Synthesis, characterization and application of a chelating resin for solid phase extraction of some trace metal ions from water, sediment and tea samples

Reactive & Functional Polymers 72 (2012) 722–728

Contents lists available at SciVerse ScienceDirect

Reactive & Functional Polymers journal homepage: www.elsevier.com/locate/react

Synthesis, characterization and application of a chelating resin for solid phase extraction of some trace metal ions from water, sediment and tea samples Sß ule Turan a, Sß erife Tokalıog˘lu a,⇑, Ahmet Sß ahan b, Cengiz Soykan b a b

Erciyes University, Faculty of Science, Chemistry Department, TR-38039 Kayseri, Turkey Bozok University, Faculty of Art and Sciences, Chemistry Department, TR-66200 Yozgat, Turkey

a r t i c l e

i n f o

Article history: Received 17 April 2012 Received in revised form 16 June 2012 Accepted 3 July 2012 Available online 11 July 2012 Keywords: Synthesis Characterization Chelating resin Trace metal Flame atomic absorption spectrometry

a b s t r a c t A new chelating resin, poly (2-thiozylmethacrylamide-co-divinylbenzene -co-2-acrylamido-2-methyl-1propanesulfonic acid) was successfully prepared in the present work. Its composition, morphology, and properties were studied by Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analysis, and thermogravimetric analysis. Several factors affecting the extraction of the metal ions including pH, the eluent type and concentration, flow rate, sample volume, and effect of interfering ions were investigated. The adsorption capacity of the resin for the elements studied was found in the range of 4.76–13.0 mg g1. A preconcentration factor of 150 was achieved at the optimum conditions. The limits of detection (3s/b) varied from 0.23 to 1.07 lg L1. The method validation was performed by analyzing certified reference materials (TMDA-70 Fortified lake water, SPS-WW1 Batch 111-Wastewater, RM 8704 Buffalo river sediment, GBW07605 Tea) and spiked water samples. The method was applied to separate and determine the trace levels of Cd(II), Ni(II), Co(II), Mn(II) and Pb(II) in the well water, river water, street sediment, and tea samples. Ó 2012 Elsevier Ltd. All rights reserved.

1. Introduction Trace metals are widely spread in the environment and may enter the food chain from the environment. Some trace metals are essential elements and play an important role in human metabolism. On the other hand, at high concentrations all metals are recognized as potentially toxic [1]. Cadmium is highly toxic even at low concentrations, causing damage to organs such as the kidneys, liver, and lungs. Nickel is a moderately toxic element and it is known that inhalation of this metal and its compounds can lead to serious problems, including respiratory system cancer [2]. Cobalt is an essential element for humans since it is present in vitamin B12. This metal has also been used as a treatment for anemia because it stimulates red blood cell production [3]. Manganese plays an important role in: bone and tissue formation, reproductive functions, and the activation of many enzymes, which are involved in vital metabolic processes [4]. Lead is a harmful element. It is readily absorbed through the gastrointestinal tract. In blood, 95% of the lead is in red blood cells and 5% in the plasma. Around 70–90% of the lead assimilated goes into the bones, then liver and kidneys. It leads to renal tumors. It also interferes in the metabolism of calcium and vitamin D, affects hemoglobin formation and causes anemia. It is neurotoxin and causes behavioral ⇑ Corresponding author. Tel.: +90 352 207 66 66; fax: +90 352 437 49 33. E-mail address: [email protected] (S ß. Tokalıog˘lu). 1381-5148/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.reactfunctpolym.2012.07.002

abnormalities while retarding intelligence and mental development [5,6]. The determination of trace heavy metals in different environmental samples is of great interest to analytical chemists. To fulfill this need, either very sensitive instrumental techniques and/or enrichment/separation methods should be used. Flame atomic absorption spectrometry (FAAS) is one of the most widely used instruments for determination of heavy metals at trace levels due to its simplicity, operational facility, and lower cost than other instruments. However, there are some limitations in direct determination of heavy metals because of matrix interferences and insufficient sensitivity of the instrument [7–10]. Therefore, an initial preconcentration procedure is often required prior to determination of trace metal ions by FAAS. SPE method is one of the most effective multi-element preconcentration methods because of its advantages such as ease of use, ease regeneration of solid-phase, high preconcentration factor, flexibility, low consumption of reagents, the possibility of automation, less sample handling and usually high selectivities. The choice of sorbent is a key point in SPE, because it can control the analytical parameters such as selectivity, affinity, and capacity. Therefore, preparation of new materials for selective solid-phase extraction of analytes is an important trend of solid phase extraction [11–14]. Chelating resins are superior in selectivity to solvent extraction and ion exchange due to their triple function of ion exchange, chelate formation, and physical adsorption. The functional

