WATER ROLE IN THE GASES CHEMOSORPORATION PROCESSES BY SORPTION-ACTIVE MATERIALS

The work summarizes the literature data on the hydration and chemisorption of toxic gases by polymeric sorption-active materials. The mechanisms of absorption by granular and fibrous ion-exchange and impregnated materials and the state of adsorbed water have been studied using various research methods (gravimetric, sorption-thermochemical, derivatographic, IR spectroscopic). The regularities of the hydration processes of granular strongly acidic sulfonic cationexchangers of the brands KU‑2 and KU‑23 (macroporous analogue), fibrous strongly acidic sulfonic cation- exchanger VION KS‑3, fibrous weakly acid carboxylic cation exchanger VION KN‑1 in various ionic forms are considered. Among the anion exchangers, the hydration of granular strongly basic anion- exchangers of the brand AV‑17, granular weakly basic anionexchangers of the brands AN‑25 (AN‑251 macroporous analogue) and ANKB‑35, fibrous strongly basic anion- exchangers of the brands FIBAN A‑6 and FIBAN A‑12, fibrous medium basic anion- exchangers of the brands CM‑2, fibrous weakly basic anion- exchangers of the brands CM-A1, VION AN‑1, VION AN‑3, FIBAN A‑5, FIBAN A‑11 and FIBAN AK‑22 are considered. It has been established that, by nature, the bond with the active centers of water is derided into a «bound» and a ordiner – «free». The first one is a monolayer and the nearest bonded with the ion of the ball; the other is the osmotic swelling water. It has been shown that for the effective absorption of most toxic gases and vapors (SO2, HCl, Cl2, SiF4, HF, NO2, NH3, аміни, COCl2, O3), it is necessary to have «free» water, which is not only a diffusion medium in which mass transfer proceeds, but also is a direct participant in chemisorption.

The Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate in the Presence of Strongly Basic Anion-Exchange Styrene-Divinylbenzene Anionites Dowex

The synthesis of glycerol carbonate from glycerol and dimethyl carbonate in the presence of strongly basic styrene-divinylbenzene anionites Dowex 1×2, Dowex 1×4 and Dowex 1×8 in the –OH form with different cross-linking degree of polystyrene matrix (the divinylbenzene content of 2, 4 and 8 wt.%) at 90–105 °C and a dimethyl carbonate/glycerol molar ratio equal to 2 was studied. The yield of glycerol carbonate was shown to decrease with an increase in the cross-linking degree of the anion-exchange resin. The maximum conversion of glycerol (95 %) and selectivity to glycerol carbonate (45.5 %) were observed in the presence of Dowex 1×2 at 105 °C after 5 h of the reaction. Advantages of the studied systems were demonstrated in comparison with the anion-exchange and cationexchange resins proposed in the literature.

Comparative studies on the adsorption of various radioactive nuclides from waste aqueous solutions on graphene oxide, inorganic and organic ion exchangers

Adsorption of the radionuclides 141Ce, 140La, 140Ba, 137+134Cs, 131I, 125Sb, 103Ru, 95Nb and 95Zr are studied on graphene oxide from waste aqueous solution samples and their adsorption behaviors are compared to that on the inorganic ion exchanger Ceric tungstate as well as on the strong acidic cation exchanger Dowex-50X8 H+ form, the chelating resin Chelex-100 Na+ form and the strong basic anion exchanger AG-1X8 Cl− form. The waste samples are dilute aqueous solutions resulting from previous work. These solutions contained neither oxidizing nor reducing agents, consequently, it is expected that these radionuclides are existing in their most stable oxidation states, i.e. Ce(III), La(III), Ba(II), Cs(I), Ru(III) & (IV), Sb(III) & (V), Nb(V) and Zr(IV). The adsorption is studied under static conditions for all these radioactive nuclides in the presence of each other. Gamma radiometric analysis is carried out for these radionuclides. Effect of some factors on the adsorption is studied such as pH, graphene oxide particle sizes, contact time, temperature and other parameters. Complete removal of some radionuclides is achieved from these waste solutions by adsorption on graphene oxide. Some separation alternatives for some of these radionuclides are also achieved.

Physicochemical Interactions in Systems C.I. Direct Yellow 50—Weakly Basic Resins: Kinetic, Equilibrium, and Auxiliaries Addition Aspects

Intensive development of many industries, including textile, paper or plastic, which consume large amounts of water and generate huge amounts of wastewater-containing toxic dyes, contribute to pollution of the aquatic environment. Among many known methods of wastewater treatment, adsorption techniques are considered the most effective. In the present study, the weakly basic anion exchangers such as Amberlyst A21, Amberlyst A23 and Amberlyst A24 of the polystyrene, phenol-formaldehyde and polyacrylic matrices were used for C.I. Direct Yellow 50 removal from aqueous solutions. The equilibrium adsorption data were well fitted to the Langmuir adsorption isotherm. Kinetic studies were described by the pseudo-second order model. The pseudo-second order rate constants were in the range of 0.0609–0.0128 g/mg·min for Amberlyst A24, 0.0038–0.0015 g/mg·min for Amberlyst A21 and 1.1945–0.0032 g/mg·min for Amberlyst A23, and decreased with the increasing initial concentration of dye from 100–500 mg/L, respectively. There were observed auxiliaries (Na2CO3, Na2SO4, anionic and non-ionic surfactants) impact on the dye uptake. The polyacrylic resin Amberlyst A24 can be promising sorbent for C.I. Direct Yellow 50 removal as it is able to uptake 666.5 mg/g of the dye compared to the phenol-formaldehyde Amberlyst A23 which has a 284.3 mg/g capacity.

