Elżbieta Kociołek-Balawejder

A macromolecular N-chlorosulfonamide as oxidant for thiocyanates

Abstract A redox copolymer, macroporous poly(S/DVB) resin having N -chlorosulfonamide groups – obtained by chemical modification of Amberlyst 15 – was used for removal of thiocyanates from aqueous solutions. This resin contains active chlorine in functional groups (2.15 mmol/g) and shows oxidative properties. It was employed in static and flow systems to oxidise thiocyanate ions to less toxic compounds. The reactions were carried out in aqueous media containing 116 or 580 mg SCN − /dm 3 at different pH values. The data showed that the –SO 2 NClNa groups containing resin easily oxidised thiocyanates forming sulphates and cyanates. Cyanates are unstable under the reaction conditions (hydrolysis). The concentration of thiocyanates dropped below 0.5 mg/dm 3 in most of the tested solutions. The thiocyanate-oxidising capacity of the resin was found to be 0.55 mmol/g. The kinetic course of the reaction strongly depends on the pH of the reaction medium (acidic medium>neutral medium>alkaline medium). The functional groups of the reactive copolymer during thiocyanate treatment undergo dechlorination to sulfonamide groups. The exhausted copolymer can be regenerated by sodium chlorate(I) and reused for continuous processes.

Iron and aluminium oxides containing industrial wastes as adsorbents of heavy metals: Application possibilities and limitations.

Industrial wastes with a high iron or aluminium oxide content are produced in huge quantities as by-products of water treatment (water treatment residuals), bauxite processing (red mud) and hard and brown coal burning in power plants (fly ash). Although they vary in their composition, the wastes have one thing in common – a high content of amorphous iron and/or aluminium oxides with a large specific surface area, whereby this group of wastes shows very good adsorbability towards heavy metals, arsenates, selenates, etc. But their physical form makes their utilisation quite difficult, since it is not easy to separate the spent sorbent from the solution and high bed hydraulic resistances occur in dynamic regime processes. Nevertheless, because of the potential benefits of utilising the wastes in industrial effluent treatment, this issue attracts much attention today. This study describes in detail the waste generation processes, the chemical structure of the wastes, their physicochemical properties, and the mechanisms of fixing heavy metals and semimetals on the surface of iron and aluminium oxides. Typical compositions of wastes generated in selected industrial plants are given. A detailed survey of the literature on the adsorption applications of the wastes, including methods of their thermal and chemical activation, as well as regeneration of the spent sorbents, is presented. The existing and potential ways of modifying the physical form of the discussed group of wastes, making it possible to overcome the basic limitation on their practical use, are discussed.

Synthesis and characterization of hybrid materials containing iron oxide for removal of sulfides from water

Hybrid materials containing iron oxides based on macroporous and gel-type sulfonic and carboxylic cation exchangers as supporting materials were obtained. Multiple factors, including the kind of functional groups, ion exchange capacity, and polymer matrix type (chemical constitution and porous structure), affected the amount of iron oxides introduced into their matrix (7.8-35.2% Fe). Products containing the highest iron content were obtained using carboxylic cation exchangers, with their inorganic deposit being mostly a mixture of iron(III) oxides, including maghemite. Obtained hybrid polymers were used for removal of sulfides from anoxic aqueous solutions (50-200mgS(2-)/dm(3)). The research showed that the form (Na(+) or H(+)) of ionic groups of hybrid materials had a crucial impact on the sulfide removal process. Due to high iron oxide content (35% Fe), advantageous chemical constitution and porous structure, the highest removal efficiency (60mgS(2-)/g) was exhibited by a hybrid polymer obtained using a macroporous carboxylic cation exchanger as the host material. The process of sulfide removal was very complex and proceeded with heterogeneous oxidation, iron(III) oxide reductive dissolution and formation of sulfide oxidation and precipitation products such as iron(II) sulfides, thiosulfates and polysulfides.