Sß. Turan et al. / Reactive & Functional Polymers 72 (2012) 722–728

group atoms capable of forming chelate rings usually include oxygen, nitrogen, and sulfur. These groups can be introduced into the polymer by chemical transformation of the matrix or by the synthesis of sorbent from monomeric ligands. The insertion of suitable specific functional groups into the polymeric matrix makes them capable of reacting with metal ions [15–17]. Polymer–metal complexes are composed of polymeric ligand and metal ions. In solution, polymer–metal complexes form microheterogeneous regions occupied by the polymer backbone, where physicochemical properties differ from those of the bulk solution. Most significant reaction patterns of polymer metal complexes are attributed to the characteristic nature of these microheterogeneous regions. Polymer metal complexes show unique characteristics in absorption spectra, coordination structures, stability, redox reactions, catalytic activities, electrochemical reactions, and other areas compared to those of corresponding low molecular metal complexes. Complexation of polymeric ligand with metal ions and ligand substitution reaction of polymer–metal complexes are used to separate metal ions and/or small molecules [18]. Polymer complexes can be obtained by mixing polymer solutions (e.g. a polyacid with a polybase) or by template polymerization. Complexation of metal ions in solution is an important process in several areas, for example, in the body design of functional groups for chelating ion-exchange materials [19], and catalysts [20]. The scope of applications of metal complexation polymers should increase considerably in the future. Numerous studies concerning the synthesis and characterization of the selective chelating sorbents and the wide applicability of these resins in the removal of metals from various samples as well as in selective metal ion recovery processes have been published [21–23]. Gong et al. synthesized a new polyacrylacylaminourea chelating fiber and studied the properties of the chelating fiber for the preconcentration and separation of trace In(III), Bi(III), Cr(III), V(V), and Ti(IV) [24]. Colella et al. proposed a poly(acrylamidoxime) chelating resin for the concentration of trace metals from aqueous solutions [25]. S ß enkal et al. described the synthesis and characterization of a thioureasulfonamide pendant resin derived from crosslinked polystyrene and used for preconcentration of Cd and Pb in water samples [26]. Tokalıog˘lu et al. synthesized a new chelating resin and the resin was used for selective separation, preconcentration and determination of some trace metal ions in water samples [14]. Hazer and Kartal proposed a solid phase extraction method for the determination of Uranium(VI) in water samples. A new chelating resin including three different functional groups was used as a solid phase [27]. Segatelli et al. reported a preconcentration method using cadmium imprinted polymer prepared by bulk method [28]. In this study, poly [2-thiozyl methacrylamide (TMAAm)co-divinylbenzene (DVB)-co-2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS)] (TMAAm-co-DVB-co-AMPS) resin was synthesized and used for the separation and preconcentration of

723

some trace metal ions in water, street sediment and tea samples. The AMPS is a relatively strong acid [29]. The most studied interpolymer complexes are those between polybases (e.g. poly(N-vinyl-2-pyrrolidone) and polyacids-polyacrylic (PAA), polymethacrylic (PMA) [30–32] and with poly (itaconic acid) monoesters [33]. The TMAAm as a component in copolymers with AMPS has not been previously reported. Various factors influencing the separation and preconcentration of Cd(II), Ni(II), Co(II), Mn(II) and Pb(II), such as pH, concentration of eluting reagent, flow rate, sample volume, adsorption capacity, matrix components, have been investigated. 2. Experimental 2.1. Instrument A PerkinElmer A Analyst 800 model flame atomic absorption spectrometry (Waltham, MA, USA) equipped with hollow cathode lamps was used for the determination of Cd(II), Ni(II), Co(II), Mn(II), and Pb(II). The equipment was operated at conditions recommended by the manufacturer. Acetylene/air flow rate was 2.0/ 17 L min1 for all the elements. The pH measurements were carried out in a WTW pH315i apparatus equipped with a combined pH electrode. The FTIR spectra of the resin were recorded on a Jasco 460 Plus FTIR spectrometer (Jasco Co., Tokyo, Japan) using a KBr disc. Elemental analyses were carried out by a Leco CHNSO-932 auto microanalyser (St. Joseph, MI, USA). The microstructure of the polymer was examined by a Leo 440 model scanning electron microscopy (SEM). Thermal data was obtained by using a Perkin Elmer Diamond TG-DTA thermobalance in N2 atmosphere. The thermal stability of the resin was investigated by thermogravimetric analysis (TG) in a nitrogen stream at a heating rate of 10 °C min1. 2.2. Reagents and solutions All reagents and solvents used were of analytical reagent grade. All metal stock solutions (1000 lg mL1) were prepared by dissolving an appropriate amount of their nitrate salts in 1 mol L1 HNO3. The working solutions were prepared by dilution of the stock solutions immediately prior to their use. The required pH adjustments were made by the use of buffer solutions. Buffer solutions were prepared by using 1 mol L1 acetic acid-sodium hydroxide (pH 3–6) and 1 mol L1 ammonia-hydrochloric acid (pH 8). 2-Aminothiazole (Merck, Darmstadt, Germany) and methacryloyl chloride (Alfa Easer, MA, USA) were used as received. 2,20 -Azobisisobutyronitrile (AIBN) (Merck) was purified by successive crystallizations from chloroform–methanol mixture. The crosslinker divinylbenzene (DVB) (Merck) was used as received. 2-Acrylamido-2-methyl-1propanesulfonic acid (AMPS) (Merck) was used without further purification.

Fig. 1. Synthesis scheme of 2-thiozyl methacrylamide monomer.

724

Sß. Turan et al. / Reactive & Functional Polymers 72 (2012) 722–728

Fig. 2. The structure of the poly (TMAAm-co-DVB-co-AMPS) chelating resin and its FT-IR spectrum.

