CC BY
20
Section 8. Chemistry
D OI: http://dx.doi.org/10.20534/AJT-16-11.12-63-66
Daminova Shahlo Sharipovna, Tashkent Chemical Technological Institute, Department of «Technology of silicate materials and rare precious metals»,
Scientific Researcher E-mail: [email protected] Kadirova Zukhra Chingizovna, Tashkent Chemical Technological Institute, Center of Excellence,
Dr. Engineering, PhD in Chemistry, E-mail: [email protected] Sharipov Khasan Turabovich, Professor, Tashkent Chemical Technological Institute, Department of "Technology of silicate materials and rare precious metals",
E-mail: [email protected]
Sorption of Ag(i) ions on Pad 400 impregnated resin
Abstract: The polymer matrix (PAD-400) was impregnated by diethyldithiophosphate and used for sorption of silver ions from solutions. The impregnated sorbents were characterized by FTIR, SEM and DTA data. It was established that silver ions have been sorbed from solutions with impregnated sorbents due to formation of the metal-impregnate surface complexes. The sorption process is described better with Freundlich equation.
Keywords: sorption, diethyldithiophosphate, silver ions.
1. Introduction mean pore diameter (Hg) 362 A, surface area (BET) —
Study of organothiophosphorus acids and their de- 684 m 2/g). Diethyldithiophosphoric acid ((i-EtO)2PS)2H)
rivatives are very actual due to wide possible applica- was purchased from Sigma Aldrich GmbH. Before im-tions [1, 863] in hydrometallurgy [2, 149], waste wa- pregnation PAD-400 was rinsed with methanol and then ter treatment [3, 1636]. Dialkyldithiophosphoric acid with water to remove impurities. 7 g of potassium dieth-compounds are well known agents for impregnation of yldithiophosphate dissolved in 250 cm 3 of methanol was polymeric sorbents used for sorption of metal ions [4, added to 10 g of PAD-400, all ingredients were shaken for 201] applied for extraction ofnoble metals [5, 545] due 3 h at 293 K. After impregnation, SIR was rinsed by deion-to formation of stable metal complexes [6, 369]. ized water. The concentration of diethyldithiophosphoric
The aim of study is preparation of PAD-400 resin im- acid in PAD-400 matrix was determined by using gravimet-pregnated by diethyldithiophosphoric acid ((EtO)2PS)2H ric method. The content of (EtO)2PS)2H in PAD-400 was for sorption ofAg+ ions from nitrate solutions. ~ 50% (CHNS-analyzer EA-1108, Carlo-Erba). The pre-
2. Experimental pared impregnated sorbent was used in further metal sorp-
PAD-400 (Purolite) is a commercial granular macropo- tion studies in batch reactor. The metal ions contents were
rous styrene-divinylobenzene resin (moisture retention — analyzed by using atomic absorption spectroscopy (Aana-55%, grading < 1180 ^m, uniformity coefficient — 1.43, lyst-800, Perkin Elmer) after sorption from 0.05-0.02-mean diameter — 543 ^m, pore volume (Hg) — 0.7 ml/g, 0.04 mol/l solutions. The ligand coordination was studied
by FTIR absorption spectra in the range of400-4000 cm 1 (FTIR 2000, Perkin-Elmer), KBr pellets. The SEM/EDX
data obtained by Zeiss EVO MA 10/Aztec Energy Advanced X-Act (Zeiss SMT LTD/Oxford Instruments).
Figure 1. Microstructure of the PAD 400 granule (a) and the PAD 400 granule impregnated by (EtO^PS2K (b), PAD 400 granule after Ag+ ions sorption (c), the inner part of PAD 400 granule after Ag+ ions sorption (d) the inner part of the PAD 400 granule impregnated by (EtO^PS2K after Ag+ ions sorption (f)
3. Results and discussion
The microstructure of the PAD 400 granule (a) and the PAD 400 granule impregnated by (C2 H5o)2PS2K (b) shows on Fig. 1. The SEM-EDX analysis indicates the PAD-400 granules have some content of F (Figure 1a). The surface of the impregnated sorbent granule is characterized by P, S and K peaks from (C2 H5O)2PS2K (Fig. 1b). The appearance of the silver EDX peaks on the granule surface can evidence the silver ions sorption with the PAD 400 sorbents (Figure 1 c). However, silver ions have not been detected inside of the PAD-400 granules (Figure 1d), as well as, the PAD-400 granules impregnated with diethyldithiophosphoric acid, although, the presence of PSS-groups within the impregnated granules is confirmed by EDX (Figure 1e).
Obviously, the influence of steric factors causes a good impregnation and sorption for the PAD-400 sample
(pore size 362 A). The silver ions sorption capacity (qj of sorbents have been determined for sorbents experimentally for each sorbent system. According obtained isotherm graph the sorption parameters were calculated from the Langmuir and Freundlich models (Table 1) The characteristic S-shape of the sorption curve has a plateau indicating that the adsorption on impregnated sorbents is step-multilayer process. Indeed, the sorption process is described better with Freundlich equation, which gives an indication on the significant contribution of the chemical interaction in comparison with the physical adsorption. Sorption mechanism can be considered with both physical sorption of metal ions on the adsorbent surface and strong chemical reaction in the presence of the impregnated sorbent, which increases the metal sorption on impregnate. It is shown that sorption increases from the initial PAD-400 sorbent to the impregnated sorbents.
