Iron Ionic Imprinted Polymers IIps for Separation and Preconcentration of Iron from Crude and Fuel Oil

A novel Iron ion-imprinted polymers (IIPs) was synthesized by bulk polymerization using different types of monomers such as 1-vinyl imidazole and Styrene, respectively. Molar ratios of monomer, template and cross-linking agent for polymerization, various monomers and solvents were studied to obtain the largest adsorption capacity for Iron. The prepared Iron-IIPs were characterized using energy dispersive X-ray spectroscopy (EDX), Fourier - transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The three-dimensional network structure surfaces of Iron-IIPs are unaffected by the elution procedure. Iron ions were successfully eluted from IIPs using a mixed solution from ethanol and acetic acid. The maximum adsorption capacity of Iron-IIPs was is (514.5)µmol/g for Iron-IIP1(using styrene as a monomer) and (429.1) µmol/g for Iron-IIP2(using 1-vinyl imidazole as a monomer). The adsorption by Iron-IIPs followed a Langmuir isotherm models. Solid-phase extraction (SPE) syringe packed with ionic imprinted polymers (IIPs) were used to selective separation for Iron ion from Crude or fuel oil and digest the polymer to determination the Iron by


Introduction
Trace element detection is critical in the petroleum industry since it informs geologists about crude oil sources, movement, and kinds [1]. Metallic elements are naturally present in crude oil, and they come from the plants that were transformed to oil, as well as the rocks and soils that were present near the oil throughout its formation. Contamination of crude oil during storage or transportation owing to contact with, and corrosion of tanks or pipes is another This work is licensed under a Creative Commons Attribution 4.0 International License.

Instrument
The control was performed using atomic absorption spectrophotometer pginstrument (England), the use of UV 1800pc spectrophotometer (Shimadzu, japan), scanning electron microscopy SEM ZEISS (United States), EDX MIRA3 TESCAN (Czechoslovakia), FTIR FTIR 8000 (Shimadzu, Japan) and ultrasonic (W.GERMANY) was used to stir up the copolymer solution.

Preparation ionic imprinted polymer
For preparation first Iron molecularly imprinted polymer (Iron-IIP1), 1mmol (0.27 g) from Iron (III) chloride hexahydrate FeCl 3. 6H 2 O dissolved in little amount of methanol then mixed with 20 mmol (2.08 g) styrene as the monomer, after that added 40 mmol (7.92 g) ethylene glycol dimethacrylate (EGDMA) to the solution as the crosslinker, followed that 0.3 mmol (0.07 g) benzoyl peroxide dissolved in 3ml chloroform and add to the mixture as the initiator.
All these materials were dissolved in 5 ± 1ml methanol (CH3OH). While the second Iron-MIP2 were achieved by mixed the same amount of Iron (III) chloride hexahydrate FeCl 3. 6H 2 O as the template with 20 mmol (1.88g) 1-vniyl imidazole as the monomer after that added 40 mmol (7.92 g) ethylene glycol dimethacrylate (EGDMA) to the solution as the crosslinker and 0.3 mmol (0.0 g) benzoyl peroxide as the initiator which dissolved in 5 ± 1ml of metha CH H F C ished, the molecularly imprinted polymer became solid, and the polymer was dried and smashed to yield a polymer particle. The templet extract from MIP by soxhlate in CH3OH/CH3COOH (10:1 v/v).
Respectfully, Non-molecularly imprinted polymers are made using the same ingredients and circumstances as Iron-IIP1 and Iron-IIP2, but without the Iron (III) chloride hexahydrate FeCl 3 .6H 2 O (template). The same distribution was used in the preparation of non-imprinted polymers (NIPs), but without the template.

Sampling Procedure
Prepare a stock solution 1000 ppm of Iron in organic medium by dissolved (1.205  ng/ml) for preconcentration method to determination the little amount note detect direct in flame atomic absorption spectrophotometer. Also, brought several samples of crude and fuel oil.

The Sampling Device
Each syringe was loaded with varied weights (0.1 and 0.2gm) of IIPs in a 10 ml solid phase extraction syringe.

Extraction and digestion procedure
Iron ion was extracted from synthetic solution, diluted synthetic solution and crude or fuel oil using Iron-IIP1 (styrene as a monomer) and Iron-IIP2 (1-vinyl imidazole as a monomer) by solid phase extraction (SPE) syringe. This syringe was prepared by packing it with an IIP 0.2 mg, the size of its container 10 ml. The solution containing Iron pass through SPE syringe by vacuum process using peristaltic pump in different rate.
IIP was collected from column in the small beaker, dried for 60 minutes, than a 1mL of concentrated sulfuric acid is added to it and left for a 8 minute, the next step concentrated nitric acid 1ml is added to it and heated at a 60 temperature after that added deionized water to the mixture, later estimated directly by flame atomic absorption spectrophotometer.

FT-IR
Spectral analysis was used to determine the interaction between Iron ion and monomer. The Cesium Iodide (CsI) pellet technique registered the FT-IR spectrum in the range of 250-4000 cm -1 . Figure (1) shows the FT-IR spectra of Iron-IIP1 before and after elution (1). Both spectra exhibit comparable backbones, indicating that the elution procedure has no effect on the  (1) and (2).

