Influence of anionic form on thermal degradation of TMAHP–cellulose

Trimethylammoniumhydroxypropyl (TMAHP)–cellulose in 10 anionic forms (F^?, Cl^?, Br^?, I^?, HSO, NO, OH^?, HCO, H₂PO, CH₃COO^?) was prepared, and the influence of each anion on thermal degradation in inert atmosphere was studied. With the help of dynamic and isothermal thermogravimetry (TG) it was found that H₂PO ions had the greatest retarding effect on TMAHP–cellulose degradation. From the values of rate constants it can be seen that all ionic forms of TMAHP–cellulose have the starting rate of thermal degradation greater than unmodified cellulose. The calculated values of activation energy of thermal degradation for different ionic forms are decreasing in following sequence: H₂PO > F^? > NO > I^? > Br^? > HCO > Cl^? > HSO > OH^? > unmodified cellulose > CH₃COO^?. From the results of pyrolyse measurements in combination with gas chromatography and mass spectrometry (Py–GC–MS) it follows that the products of the elimination of quarternary ammonium salts are trimethylamine, 3-hydroxy-2-propanone, and, in the case of OH^? form, water. In all other ionic forms the third product is the corresponding acid.     

Denitrifying kinetics involving the distributed ratio of reductases

A suspended-growth batch reactor was used to denitrify synthetic wastewater containing various proportions of nitrate and nitrite. A competitive phenomenon between nitrate- and nitrite-reductase was studied utilizing various proportions of nitrate and nitrite in an anaerobic environment with a temperature of 30°C and methanol as carbon source. By using a non-linear regression technique, biokinetic constants of the maximum specific reduction rates of nitrate and nitrite (k₁, k₂) and the Monod half-saturation coefficients of nitrate and nitrite (K_s1, K_s2) for the proposed two-step denitrifying kinetics were 1·29 day^?1, 0·89 day^?1 and 14·3 mg NO-N dm^?3, 10.9 mg NO-N dm^?3, respectively. The result obtained from a series of chemostat studies indicated the Monod-type kinetic model was more accurate when the distributed ratio of nitrate- and nitrite-reductase in the proposed two-step denitrifying kinetics was taken into account.     

Liquid–solid mass transfer for cocurrent gas–liquid upflow through solid foam packings

This article presents the liquid–solid mass transfer characteristics for cocurrent upflow operated gas–liquid solid foam packings. Aluminum foam was used with 10, 20, and 40 pores per linear inch (PPI), coated with 5 wt % Pd on γ‐alumina. The effects of gas velocity (u_g = 0.1?0.8 m m s^?1) and liquid velocity (u_l = 0.02 and 0.04 m m s^?1) are studied using the Pd/Bi catalyzed oxidation of glucose. The volumetric liquid–solid mass transfer coefficient, k_lsa_ls, is approximately the same for 10 PPI and 20 PPI solid foams, ranging from 2 × 10^?2 to 9 × 10^?2 m m s^?1. For 40 PPI solid foam, somewhat lower values for k_lsa_ls were found, ranging from 6 × 10^?3 to 4 × 10^?2 m m s^?1. The intrinsic liquid–solid mass transfer coefficient, k_ls, increases with increasing liquid velocity and was found to be proportional to u. Initially, k_ls decreases with increasing gas velocity and after reaching a minimum value increases with increasing gas velocity. The values for k_ls range from 5.5 × 10^?6 to 8 × 10^?4 m m s^?1, which is in the same range as found for random packings and corrugated sheet packings. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Influence of anionic form on thermooxidation of TMAHP–cellulose

With the help of DTA, DTG elementary analysis of carbonized residues and ESR spectroscopy the influence of anionic form on thermooxidation of trimethylammoniumhydroxyprophyl (TMAHP)–cellulose was studied. At 300°C the percentage of carbon in carbonized residue thermolyzed in oxidative atmosphere is higher than for the sample degraded in inert atmosphere. The percentage of hydrogen decreases simultaneously. The concentration of free radicals in thermolyzed residue also increases due to the presence of oxygen. We propose that oxygen is abstracting the hydrogen atoms from polysaccharide and unpaired electrons on carbon atoms are produced. At 400°C the percentage of carbon in residues prepared at inert atmosphere is higher than for residue formed at oxidative atmosphere. Also the concentration of free radicals in thermolyzed residues obtained in inert atmosphere is greater than for those from oxidative ones. That is why suppose that at this temperature oxygen is bonded to polysaccharide residue and free radicals are terminated. From the semiquantitative DTA we can make the following sequence of samples according to their increasing thermooxidative effect: unmodified cellulose < A–HSO < A–Br^? < A–I^? < A–NO < A–H₂PO < A–CH₃COO^? < A–HCO < A–F^? < A–Cl^?1 < A–OH^p?.     