A copolymer with N-chlorosulfonamide pendant groups as oxidant for residual sulfides

Abstract Sulfides are ones of the most obnoxious and troublesome contaminants of water. Potable and industrial waters have to be sulfide free. A macromolecular analogue of chloramine T was prepared and developed as the solid phase oxidising reagent for sulfide ions. The resin was prepared starting from Amberlyst 15 by the following series of reactions: chlorosulfonation, sulfonamidation and N -chlorination. The resulting copolymer which contained active chlorine in functional groups (2.15 mmol Cl*/g) was used as an efficient and regenerable agent for sulfide ion removal from solutions by their transformation to non-toxic sulfates. The experiments were carried out in static and dynamic regimes using solutions containing 64.0 or 320.0 mg S 2− /dm 3 . The effects of various parameters on the reaction course were studied (ratio of the reagents, alkalinity of the reaction media, flow rate in column processes). It was possible to oxidize S 2− directly and quantitatively to SO 4 2− , even in static condition, if an excess of active chlorine relative to the stoichiometry was used. In the column processes sulfide-free effluents ( 2− /dm 3 ) were obtained. By reacting a stoichiometric amount of reagents in batchwise conditions not only sulfate but also various intermediate products, such as elemental sulfur, polysulfide, thiosulfate and sulfite were found in solution.

A redox copolymer having N-chlorosulfonamide groups for cyanide ion decomposition in dilute aqueous solutions

Abstract A redox copolymer, macroporous poly(S/DVB) resin having N -chlorosulfonamide groups was used for removal of cyanide ions from aqueous solutions. This resin contains active chlorine in functional groups (2.3 mmoUg, i.e., 4.6 meq/g) and shows oxidative properties. The possibility of using this resin for oxidation of cyanide ions to less toxic or non-toxic compounds was investigated in aqueous media containing different amounts of these ions (26–2600 mg CN − /dm 3 ) and at different pH values. Examples of the use of the macromolecular chloramine as a polymer supported reagent for oxidation of cyanides in static and dynamic conditions are given. The data showed that the oxidative properties of the N -chlorosulfonamide resin in contact with cyanide ions are remarkable. Active chlorine easily oxidized cyanides forming cyanates (1000-times less toxic than cyanides). In contact with the resin the concentration of cyanides in the majority of tested solutions dropped below 0.05 mg CN − /dm 3 . During oxidation processes the -S0 2 NCINa groups transform to −SO 2 NH 2 groups. They can be regenerated by the use of hypochlorite solutions.

Synthesis and main properties of uniformly chlorosulfonyl-substituted styrene-divinylbenzene resins

Cinetique de la chloruration de resines commerciale echangeuses de cation styrenesulfonate-divinylbenzene

CuO-Loaded Macroreticular Anion Exchange Hybrid Polymers Obtained via Tetrachlorocuprate(II) Ionic Form

Amberlite IRA900 Cl, the macroreticular, polystyrene/divinylbenzene anion exchanger containing quaternary ammonium groups, was used as the support for copper(II) oxide deposition, and, as a result a new hybrid ion exchanger (HIX) was obtained. The CuO deposit was introduced into the anion exchanger structure in two steps conducted batchwise at ambient temperature. First, the functional groups were transformed from the into the form, using 5 mol dm−3 NaCl or HCl solution with CuCl2 being added, and then the intermediate product was contacted with NaOH/NaCl solution to precipitate CuO within the polymer beads. A HIX containing as much as 11.5% Cu was obtained. The distribution of the inorganic load within the porous matrix of polymer beads was atypical; CuO was mainly deposited in the outer parts of the beads and only a small amount was in their inner parts. This may be advantageous in some practical applications concerning the removal of harmful admixtures from waters in sorption processes.