Table 1 - Calculated parameters of the Ag+ ions sorption on the PAD-400 sorbents
Sorbent Lang muir Freundlich
q o b R2 D Kf n R2
mmol/g mg/g l/mmol kJ/mol
PAD-400 17.24 1862.07 0.28 0.9070 -20.46 3.85 1.09 0.974
(i-EtO)2PS2K-PAD400 13.33 1440.00 0.95 0.8670 -21.47 5.79 1.93 0.9770
The FTIR spectrum of the PAD400 sample has polystyrene characteristic frequencies, e. g. 1600-1700 cm-1, 705-795 cm-1 bands identified as the stretching and deformation vibrations frequencies ofmonosubstituted aromatic hydrocarbons. The presence of absorption bands at 2925-3081 cm-1 and at 1350-1512 cm-1 related to n to vas and vs vibrations of aliphatic C-C bonds, C-H, CH2, CH3. The styrene absorption bands at 708, 795, 1605 and 1631 cm-1 and bands in the region 1700-2000 cm-1 called as "five fingers" are clearly visible. The FTIR spectrum of the sorbent containing PSS-functional groups has new
intensive bands at 1376-1350 cm-1, 990-850 cm-1. These bands related to the P-O-R. R-O groups vibrations, and stretching P = S vibrations were observed for PAD400 impregnated with (EtO)2PS2K (I) (Table 1). The spectra of the sorbents after sorption from Ag+ solutions considerably differ from spectra of the sorbents, which indicates formation of metal complexes with dithiophosphoric fragment. In comparison with (i- EtO)2PS2 K, low-frequency shift of the bands (20-30 cm-1) were observed due to formation of the metal-sulfur bonds and lower P=S bond order in 4-membered chelate ring.
Table 2 - Characteristic FTIR bands
Sample n D n D
(i- EtO)2PS2 K 687 577, 547
(i-EtO)2PS2 K -PAD-400 (I) 687, 618 0 570, 550 7
Ag+- ((i- EtO)2PS2) -PAD-400 (II) 653 34 551 26
Two endothermic effects at 103, 175 and four exothermic effect at 290, 430, 600 and 810 °C are found on the DTA curves of the PAD-400 sorbent. The total mass loss by the TG curve is equal 98.24%. The DTA curve of the PAD-400 impregnated with (EtO)2PS2K sorbent is characterized by two endo-effects at 85, 240 °C and four exo-effects at 280, 520, 735 and 800 °C. The PAD-400 sorbent impregnated with (EtO)2PS2K has three
endo-effects at 130, 210, 258 °C and three exo-effect at 526, 740, 800 °C after sorption ofAg+ ions from solution. The TG curve of impregnated samples shows total mass loss in the range of 98.65% at 900 °C temperature.
4. Conclusions
According to FTIR, SEM and DTA, it was found that sorption of silver ions from solutions with impregnated sorbents can occur via formation of the
metal-impregnate surface complexes. The polyfunctional ligands adsorbed on the surface of the polymer matrix, and these ligands interacted with the polymer porous
structure fixing in large cavities on the polymer surface. The metal ions bonded with the ligand functional groups forming metal complexes during sorption.
References:
1. Alimarin I. P., Ivanov V. M. Extraction with thio and dithio phosphorus acids//Russian Chemical Reviews. -1989. - T. 58. - No. 9. - C. 863.
2. Strikovsky A. G., Jerabek K., Cortina J. L., Sastre A. M., Warshawsky A. Solvent impregnated resin (SIR) containing dialkyl dithiophosphoric acid on Amberlite XAD-2: extraction of copper and comparison to the liquid-liquid extraction//Reactive and Functional Polymers. - 1996. - T. 28. - No. 2. - C. 149-158.
3. Ying X., Fang Z. Experimental research on heavy metal wastewater treatment with dipropyl dithiophos-phate//Journal of hazardous materials. - 2006. - T. 137. - No. 3. - C. 1636-1642.
4. Jerabek K., Hankova L., Strikovsky A. G., Warshawsky A. Solvent impregnated resins: relation between impregnation process and polymer support morphology I. Di- (2-ethylhexyl) dithiophosphoric acid//Reactive and Functional Polymers. - 1996. - T. 28. - No. 2. - C. 201-207.
5. Rovira M., Hurtado L., Cortina J. L., Arnaldos J., Sastre A. M. Impregnated resins containing di (2-ethylhexyl) thiophosphoric acid for extraction of palladium (II). I. Preparation and study of the retention and distribution of the extractant on the resin//Solvent extraction and ion exchange. - 1998. - T. 16. - No. 2. - C. 545-564.
6. Sharipov K. T., Daminova S. S., Talipova L. L. Crystal and Molecular Structure of Rhodium (III) Diisopropyldi-thiophosphate//Journal of Structural Chemistry. - 2002. - T. 43. - No. 2. - C. 369-372.
D OI: http://dx.doi.org/10.20534/AJT-16-11.12-66-71
Daminova Shahlo Sharipovna, Tashkent Chemical Technological Institute, Department of «Technology of silicate materials and rare precious metals», Scientific Researcher E-mail: [email protected] Talipov Samat,
Institute of Bioorganic Chemistry, Academy of Sciences of Republic Uzbekistan, PhD in Chemistry, E-mail: [email protected] Kadirova Zukhra Chingizovna, Tashkent Chemical Technological Institute, Center of Excellence,
Dr. Engineering, PhD in Chemistry, E-mail: [email protected] Sharipov Khasan Turabovich Professor, Tashkent Chemical Technological Institute, Department of "Technology of silicate materials and rare precious metals",
E-mail: [email protected]
Synthesis and crystal structure of co, cd, bi mixed-ligand complexes of diisopropyldithiophosphate and 2-amino-1-methylbenzimidazole
Abstract: The crystal and molecular structures of the mixed-ligand ternary complexes [Cd (MAB)2 (iso-ProPS2)2], [Co (MAB) (iso-ProPS2)2], [Bi (MAB) (iso-ProPS2)3] were determined. The aminobenzimidazole ligands were monodentate coordinated via endo-cyclic N atom. The monodentate coordination in the Cd