Solution properties and unperturbed dimensions of poly (vinylpyrrolidone)

The dilute solution properties of nine poly(vinylpyrrolidone) fractions in methanol covering the molecular weight range 6.76 × 10⁴ to 1.02 × 10⁷ were studied. Constants a and K_m of the Mark-Houwink-Sakurada (M.H.S.) equation were found to be 0.60 and 2.64 × 10^?4 respectively using light scattering and intrinsic viscosity data and were compared with the literature values. The second virial coefficient, A₂ decreases gradually as the molecular weight increases while the root-mean-square radius of gyration, ² increases. The dependence of A₂ on molecular weight is in agreement with other flexible polymers dissolved in moderate to good solvents. The unperturbed chain dimension, (r/M) was calculated using the Stockmayer-Fixman (S—F) equation and a value of 4.9 × 10^?17 cm was obtained. The S—F plot slightly bends in the region of high molecular weight which is according to expectation.     

Thermal decomposition of potassium persulfate in aqueous solution at 50°C in the presence of ethyl acrylate

Potassium persulfate modes of thermal decomposition and reactions with ethyl acrylate in aqueous solution at 50°C in nitrogen atmosphere have been investigated. It has been found that the rate of persulfate decomposition may be expressed as ?d(S₂O)/dt ∝ (S₂O)^{1.00 ± 0.06} × (M)^0.92±0.05 while the steady state rate of polymerization (R_p) is given by R_p ∝ (S₂O)^{0.50 ± 0.50} × (M)^{1.00 ± 0.06} in the concentration ranges of the persulfate, 10^?3?10^?2 (m/L), and monomer (M), 4.62?23.10 × 10^?2 (m/L), i.e., within its solubility range. In the absence of monomer, the rate of persulfate decomposition was slow and first order in persulfate at the early stages of the reaction when the pH of the solution was above 3.0. The separating polymer phase was a stable colloid at low electrolyte concentrations even in the absence of micelle generators. It has been shown that the oxidation of water soluble monomeric and oligomeric radicals by the S₂O ions in the aqueous phase, viz., \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm M}_j^ \cdot + {\rm S}_2 {\rm O}_8^{2 - } \to {\rm M}_j - {\rm O} - {\rm SO}_3^ - + {\rm SO}_4^{ \cdot - } $\end{document} is not kinetically significant in this system. It has been found that the reaction \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm M} + {\rm S}_2 {\rm O}_8^{2 - } \rightarrow{k}{\rm M} - {\rm O} - {\rm SO}_3^ - + {\rm SO}_4^{ \cdot - } $\end{document} would also lead to chain initiation at the outset of the polymerization reaction. k has been estimated as 5.41 × 10^?5 (L/m/s) at 50°C. Taking k_p as 10³ (L/m/s), k_t has been estimated as 0.168 × 10⁶ (L/m/s). The partition confficient (β) of the monomer between the polymer phase and the aqueous phase was found to be 16 ± 2, at 50°C. The rate constant for persulfate ion dissociation has been found as 1.40 × 10^?6 s^?1 at 50°C.     

Kinetics of methyl methacrylate grafting polymerization onto flaky aluminum powder

With ammonium persulfate (APS) as the initiator, the kinetics of methyl methacrylate (MMA) grafting polymerization onto flaky aluminum powder (Al) was studied. It was found that the experimental apparent grafting polymerization rate, R_g = KC × C × C, was basically consistent with the theoretical result based on the theory of stable polymerization and equivalent activity, R_g = KC × C × C_MMA. The activation energy of grafting, homogenous, and total polymerization rate was calculated as 65.1, 35.4, and 37.5 kJ mol^?1, respectively. It could be validated that the relationship among these activation energies accorded with the theoretical result of parallel reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of Mg‐Al hydrotalcite by urea method and its catalytic activity for transesterification

Layered double hydroxides based on the structure (Mg₆Al₂(OH)₁₆CO₃·4H₂O) were synthesized by urea hydrolysis method and characterized by XRD, FTIR, SEM, and EDS. The results revealed that pH played a crucial role in the Mg‐Al hydrotalcite precipitation by controlling [urea]/[NO] molar ratio in reaction solution at 378 K and the optimized [urea]/[NO] molar ratio was 4.0. The sample calcined at 773 K was used as a solid catalyst for biodiesel synthesis. The catalyst was found to have a high catalytic activity in transesterification of rape oil to methanol with about 94% oil conversion at 338 K for 3 h. The water content of the oil could be kept below 2.0 wt % and free fatty acid content of the oil could be kept below 3.0 mg KOH·g[oil]^?1 in order to get the best conversion. So, the solid catalyst was more tolerant to free fatty acid and water in rape oil than homogeneous basic‐catalysts. Moreover, the catalyst could be reused, but catalytic activity decreased on reuse of the catalyst although it remained highly active for the five uses. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

