Styrene-acrylonitrile-copolymer and acrylonitrile-butadiene-styrene-copolymer: a study on extractable and migratable oligomers.

Styrene-acrylonitrile-copolymer (SAN) and acrylonitrile-butadiene-styrene-copolymer (ABS) are gaining in importance as food contact materials. Oligomers and other non-intentionally added substances can migrate into foodstuffs. Five SAN and four ABS samples from the German market and manufacturers were extracted and the extractable oligomers were characterised by high performance liquid chromatography-mass spectrometry/ultraviolet detection/chemiluminescence nitrogen detection/fluorescence detection and gas chromatography-mass spectrometry. Trimers, formed from acrylonitrile and styrene units, were determined to be the dominating group of extractable oligomers in SAN and ABS in concentrations of about 4900-15800 mg/kg material. Furthermore, styrene-acrylonitrile dimers, styrene oligomers, styrene monomer and ethylbenzene were identified in the sample extracts. Migration testing with three consecutive migrations for multiple use articles was performed for two SAN articles. Migration of trimers into water, 3% acetic acid, 10% and 20% ethanol under hot-fill conditions (70°C, 2 h) was not detectable above 9 µg/dm2, while 50% ethanol acting as a food simulant for milk (124 µg/dm2 trimers during the third migration) was shown to overestimate the actual migration into milk (< 11 µg/dm2 trimers at 70°C, 2 h). 2-Amino-3-methyl-1-naphthalenecarbonitrile (AMNC), an oligomer degradation product and a primary aromatic amine, was detected in all material sample extracts (0.3-17.1 mg/kg material) and was released into food simulants in low amounts (< 0.014 µg/dm2 during the third migration into 50% ethanol at 70°C, 2 h).

Evaluation of the detoxication efficiencies for acrylonitrile wastewater treated by a combined anaerobic oxic-aerobic biological fluidized tank (A/O-ABFT) process: Acute toxicity and zebrafish embryo toxicity.

Acrylonitrile (ACN) wastewater generated during ACN production has been reported to be toxic to many aquatic organisms. However, few studies have evaluated toxicity removal of ACN wastewater during and after the treatment process. In this study, the detoxication ability of an ACN wastewater treatment plant (WWTP) was evaluated using Daphnia magna, Danio rerio and zebrafish embryo. This ACN WWTP has a combined anaerobic oxic-aerobic biological fluidized tank (A/O-ABFT) process upgraded from the traditional anaerobic oxic (A/O) process. Moreover, the potential toxicants of the ACN wastewaters were identified by gas chromatography-mass spectrometry (GC-MS). The raw ACN wastewater showed high acute and embryo toxicity. 3-Cyanopyridine, succinonitrile and a series of nitriles were detected as the toxic contributors of ACN wastewater. The A/O process was effective for the acute and embryo toxicity removal, as well as the organic toxicants. However, the A/O effluent still showed acute and embryo toxicity which was attributed by the undegraded and the newly generated toxicants during the A/O process. The residual acute and embryo toxicity as well as the organic toxicants in the A/O effluent were further reduced after going through the downstream ABFT process system. The final effluent displayed no significant acute and embryo toxicity, and less organic toxicants were detected in the final effluent. The upgrade of this ACN WWTP results in the improved removal efficiencies for acute and embryo toxicity, as well as the organic toxicants.

Co-recycling of acrylonitrile-butadiene-styrene waste plastic and nonmetal particles from waste printed circuit boards to manufacture reproduction composites.

