Polyvinylpyridine Resin Research Articles

Modeling of the separation of lactic acid from an aqueous mixture by adsorption on polyvinylpyridine resin and desorption with methanol

Abstract The main objectives of this work are to model the separation of lactic acid from an aqueous mixture by adsorption on a polyvinylpyridine resin (Reillex® 425), and to model the desorption of adsorbed lactic acid with methanol. The adsorption equilibrium isotherm of lactic acid in aqueous mixtures in Reillex® 425 has been measured. A theoretical model describing the column adsorption dynamics of lactic acid from an aqueous solution and its desorption with methanol has been developed and validated with experimental data. The model has been employed to design and optimize a simulated moving bed (SMB) process for recovering lactic acid from a lactic acid/water mixture containing 5% w/w of lactic acid, using the triangle theory and the separation volume method. The simulation results show that it is possible to obtain concentrated lactic acid (80% in water) with high recovery (95%) from lactic acid/water mixtures by SMB. The feasibility of recovering methanol from the extract and raffinate streams of the designed SMB process by distillation has also been analysed.

Poly(acrylamide) grafts on spherical polyvinyl pyridine resin for removal of mercury from aqueous solutions

Poly(acrylamide) is grafted onto cross-linked poly (4-vinyl pyridine) (P4-VP) resin “Reillex 425”. Its quaternization with potassium chloroacetate results in cross-linked poly (4-vinyl pyridine) having carboxymethyl pyridinium groups. This resin is grafted with acrylamide after redox initiation through the carboxyl groups with cerium ammonium nitrate. The resulting resin with 111.7 wt% of poly(acrylamide) grafts is a high capacity (3.36 mmol g −1) mercury specific sorbent. Experiments performed under identical conditions with some other ions such as Zn(II), Pb(II), Fe(III) and Cd(II) showed that those metal ions are not sorbed by the resin. Flexible graft chains of poly(acrylamide) provide nearly homogeneous reaction conditions in mercury uptake. Regeneration of the mercury loaded polymer can be achieved by acetic acid treatment.

Functional resins in palladium catalysis: promising materials for Heck reaction in aprotic polar solvents

The performances of palladium metal catalysts supported by organic resins containing tertiary amino, cyano, carboxyl, and pyridyl groups have been investigated in standard Heck reactions. The catalysts were prepared by either immobilization in the resins of palladium(II) precursors and chemical reduction thereof or by deposition of solvated metal atoms obtained by means of metal vapor synthesis (MVS). Particular attention was paid to the nature of catalysis in the presence of these materials. As the observed catalytic activity turned out to be generally associated with metal leaching, the reaction was most likely catalyzed in solution by soluble, active palladium species. However, a MVS 1% (w/w) catalyst supported by a commercial polyvinylpyridine resin cross-linked with divinylbenzene exhibited an appreciable catalytic activity with a possible partial contribution from supported active palladium species.

Distribution of 14 elements from two solutions simulating Hanford HLW Tank 102-SY (acid-dissolved sludge and acidified supernate) on four cation exchange resins and five anion exchange resins having different functional groups

As part of the Tank Waste Remediation System program at Los Alamos, we evaluated a series of cation exchange and anion exchange resins for their ability to remove hazardous components from radioactive high-level waste (HLW). The anion exchangers were ReillexTM HPQ, a polyvinylpyridine resin, and four strong-base polystyrene resins having trimethyl, triethyl, tripropyl, and tributyl amine as their respective functional groups. The cation exchange resins included AmberlystTM 15 and AmberlystTM XN-1010 with sulfonic acid functionality, DuoliteTM C-467 with phosphonic acid functionality, and polyfunctional DiphonixTM with diphosphonic acid, sulfonic acid, and carboxylic acid functionalities. We measured the distributions of 14 elements on these resins from solutions simulating acid-dissolved sludge (pH 0.6) and acidified supernate (pH 3.5) from underground storage tank 102-SY at the Hanford Reservation near Richland, Washington, USA. To these simulants, we added the appropriate radionuclides and used gamma spectrometry to measure fission products (Ce, Cs, Sr, Tc, and Y), actinides (U, Pu, and Am), and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr). For each of the 252 element/resin/solution combinations, distribution coefficients (Kds) were measured for dynamic contact periods of 30 minutes, 2 hours, and 6 hours to obtain information about sorption kinetics from these complex media. Because we measured the sorption of many different elements, the tabulated results indicate which unwanted elements are most likely to interfere with the sorption of elements of special interest. On the basis of these 756 measured Kd values, we conclude that some of the tested resins appear suitable for partitioning hazardous components from Hanford HLW.

Simultaneous fermentation and separation of lactic acid in a biparticle fluidized-bed bioreactor

A bioreactor configuration has been tested for simultaneous fermentation and separation of the desired inhibitory product, lactic acid. The bioreactor is a fluidized bed of immobilized Lactobacillus delbreuckii. Another solid phase of denser sorbent particles (a poly-vinyl pyridine resin) was added to this fluidized bed. These sorbent particles fell through the bed, absorbed the product, and were removed. In test fermentations, the addition of the sorbent enhanced the fermentation and moderated the fall of the pH. The biparticle fluidized-bed bioreactor utilizing immobilized microorganisms and adsorbent particles has been shown to enhance the production of lactic acid fourfold in this nonoptimized system.