The degradation and prestabilization of acrylonitrile copolymers

The degradation and prestabilization of polyacrylonitrile (PAN) were investigated with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The initial temperature, initial loss‐weight temperatures, and loss‐weight were significantly lowered when ammonium itaconate (AIA) was used as comonomer. One exothermal peak of PAN (homopolymer) was shown in the DSC curves, while there were four exothermal peaks of poly(AN‐AIA). FTIR spectra results confirm the degradation process of NH groups. During the heating process, NH groups (3030 cm^?1) were changed into NH (2955 cm^?1) and then NH groups (2920 cm^?1). The dissociated H⁺ could initiate the cyclization reactions of C?N companied with heat released. The effect of ammonia on degradation and prestabilization of PAN was also studied. It was found that ammonia could accelerate prestabilization of acrylic precursors. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Adiabatic compressibility of polyelectrolytes: Poly(N-dimethylaminoethyl methacrylate) and its copolymer with acrylic acid

The adiabatic compressibility of poly(N-dimethylaminoethyl methacrylate) and of three copolymers of N-dimethylaminoethyl methacrylate and acrylic acid, ranging in composition from 33 to 58 mole-% amino groups, has been studied. The ?V of the polymer shows a slight decrease (2.4 cc/mole), while the ?K is found to have increased considerably (51 × 10^?4 cc bar^?1 mole^?1) compared to that of the monomer. The latter is apparently due to the more compressible nature of the polymer than that of its monomer. The experimentally observed ?K₂⁰ and ?V₂⁰ values for the three copolymers containing 58%, 43%, and 33% amino groups are ?2.5 × 10^?4 cc bar^?1 mole^?1 and 164.5 cc/mole, ?32 × 10^?4 cc bar^?1 mole^?1 and 177.5 cc/mole, and ?55 × 10^?4 cc bar^?1 mole^?1 and 211.3 cc/mole, respectively, whereas the calculated values are less by 19.4 × 10^?4 cc bar^?1 mole^?1 and 3.2 cc/mole, 49.5 × 10^?4 cc bar^?1 mole^?1 and 19.9 cc/mole, and 73 × 10^?4 cc bar^?1 mole^?1 and 16.4 cc/mole, respectively. This decrease is attributed to the interaction of acid and base groups in the molecules. The ?K₂⁰ and ?V₂⁰ values have been resolved into their ionic components ?K and ?V. Since the magnitude of electrostriction is higher in fully neutralized salt than in unneutralized salt, the ?K_2i⁰ and ?V_2i⁰ values are lower as expected. The difference in these values for the polybase and its salt is 23.7 × 10^?4 cc bar^?1 mole^?1 and 7.5 cc/mole, respectively, which may be due to the electrostrictive effect. In excess NaCl (1.0M), the magnitude of electrostriction is somewhat reduced and ?V_2i⁰ and ?V_2i⁰ approach values more or less equal to those of the unneutralized polymer. The 100% neutralized hydrochloride salt of poly(N-dimethylaminoethyl methacrylate) shows greatly increased reduced viscosity over that of the feebly basic parent polymer due to the characteristic polyelectrolytic expansion in dilute aqueous solution. The copolymer containing excess amount of amino groups (58%) shows similar behavior, while the other two copolymers containing fewer amino groups (43% and 33%) show a contraction of chains, which may be ascribed in interaction of the carboxyl ions that are freshly formed on dilution with the amino groups in the copolymer chain.     

Fotosensibilisierte Ausbleichung von Azomethinfarbstoffen

Fotosensitized Fading of Azomethine Dyes The quantum yields of photofading of the azomethine dyes 1a—h were determined in the presence of the sensitizers benzophenone (B), michler's ketone (MK) and anthracen (A), in isopropanol and benzene. In isopropanol, excluding oxygen, the leuco dyes 5 are formed by benzophenone in high quantum yield (Φ = 0.4). Photofading also takes place using Michler's ketone (Φ ≅ 3 · 10⁻³) and anthracene (Φ ≅ 1 · 10⁻⁴), but 5 was not found. With benzophenone (Φ ≅ 7 · 10⁻³), Micher's ketone (Φ ≅ 1 · 10⁻³) and anthracene (Φ ≅ 1 · 10⁻⁴) as sensitizers the chromophore of 1a—h were destroyed, when oxygen was present. The photofading with benzophenone and Michler's ketone is a result of radicalic processes. Radical scavangers 8 and 9 , therefore, give a strong decrease of the quantum yield of photofading. The photofading in benzene corresponds to the results in isopropanol considering the lower potential of this solvent for photoreduction processes.     

