SELECTION OF A CATION EXCHANGE RESIN TO PRODUCE LACTIC ACID SOLUTIONS FROM WHEY FERMENTATION BROTHS

ABSTRACT

Lactic acid can be made by fermentation from inexpensive cheese whey. The acid is at present fairly costly, however, partly because of the costs of recovery and purification of the acid from the fementation broths. The present study has been undertaken to investigate a process that might reduce these costs. A number of commercial resins have been evaluated as ion exchangers for the production of lactic acid solutions. Amberlite IR-120, a gel strong cationic ion exchanger, was found to be the best resin. The loaded resin was regenerated efficiently. The results suggest that such a process is both technically and economically feasible.     

Ion-Exchange Kinetics for the Removal of Potassium from Crude Polyols on Strong Acid Resins

Abstract

Batch dynamics for the uptake of potassium from crude polyols on Amberlite 252, a strong acid ion-exchange resin, are obtained over a wide range of conditions. Experimental data have been analyzed using a homogeneous model with finite solution volume. An increase of diffusion coefficients with the resin weight used in the purification is observed. An asymptotic maximum value, approaching the value of the diffusion coefficient in bulk solution, is reached for high resin weights or low values of external concentration. The heterogeneous nature of the resin matrix and the large size of the diffusing molecule is proposed as an explanation of this behavior. The proposed purification procedure finds general applicability for other polyol types, being economically and technically feasible.     

HOT TEST OF A TALSPEAK PROCEDURE FOR SEPARATION OF ACTINIDES AND LANTHANIDES USING RECIRCULATING DTPA-LACTIC ACID SOLUTION

Abstract

Results are reported from a hot test of a TALSPEAK type process for separation of higher actinides (Am, Cm) from lanthanides. Actinides and lanthanides are extracted by 1 M HDEHP and separated by selective strip of the actinides, using a mixture of DTPA and lactic acid (reversed TALSPEAK process). In order to minimize the generation of secondary waste, a procedure using recirculating DTPA-Lactic acid solution has been developed. A separation factor between Am and Eu of 132 was achieved. In regard to separations of Am and Cm from commercial HLLW, this corresponds to 1.5 % of the lanthanide group remaining with the actlnldes. The loss of Am was about 0.2 %.     

Kraft Lignin-Based Rigid Polyurethane Foam

Abstract

Kraft pine lignin was derivatized to a liquid polyol through oxypropylation. The resulting polyol was characterized by GPC, FT-IR, H¹, C¹³, and P³¹ NMR and was compared to commercial polyols in view of the mechanical property of the corresponding rigid polyurethane foams for the first time. A series of lignin-based PU was synthesized by replacing varying weight percentages of the amount of sucrose polyol and glycerol polyol, two commonly used commercial polyols employed in the control foam preparation. All foams had a low density of ～30 Kg m^?3 and showed typical linkages of PU in the FT-IR spectra. The diameter of closed-cells was ～650 μm for most of the foams as revealed by SEM images. The optimal compressive property of rigid PU foams was obtained using lignin polyol without the addition of any other commercial polyols primarily attributed to the rigidity of lignin aromatic structure and the high functionality of lignin hydroxyl groups.     

Efficient In-Situ Regeneration Method of the Catalytic Activity of Aged TWC

The expansion of durability of deactivated “three-way” catalysts (TWCs) used in gasoline-driven cars by applying efficient, economically viable and environmentally friendly methods for the in␣situ regeneration of their performance to acceptable levels was investigated. New experimental results on the use of a weak oxalic acid washing solution as a means of an efficient regeneration method of a severely aged (83,000 km mileage) commercial TWC are presented. Oxalic acid is shown to be the most efficient extracting agent of phosphorus, a severe poison of TWCs, among acetic acid, citric acid, NTA and EDTA investigated. X-ray diffraction studies provided strong evidence that washing of the aged TWC results in the removal of CePO₄, AlPO₄ and (Mg,Ca,Zn)₃(PO₄)₂ type phosphates leading to a significant increase of BET area and pore volume, as well as of CO and NO conversions (catalytic activity tests). The latter is strongly related with the increase in the number of active catalytic sites, as illustrated by in␣situ DRIFTS studies, after opening closed pores and uncovering additional catalyst surface.     

