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Lead which is a kind of heavy metal has a lot of usage in industrial properties such as battery industry, tetraethyl lead production, armament, paint manufacture. It has a lot of danger to environment due to its insertion to environment and poisonous effect. In this study , we tried to decrease battery industry wastewater lead polluted, with the use of Iron Magnetite Nano-particles(IMNP). Changing in physico chemical parameters such as pH, IMNP concentration , temperature , lead primary concentration, as well as plotting the Freundlich and Langmuir diagrams prepared the best condition for adsorption. The maximum used IMNP concentration is 5gl-1. The maximum value of pH and temperature for maximum adsorption were determined to be 12 and 70 oC respectively. Industrial apply is suggested in results.
Key words : Pb removal, battery industry, Iron Magnetite Nano-particles, environment, wastewater .
The removal of heavy metals from waters and wastewaters is important in terms of protection of public health and environment due to their accumulation in living tissues throughout the food chain as a non-biodegredable pollutants [1,2]. The effluents of a wide range of industrial applications, including microelectronics, electroplating, battery manufacture, dyestuffs, pharmaceutical, metallurgical, chemicals and many others causes heavy metals pollution in environment [2-5]. Lead (Pb) is one of the major environmental pollutants. Lead enters the environment as a result of both natural process and anthropogenic activities. Natural processes include pedogenic mineral breakdown and translocation of products, as well as sedimentation from dust storms, volcanic eruptions and forest fires. Anthropogenic activities of lead contamination include mining and smelting operations, battery recycling, combustion of leaded gasoline, urban and industrial wastes, continuous use of fertilizers, pesticides and use of Pb bullets [6-8]. Pb heads the list of environmental threats because, even at extremely low concentrations, lead has been shown to cause brain damage in children  M. Ahmedna, W.E. Marshall, A.A. Husseiny, R.M. Rao and I. Goktepe, The use of nutshell carbons in drinking water filters for removal of trace metals, Water Res. 38 (2004), pp. 1062-1068. Article | PDF (195 K) | View Record in Scopus | Cited By in Scopus (24)[9,10]. Several methods have been applied over the years on the elimination of these metal ions present in industrial wastewaters and soils. The commonly traditional methods used for removal of heavy metal ions from aqueous solutions include ion-exchange, solvent extraction, chemical precipitation, phytoextraction, ultrafiltration, reverse osmosis, electrodialysis and adsorption [11-14]. A major drawback with precipitation is sludge production. Ion exchange is considered a better alternative technique for such a purpose. However, it is not economically appealing because of high operational cost [9,15].
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E-mail address: [email protected] (Gh. Amoabediny)
Adsorption using commercial activated carbon is an effective purification and separation technique used in industry especially in water and wastewater treatments that can remove heavy metals from wastewater . Activated carbon surfaces have a pore size that determine its adsorption capacity . However, activated carbon remains an expensive material for heavy metal removal. In recent years, various adsorbents have been used for removal of Pb(II) from aqueous solution [1,18-27]. However, new adsorbents with high adsorption capacity and economic materials are still needed.
The objective of the present work is to investigate potential of IMNP in the removal of Pb(II) ions from battery industry wastewater. The effects of pH, IMNP concentration, lead primary concentration and temperature on the adsorption capacity of IMNP were studied. The Langmuir and Freundlich isotherm models were used to describe equilibrium data.
2.1. Preparation of IMNP:
In this study producted IMNP by sedimentation ions iron(III) and iron(II) in aqueous ammonia solution, solutions of 1M iron(III) chloride hexahydrate (FeCl3.6H2O) and 2M iron(II) chloride tetra hydrate (FeCl2.4H2O) were prepared by dissolving FeCl3.6H2O (10.8120 g, 0.04 mol) in 40mL H2O and FeCl2.4H2O (3.9762 g, 0.02 mol) in 10mL 2 M HCl, respectively. The two solutions were then mixed together prior to their addition to 500mL of 0.7M aqueous ammonia solution with continuous 'mechanical' stirring at room temperature (22 ±1oC). After stirring for 30 min, the precipitate was washed twice with water (1 L), by magnetic sedimentation and added to 500 ml deoxygenated water[28,31].
2.2. Coat IMNP by Silica:
In water bath 40oC mixed 100ml ethanol, 5ml water, 8.5ml aqueous ammonia solution 25%, 1.5ml TEOS(tetra ethyl ortho silicat) in a three-necked flask. after 30 min added 1g IMNP and stirred with mechanical stirring. After 1hour, the precipitate was washed with water and ethanol, by magnetic sedimentation .
3. Results and discussion:
3.1.1. Characterization of IMNP:
The particle size of the synthesized oxides was determined by particle analyzer(zetasizer-nanozs malvern England) and imaged by transmission electron microscope, TEM, (Jeol, JEM-2000EX). The specific surface area of the products was determined from the nitrogen adsorption isotherm using the BET method (Micromeritics, Gemini2370). The coating of nanoparticles determined by FT-IR (BRUKER, Vector22). In Fig.1 and Fig.2 show the particle size distribution and TEM image of the colloidal particles, respectively. The particle size of the synthesized oxides was in the range of 10-50 nm. The specific surface area of the IMNP was determined to be 44.36 m2g-1. Fig.3 shows coating of nanoparticles exist frequencys domain 458, 799, 1090 cm-1 are demonstrator vibrations stretching symmetric and stretching asymmetric of Si-O.
Fig.1. The size distribution of IMNP, synthesized by coprecipitation method.