2.3. Synthesis of 2-thiozyl methacrylamide (TMAAm) monomer 2-Thiozyl methacrylamide (TMAAm) monomer was synthesized according to the literature [34,35]. The reaction scheme of the monomer is shown in Fig. 1. 2.4. Synthesis of chelating resin The preparation of poly (TMAAm-co-DVB-co-AMPS) resin was carried out with a radical initiator in dimethylformamide solution. The two appropriate monomers, TMAAm (1.0 g, 6.0 mmol) and AMPS (0.41 g, 2.0 mmol), the cross linking reagent, DVB (0.26 g, 2.0 mmol), and the initiator AIBN (0.018 g, 0.1 mmol) were added to a polymerization flask. The solution was purged with nitrogen

for about 10 min, and the reaction mixture was heated at 70 ± 1 °C. for 3 h in an oil bath. The mixture was then cooled to room temperature and slowly poured. Solid chelating resin was filtered and washed with abundant diethylether and dried under vacuum at 50 °C until a constant weight was obtained. The obtained chelating resin is 1.336 g (yield: 80%). The chelating resin yield was calculated from the conversion of monomer to polymer resin as follows:

Yield ð%Þ ¼ ðwr =wo Þ  100 where wr and wo denote the weights (g) of chelating resin and total feed monomers, respectively. 2.5. Characterization of chelating resin Characterization of poly (TMAAm-co-DVB-co-AMPS) resin was carried out as described below.

Fig. 3. SEM image of the poly (TMAAm-co-DVB-co-AMPS) resin.

Fig. 4. TG-DTA curves of poly(TMAAm-co-DVB-co-AMPS) resin.

Sß. Turan et al. / Reactive & Functional Polymers 72 (2012) 722–728

TMAAm phase and the AMPS phase again. As for the resin systems, the fracture surfaces present a rough and irregular appearance with many holes or indentations which indicates that there are many micro-phase-separations uniform distribution in the fracture surface.

100

Recovery, %

80 60

Ni Cd

40

Co Mn

20

Pb

0 0

2

4

6

8

10

pH Fig. 5. Effect of pH on the recovery of metal ions (eluent: 10 mL of 1 mol L1 HNO3, adsorbent: 0.60 g, sample flow rate: 2 mL min1, n = 3).

Table 1 Effect of the concentrations of eluting solutions on the recoveries of metal ions (pH 5, n = 3). Eluent

Volume (mL) Recovery ± s (%) Ni(II)

1.0 mol 1.0 mol 2.0 mol 3.0 mol 1.0 mol 2.0 mol 3.0 mol

725

L1 L1 L1 L1 L1 L1 L1

HNO3 HNO3 HNO3 HNO3 HCl HCl HCl

5 10 10 10 10 10 10

Cd(II)

Co(II)

Mn(II) Pb(II)

86 ± 1 94 ± 0 82 ± 0 72 ± 0 100 ± 1 101 ± 2 98 ± 2 97 ± 2 99 ± 0 95 ± 1 98 ± 0 97 ± 0 102 ± 2 97 ± 1 100 ± 1 95 ± 1 97 ± 3 36 ± 0 98 ± 1 74 ± 1 93 ± 3 47 ± 1 91 ± 2 86 ± 1 94 ± 3 40 ± 1 93 ± 1 97 ± 1

57 ± 0 101 ± 1 98 ± 1 101 ± 2 74 ± 2 84 ± 3 96 ± 1

2.5.4. Thermogravimetric analysis The TG-DTA curves of poly(TMAAm-co-DVB-co-AMPS) resin were given in Fig. 4. The first weight loss region appears around 100–200 °C associated with dehydration of partially degradated of amide groups. The initial degradation temperature and 80% weight loss of resin was found to be at 202 °C and 700 °C, respectively. Thermal degradation of resin was formed by three steps. The weight loss of the first step was found to be 18.5% between 202 and 276 °C. The weight loss of the second step was found to be 30% between 276 and 380 °C. The weight loss of the third step was found to be 31.5% between 380 and 700 °C. 2.6. Column preparation A glass column (100 mm length and 10 mm i.d.) with glass wool over its stopcock was used during the study. A total of 600 mg of chelating resin was placed into the column. A small amount of glass wool was placed on top to avoid disturbance of the adsorbent during the sample passage. The column was preconditioned by the buffer solution having the same pH with the sample solution prior to use. After each elution, the adsorbent in the column was washed with 5–10 mL of the eluting solution and water subsequently. 2.7. Recommended procedure

