The synthesis of new complexing adsorbents with thiophenol (MPhS) and aminobenzthiazolpropyl (ABTS) groups grafted onto the surface of silica gels are considered. The extraction of precious metals (Au(III), Ag(I), Pd(II), Pt(II,IV), Rh(III), Ir(IV), Ru(IV), Os(IV)) from solutions of hydrochloric acid by MPhS and ABTS adsorbents. Contact time, acidity, temperature (25 – 95 °C), and the presence of a labilization agent tin(II) chloride is examined. It is shown that the adsorption properties of MPhS for precious metals are better than ABTS. It was proved by luminescence spectroscopy that gold, silver and platinum in the surface complexes with sulfur-containing groups are in lower oxidation states; and by the EPR method it was proved that ruthenium and osmium in surface complexes are in oxidation state +3. The formation of luminescent Ag(I), Au(I) and Pt(II) complexes on the surface of the MPhS, colored Ru(III) complexes on the surface of MPhS and ABTS, and mixed-ligand complexes of Pt(II) with surface aminobenzthiazole groups and Michler’s thioketone were used for developing methods of their adsorption luminescent, adsorption-photometric and test determinatio

Синтетичні барвники широко використовуються в харчовій, фармацевтичній, паперовій та текстильній промисловості.Однак деякі з них можуть бути небезпечними для здоров'я людини.Для очищення стічних вод виробництв від барвників, а також контролю їх вмісту в продуктах найбільш поширеними є сорбційні методи вилучення.Найчастіше для очищення вод від синтетичних барвників використовують вуглецеві сорбенти, які отримують з дешевих натуральних матеріалів

Silica based adsorbents modified with polyhexamethylene guanidine and sulfonic derivatives of nitroso naphthols - nitroso-N salt (NNS) and nitroso-R salt (NRS), have been proposed for preconcentration and solid-phase photometric determination of Ni(II) in industrial solutions. Adsorbents with the surface concentration of the reagents of 1.5 and 3 μmol/g have been studied. Adsorbents with NNS functional groups quantitatively extract Ni(II) at pH 5.5-7.5, while with NRS functional groups – at pH 5.5-7.0, giving complex compounds with the composition Ni(II) : Reagent = 1 : 3. After Ni(II) adsorption the adsorbents became orange (λ = 510 нм) or brown (λ = 490 нм) for NNS and NRS respectively. The pH range of maximum color intensity coincides with the pH range of the quantitative extraction of Ni(II). The procedure of solid-phase photometric determination of Ni(II) in form of diffuse reflectance spectroscopy has been developed. The analytical range of the procedure is 0.1 – 3.0 μg of Ni(II) per 0.1 g of the adsorbent with the surface concentration of the reagent of 1.5 μmol/g and 0.15 – 6 μg of Ni(II) per 0.1g of the adsorbent with the surface concentration of the reagent of 3 μmol/g. The procedure was used for determination of Ni(II) in the rinsing and waste waters of galvanic manufactory. The results accuracy was confirmed by ICP-OES analysis.

Silica modified with 2-nitroso-1-naphthol-4-sulfonic acid (NNS), quantitatively extracting palladium(II) from solutions in the pH range 1–8, is proposed for the preconcentration and photometric determination of palladium(II) in the adsorbent phase. In the sorption of palladium(II) from solutions with pH 1–3, complex compounds of the stoichiometry Pd : NNS = 1 : 2 were formed on the adsorbent surface. They has intense lilac color and a maximum in diffuse reflectance spectrum at 550 nm. A procedure is developed for sorption–photometric determination of palladium in the version of diffuse reflectance spectroscopy with a limit of detection 0.03 µg per 0.1 g of the sorbent. The analytical range is 0.1–10 µg/0.1 g. The procedure was tested in the determination of palladium in wastewater and water extract from the soil.