Fig.2. The TEM micrographs of magnetite synthesized by coprecipitation method
Fig.3. Spectrum Fourier Transform Infrared(FT-IR) silicon coated IMNP
3.1.2. Characterization of battery industry wastewater:
Concentration Pb in battery industry wastewater determined by Atomic Adsorption(Shimadzu A.A-670/G V-7). other parameters such as pH and temperature was determined and show in Table.1.
Battery industry wastewater
23Table.1. Characterization of battery industry wastewater
3.1.3. Utilization IMNP for removal of Pb from wastewater in various concentration:
we used IMNP for removal various concentration of Pb in wastewater. deal of Pb determined by Atomic Adsorption before and after adsorption. The uptake percentage () can be defined as:
and the removed amount of Pb per unit area of the oxide qe, (molm-2) as:
Where Ci is the initial Pb concentration in mgl-1 and Ce is the Pb concentration in the aqueous phase at equilibrium in mgl-1, Cm is the IMNP concentration (mgl-1), and SP is the surface area of the solid phase (m2g-1). The adsorption experiments were performed by mixing aqueous wastewater with aqueous suspensions of IMNP using a mechanical rotatory shaker.
3.1.4. Effect of pH to adsorption:
Experiments were conducted to study the effect of solution pH on Pb ion adsorption by using 50 ml suspension of 5 gl-1 of magnetite and Pb ion solution of 150 ppm at room temperature (22 ±1oC). The pH of the solution was kept constant by the addition of 0.1 M NaOH or 0.1 M HNO3 as needed at pH value of 2 to12. The mixture was agitated on a rotatory shaker at 250 rpm for 30 min. The Pb ion bounded magnetite was then removed from the solution by an external magnetic field.the effect of pH on the adsorption of Pb ions was shown in Fig.4. It can be seen that the higher pH favors to the higher uptake Pb ion. In acidic medium, a weak adsorption occurs and above pH=5, an increase in pH results in a significant increase in sorption of the Pb ions. This trend could be explained by considering of protonation of oxides functional groups or may be due to the ion exchange of Pb+2 in wastewater with Fe+2 ions in the Fe3O4 lattice structure. Similar observation has been reported by Uheida et al. .
Fig.4. The effect of pH on adsorption of Pb ions using IMNP
3.1.5. Effect of Pb ions initial concentration to adsorption:
Initial concentration of Pb is one of the effective parameters to adsorption, studded concentration value from 5ppm to 1000ppm in 50 ml solutions containing and 5gl-1 of magnetite iron oxide nanoparticles. The experiment was done at pH value of 8.5 at room temperature (22 ±1oC). The mixture was agitated on a rotatory shaker at 250 rpm for 30 min. InFig.5 and Fig.6 show the Langmuir and Freundlich diagrams. It is evident that more of the loaded Co ions must have penetrated further into the bulk of the oxide structure. value of K and qmax of Langmuir equation were calculated by Excel program according to the following equation(2-3):
Fig.5. The fitting of the experimental data to Langmuir equation
value of K and n of Freundlich equation were calculated by Excel program according to the following equation(2-4):
Fig.6. The fitting of the experimental data to freundlich equation
3.1.6. Effect of temperature to adsorption:
To investigate the influence of temperature on adsorption of Pb+2 ions a set of experiment Carried out at 10-70 oC in 50 ml solutions containing 150ppm of Pb+2 ions, 5 gl-1 of IMNP. The experiment was done at pH value of 8.5 and in 100 ml capped glassy tubes. The effect of temperature on the adsorption of Pb+2 ions was shown in Fig.7.
Fig.7. The effect of temperature on adsorption of Pb+2 ions using IMNP
3.1.7. Effect of concentration of IMNP to adsorption:
To investigate the influence of concentration of IMNP on adsorption of Pb+2 ions a set of experiment Carried out at 2-5gl-1 of IMNP in 50 ml solutions containing 6.89-10-5 moll-1 of Pb+2 ion, pH value of 8.5 at room temperature (22 ±1oC). Fig.8 shows the effect of different concentration of IMNP on adsorption of Pb+2 ions. It can be seen that the higher concentration of IMNP favors to the higher uptake Pb+2 ion. This trend could be explained by increase of free sites on surface of IMNP.
Fig.8. The effect of different concentration of IMNP on adsorption of Pb+2 ions
3.2.1. recovery of Pb+2 and IMNP:
The recovery of Pb+2 from IMNP was studied at pH=2 using nitric acid as eluting solution. Uheida et al.  reported that about 75% recovery of Pb+2 was achieved from hematite. In this study, recoveried about 80 percent nano particles and again used concentrated lead.
The removal of lead(Pb+2) ions from battery manufacture wastewater using IMNP was studied. The sorption capacity of Pb+2 ion increases by rising concentration of Pb+2 ion. So utilize this method is profitable for refinement high pollution industrial wastewater as battery manufacture wastewater. Our results show that maximum Pb+2 percent elimination(99.8%) is in this qualifications:1000 ppm concentration of Pb+2, pH value 12, temperature of 70oC and nano particles concentration 5g. results showed that uptake of lead increases with temperature but creation temperature supper than room temperature(22±1oC) in industry is expensive therefore perused optimum qualifications in ambient temprature. pH battery industry wastewater is about 4 therefore maximum Pb+2 elimination in this qualifications is about 70 percent. The surface adsorption of Pb+2 ions on IMNP was quantitatively modeled by considering ion exchange and surface complexation as the possible uptake mechanisms. The adsorbed lead ions can be recovered about 80 percent. IMNP are a potential sorbent removing efficiently Pb+2 ion, can be competitive with the conventional technologies.