Physicochemical Interactions in Systems C.I. Direct Yellow 50 – Weakly Basic Resins: Kinetic, Equilibrium, and Auxiliaries Addition Aspects

Intensive development of many industries, including textile, paper or plastic, which consume large amounts of water and generate huge amounts of wastewaters containing toxic dyes, contribute to pollution of the aquatic environment. Among many known methods of wastewater treatment, adsorption techniques are considered as the most effective. In the present study the weakly basic anion exchangers such as Amberlyst A21, Amberlyst A23 and Amberlyst A24 of the polystyrene, phenol-formaldehyde and polyacrylic matrices were used for C.I. Direct Yellow 50 removal from aqueous solutions. The equilibrium adsorption data were well fitted to the Langmuir adsorption isotherm. Kinetic studies were described by the pseudo-second order model. The pseudo-second order rate constants were in the range of 0.0609-0.0128 g/mg·min for Amberlyst A24, 0.0038-0.0015 g/mg·min for Amberlyst A21 and 1.1945-0.0032 g/mg·min for Amberlyst A23, and decreased with the increasing initial concentration of dye from 100-500 mg/L, respectively. There were observed auxiliaries (Na2CO3, Na2SO4, anionic and non-ionic surfactants) impact on the dye uptake. The polyacrylic resin Amberlyst A24 can be promising sorbent for C.I. Direct Yellow 50 removal as it is able to uptake 666.5 mg/g of the dye compared to the phenol-formaldehyde Amberlyst A23 of the 284.3 mg/g capacity.

Application of Ion Exchange Resin in the Advanced Treatment of Condensate Water

The advanced treatment of condensate water is important for efficient reuse of water resources, especially in confined space. In this work, a novel integrated process of ion exchange resins and activated carbon is proposed to remove various pollutants in condensate water. A fixed bed column of pre-treated basic anion exchange resin, acidic cation exchange resin, mixed ion exchange resins and modified activated carbon was applied to remove ionic pollutants, organic pollutants and adjust the pH value of output water. The effects of the types, amount ratios and the sequence of ion exchange resins were investigated using two types of condensate water. The results showed that the output water of the fixed bed column had an average TOC of 30~70 ppm, conductivity under 5 μS/cm, pH value of 5~8, which could meet the requirements of sanitary water. The saturated adsorption capacities of the basic anion exchange resin and the acidic cation exchange resin were calculated to be 0.87 mol/L and 1.82 mol/L, respectively. Under the actual operating conditions, continuous dynamic test was carried out over a condensate water treatment module consisting of two adsorption columns and four exchange columns to evaluate its real service life.

Size-Controlled Transformation of Cu2O into Zero Valent Copper within the Matrix of Anion Exchangers via Green Chemical Reduction

Composite materials containing zero valent copper (ZVC) dispersed in the matrix of two commercially available strongly basic anion exchangers with a macroreticular (Amberlite IRA 900Cl) and gel-like (Amberlite IRA 402OH) structure were obtained. Cu0 particles appeared in the resin phase as the product of the reduction of the precursor, i.e., copper oxide(I) particles previously deposited in the two supporting materials. As a result of a one-step transformation of preformed Cu2O particles as templates conducted using green reductant ascorbic acid and under mild conditions, macroporous and gel-type hybrid products containing ZVC were obtained with a total copper content of 7.7 and 5.3 wt%, respectively. X-ray diffraction and FTIR spectroscopy confirmed the successful transformation of the starting oxide particles into a metallic deposit. A scanning electron microscopy study showed that the morphology of the deposit is mainly influenced by the type of matrix exchanger. In turn, the drying steps were crucial to its porosity and mechanical resistance. Because both the shape and size of copper particles and the internal structure of the supporting solid materials can have a decisive impact on the potential applications of the obtained materials, the results presented here reveal a great possibility for the design and synthesis of functional nanocrystalline solids.

Selective removal of nitrate using a novel asymmetric amine based strongly basic anion exchange resin

In this study, a novel asymmetric amine-based strongly basic anion exchange resin SE-1 was synthesized successfully via the reaction of chloromethylated styrene–divinylbenzene copolymer with N, N-dimethyloctylamine. The sorption performance of SE-1 for selective removal of nitrate in aqueous solution was compared to a commercially available nitrate specialty resin, namely Purolite A 520E (A 520E). It was found that the kinetic data could be described better by the pseudo-second-order model, and SE-1 indicated a faster sorption kinetics than A 520E resin. The Langmiur model was more appropriate for explicating the sorption isotherm. Importantly, SE-1 exhibited a greater sorption capacity for nitrate regardless of the absence or presence of competing anions in solutions. The result of column tests reinforced the feasibility of SE-1 for practical application in groundwater treatment.

Hemicellulose Recovery from Spent-Sulfite-Liquor: Lignin Removal by Adsorption to Resins for Improvement of the Ultrafiltration Process

In this work, three polymeric resins were examined as alternatives for the separation of hemicellulose and lignin. The aim was to remove the lignin from spent-sulfite-liquor (SSL) prior to ultrafiltration, producing a hemicellulose-rich retentate with high purity, and increase the capacity of the membrane filtration. The lignin in the SSL was sulfonated; thus, two of the resins were anion exchangers and 1 was hydrophobic. The data from the equilibrium studies and adsorption kinetics were fitted to established models, and the results were interpreted based on these observations. The strongly basic anion exchanger performed best with regard to lignin removal. The adsorption followed the Sips isotherm, indicating that the process was cooperative with chemisorption as the main reaction between the adsorbate and adsorbent based on the kinetics. Regeneration of the adsorbent was also possible, wherein 100 g/L NaCl was sufficient to recover 98% of the lignin. The lignin removal had a positive effect on the ultrafiltration process, in which the flux increased by 38% and the extent of separation between the hemicellulose and lignin rose from 17% to 59%.