This study investigated the feasibility of using acrylonitrile-butadiene-styrene (ABS) waste plastic and nonmetal particles from waste printed circuit boards (WPCB) to manufacture reproduction composites (RC), with the aim of co-recycling these two waste resources. The composites were prepared in a twin-crew extruder and investigated by means of mechanical testing, in situ flexural observation, thermogravimatric analysis, and dimensional stability evaluation. The results showed that the presence of nonmetal particles significantly improved the mechanical properties and the physical performance of the RC. A loading of 30 wt% nonmetal particles could achieve a flexural strength of 72.6 MPa, a flexural modulus of 3.57 GPa, and an impact strength of 15.5 kJ/m2. Moreover, it was found that the application of maleic anhydride-grafted ABS as compatilizer could effectively promote the interfacial adhesion between the ABS plastic and the nonmetal particles. This research provides a novel method to reuse waste ABS and WPCB nonmetals for manufacturing high value-added product, which represents a promising way for waste recycling and resolving the environmental problem.

Pervaporative removal of acrylonitrile from aqueous streams through polydimethylsiloxane membrane.

This study describes the successful separation of acrylonitrile (ACN) from dilute aqueous streams using pervaporation process. The influences of ACN feed concentration, permeate pressure, operating temperature, feed flow rate and membrane thickness on the membrane separation performance were investigated. The results showed that with an increase in ACN concentration in the feed solution, the permeation flux of ACN increased while the enrichment factor decreased. It was also indicated that increasing the permeate pressure reduced the driving force for mass transfer and consequently the permeation flux dropped while the enrichment factor enhanced. Polydimethylsiloxane membranes used in this study showed very good properties in the separation process, leading to enrichment factors in the range of 70-140. Furthermore, the activation energy for pervaporation of both ACN and water calculated from Arrhenius plot indicated that the permeation of water through the membrane was more temperature dependant than ACN.

In vitro anti-influenza screening of several Euphorbiaceae species: structure of a bioactive Cyanoglucoside from Codiaeum variegatum.

A bio-guided screening against influenza A virus (FLUAV) was carried out with seven Euphorbiaceae species. The results showed that chromatographic fractions from Phyllantus niruri, Euphorbia pulcherrima and Codiaeum variegatum had relevant anti-FLUAV activity, although only chromatographical subfractions from C. variegatum kept the activity. From this plant, the active compound against FLUAV was isolated. Its structure was assigned as 2-(3,4,5)-trihydroxy-6-hydroxymethyltetrahydropyran-2-yloxymethyl)acrylonitrile (1) on the basis of NMR, mass spectrometry and X-ray diffraction analysis. The compound displayed virucidal activity without impairment of haemagglutination properties of the used virus strain. This is the first report indicating antiviral activity of a cyanoglucoside.

Adsorptive removal of acrylonitrile by commercial grade activated carbon: kinetics, equilibrium and thermodynamics.

The potential of activated carbons--powdered (PAC) and granular (GAC), for the adsorption of acrylonitrile (AN) at different initial AN concentrations (50

Ultrasonic effects on electroorganic processes. Part 27. Electroreduction of acrylonitrile at suspended lead particle-electrode.

Ultrasonic effect on the electroreduction of acrylonitrile at suspended lead particle-electrode was examined. The product selectivity for adiponitrile, which was formed as the corresponding hydrodimeric product along with propionitrile as the hydromonomeric one in the cathodic reduction of acrylonitrile, was increased by addition of lead particles as a particle-electrode, and moreover the selectivity was further increased under ultrasonication. This ultrasonic effect is rationalized as due to not only mass transport of lead particles to the feeder cathode but also an increase in the effective surface area of particle-electrode by ultrasonic dispersion. A mechanism for the ultrasonic effect is discussed in detail on the basis of the reaction system.

Removal of nitriles from synthetic wastewater by acrylonitrile utilizing bacteria.

