The results of the study of chemical modification of synthetic boehmite (γ-AlO(OH)) surface with phosphonic complexone - imino-N,N-diuacetic-N-methylene phosphonic acid (PMIDA) to obtain a new complexing material capable of binding heavy metal ions are presented. The technique of simple one-step modification of boehmite by its treatment with aqueous solution of PMIDA (pH 2, temperature 20oC, time 6 h) was developed. The IR spectrum of the obtained PMIDA- boehmite shows bands characteristic of phosphonic -PO(OH)2 (900-1300 cm-1) and carboxyl -COOH (1637 cm-1 and 1386 cm-1) groups. As a result of modification, a dense coating (0.61 mmol/g or 1.5 groups/nm2) is formed on the surface of boehmite, in which the phosphonic group of PMIDA is the ‘anchor’ of the modifier, and the free iminodiacetate group shows complexing properties. The phosphonic coating was found to be hydrolytically stable at pH 2-7. It is shown that the sorption of metal ions (Ni(II), Cu(II)) by PMIDA- boehmite occurs in a more acidic environment compared to the original boehmite (shift of pH50by 2-3 units). Cu(II) ions bind to the -N(CH2COOH)2 group of fixed PMIDA more strongly than Ni(II) ions, similarly to the case for complexonates of these metals with PMIDA in solutions. PMIDA- boehmite can be recommended as a new effective material for sorption extraction and concentration of heavy metal ions under static conditions (sorption time 60 min). The developed method of fixation of iminodiacetate group using PMIDA can also be used in relation to other oxide carriers.

New palladium catalysts based on Pd(II) coordination heterogenization on the surface of synthetic boehmite chemically modified with nitrilotris(methylenephosphonic) acid (NTP) were ob-tained. The catalysts were prepared by impregnating the carrier (boehmite (gamma-AlOOH), NTP-boehmite (NTP-gamma-AlOOH)) with a PdCl2 solution followed by the reduction of Pd(II) to metallic palladium with potassium formate. The resulting samples were characterized by XPA, SEM, XPS, BET, and IR spectroscopy. The carriers have a high specific surface area (100-250 m(2)/g) and a mesoporous structure. The content of palladium in the obtained metal catalysts is 2-4 wt%, with an average particle size of 10-50 mu m. An analysis of the XPS spectra of the catalysts (Pd3d, N1s, P2p) shows that they contain metallic palladium Pd(0) and ionic forms of Pd(II) bonded to the oxygen and nitrogen atoms of the support. The possible composition of Pd(II) surface complexes on boehmite and NTP-boehmite was established by modeling the sorption vs. pH curve according to the theory of surface complexation. The reaction of the selective oxidation of benzyl alcohol to benzaldehyde in an aqueous solution (4 vol.% alcohol, 60 degrees C, 1 h) using atmospheric oxygen was chosen as a model reaction for evaluating the catalytic activity, which corresponds to the principles of "green chemistry": 2C(6)H(5)CH(2)OH+O-2= 2C(6)H(5)COH+ 2H(2)O. The oxidation process was moni-tored by measuring the IR spectra of the chloroform extract of the reaction mixture using the in-tensities of the absorption bands of alcohol (3100-3600 CM-1 (nu O-H)) and aldehyde (1700 CM-1(nu C=O)). The following series of catalyst activity was established: Pd(II) > Pd(0)/NTP-gamma-AlOOH > Pd(0)/ gamma- AlOOH > Pd(II)/ gamma-AlOOH >> Pd(II)/NTP-gamma-AlOOH. The metallic form of palladium is required for the catalytic activity. The coordination fixation of palladium on NTP-boehmite due to chelate binding by an aminophosphonic group increases catalyst activity compared to monodentate binding by hydroxo groups of unmodified boehmite.