2.5.1. Elemental analysis The elemental analysis results of the poly (TMAAm-co-DVB-coAMPS) resin are as follows: found (%): C, 56.88; H, 6.20; O, 15.80; N, 8.30; S, 12.82; calculated (%): C, 57.03; H, 6.14; O, 15.84; N, 8.32; S, 12.67. The results have shown that there is a good agreement between experimental and theoretical values. 2.5.2. IR spectra The structure of the synthesized chelating resin and its FT-IR spectrum are illustrated in Fig. 2. FTIR spectra (KBR pellet), cm1: 3430 (tNH), 3050 (tCH in thiazole ring), 2980, 2940 and 2860 (ta CAH and ts CAH in CH3 and CH2), 1680 (tNAC@O), 1430 (tCAN of ANAC@O), 1600, 1510, 1480 (tC@C in thiazole ring), 1380, 1358 (ta and ts CH3), 1040 (tSO), 800, 570 (tCH and tC@C out of thiazole ring). 2.5.3. The SEM micrograph of the resin The morphology of the poly (TMAAm-co-DVB-co-AMPS) resin was assessed by SEM (micrograph shown in Fig. 3). Microscopic observation suggested that the poly (TMAAm-co-DVB-co-AMPS) resin were immersed in a partially haematic exudate. SEM revealed an existence of the organized fibrin clot, matrix which is usually evident in TMAAm and AMPS unit after implant. Platelet adhesion and aggregation involved the whole gel surface. A few erythrocytes and leukocytes were detected in limited areas of the samples. Monocytes, macrophages and/or fibroblasts from fibrotic tissue of the surrounded cage were absent. Interestingly, a presence of neoangiogenesis was evident only in the capsule surrounding the Hyal cage. The homogenous distribution of tiny depressions over the entire surface can be taken as a tiny casting defect as such defects are not visible in the SEM micrograph of the fractured surface. The fractured surface however, shows a dominant starch phase enclosing the TMAAm domains, whereas the swollen and dried films show a fibrous structure of starch protruding from the fair-sized domain boundaries. This indicated good adhesion between the

A model solution of 25 mL containing 10 lg of Cd(II), 20 lg of Ni(II), 20 lg of Co(II), 10 lg of Mn(II), and 60 lg of Pb(II) and adjusted to pH 5 with acetate buffer was passed through the column packed with 0.60 g of the adsorbent at a flow rate of 2 mL min1. The retained ions were eluted by 10 mL of 1 mol L1 HNO3 at a flow rate of 2 mL min1. The eluent was analyzed for the determination of metal ions by FAAS. The blank analysis were made in the same way without analyte. 2.8. Sample preparation River water from Yesßilırmak, Amasya, and well water from Kayseri, were collected in pre-washed polyethylene bottles and were filtered through a Millipore cellulose membrane filter (pore size of 0.45 lm). The samples were acidified with concentrated HNO3. The pH of the water samples was adjusted to pH 5 by using diluted NaOH and then the related buffer solution. Portions of 0.2 g of RM 8704 Buffalo river sediment and street sediment samples from the Organized Industrial Region in Kayseri were taken in a 100 mL beaker and 10 mL of aqua regia was added. The mixture was evaporated to dryness on a hot plate. The evaporation procedure was repeated with 10 mL of aqua regia once more. After evaporation, distilled water was added to the residue and then it was filtered through a blue band filter paper. The filtrate was diluted to 25 mL with distilled water. The pH of the filtrate was adjusted to pH 5 by using diluted NaOH and then the related buffer solution and the method described above was applied. About 1.0 g of GBW07605 Tea certified reference material and tea samples were accurately weighed into 100 mL beakers, 10 mL of concentrated HNO3 was added to each beakers. After evaporating near to dryness on a hot plate at about 130 °C, 3 mL of concentrated H2O2 was added. The mixture was again evaporated near to dryness and then it was filtered through a blue band filter paper with distilled water. The filtrate was diluted to 25 mL with distilled

726

Sß. Turan et al. / Reactive & Functional Polymers 72 (2012) 722–728

Table 2 Effect of some ions on the recovery of analytes (pH 5, eluent: 10 mL of 1 mol L1 HNO3, n = 3). Ion

Concentration (lg mL1)

Salt

Na+

1000 2500 5000 2500 500 1000 2500 100 250 100 250 250 10 10 10 10 10 10 10 10 10 250 250

NaCl

Na+ K+

Mg2+ Ca

2+

Fe3+ Zn2+ Cu2+ Al3+ Co2+ Mn2+ Ni2+ Pb2+ Cd2+ NO3SO2 4 Cl

Ni(II)

Cd(II)

Co(II)

Mn(II)

Pb(II)

Ca(NO3)24H2O Fe(NO3)39H2O Zn(NO3)26H2O Cu(NO3)23H2O Al(NO3)39H2O Co(NO3)26H2O MnSO4H2O Ni (NO3)26H2O Pb(NO3)2 Cd(NO3)24H2O KNO3 Na2SO4

98 ± 3 97 ± 2 99 ± 3 96 ± 1 99 ± 1 95 ± 2 98 ± 1 100 ± 1 100 ± 1 98 ± 1 92 ± 0 97 ± 2 87 ± 1 97 ± 1 94 ± 1 94 ± 1 86 ± 1 99 ± 0 – 100 ± 1 97 ± 0 100 ± 1 100 ± 0

100 ± 0 93 ± 1 92 ± 2 99 ± 2 98 ± 1 98 ± 1 96 ± 1 97 ± 1 96 ± 1 99 ± 1 94 ± 1 100 ± 1 99 ± 2 99 ± 1 99 ± 2 98 ± 1 98 ± 1 97 ± 1 94 ± 2 100 ± 2 – 99 ± 1 100 ± 0

97 ± 1 98 ± 0 87 ± 2 94 ± 1 97 ± 1 97 ± 1 79 ± 1 97 ± 1 100 ± 1 99 ± 0 92 ± 1 97 ± 0 75 ± 1 91 ± 1 76 ± 1 93 ± 1 – 95 ± 1 92 ± 1 97 ± 1 100 ± 1 98 ± 0 97 ± 1