Electrochemical Separation of Hydrogen Sulfide from Natural Gas

Abstract

An electrochemical process has been developed for the removal of H₂S from contaminated natural gas. Removals as high as 80.7% have been achieved from a simulated process gas (2000 ppm H₂S). H₂S is removed by reduction to the sulfide ion and hydrogen gas at the cathode. The sulfide ion migrates to the anode through a molten electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. No materials are required beyond initial electrolyte membrane installation; the H₂S is converted in one step to elemental sulfur making it an economically attractive process both from the lack of raw materials and the lack of any solvent regeneration.     

Purification by Liquid Extraction of Recovered Polyols

Abstract

Polyether polyols can be recovered from polyurethane wastes by chemical recycling. After a two–phase glycolysis, a polyol rich product is obtained, but to be applied in the same use of a raw polyol, it has to be purified. Liquid extraction is a non‐aggressive technique suitable for the polymer purification. Therefore, a study has been conducted dealing with the effect of extraction conditions with aqueous solutions on the purification of polyol. Temperature, mass ratio of solvent used, and pH of the solution were modified to achieve the maximum polyol purity. Due to the rheological properties of the polyol, the requirement of mechanical aid to provide proper phase separation has been also studied.     

Electrochemical Regeneration of Zn-Saturated Granular Activated Carbon from Electroplating Wastewater Plant

An electrically assisted regeneration (EAR) process was used to assess the effectiveness of regenerating exhausted granular activated carbon (GAC) preloaded with electroplating wastewater containing hyper Zn concentration at a concentration of 950.5 mg L ^?1  (1.45 × 10 ^?2  mol L ^?1 ). The electrochemical rege-neration process supplied with direct current was controlled at a constant voltage of 5.0 V. Two regeneration methods were tested and compared: first, acid washing (pH 1.0) and, second, electrically assisted acid washing. Results showed that the Zn adsorption capacity of GAC regenerated by EAR was significantly higher than that of GAC regenerated by acid washing. The effectiveness of the Zn desorbing efficiency from GAC was enhanced by electric current in the electrochemical regeneration process. Using the EAR method, a regeneration efficiency of 88.3% was observed for GAC, whereas using acid regeneration, the efficiency was only 25.3%. These observations reveal that EAR could be a potential alternative to acid washing for the regeneration of GAC saturated with Zn.     

ION EXCHANGE KINETICS OF DL-LYSINE MONOHYDROCHLORIDE ON AMBERLITE IRA-420

ABSTRACT

The ion exchange kinetics of DL-lysine monohydrochloride on Amberlite IRA-420 have been studied. Ionic diffusivity of hydroxyl anion, which is supposed to be equal to the interdiffusion coefficient, has been evaluated by fitting experimental kinetic data to a theoretical model based on the continuity equation of the CI" anion in solution filling the pores of the resin. Because of changes of both viscosity with ionic concentration and co-ion behavior in solution at high concentrations, a variation of ionic diffusivity of hydroxyl anion has been observed. In order to predict the dynamic behavior of fixed beds a simple mathematical model including both equilibrium isotherm and ionic diffusivity of hydroxyl anion has been developed. Likewise, resin regeneration using NaOH solutions has been investigated. The results show the feasibility of the procedure of purification and regeneration and they have been used to design a plant for the treatment of 50 Tm/yr of DL-lysine monohydrochloride.     

Attempts to reduce NOx exhaust emissions by using reformulated biodiesel

Biodiesel is a renewable, domestically produced fuel that has been shown to reduce particulate, hydrocarbon, and carbon monoxide emissions from diesel engines. Under some conditions, however, biodiesel produced from certain feedstocks has been shown to cause an increase in nitrogen oxides (NO_x). This is of special concern in urban areas that are subject to strict environmental regulations. Although soy-based biodiesel may increase the emission of nitrogen oxides, it is the most easily accessible in North America. We investigated two routes to reformulate soy-based biodiesel in an effort to reduce nitrogen oxide emissions. In one of these, soy-oil methyl esters were modified by conversion of a proportion of the cis bonds in the fatty acid chains of its methyl esters to their trans isomers. In the other approach, polyol derivatives of soybean oil were transesterified to form soy methyl polyol fatty acid esters. The NO_x emissions of these modified biodiesels were then examined, using a Yanmar L100 single cylinder, four stroke, naturally aspirated, air cooled, direct injection diesel engine. Using either isomerized methyl oleate or isomerized soy biodiesel, at 20% blend level in petroleum diesel (‘B20’), nitrogen oxide emissions were elevated by between 1.5 and 3 percentage points relative to the combustion of a B20 blend of commercial biodiesel. Nitrogen oxide emissions were reduced in proportion to blend level during the combustion of polyol biodiesel, with a 20% blend in petrodiesel resulting in a reduction of about 4.5 percentage points relative to the emissions of a comparable blend of commercial soy biodiesel.     