Using macroporous N-chlorosulfonamide S/DVB copolymer as an aid to iron removal from water*

The de-ironing of water is a basic stage in water-treating technology. Consequently, the oxidation of easily soluble Fe(II) to poorly soluble Fe(III) compounds is indispensible. In order to oxidize Fe(II) ions to Fe(III), a macromolecular and macroporous product in bead form was used: polystyrene cross-linked by divinylbenzene, which contains pendant N-chlorosulfonamide groups in both the sodium and hydrogen forms. To assist the process of removing residual iron from water, this polymer - a macromolecular analog of Chloramine T, containing more than 4.0 mequiv of active chlorine/g - was prepared, starting from the sulfonate cation exchanger Amberlyst 15 by a three-step transformation of its functional groups. The investigations were carried out using both the batchwise and column methods, and 0.0025 M as well as 0.02 M FeSO4 solutions with different acidity were used. We found that the oxidation of ferrous ions to ferric by N-chlorosulfonamide copolymer was effective and was favored by a low pH. The oxidative ability of the copolymer was 225 mg Fe(II)/g. We established that the oxidation reaction could be operated in two directions. In acidic media (pH < 2.5), Fe(III) ions remained in the solution as products of the reaction. The higher the pH, the more the poorly soluble ferric compounds sedimented in the inner structure of the copolymer beads. In this way, new hybrid materials were obtained, i.e., by ferrous/ferric oxides and hydroxides, by nanoparticles, modified materials which can serve as specific reacting sorbents and catalysts.

Thermal analysis of macromolecular “Haloamines”

The TG, DTG and DTA curves of macromolecular macroporous N-halogeno- and N,N-dihalogenosulfonamides are reported and interpreted. To compare their thermal behaviour with that of their unfunctionalized matrices, analogous studies were performed on the porous styrene-divinylbenzene(20%)copolymer and its sulfonamide derivative.ZusammenfassungDie TG-, DTG- und DTA-Kurven makromolekularer makroporöser N-Halogen- und N,N-Dihalogensulfonamide werden beschrieben und gedeutet. Zum Vergleich wurde das thermische Verhalten des unsubstituierten porösen Styren-(20%)Divinylbenzen-Copolymeren und seines Sulfonamids in gleicher Weise untersucht.РЕжУМЕпРИВЕДЕНы И ОБсУжДЕН ы тг, Дтг И ДTA кРИВыЕ Дль МАкРОМОлЕкУльРНых М АкРОпОРИстых N-гОлОгЕН- И N,N-ДИгАлОкЕН сУльФАМИДОВ. с цЕльУ сОпОстАВлЕНИь Их тЕР МИЧЕскОгО пОВЕДЕНИь с Их НЕАктИВНыМИ НЕжА МЕЩЕННыМИ пРОИжВОДН ыМИ, БылИ пРОВЕДЕНы АНАлОгИЧН ыЕ ИсслЕДОВАНИь пОРИстОгО сОпОлИМЕР А стИРОлА И ДИВИНИлБЕ НжОлА И ЕгО сУльФАМИДНОгО пРОИж ВОДНОгО.

Synthesis and basic characterization of a macromolecular dibromoamine: N,N-dibromo-poly(styrene-co-divinylbenzene)sulfonamide

Abstract A macromolecular-pendent-group N,N-dibromosulfonamide ([P]-SO2NBr2) having a macroporous styrene-divinylbenzene matrix structure has been obtained by three methods: by the action of (a) bromine in aqueous medium and (b) aqueous metal hypobromites in acidic medium, on the appropriate macromolecular-pendent-group sulfonamide, and by (c) the action of an aqueous metal bromide on the appropriate macromolecular N,N-dichlorosulfonamide. In the best case the product was obtained with nearly 100% functional yield and it contained 2.4 mmol g−1 -SO2NBr2 groups, i.e. ca. 0.38 g g−1 of active bromine. The stability of the resin was investigated in the range 20–100°C in the dry state as well as in aqueous media. Thermoanalysis (thermogravimetric, differential thermogravimetric and differential thermal analysis curves) was carried out up to 1000°C and its course was interpreted. The resin has brominating, oxidative and microbiocidal properties. It reacts in a reversible way: after loss of the active bromine, it can be reactivated again.