91 ± 1 79 ± 0 61 ± 2 99 ± 3 92 ± 1 86 ± 2 77 ± 1 99 ± 2 60 ± 0 97 ± 0 57 ± 3 67 ± 1 88 ± 2 93 ± 0 95 ± 2 85 ± 2 77 ± 0 – 91 ± 0 100 ± 0 99 ± 2 99 ± 0 100 ± 1

90 ± 0 72 ± 0 54 ± 0 92 ± 2 89 ± 0 71 ± 1 78 ± 1 92 ± 2 67 ± 0 97 ± 1 62 ± 2 94 ± 2 98 ± 1 100 ± 2 100 ± 2 94 ± 1 84 ± 1 92 ± 1 83 ± 2 – 100 ± 2 98 ± 0 99 ± 1

NaCl Na3PO412 H2O

98 ± 1 95 ± 2

98 ± 0 100 ± 1

98 ± 0 98 ± 1

98 ± 2 99 ± 2

95 ± 1 97 ± 0

NaNO3 KNO3

Mg(NO3)26H2O Ca3(PO4)2

1000 250

PO3 4

Recovery ± s (%)

Table 3 Determination of the analytes in the spiked well and river water samples (sample volume: 250 mL, pH: 5). Element

Cd(II)

Ni(II)

Co(II)

Mn(II)

Pb(II)

a

Well water

R (%)

Added (lg L1)

Founda (lg L1)

– 8.0 16

98 96

– 20 40

29.5 ± 2.0 48.3 ± 1.3 69.5 ± 1.8

94 100

– 20 40

98 106

– 20 40

5.98 ± 0.03 24.5 ± 1.9 42.0 ± 2.0

93 90

– 40 80

22.2 ± 3.0 65.8 ± 1.9 98.9 ± 5.7

109 96

River water

R (%)

Added (lg L1)

Founda (lg L1)

– 8.0

96

– 40

4.82 ± 0.48 46.4 ± 2.0

104

– 80

101

– 40

24.0 ± 1.2 64.6 ± 0.6

102

– 160

7.84 ± 0.47 165 ± 1

98

 x  s, n = 3.

water and it was then submitted to the preconcentration method according to the described method. Portions of 0.01 g of sediment and tea samples were used both for decreasing interfering effect of matrix on Mn(II) and to prevent the precipitation of the Mn(II). 3. Results and discussion 3.1. Effect of pH pH value plays a key role in the SPE procedure. An appropriate pH value can not only improve the adsorption efficiency, but also depress the interference of the matrix [36]. The model solutions containing 20 lg of Ni(II) and Co(II), 60 lg of Pb(II), and 10 lg of

Cd(II) and Mn(II) were prepared and the pH of the solutions was adjusted between 2 and 8. The described preconcentration procedure was followed. The results are shown in Fig. 5. The quantitative recovery (P95) for all the elements was obtained in the range of pH 4–6. Hence, pH 5.0 was selected for further studies. Protons (H+) should be considered as a competitive ion in the adsorption processes. Therefore, very low adsorption of the metal takes place from high acidic solutions. However, at higher (pH > 6) values, the adsorption efficiency decreased, it is probably due to increase in precipitation of metal ions in the form of hydroxyl complexes. These results are in good agreement with those described by previous work [37]. 3.2. Effect of concentration of eluting reagents An important factor that affects the preconcentration procedure and reusability of the resin is concentration of eluting reagents used for desorbing metal ions from the chelating resin. At optimum conditions, the effect of concentration of eluting solution on desorption of the analytes from the column was investigated by using various concentrations of HCl (1–3 mol L1) and HNO3 (1– 3 mol L1). The results are depicted in Table 1. 10 mL of 1, 2 and 3 mol L1 HNO3 eluents was sufficient to obtain the quantitative recovery of all the metal ions. So, 10 mL of 1 mol L1 HNO3 was selected for further studies because of its low concentration. 3.3. Effect of sample and eluent flow rates The effect of sample flow rate on metal ion sorption on chelating resin was investigated by varying the flow rates in the range of 2–8 mL min1 and passing the solution through the column. While the recovery values for Ni(II), Cd(II), and Co(II) changed between 91 and 101% in the flow rate ranges of 2–6 mL min1, the recoveries for Mn(II) and Pb(II) were not quantitative at flow rates higher than 2 mL min1, probably because these ions do not equilibrate sufficiently with the resin. So, 2 mL min1 was used as the sample flow rate in subsequent experiments. The effect of eluent flow rate was studied at flow rates of 2–8 mL min1. Co(II), Mn(II) and Pb(II) were

727

Sß. Turan et al. / Reactive & Functional Polymers 72 (2012) 722–728 Table 4 The analysis results of certified reference materials, street sediment and tea samples. Element

RM 8704 Buffalo river sediment a

1

Certified (lg g Cd(II) Ni(II) Co(II) Mn(II) Pb(II) a b

)

2.94 ± 0.29 42.9 ± 3.7 13.57 ± 0.43 544 ± 21 150 ± 17

Found

b

GBW07605 Tea 1

(lg g

)

2.89 ± 0.27 42.0 ± 3.6 13.25 ± 2.61 528 ± 14 140 ± 6

a

R (%)

Certified (lg g

98 98 98 97 93

0.057 ± 0.010 4.6 ± 0.5 0.18 ± 0.02 1240 ± 70 4.4 ± 0.3

Element TMDA-70 Fortified lake water Certified (lg L1) Cd(II) Ni(II) Co(II) Mn(II) Pb(II) a

)

Found

b

1

(lg g

)

Street sediment (lg g1)

Tea (lg g1)

2.00 ± 0.13 76.8 ± 3.5 13.7 ± 1.3 378 ± 19 25.6 ± 3.7

0.74 ± 0.00 2.90 ± 0.32

R (%) – 100 – 94 –

At 95% confidence level.  x  s, n = 3.