Regeneration of KU-2-8 resin with precipitation baths from viscose manufacturing

Conclusions The process of regenerating KU-2-8 resin with precipitation baths from viscose manufacturing has been investigated as compared with regeneration with sulfuric acid.It has been found that desorption of zinc from the resin by precipitation baths is rather efficient, which makes it possible to use precipitation bath in the regeneration process instead of 10% sulfuric acid solution.It has been shown that a high content of organic contaminants in the precipitation baths (COD of 2000–5661 mg O₂/liter) does not affect the sorptive properties of KU-2-8 resin.Translated from Khimicheskie Volokna, No. 6, pp. 9–10, November–December, 1984.     

SELECTIVE RECOVERY OF COAGULANTS FROM WATER CLARIFIER SLUDGE BY THE USE OF FIBROUS ION EXCHANGERS

ABSTRACT

A new technology for removal and recovery of coagulants from water clarifier sludge has been optimized at laboratory scale pilot plant level. The process is based on the use fibrous exchangers showing good kinetic and thermodynamic performance toward coagulant species (Al, Fe) present in the acidic leachate (pH 3.5) from water clarifier sludge. The innovation allows for the solution of the environmental problem related to clarifier sludge disposal (residual solids after metals leaching are safely applied to land), and quantitative recovery of coagulants to the water potabilisation operations

Process optimisation, by using real clarifier sludge from the Sinni River Water Works (Apulian Water Authority, S.E. Italy), was carried-out and results are illustrated in the paper. A commercial weak cation fibrous exchanger (Fiban K4) with carboxylate functionality, selectively removed aluminium and ferric species in “moving bed” unit operations with the resin re-circulating through the stationary exhaustion and regeneration baths. Resin regeneration was efficiently carried-out by the use of 0.4M NaOH solution for quantitative recovery of almost pure coagulants, ready for reuse. Together with process optimisation, the paper also reports some mechanistic indications on the fibrous resin performance toward polyvalent metal species retention at the resin functional groups.     

Polyurethane foams from alkaline lignin‐based polyether polyol

As a byproduct produced during biorefining, alkaline lignin (AL) possesses multiple benzene ring and phenol hydroxyl groups with high chemical reactivity, and is renewable and cheaper than petrochemical products. Here, AL was liquefied in polyethylene glycol‐400/glycerol and subsequently used to prepare polyurethane foams (PUFs). The results showed that the AL could be almost completely liquefied. The resulting lignin‐based polyether polyol (LPP) exhibited physicochemical properties similar to a commercial polyether polyol (PP). The PUFs made from LPP presented better thermal stability and higher compressive strength than those PUFs obtained from commercial PP, suggesting this could be a viable commercial application for AL. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43261.     

Catalytic wall-flow filters for the abatement of diesel particulate: regeneration parameters study

A 1% Pt on CeO₂-promoted PrCrO₃ perovskite catalyst has been synthesized over a wall-flow monolith by the in situ solution combustion synthesis (SCS) method. The role of the catalyst, highly active towards diesel particulate combustion, has been studied during the regeneration phase as a function of three different operating parameters: the inlet trap temperature at which the regeneration is induced, the residual oxygen concentration in the exhaust gases and the load of particulate at the start of the regeneration. The final aim of this study is to improve the knowledge on the catalytic regeneration process in order to derive information suitable for designing an optimized catalytic soot trap entailing minimal fuel penalties.     

Copper recovery from nickel laterite with high-iron content: A continuous process from mining waste

The waste product from the hydrometallurgical processing of nickel laterite ores can contain valuable metals, making their recovery economically viable. However, the high-impurities content, mainly iron, makes the process technically unfeasible. As a result, the separation of metals from the leach solution must be selective. Among the techniques available, the use of chelating resin is advantageous due to its selectivity and low energy consumption. Among the commercial chelating resins available, Dowex XUS 43605 has been shown to be highly selective for copper and can be used with a high impurities content. Although there are studies on the use of Dowex XUS 43605, none have evaluated a high impurities content and modelled a continuous process. For this reason, the aim of this work was to investigate copper recovery by a continuous process. The Dowex XUS 43605 chelating resin with HPPA functional group was used in ion-exchange experiments. Column experiments were performed in two steps: loading (to recover copper) and elution (to obtain a copper-rich solution). The removal of iron and the subsequent collection of copper were possible in a precipitation step using CaCO₃. The results showed that the solution obtained from elution had a copper concentration that was 10 times higher than in the loading. All of the iron was removed from the elution solution at pH 3.5 with 5% of copper losses. Copper precipitation was possible at pH 5.5. From the results obtained, a proposed flowsheet for recovering copper was suggested.     