New complexing sorbents have been manufactured via chemical surface-modification of highly dispersed boehmite (γ-AlO(OH)) by phosphonic complexones (PCs), namely, by nitrilotri(methylenephosphonic) acid (NTP), 1-hydroxyethane-1,1'-diphosphonic acid (HEDP), N -hydroxyethylimino- N , N -di(methylenephosphonic) acid (HEIDP), and imino- N , N -diacetic- N -methylenephosphonic acid (IDAMP). The manufactured PC–boehmite materials have been characterized by XRD, BET, SEM, TEM, and IR spectroscopy. Modified boehmites, in which the modifier anchor is one of the phosphonic functions of the complexone, exhibit the properties of a complexing support for double-charged metal ions. The kinetic characteristics and sorption capacities of PC–boehmites have been determined. The complexing selectivity on the modified surface are arranged in the following decreasing order: Pb(II) > Cu(II) > Zn(II) ≈ Ni(II) ≈ Co(II) ≈ Cd(II) > Ca(II). The stability of the sorbed state of metal ions changes along the series of surface-anchored complexones in the following order: IDAMP > NTP > HEDP > HEIDP. The trends elucidated point to a close correlation between complexa formation involving phosphonic complexones in solution and on the boehmite surface.

A method for the surface chemical modification of aluminum oxyhydroxide (boehmite γ-AlO (OH)) by the nitrilotris(methylene phosphonic) acid (NTP) complexing ligand is proposed. The unmodified and NTP-modified boehmites are characterized using X-ray powder diffraction, XPS, and IR spectroscopy; the acid–base and complex-forming properties of surface-grafted NTP are studied. One of the three phosphonic groups of NTP is found to be involved in binding to the boehmite surface. The surface concentration and stepwise dissociation constants of grafted NTP are determined. A study of the nickel(II) sorption as a function of aqueous acidity shows that the modifying coating increases the sorption capacity of boehmite (causing рН 50 to shift by one unit toward lower values). In terms of surface complexation theory, nickel(II) sorption from aqueous solutions may be described by models involving ≡Al–ONi + and ≡Al–ONi(OH) complexes in the case of boehmite and ≡Al–LH i Ni i –3 ( i = 0, 1, 2, or 3) complexes in the case of NTP-modified boehmite (NTP-boehmite). NTP anchorage to the surface decreases the stability of nickel(II) complexes compared to their analogues in solutions. A mechanism of nickel(II) ion binding by NTP-boehmite is suggested. The prepared new organomineral support can be used to immobilize those metal ions that form stable complexes with phosphonic acids.

The conditions of chemical modification of the surface of synthetic magnetic iron oxides (magnetite Fe3O4, maghemite γ-Fe2O3) by phosphonic complexones (PBTC, HEDP, HEIDPH, NTMP, EDTMP) are studied. It is shown that the maximum concentration of grafted groups is observed upon treating iron oxides with aqueous solutions of complexones containing two or three phosphonic groups at pH 2–3 and temperature of 50–60°C for 2–6 h. To characterize the grafted layer, various physicochemical research methods (XRD, FTIR spectroscopy, the BET method, thermal analysis, acid–base titration, sorption from solutions) were used. It is found that the modifying coating significantly increases the sorption ability of magnetic iron oxides towards metal cations (Cu(II), Cd(II)). A mechanism for binding of metal ions by modified sorbents is proposed.

The surface of synthetic magnetite (Fe3O4) and maghemite (γ-Fe2O3) nanoparticles was modified with phosphonic chelating compounds, 1-hydroxyethane-1,1-di(phosphonic acid) and nitrilotris(methylenephosphonic acid). The sorption affinity of functionalized magnetic iron oxides towards Niii under acidic conditions was increased by one order of magnitude.

Effect of complexons of polyaminopolycarboxylic acid series (IDA, NTA, EDTA, and DTPA) and polyphosphonic acid series (HEDP, NTP, and EDTP) on Cu(II) cations sorption on goethite (α-FeOOH) from aqueous solutions has been studied. Obtained results have been considered in the context of complexation reactions in bulk solution and on sorbent surface. It has been found that all complexons (except for EDTA), depending on nature, produce on goethite surface (≡FeOH) triple complexes of type A (surface–metal–complexon) of composition ≡FeOCuLH i 1+i−n and ≡FeOCuL(OH) j 1−j−n or type B (surface–complexon–metal) of composition ≡FeLH i Cu3+i-n and ≡FeLCu(OH) j 3−j−n . pH-Ranges for complex existence and stability constants for the surface complexes have been determined. Factors affecting the character of complexon effect (immobilization/remobilization) on the sorbed metal have been analyzed.