Table 5 The analysis results of certified reference materials (n = 3).

b

1

a

145 ± 0.84 327 ± 2 285 ± 1.7 302 ± 1.6 444 ± 2.7

b

SPS-WW1 Batch 111-Wastewater

Found (lg L1)

R Certifieda (%) (lg L1)

Foundb (lg L1)

R (%)

148 ± 3 314 ± 1 271 ± 1 283 ± 8 463 ± 26

102 20.0 ± 0.1 96 1000 ± 5 95 60.0 ± 0.3 94 400 ± 2 104 100 ± 0.5

18.2 ± 0.6 933 ± 32 62.4 ± 6.3 395 ± 7 98 ± 0.1

91 93 104 99 98

At 95% confidence level.  x  s, n = 3.

recovered quantitatively only at 2 mL min1 flow rate. The range was 2–4 mL min1 for Ni(II) and 2–6 mL min1 for Cd(II). Therefore, 2 mL min1 for all the elements was selected as both the sample and eluent flow rate in subsequent experiments. 3.4. Effect of sample volume In order to determine the maximum sample volume, different volumes (50, 100, 250, 500 1000 and 1500 mL) of model solutions containing 20 lg of Ni(II) and Co(II), 60 lg of Pb(II) and 10 lg of Cd(II) and Mn(II) were passed through the column. Elution was performed with 10 mL of 1.0 M HNO3. The recovery values for all the elements were found to be in the range of 93–101% in the sample volume ranges of 50–1500 mL. A preconcentration factor of 150 can be achieved by this SPE procedure when used 1500 mL of sample volume and 10 mL of eluent volume. 3.5. Effect of foreign ions To assess the possibility of analytical applications for the described method, the effects of some foreign ions, which interfere

with the determination of analyte ions and often accompany these ions in various real samples were examined under the optimum conditions. For this purpose, different amounts of each ion were added individually to model solutions containing 20 lg of Ni(II) and Co(II), 60 lg of Pb(II), and 10 lg of Cd(II) and Mn(II). As can be seen in Table 2, examined cation and anions did not interfere with the recoveries and the determination of analyte ions, except for Fe(III) interfering effect on the Ni(II), Co(II), and Mn(II) and also Co(II) effects on Ni(II), Mn(II), and Pb(II). It was found that recoveries of Ni(II), Cd(II), Co(II), Mn(II), and Pb(II) were almost quantitative in the presence of high concentrations of foreign ions. The Na(I) ions were added as both nitrate and chloride salts. The results show that 2500 lg mL1 of Na(I) ions as chloride salt interfere with Mn(II) and Pb(II) signals. However in the concentration of 2500 lg mL1 of Na(I) ions as nitrate salts, the recovery values for analyte ions were found as in the range of 92–96%. Also, the 250 lg mL1 of Ca(II) ions were added as both nitrate and phosphate salts. While the Ca(II) ions as phosphate salt interfere with the determination of both Mn(II) and Pb(II), Ca(II) ions as nitrate salt showed an interfering effect on Mn(II) signals. Probably, Mn(II) and Pb(II) ions precipitate as slightly soluble phosphate salts (Kçç Mn3(PO4)2 = 1.0  1022, Kçç Pb3(PO4)2 = 1.0  1032). As a result, the new solid-phase extractant has a good selectivity for Ni(II), Cd(II) Co(II), Mn(II), and Pb(II). 3.6. Sorption capacity of the resin There are some connections between the structure of resin and the adsorption performance of this material. From the structure of the resin, an attempt has been made to understand the mode of coordination of the metal ion with the ligand system. According to chemical structure of the resin, intermolecular hydrogen bonding is expected to exist between the sulphonic acid group and the amide group. It is well known that acids tend to self-associate with the formation of dimers [38].

