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SYNTHESIS AND RESEARCH OF SORPTION PROPERTIES OF PHOSPHORIC CATIONITE OF POLYCONDENSATION TYPE

Abstract

Phosphoric cationite differing high thermo chemical stability and mechanical durability, was received and investigated by phosphorylation of styrene-furfural polymer. Sorption properties of received cationite in a number of ions of metals - copper, nickel, cobalt, calcium, magnesium, etc. were investigated depending on рН of environment, ionic form of cationite and concentration of investigated cations. It was established that received cationite can be used in sorption processes of investigated cations from various waters.

Keywords: sorption, styrene, furfural, phosphorylation

1. Introduction

Purposeful development of new polymeric materials, including ion-exchange polymers with the set properties is one of the major scientific directions. Using of ion-exchange polymers in various industries demands creation of ionites possessing high thermal and chemical stability, stability in regard to ionizing radiation and a number of specific properties. Creation of wide assortment of domestic ion-exchange materials allows carrying out fuller extraction of metal ions from complex ores and various metallurgical products. Despite of significant number of researches devoted to ion-exchange method of extraction and division of metals, the decision of a problem is important and actual problem for a hydrometallurgical industry. The requirements presenting to ionites by industry concerning thermo chemical stability, radiating stability, mechanical durability, selectivity to metal ions increase in view of wide application of ion-exchange polymers in many areas of a national economy, science and techniques. These requirements are not satisfied by such universal ion-exchanger as KU-1, КU-2, SBS, etc. in spite of the fact that they possess high sorption and kinetic properties [1,2].

Phosphorus-containing ion-exchangers take the important place from the physical and chemical point of view among known ionites [3,4]. These ionites possess a number of valuable properties, such as high selectivity, thermo chemical stability, radiating stability that allows using them in many areas of industry and national economy [5]. Now the big experimental material of receiving of various types of phosphorus-containing ionites is saved. Studying of properties of specified ion-exchange polymers has allowed planning the basic ways of their use in many areas of science and industry [6].

2. Experimental

Phosphoric cationite of polycondensation type on the basis of styrene-furfural polymer has been chosen as object of research. For its receiving the preliminary bulked up styrene-furfural polymer in three-chloride phosphorus placed into three-neck flask with a mixer and a return refrigerator and phosphorylated by three-chloride phosphorus with use as the catalyst of waterless three-chloride aluminium. Mole ratio of reagents polymer: three-chloride aluminium: three-chloride phosphorus = 1:2:4. Reaction was performed at 750oС within 6 h, then ionite separated from three-chloride phosphorus and washed by moistened alcohol, reducing the concentration consistently up to 50, 30, 20 %, and than washed by cooled distilled water before neutral reaction of washing waters.

The sample of ionites from a flask was transferred to the cylinder with capacity of 100 sm3 and condensed layer ionites by knocking on a firm surface of a bottom of cylinder for determining of dynamic exchange capacity (DEC). Volume of ionites lead up to 100 sm3 and by means of the distilled water transferred it to a column, leaving a layer with height 1-2 sm above a level of ionites. Ionite in a column washed by distilled water from acids, passing it from top to down with a speed 1,0 dm3/h. The filtrate was collected in cylinders with capacity of 250 sm3 after passing of a working solution of ionite with concentration 0,1 N through a column. Filtrate collected on 100 and 250 sm3 according to concentration of a working solution in the second and the subsequent cycles of saturation before occurrence of ions of working solution in a filtrate (determined after the first cycle). Then the total amount of a filtrate after occurrence in a portion of a filtrate of ions of a working solution was calculated. For determination of full dynamic exchange capacity proceeded passing a solution before alignment of concentration of a filtrate with concentration of a working solution. The control of saturation was spent by titration of test by a solution of an acid with the mixed indicator before change of painting.

Size to static exchange capacity (SEC) on ions of calcium, magnesium, copper, nickel and cobalt was calculated for samples of ionites, contacted with a solution of calcium, copper, nickel and cobalt salts and a modeling solution within seven days.