Coordination equilibria in the Co(II)–Ni(II)–2-aminopropanoic acid (HAla)–EDTA system have been studied spectrophotometrically at different molar ratios of the reagents in a wide pH range. It has been found that, when metal ions are in excess with respect to EDTA at pH 5–9, polyheteronuclear complexonates [(CoAla)Edta(NiAla)] 2– , [(CoAla 2 )Edta(NiAla 2 )] 4– , [(NiAla 2 )Edta(CoAla 2 ) 2 ] 4– , [(CoAla 2 )Edta(NiAla 2 ) 2 ] 4– , and [(NiAla 2 ) 2 Edta(CoAla 2 ) 2 ] 4– form in a solution. The equilibrium constants of formation of these complexes and their overall stability constants have been calculated. Possible structures of the polynuclear complexonates are discussed.

The influence of some complexing agents of (poly)aminopolycarboxylic acids (diethylenetriaminopentaacetic acid (DTPA), ethylenediaminotetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and iminodiacetic acid (IDA)) on the sorption of Cu 2+ by crystal and amorphous (hydr)oxides of Fe(III), Al(III), and Mn(IV) that are widespread mineral components of soils was studied. The obtained results are considered in terms of complex-formation in the solution and on the sorbent’s surface. The effect of the complexing agents on the metal sorption (mobilization/immobilization) is determined by (1) the stability, structure, and sorption capability of compexonates formed in the solution; (2) the acidity, and (3) the nature of the sorbent. The desorption effect on Cu 2+ cations was found to change in the following sequence of complexing agents: EDTA > DTPA ≫ NTA > IDA. The high-dentate complexing agents (EDTA, DTPA) had the greatest impact on ?u 2+ cations bound with crystalline (hydr)oxides of Fe, Al, and Mn. The low denticity of the complexing agents (IDA, NTA) and binding of ?u 2+ with amorphous sorbents leads to the weakening of desorption. The decrease in acidity promoted the mobilization of the metal under the influence of complexing agents; the increase in acidity caused its immobilization. The growth in the mobility of heavy metals bound with soil (hydr)oxides of Fe, Al, and Mn due to the complexing agents entering the surface and ground water is considered a factor of ecological risk.

Complexation in the Co(II)‒Ni(II)‒aminoethanoic acid (HGly)‒EDTA (H4Edta) system was studied at different molar ratios of components by absorption spectrophotometry. The mathematical modeling of A = f(pH) curves was used to establish that bi-, tri-, and tetranuclear heteroligand complexes like [(CoGly)Edta(NiGly)]2‒, [(CoGly2)Edta(NiGly2)]4‒, [(CoGly2)Edta(NiGly2)2]4‒, [(CoGly2)2Edta(NiGly2)]4‒, and [(CoGly2)2Edta(NiGly2)2]4‒, whose accumulation fraction attained 80‒100% at optimal pH values, were formed depending on the ratio of reagents and the acidity of a medium. The formation equilibrium and total stability constants of these complexes were calculated, and a hypothesis about their structure was made.

Complexation in systems containing vanadyl cations and organophosphonic acid complexone anions (POC, Pocj), such as 1-hydroxyethylidenediphosphonic acid (HEIDP, Heidp4−), nitrilotrimethylphosphonic acid (NTP, Ntp6−), and 2-phosphonobutane-1,2,4-tricarbocylic acid (PBTC, Pbtc5−), was studied by absorption spectroscopy and potentiometry. The molar and protonic compositions of the complexonates formed and the regions of their formation and existence were determined. The equilibrium constants of reactions and the stability constants of the complexonates were calculated. Experimental data were processed by the mathematical models that were able of evaluating the possibility of the existence of a wide spectrum of complex species in solution and to select the species sufficient to confirm experimental data.

The results of mathematical simulation of sorption equilibria with the participation of divalent cations of heavy metals (HMs), chelant (EDTA), and insoluble forms of humic acids (HAs) are discussed. It is shown that the formation of chelates of metals with EDTA in solutions results in the decreasing sorption of the metals by humic acids. We also analyzed the effect of the acidity of the medium and the HM: EDTA: HA ratio (in a wide range) on the desorption of metals. The desorbing effect of EDTA on the metals is the highest at pH 3–5 and increases with an increase in the concentration of EDTA and a decrease in the concentration of HAs. With respect to the remobilization of metals under the impact of EDTA, the metal cations can be arranged into the following sequence: Cu(II) > Ni(II) > Pb(II) ≫ Cd(II) > Co(II) > Zn(II). The obtained data have been used to analyze the remobilization / extraction of HMs from soils with a high content of humic substances.