > Jz jobe-tree > Cypress =° Willow leaves. Adsorbed iron was found to be released from walnut and pomegranate leaves by changing pH, adding competing ions or using a complexing agent. Using a compexing agent was found to be the most efficient way for releasing iron ions from leaves. The results of the present work fit well with the Freundlich adsorption isotherm and the parameters were calculated. Also, Langmuir adsorption isotherm was satisfied incase of walnut leaves only. The interaction between iron ions and leaves was found to be first order with respect to iron ions. A mechanism based on the assumption that adsorption was the main controlling factor for the removal process was suggested. Anees A. Abou-Attayeb Supervisors Prof. Badi Dauod Dr. Mohammed Ai. Al-Subu 1999  Zajel / An-Najah National University