Table 6 Comparison of detection limit, preconcentration factor and sorption capacities of the described method. Element

Adsorbent

Detection limit (lg L1)

Preconcentration factor

Sorption capacity (mg g1)

References

Co, Ni Cd, Pb

Silica gel-polyethylene glycol Alumina coated with sodium dodecyl sulfate-1-(2-pyridylazo)-2naphthol Chromotropic acid coated alumina

0.37, 0.71 0.15, 0.17

83.3 250

6.49, 8.33 11.1, 16.4

[1] [39]

0.14, 0.27, 0.28, 0.53 0.52, 178 2.0, 5.0, 7.5, 25 0.27, 0.59, 1.29 2, 2

50–75

10.3–15.4

[40]

50 40–100 22–25 200

2.14, 2.00 3.24–3.42 – 11.46, 7.05

[41] [42] [43] [44]

50 50–100 150

– 0.590–0.833 4.76–13.0

[45] [46] This work

Cd, Mn, Ni, Pb Mn, Ni Cd, Co, Ni, Pb Cd, Co, Ni Co, Ni Ni, Pb Ni, Co, Cd Cd, Ni, Co, Mn, Pb

Nanometer TiO2 o-Aminophenol-amberlite XAD-2 Pyrocatechol functionalized amberlite XAD-2 5,7-Dichloroquinoline-8-ol immobilized styrene–ethylene glycol dimethacrylate Aspergillus niger loaded silica gel Silica gel modified by 2,4,6-trimorpholino-1,3,5-triazin Poly(TMAAm-co-DVB-co-AMPS) resin

1.6, 5.2 0.29, 0.20, 0.23 0.23, 0.71, 0.44, 0.20, 1.07

728

Sß. Turan et al. / Reactive & Functional Polymers 72 (2012) 722–728

In order to determine the adsorption capacity, the model solutions of 25 mL containing 5.0–600 lg mL1 of Ni(II), 5.0–900 lg mL1 of Co(II), 20–900 lg mL1 of Pb(II) and 20– 750 lg mL1 of Cd(II) were passed through the column containing 0.60 g of chelating resin. Adsorption isotherms were consistent with the Langmuir equation [10]. The adsorption capacity of resin for Ni(II), Co(II), Pb(II), and Cd(II) was 4.76, 9.28, 13.0, and 10.7 mg g1, respectively, and binding equilibrium constants were found to be 0.133 for Ni(II), 0.025 for Co(II), 0.007 for Pb(II), and 0.044 L mg1 for Cd(II). The adsorption isotherm for Mn could not studied because of the precipitation of 10 lg mL1 of Mn(II) at pH 5. 3.7. Analytical figures of merit The precision of the method was determined by performing successive ten retention and elution cycles. The recoveries (R% ± s) were found to be 100 ± 2 for Ni(II), 98 ± 2 for Co(II), 99 ± 3 for Pb(II), 101 ± 1 for Cd(II), and 97 ± 2% for Mn(II). The limit of detection (DL) was calculated according to DL = 3 s/b, where s, is the standard deviation of 12 measurements of blank and b, is the slope of the calibration graph. The DL values were found to be 0.71 lg L1 for Ni(II), 0.44 lg L1 for Co(II), 1.07 lg L1 for Pb(II), 0.23 lg L1 for Cd(II), and 0.20 lg L1 for Mn(II). In the calculation of DL values of the method, the 150-fold preconcentration factor was taken into consideration. 3.8. Accuracy and applications of the method In order to estimate the accuracy of the described method, different amounts of the investigated metal ions were spiked in the various water samples. The preconcentration procedure was applied to these samples. A good agreement was obtained between the added and found analyte contents using the recommended procedure (Table 3). The recovery values for the analyte ions were in the range of 90–109%. The analyses of the various certified reference materials were also performed to assess accuracy of the method under optimal experimental conditions. The results in Tables 4 and 5 show that the found values were in good agreement with the certified values. 4. Conclusion Solid phase extraction with poly (TMAAm-co-DVB-co-AMPS) resin is an effective separation and preconcentration technique for Cd(II), Ni(II), Co(II), Mn(II), and Pb(II). The resin has a good stability and selectivity. Most of the coexisting ions did not interfere at high concentrations. It was found that the resin could be reused up to about 300 cycles without decrease in the recoveries of the analytes. Another advantage of the method is permitting study in acidic medium that minimize precipitation of metal hydroxides. Table 6 compares the detection limit, preconcentration factor and adsorption capacity values obtained in the present work with those reported in other studies. The resin shows the lower detection limits and a higher sorption capacity than the other methods, except for Refs. [39,40]. The preconcentration factor of the method is comparable and/or higher than those of previous works. The method can be applicable for the determination of trace metal ions in a well, river, waste water, street sediment, and tea samples with high accuracy and precision.