A novel biosorbent based on pine (Pinus sylvestris) sawdust with chemical grafted thiourea groups was proposed for preconcentration of precious metals. A simple procedure was proposed for the synthesis of biosorbent by treating of sawdust with ammonium thiocyanate solution and a subsequent heat treatment at 160 degrees C. The biosorbent has been studied by thermogravimetry/differential scanning calorimetry (TGA/DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The adsorption properties for precious metals ions (Au3+, Pd2+, Pt2+, Pt4+, Ir4+, Rh3+, Ru4+) extraction have been studied. Biosorbent quantitatively extracted precious metals from dilute solutions of hydrochloric acid (0.5-4.0 M). Iron and non-ferrous metals were not extracted in these conditions. The adsorbent showed high adsorption capacity for precious metals: 0.4 (Au3+), 1.7 (Pd2+), 1.0 (Pt2+), 0.8 (Pt4+), 0.45 (Ru4+), 0.55 (Rh3+), 0.4 (Ir4+) mmol/g. Biosorbent was used for extraction and preconcentration of precious metals from industrial solutions of refinery. Enriched for precious metals desorbing solution was obtained as a result. It is possible to obtain precious metals powder by combustion of biosorbent after adsorption of precious metals.

2-Mercapto-5-benzimidazolesulfonic acid (MBI), also noncovalently bound to a silica surface, is proposed as a reagent for the low-temperature luminescence determination of Cu(I), Ag(I), Au(I), and Pt(II). Luminescence excitation and luminescence spectra of metal complexes with MBI in solutions and on the adsorbent surface represent broad unstructured bands in the regions 250–400 and 450–700 nm, respectively. The developed procedures for the luminescence and sorption–luminescence determination of Cu, Ag, Au, and Pt with limits of detection at a level of 0.001–0.01 μg on 0.1 g of adsorbent are tested in the determination of metals in natural and industrial samples.

Sorbents based on inorganic oxides sequentially modified with polyhexamethylene guanidine, ferrozine, and ferene S are proposed for the preconcentration and determination of iron(II). Upon sorption from solutions with pH 2.5–7.0, colored iron(II) complexes with ferrozine and ferene S, having broad bands with maxima at 560 and 600 nm in the diffuse reflectance spectrum, respectively, formed on the sorbent surface. Procedures for the sorption–photometric determination of iron(II) using diffuse reflectance spectroscopy were developed. The limits of detection for iron(II), calculated by the 3s criterion were 0.005 and 0.006 μg per 0.1 g for sorbents based on silica with immobilized ferrozine and ferene S, respectively. The linearity of calibration curves remains up to 5 and 10 μg per 0.1 g for sorbents based on silicon and aluminum oxides, respectively. The procedures were tested in the determination of the total iron concentration in bottled drinking waters and alcoholic drinks.

The adsorption of polyhexamethyleneguanidine hydrochloride (PHMG HC) from aqueous solutions on silica and crystalline cellulose (CC) surfaces in batch and dynamic modes have been studied. The formation of PHMGC sorbates is due to.n interaction of highly basic amino groups of P.MG. (pK(a) = 13.5), which are protonated in wide range pH and capable of forming hydrogen bonds with a hydroxylated surface. Quantitative sorption of PGMGH on silica gels occurs in the pH range 2-8 while on CC-only in the pH range 6-9. This difference in PHMGC sorption behavior can be explained by different bond strengths, since the pKa of silica gel hydroxyl groups is 7.1, and CC is 10, 12 -for the secondary groups and 14 -for the primary groups. By a capillary electrophoresis method, it has been shown that there is a tendency for more "light" polyguanidine oligomers to concentrate on silica, with their subsequent displacement by more "heavy" oligomers that do not desorb even from concentrated HCl solutions. Sorption of PHMGC on cellulose, unlike silica, is completely reversible. The use of cellulose for preconcentration of PHMGC with its subsequent determination in a sorbent phase by sorptionphotometric, colorimetric and test-methods, as well as photometric method in solution after desorption (limit of detection = 0.012 mg/l) is proposed.

Adsorbents based on silica sequentially modified by polyhexamethylene guanidine and nitroso-R salt or nitroso-N salt are proposed for the preconcentration and adsorption-photometric determination of iron. It is shown that these adsorbents quantitatively recovered Fe(III) at pH 3.5–4.0 and Fe(II) at pH 4.5–7.0. In the adsorption of Fe(III) and Fe(II), intensely colored green complexes formed on the adsorbent surface. Based on the absence of signals in EPR spectra, it was concluded that iron in the oxidation state +2 was included into surface complexes with nitroso-R salt or nitroso-N salt. When Fe(III) interacted with nitroso-R salt or nitroso-N salt immobilized on the adsorbent surface, it was reduced to Fe(II). Diffuse reflection spectra of the surface complexes of iron(II) were broad bands with maxima at 720 and 710 nm. Procedures of the adsorption-photometric determination of iron in natural waters and snow samples were developed with the limit of detection of 0.05 μg of iron per 0.2 g of the adsorbent.