Separate samples of ionites were processed by solutions of nickel sulfate and modeling solutions with various рН for determination of IR spectra on spectrophotometer Specord IR 75. Then the pellets with KBr according to [7] have been prepared and investigated.

3. Results and discussion

The opportunity of receiving the new sulfo-cations on the base of new styrene-furfural polymer has been shown by us in [8]. Styrene-furfural polymer has been used with the purpose of receiving of phosphorus-containing cationite as a polymeric matrix. Conditions of phosphorylation process of polymer were selected from the tests which have been saved up with reference to reactions of phosphorylation of low- and high-molecular compounds [9]. The scheme of reaction of receiving of phosphoric cationite by phosphorylation of styrene-furfural polymer with subsequent oxidation in nitric acid can be presented as follows:

The received polymer had exchange capacity of 5.5-5.6 mg-eq/g on 0.1N solution of NaOH and contained 16.5 % of phosphorus.

Polymer after washing by water was contacted with concentrated nitric acid within 7 h at 600oС with the purpose of increase the exchange capacity, i.e. translation of phosphonous groups into phosphonic one. As a result the most part of phosphonous groups was oxidized up to phosphonic ones. Thus the maintenance of phosphorus in polymer did not change, and size of exchange capacity increased up to 7.6-8.0 mg-eq/g.

The basic properties of phosphoric cationite received at various mole ratio of styrene to furfural are shown in Table 1.

From the data of Table 1 it is visible that phosphoric cationite with the best parameters were received at mole ratio of styrene to furfural 1:1. Optimum conditions of carrying out of synthesis of styrene-furfural polymer have been established: reaction temperature - 90°С, concentration of catalyst ZnCl2 - 0.07 moles on mole of furfural and mole ratio of styrene to furfural 1:1 on the basis of the lead researches.

Table1. The effect of a parity of initial substances on properties of received cationite

 

Parameters

Unit of measure

Mole ratio of styrene to furfural

1:2

1:1.5

1:1

Bulk weight

g/ml

0.68

0.6

0.5

Specific volume

ml/g

2.2

2.8

3.5

Static exchange capacity:

on 0.1 N solution of NaOH

mg-eq/g

5.6

6.5

7.0

on 0.1 N solution of NaCl

-//-

0.8

0.9

1.0

on 0.1 N solution of СaCl2

Н-form

-//-

2.6

3.0

3.2

Na-form

2.8

3.2

3.6

on 0.1 N solution of MgCl2

Н-form

-//-

2.6

3.0

3.4

Na-form

2.8

3.4-4.2

3.6-4.2

on 0.1 N solution of CuSO4

Н-form

-//-

1.8

2.0

2.4

Na-form

2.0

2.2

2.8

Mechanical durability

%

99.5

99.0

99.0


For phosphoric cationites the various types of bonds of metal with ionogenic groups of ionite are characteristic: the ionic bonds, the mixed ionic-coordination bonds and cleanly coordination ones. The type of bonds is determined by ability of metal to formation of donor-acceptor complexes and a degree of dissociation of ion-exchanger. The formation of ionic-coordination bonds with uniform distribution of electronic density on four-membered cycle is possible for the metals capable to complex formation. It was interesting to study such properties of investigated phosphoric cationite as sorption ability to ions of copper, nickel, calcium, sodium, cobalt and uranyl, having great value in modern technique, to reveal the influence of various factors on sorption process of these cations, and also their mechanism of sorption with using of IR-spectroscopic analysis. With this purpose the interaction of cationite in Na-and H-forms with solutions of copper, nickel and cobalt sulfate, sodium and calcium chloride, and uranyl nitrate has been studied. Results of researches are resulted in Table 2.