This study describes the ability of two bacteria strains, isolated from an ABS resin manufacturing wastewater treatment system, to remove high acrylonitrile concentrations. Straight chain aliphatic nitrile compound (propionitrile, allyl cyanide); branch chain aliphatic nitrile compound (isobutyronitrilc) and aromatic nitrile compound (benzonitrile) removal by Comamonas testosteroni and Acidovorax sp. was also investigated. The results are: Comamonas testosteroni and Acidovorax sp. can remove acrylonitrile completely up to 1904.8 mg/L within 66.6 h and 1538.5 mg/L within 143.3 h, respectively. Comamonas testosteroni degraded acrylonitrile faster than Acidovorax sp., and accumulated much more acrylic acid in the medium than Acidovorax sp. The addition of acrylamide to the medium was removed by Comamonas testosteroni and Acidovorax sp. Both strains utilized acrylic acid, a metabolic by-product of acrylonitrile, as a carbon source and ammonium nitrogen, a metabolic by-product of acrylonitrile, as a nitrogen source for growth. Comamonas testosteroni and Acidovorax sp. removed propionitrile completely up to 1352.8 mg/L and 975.7 mg/L within 166.9 h, respectively. With isobutyronitrile as a substrate, more than 97.8% could be removed within 169.8 h by Comamonas testosteroni up to 1352.8 mg/L, and by Acidovorax sp. up to 975.7 mg/L. These two strains could remove allyl cyanide completely up to 775 mg/L within 49.1 h and benzonitrile completely up to 442.7 mg/L within 31.1 h. Because Comamonas testosteroni and Acidovorax sp. have good degrading ability for removing nitrile compounds they are expected to play an important role in the treatment of nitrile compounds.

Activity of sulphate reducing bacteria according to COD/SO4(2-) ratio of acrylonitrile wastewater containing high sulphate.

This study was performed to evaluate the biodegradability of acrylonitrile wastewater, microbial inhibition effect of acrylonitrile wastewater on removal efficiency and the activity of sulphate reducing bacteria (SRB) according to COD/sulphate ratio. Acrylonitrile wastewater was hardly biodegradable in a biodegradability test, however, SRB activity was 57% for overall consumption of electron donor and it was relatively high value compared to 17% of reference test with glucose. COD removal of acrylonitrile wastewater was improved to 57% and 61% from 20% as the COD/sulphate ratio were 0.5 and 0.3 by sulphate addition to acrylonitrile wastewater. First order reaction rate constants k on organic removal of acrylonitrile wastewater were 0.001, 0.004 and 0.004 at each COD/sulphate ratio of 0.9, 0.5 and 0.3. Thus it was suggested that the activity of SRB was a significant factor for removing organics and sulphate simultaneously in acrylonitrile wastewater.

Combined Fenton-MF process increases acrylonitrile removal.

The Fenton oxidation process is possessed of the advantages of both oxidation and coagulation processes. In addition to these functions, Fenton's reagent is also a typical initiator of polymerization. The application of the Fenton-microfiltration process for removal of acrylonitrile (AN), which is the major raw material for manufacturing ABS reins, was investigated. As for Fenton oxidation, in the range of pH 2 to pH 4, AN removal efficiency increased as the pH increased. In experiment of the same initial molar ratio of [FeSO4]0/[H2O2]0, the higher dosage can obtain the higher removal efficiency. At pH 4, the AN removal increased as the [H2O2]0 increased for each [FeSO4]0. Acrylic acid and acrylamide were detected in the solution after Fenton oxidation. On the other hand, acrylamide, polyacrylamide, and polyacrylic acid exist in the precipitate after the Fenton oxidation of AN solution. Moreover, it was also found that the operational mode is an important factor of the combined Fenton-MF process.

Rapid radiochemical and chemical quality control of [11C]putrescine.

A short (4.6 x 50 mm) cation exchange column was used in conjunction with conductivity and radioactivity detectors to determine the radiochemical purity (> 99%) and specific radioactivity (0.5-1.0 Ci/mu mol) of [1-11C]putrescine prepared via Michael addition of [11C]cyanide to acrylonitrile. The absence of acrylonitrile, a rodent carcinogen, from the final preparation was verified at the 50 ng level capillary vapor-phase chromatography (VPC) using a nitrogen-phosphorus detector. Routine VPC analysis using a Poropak Q column and flame ionization detection showed that preparations contained no more than 1 microgram of acrylonitrile.