Sodium 2,3-dimercapto-1-propanesulfonate (unithiol) which forms complexes with copper(I), silver(I) and gold(I) with intense luminescence at 77 K was used for low-temperature luminescent determination of copper, silver and gold. Sorbent obtained by consecutively modification of silica with polyhexamethylene guanidine and unithiol quantitatively extracts copper(II), silver(I) and gold(III) in the pH range of 1-8. The luminescence-excitation and luminescence-emission spectra of copper(I), silver(I) and gold (I) complexes with unithiol, including the last bounded to the silica surface, are located in the range 200-350 nm and 500-700 nm, respectively. The methods of luminescent determination in solutions and sorption-luminescent determination of copper, silver and gold were developed. Sorption preconcentration and subsequent luminescent determination of components in the solid sorbent phase allow to reduce their limits of detection tenfold. Luminescent determination in solutions and sorption-luminescent determination techniques were used to determine copper in natural and technogenic waters and gold in gold-containing flotation concentrate.

A new adsorbent is synthesized on the basis of silica consecutively modified by polyhexamethylene guanidine and 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron) for the group preconcentration of Fe(III), Al(III), Cu(II), Pb(II), Zn(II), and Mn(II) followed by determination by inductively coupled plasma atomic emission spectrometry. The adsorbent in the batch mode quantitatively (recovery 98−99%) extracts Fe(III), Al(III) and Cu(II) ions at pH 4.0 and Fe(III), Al(III), Cu(II), Pb(II), Zn(II), and Mn(II) ions at pH 7.0; the time of attainment of an adsorption equilibrium does not exceed 10 min. Consecutive preconcentration at pH 4.0 and 7.0 in the batch and dynamic modes ensures the quantitative separation of Fe(III), Al(III), and Cu(II) from Pb(II), Zn(II), and Mn(II) and their separate determination. The quantitative desorption of metals was attained with 0.5−1.0 M HNO3 (5 or 10 mL). In preconcentration from 200 mL of solution with 5 mL of a desorbing solution, the preconcentration coefficient was equal to 40. The developed procedure was used for the determination of metal ions in river waters of Krasnoyarsk Krai. The results obtained were verified by the added−found method.

The adsorption of osmium(VIII) from sulfuric and hydrochloric acid solutions and gas phase on silicas chemically modified by dithiocarbamate, thiodiazolthiol, mercaptophenylpropylurea, and aminobenzothiazolpropyl groups is studied. A procedure is developed for the adsorption-photometric determination of osmium, including the adsorption of osmium(VIII) from the gas phase on silicas chemically modified by sulfur-containing groups and the determination of osmium in the adsorbent phase by diffuse reflection spectroscopy. The procedure was used to determine osmium in a certified reference material of the composition of a matte ore thermal melting and process waters.

Для концентрирования и сорбционно-фотометрического определения кобальта предложен сорбент на основе кремнезема, последовательно модифицированного полигексаметиленгуанидином и нитрозо-Р-солью. Данный подход позволяет получать сорбенты с контролируемой поверхностной концентрацией реагента. Сорбент извлекает кобальт(II) из растворов с рН 5–9 и коэффициентами распределения 5 ? 103 1 ? 104 см3/г. Рассмотрены особенности влияния Fe(II) и Fe(III) на концентрирование и определение кобальта. Мешающее влияние Fe(II) устраняют его окислением до Fe(III). Показано, что метрологические характеристики методик зависят от поверхностной концентрации реагента. Предел обнаружения кобальта составляет 0.01 мкг на 0.1 г сорбента. Разработанные методики использованы при определении подвижных форм кобальта в почвах.

An adsorbent based on silica consecutively modified with poly(hexamethylene guanidine) and nitroso-R-salt is proposed for the adsorption preconcentration and photometric determination of cobalt. The approach gives adsorbents with the controlled surface concentration of the reagent. The adsorbent extracts cobalt(II) from solutions of pH 5–9 with partition coefficients of 5×103–1 × 104 cm3/g. The specific features of the influence of Fe(II) and Fe(III) on the preconcentration and determination of cobalt are considered. The interference with Fe(II) is eliminated by its oxidation to Fe(III). It is shown that the performance characteristics of the procedures depend on the surface concentration of the reagent. The limit of detection for cobalt is 0.01 μg per 0.1 g of the adsorbent. The developed procedures were used for the determination of mobile cobalt species in soils.