Table 2. Sorption of cations of metals by phosphoric cationite

 

0.1 N substances

Н-form

Na-form

рН

sorbed, mg-eq/g

factor of distribution, ml/g

рН

sorbed, mg-eq/g

NaOH

13

6.6-7.6

184

-

-

NaCl

8.13

0.8-1.0

11.5

-

-

CaCl2

6.5

1.1-1.2

120

6.5

3.57-3.6

CuSO4

4.8-5.0

1.2-1.3

66

4.8-5.0

1.75-1.8

CuSO4

11

2.64-2.7

733

11

3.08-3.1

CuSO4

-

-

-

2.35

1.0-1.1

NiSO4

7.6

1.1-1.2

20

2.25

1.0

NiSO4

10

2.0-2.1

84

3.8

3.6

NiSO4

-

-

-

7.6

2.0

NiSO4

-

-

-

10

3.75-3.8

CoSO4

8

2.0-2.05

35

2.36

0.8-0.9

CoSO4

-

-

-

3.18

2.4

CoSO4

-

-

-

8

2.65

The data of Tables 2 testify about influence of the nature of cation on sorption. It was found that investigated cations are sorbed by cationite unequal and on ability to sorption can be located in the following order:

Ni2+ > Cu2+ > Co2+ > Na+

We had been determined IR-spectra of cationite in Н-and Na-form, sated by ions of copper with the purpose of exposure the mechanism of sorption of cations of metals. According to literary data of frequency of fluctuations for phosphorus groups lay in the field of 700-2560 sm-1. In a cationite spectrum in the H-form it is observed bands at 1150 sm-1 corresponding to valence fluctuations of phosphorus-oxygen bond. The absorption band at 1150 sm-1 does not disappear in a spectrum of cationite in the Na-form. Cationite contains phosphoric groups differing on acid properties with рК1 = 2.8; рК = 7.5. Stronger hydrogen bond forms phosphoryl oxygen with OH-groups, than phosphoric groups are less dissociated. Therefore it is possible to expect that in process of saturation of cationite by sodium a maximum of band corresponding to fluctuations of phosphorus-oxygen bond will be displaced a little into long-wave area as a result of destruction of weaker hydrogen bond. Non-sharp wide bands in the field of 2600-2860 sm-1 and 2100-2600 sm-1 referred to valence fluctuations P-OH connected by hydrogen bonds are observed in a spectrum of cationite in H-form. These bands disappear in a spectrum of cationite sated by sodium. In spectra of cationite sated by ions of metals, unlike a spectrum of cationite in H-form, appears bond at 1060 sm-1 for uranyl and 1055 sm-1 for copper and nickel.

4. Conclusions

Phosphoric cationite differing by high thermal and chemical stability and mechanical durability has been received and investigated by phosphorylation of styrene-furfural polymer. The structure and properties received cationite were investigated with application of chemical methods in a combination of IR-spectroscopy, potentiometry, photocalorimetry, etc. It was shown that ions of copper, nickel, cobalt and uranyl-ion are sorbed by phosphoric cationite due to an ionic exchange and partially due to formation of coordination bands with ionogenic group of cationite. The analysis of the received data testifies that investigated phosphoric cationite has enough high sorption ability to ions of metals.

References

1. Zlonensky Ju.P., Davorov G.N., Zh. Phys. Khimii, 1981. №.6. P. 1564.

2. Ugl’anskaja V.A., Zav’alova T.A., Romanenko E.F. et al, Zh. Prikl. Khimii, 1981. №11. P. 2868.

3. Ergozhin E.E., Khalikova V.K., Rafikov C.R., Mukhitdinoiva B.A., ISBMS, 1981. №11. P. 862.

4. Tursunov T. Dissertation of candidate of sciences. Kiev. IVS RAN. 1985.

5. Balakin V.M., Dranitsina N.V., Kholmansky Ju.B. et al, Zh. Prikl. Khimii. 1981. №4. P. 781.

6. Leikin Ju.A., Rataichak V.S. S.M.: Khimija, 1971. V. 3. P. 86.

7. Pulatov Kh.L., Tursunov T.T., Nazirova R.A., II S-Peterburg Conf. of Young Scientists, S-Peterburg. 2006. P. 9.

8. Ugl’anskaja V.A., Chikin G.A., Selemenev V.F. Zav’alova T.A., Infrakrasnaja spektroskopija ionoobmennykh materialov. Voronezh: MGU. 1989. 208p.

9. Grissbakh R. Teorija i Practika Ionnogo Obmena. M.:IL. 1963. P. 3