Radioactive Markers in Analysis of Amino Acid Chromatograms

Abstract

Radioactive markers in ion exchange chromatography of amino acid mixtures of biological samples is one of several methods used to identify a particular amino acid. It is shown that in fractions of column effluents-C¹⁴-labeled amino acids can be detected relatively easily and economically by liquid scintillation or gas flow systems. The interference of the small quantity of labeled amino acid required to give a significant counting rate with the color yield of the amino acids under investigation has been shown to be negligible.     

Equilibria and kinetics for reactive extraction of lactic acid using Alamine 336 in decanol

Lactic acid is an important commercial product and extracting this from aqueous solution is a growing requirement in fermentation‐based industries. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid–amine (solvent) system used. The equilibrium complexation constants for ratios of (1:1) and (2:1) have been estimated. The kinetics of extraction of lactic acid by Alamine 336 in decanol has also been determined. The reaction between lactic acid and Alamine 336 in decanol in a stirred cell falls in Regime 3, ie extraction accompanied by a fast chemical reaction occurring in the diffusion film. The reaction has been found to be zero order in Alamine 336 and first order in lactic acid with a rate constant of 0.21 s^?1. These data will be useful in the design of extraction processes. © 2002 Society of Chemical Industry     

Effect of the Additive Fire Retardants on the Properties of Rigid Polyurethane Foams,Obtained Using Hydroxyethyl Derivatives of Oxamide and Polymeric 4,4′-diphenylmethane Diisocyanate

The present work investigates the effect of polyol structure and physical addition of boric acid and N,N′-bis(2-hydroxyethyl)oxamide on the properties of rigid polyurethane foams. The product of hydroxyalkylation of oxamide by ethylene carbonate has been used as a polyol component. The new polyol has been foamed using polymeric 4,4′-diphenylmethane diisocyanate, water, and triethylamine. To decrease the flammability of the foams, boric acid, and N,N′-bis(2-hydroxyethyl)oxamide were used as the additive flame retardants. It has been found, that chemical modification of the foam structure by means of oxamide groups decreases their flammability only to a small extent, whereas physical addition of N,N′-bis(2-hydroxyethyl)oxamide does not influence the flammability. However, the addition of boric acid to the foam composition resulted in a distinct decrease of foam flammability, according to the amount of boric acid added. All the foams, modified and nonmodified by boron, have been categorized into flammability class HF-1, according to the applicable standard. The introduction of flame retardants had its impact on the properties of polyurethane foams obtained, as described in this work.     

Properties of orthotropic glass–polypropylene composites manufactured by weaving of prepregtapes and other routes

Abstract

This paper reports a study of the melt impregnation and weaving of glass–polypropylene prepreg tapes into sheet for use as a precursor for pressed thermoplastic composite products and a comparison of the properties attainable with those achievable by other comparable routes. Melt impregnation has been used successfully to manufacture well impregnated tapes, with and without internal coupling agent. It appears that weaving could be an economically viable process for converting unidirectional tape into a conformable, press formable prepreg. The properties of glass–polypropylene laminates manufactured by pressing the tape woven product were compared with those of other glass–polypropylene composites, including crossply laminate made from Plytron and samples prepared by film stacking. Quasi-static mechanical properties were found to be comparable with those of Plytron and superior to those of the other materials. In the coupled samples, coupling was somewhat less effective than in Plytron. The impact behaviour of the pressed, tape woven products was impressive and superior to any of the other materials tested.     

EFFECT OF PRETREATMENT ON KINETICS OF CONVECTION DRYING OF ONION

ABSTRACT

Onion of two varieties, i.e. Oporto and Blonska was dried by convection at 60°C and 2 m/s. Prior to drying sliced onion was subjected to following treatments: soaking in water, dipping in starch solution, dipping in starch solution supplemented either with ascorbic acid or CaCl₂, and dewatering by osmosis in sucrose solution. Drying of raw onion was taken as a reference.

It has been found that both variety and pretreatment affect the course and rate of drying. Soaking in water and dipping in starch solution either increase rate of drying or have no effect on the kinetics of the process. Supplementing the starch solution with ascorbic acid or CaCl₂ adversely affects the rate of drying. Unfavorable effect on the rate of drying has also osmotic dewatering preceding convective drying.