Acknowledgment The authors are grateful to the Unit of the Scientific Research Projects of Erciyes University for financial support of this Project (Grant No. FBY-10-3023). References [1] N. Pourreza, J. Zolgharnein, A.R. Kiasat, T. Dastyar, Talanta 81 (2010) 773–777. [2] E.L. Silva, P. dos S. Roldan, M.F. Giné, J. Hazard. Mater. 171 (2009) 1133–1138. [3] V.A. Lemos, L.N. Santos, A.P.O. Alves, G.T. David, J. Sep. Sci. 29 (2006) 1197– 1204. [4] M. Burguera, J.L. Burguera, D. Rivas, C. Rondón, P. Carrero, O.M. Alarcón, Y.P. de Peña, M.R. Brunetto, M. Gallignani, O.P. Márquez, J. Márquez, Talanta 68 (2005) 219–225. [5] F.W. Fifield, P.J. Haines, Environmental Analytical Chemistry, Blackie Academic & Professional, London, 1995. [6] Sß. Tokalıog˘lu, T. Oymak, S ß . Kartal, Microchim. Acta 159 (2007) 133–139. [7] V.K. Jain, H.C. Mandalia, H.S. Gupte, D.J. Vyas, Talanta 79 (2009) 1331–1340. [8] W. Ngeontae, W. Aeungmaitrepirom, T. Tuntulani, A. Imyim, Talanta 78 (2009) 1004–1010. [9] S. Ayata, S.S. Bozkurt, K. Ocakoglu, Talanta 84 (2011) 212–215. [10] O. Hazer, S ß . Kartal, S ß . Tokalıog˘lu, J. Anal. Chem. 64 (2009) 609–614. [11] J. Fan, C. Wu, H. Xu, J. Wang, C. Peng, Talanta 74 (2008) 1020–1025. [12] Y. Cui, X. Chang, X. Zhu, H. Luo, Z. Hu, X. Zou, Q. He, Microchem. J. 87 (2007) 20–26. [13] B. Rezaei, E. Sadeghi, S. Meghdadi, J. Hazard. Mater. 168 (2009) 787–792. [14] Sß . Tokalıog˘lu, V. Yılmaz, Sß. Kartal, A. Delibasß, C. Soykan, J. Hazard. Mater. 169 (2009) 593–598. [15] S. Pramanik, S. Dhara, S.S. Bhattacharyya, P. Chattopadhyay, Anal. Chim. Acta 556 (2006) 430–437. [16] B.S. Garg, R.K. Sharma, N. Bhojak, S. Mittal, Microchem. J. 61 (1999) 94–114. [17] H. Bag˘, A.R. Türker, R. Cosßkun, M. Saçak, M. Yig˘itog˘lu, Spectrochim. Acta B 55 (2000) 1101–1108. [18] J.C. Salamone, Polymeric Materials Encyclopedia, vol. 6, CRC Press, London, 1996. [19] S.K. Sahni, J. Reedijk, J. Coord. Chem. Rev. 59 (1984) 1–139. [20] Z.M. Michalska, K. Strzelec, J.W. Sobczak, J. Mol. Catal. A. Chem. 156 (2000) 91– 102. [21] M.V. Dinu, E.S. Dragan, React. Funct. Polym. 68 (2008) 1346–1354. [22] A.A. Atia, A.M. Donia, A.M. Yousif, React. Funct. Polym. 56 (2003) 75–82. [23] C. Ni, C. Yi, Z. Feng, J. Appl. Polym. Sci. 82 (2001) 3127–3132. [24] B. Gong, X. Li, F. Wang, H. Xu, X. Chang, Anal. Chim. Acta 427 (2001) 287–291. [25] M.B. Colella, S. Siggia, R.M. Barnes, Anal. Chem. 52 (1980) 967–972. _ [26] B.F. Sßenkal, M. Ince, E. Yavuz, M. Yaman, Talanta 72 (2007) 962–967. [27] O. Hazer, Sß. Kartal, Anal. Sci. 25 (2009) 547–551. [28] M.G. Segatelli, V.S. Santos, A.B.T. Presotto, I.V.P. Yoshida, C.R.T. Tarley, React. Funct. Polym. 70 (2010) 325–333. [29] J. Travas-Sejdic, A.J. Easteal, Polymer 41 (2000) 7451–7458. [30] I. Rainaldi, C. Cristallini, G. Ciardelli, P. Giusti, Polym. Int. 49 (2000) 63–73. [31] J.Z. Yi, S.H. Goh, Polymer 42 (2001) 9313–9316. [32] G. Pollaco, M.G. Cascone, L. Petarca, A. Peretti, Eur. Polym. J. 36 (2000) 2541– 2544. [33] E. Meaurio, L.C. Cesteros, I. Katime, Polymer 39 (1998) 379–385. [34] M.M. Azab, J. Polym. Res. 12 (2005) 9–15. _ Erol, C. Soykan, J. Macromol. Sci. A 39 (2002) 405–417. [35] I. [36] G. Xiang, Y. Zhang, X. Jiang, L. He, L. Fan, W. Zhao, J. Hazard. Mater. 179 (2010) 521–525. [37] S. Vellaichamy, K. Palanivelu, J. Hazard. Mater. 185 (2011) 1131–1139. [38] S.M. Milosavljevic, Infrared Spectroscopy, vol. 2. Belgrade, 1994. [39] M. Ezoddin, F. Shemirani, Kh. Abdi, M.K. Saghezchi, M.R. Jamali, J. Hazard. Mater. 178 (2010) 900–905. [40] A. Ramesh, B.A. Devi, H. Hasegawa, T. Maki, K. Ueda, Microchem. J. 86 (2007) 124–130. [41] P. Liang, Y. Qin, B. Hu, T. Peng, Z. Jiang, Anal. Chim. Acta 440 (2001) 207–213. [42] M. Kumar, D.P.S. Rathore, A.K. Singh, Talanta 51 (2000) 1187–1196. [43] V.A. Lemos, E.M. Gama, A. da S. Lima, Microchim. Acta 153 (2006) 179–186. [44] R.S. Praveen, S. Daniel, T.P. Rao, Talanta 66 (2005) 513–520. [45] S. Baytak, A. Koçyig˘it, A.R. Türker, Clean 35 (2007) 607–611. [46] T. Madrakian, M.A. Zolfigol, M. Solgi, J. Hazard. Mater. 160 (2008) 468–472.