SEM
Morphological analysis is an important characteristic for understanding the size and arrangement of areas where Iron ion was removed. SEM images were used to assess the morphology of the Fe-IIPs. For Iron-IIP1 Figure

Adsorption time
In the industrial use of produced IIPs, the adsorption rate is a critical factor. The effects of adsorption capacity on adsorption time (1, 3, 5, 10, 30, 60, and 120 minutes) were investigated, with the findings for two IIPs given in Figure (7). The adsorption capacity increases dramatically in the first 5 minutes, showing that the adsorption of Iron ion in organic solution with produced Fe-IIPs is quite rapid at initially. Then, as the adsorption duration is increased from 5 to 10 minutes, the adsorption capacity improves somewhat before remaining constant after 10 minutes. Adsorption kinetics show that the binding sites in prepared Iron-IIPs have a high affinity for Fe ions, resulting in high adsorption efficiency.

Maximum adsorption capacity
Appraise the ad sorption achievement of Iron -IIPs, the effect of initial Iron ion concentration ranging from (0.178) to (12.5) µmol/ml on adsorption capacity was studied using the following equation [33]. Where Q is the binding capacity of MIPs (µmol/g), C f is the final Iron concentration (µmol/ml), Ci is the initial Iron concentration (µmol/ml), Vs is the volume of solution tested (ml) and MMIP is the mass of dried polymer (mg).
The adsorption capacity increases dramatically at initially, then steadily increases as the concentration of Iron ion rises, as seen in Figure (8). The mass transfer driving force operates by increasing the differential between the concentration of Fe ion in bulk solution and around the surface of IIPs as the initial Iron) ion concentration rises, resulting in a large increase in equilibrium adsorption capacity. When the iron concentration is more than 8 mol/ml, however, the quantity of adsorbed metal remains constant.
Langmuir isotherm models may be used to calculate Iron -IIPs' maximal adsorption capacity.
Shown in Figure (9). The maximum adsorption capacity is (514.5) µmol/g for Iron -IIP1 and (429.1)µmol/g for Iron -IIP2. The Iron -IIPs prepared in this work has the high adsorption capacity. The uniform and attainable imprinted binding sites greatly enhance the adsorption execution of Iron ions by the prepared Fe-IIPs. Moreover, the binding between monomers and Iron is very stable, allowing for simpler chelation formation. The Langmuir adsorption isotherm equation shown in the following [33].
--------- (2) Where Q is the binding capacity, Q max is the maximum apparent binding capacity, C free is the free analytical concentration at equilibrium (µmol/L), and Kd is the dissociation constant at binding site. In a linear plot of Q/C free vs. Q, the equilibrium dissociation constant was estimated from the slopes, and the apparent maximum number of binding sites was derived from the yintercepts.

Determination of Fe ion in synthetic organic solution
Series of synthetic solution was prepared to study the recovery of SPE-FAAS by using Iron-IIPs shows in Table (6).

Preconcentration in organic solution
Preparations of 100 ml of sample containing 5.0 ng/ml of Iron ion by using base oil were loaded into the Iron-IIPs SPE syringe at 1.0 ml/min. After the sample loading, for 5 minutes, air was circulated through the column. Then, Iron-IIP was collected from column in the small beaker and add 1mL of concentrated sulfuric acid left for a 8minute. After that concentrated nitric acid 1ml is added to it and heated at a 60 temperature and added distilled water to the mixture to complete volume to 5ml, later estimated directly by flame atomic absorption spectrophotometer. The loading of 100 ml solution sample with a digest volume 5ml    Each extraction process considered results in a possible 20-fold increase in analyte concentration. It is a concentration of 5-25 ng/ml, which is easily measurable by GFAAS but not by FAAS, assuming we have a quantitative recovery.
Table (7) shows the typical performance information for the Iron-IIPs SPE and preconcentration method .The precision of the method for a standard, evaluated as the relative standard deviation (n = 8) was 3.5 ng/ml of Fe ions. The limit of detection, defined as the concentration of analyte that generates signals that are three times the blank's standard deviation plus the net blank's standard deviation ferocity for 100 ml of sample volume were 10 ng/ml.

Determination of Fe ion in Crude and fuel oil.
Samples of crude and fuel oil have been brought in from the refinery. After that, these solutions were added to the Iron-IIP-SPE packed column system in the same way as before.
Table (8) shows the acquired findings as well as the recovery tests.

Conclusion
Novel Iron-IIPs was prepared by bulk polymerization. Styrene and 1-vinyl imidazole selected as functional monomer and EGDMA as crosslinker. Besides, benzyl peroxide was used as an initiator in the presence of chloroform solvent. The optimal molar ratios of Iron ion to monomer and croslinker dosage were studied. The irregular shapes and three-dimension network structure of polymers it was possible to notice by SEM. The results of FT-IR and EDX proved the successful elution of Fe ions by CH3OH/CH3COOH (10:1 v/v) solution. Effects of operating time and initial Iron ion concentration on adsorption performance were investigated. Adsorption by IIPs was fast (adsorption equilibrium was reached within 10 min) and followed Langmuir isotherm models. The maximum adsorption capacity of the IIPs is (568)µmol/g for Iron-IIP1 and (491) µmol/g for Iron -IIP2, which is higher than other sorbents reported in literatures. The elution procedure has very little effect on the cavity structure and chemical properties of the polymers, demonstrating that Iron -IIPs are highly stable and regenerable.