Zur Kinetik der photoinduziertenRadikalpolymerisation mit Elektronendonator/Elektronenakzeptor-Initiatorsystemen

Kinetics of Photoinduced Radical Polymerization with Electron Donor/Electron Acceptor Initiator Systems By means of benzyltriphenylphosphonium tetrafluoroborate (P^⊕) and anthracene (An) as photoinitiator system and methylmethacrylate (MMA) as monomer the influences of several reaction parameters on the polymerization quantum yield Φ_p, were studied. The following principal reactions proceed: electron transfer between excited An (¹An) and P^⊕ salt (k_q = 2,5 · 10⁹ M⁻¹ s⁻¹), quenching of ¹An by MMA (k = 1,3 · 10⁷ M⁻¹ s⁻¹), reaction between a ¹An…P^⊕ salt complex and MMA. The last reaction is assumed, since from the disappearance of An and the formation of An cation radical, respectively, rate constants k > 10⁸ M⁻¹ s⁻¹ have been calculated. Furthermore, it is assumed, that only the quenching of ¹An by MMA (Φ_p = 3,8) and the addition of free radicals, produced by the photoinduced electron transfer, lead to polymer formation. Kinetic equations were developed, which can explain the effect of P^⊕-salt concentration, light intensity and MMA concentration on Φ_p data. The quotient obtained for k_p/k is in the range of 0,053 to 0,087 M^−0,5 s^−0,5, depending on the used experimental parameters. Polymerization degrees P_n of 260–590 were found, which also depend on the experimental parameters.     

Polymerization initiation by N-p-tolylglycine: Free-radical reactions studied by pulse and steady-state radiolysis

The extensive use of N-p-tolylglycine (NTG) and analogous compounds in adhesive bonding technologies requires a better understanding of their role in initiating free-radical polymerization. The fast oxidation and reduction reactions of NTG proceed via the formation of various free radicals and radical cation and anion intermediates. These intermediates were identified and their reactivity with oxygen, to produce the corresponding peroxyl radicals, was measured. Hydroxyl radicals (?H) were used to initiate oxidation reactions of NTG, while the reduction reactions were initiated with hydrated electrons (e). OH radicals react with NTG predominately by addition to the aromatic ring followed by OHÞ elimination to produce NTG⁺· radical cations. In the presence of oxygen, the OH–NTG^? adduct also reacts with oxygen to produce peroxyl radicals. The reaction of NTG with e forms the radical anion, which subsequently protonates on the aromatic ring to produce cyclohexadienyl radicals, or undergoes an amine elimination to yield an acetic acid free radical and 4-methylaniline. Hydroperoxyl radicals (HO) abstract hydrogen from the α position of NTG to form the corresponding alkyl free radical. © 1994 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Photochemische Primärprozesse von Xanthenfarbstoffen. III. Blitzlichtspektroskopische Untersuchungen zum Einfluß von kationischen Mizellen auf die Photoredoxprozesse von Selenopyronin

Photochemical Primary Processes of Xanthene Dyes. III. Investigations of the Influence of Cationic Micelles on the Photoredox Processes of Selenopyronine by Flash Excitation Cationic micelles have no influence on the decay of the triplet state of selenopyronine (³F⁺). The products of photoredox reactions ³F⁺ + ³F⁺ (F⁺) → F^· + F and ³F⁺ + DABCO → F^· + DABCO live longer in the presence of the cationic micelles. The reason for the change of the lifetime is a separation of the photoredox products by micelles. F^. is stored in the interior of the micelles. The positively charged F and DABCO are repelled from the micelles and the electron back transfer is hindered.     

Solvent extraction of the trivalent lanthanides and yttrium by mixtures of 3,5-diisopropylsalicylic acid and neutral organophosphorus compounds

Neutral organophosphorus compounds containing a phosphoryl or thiophosphoryl group were found to cause appreciable synergistic shifts in the pH₅₀ values for the extraction of the trivalent lanthanides and yttrium from chloride media by solutions of 3,5-diisopropylsalicylic acid (DIPSA) in xylene. For the series of compounds with R = n-butyl, the synergistic effect increases in the order (RO)₃PS < (RO)₃PO < (RO)₂RPO < (RO)R₂PO < R₃PO. The synergistic effects are greater for lutetium(III) than for lanthanum(III) and, as a result, the separation across the lanthanide series (pH–pH) increases from only 0·17 pH unit for 0·25 M DIPSA alone to, for example, 0·85 pH unit for a mixture of 0·25 M DIPSA and 0·25 M triisobutylphosphine oxide (TIBPO). Mixtures of DIPSA and TIBPO give somewhat better separation factors between the light and middle lanthanide fractions (β = 3·0) than the commercial Versatic 10 acid (β = 2·6), and separation factors comparable to those of the latter extractant between the heaviest lanthanides (thulium to lutetium).     

Curing of a polysulfide sealant with sodium birnessite

Sodium birnessite (Na₂MnMnO₁₃ · H₂O), a layered manganese(IV) oxide–based phase, gives a liquid polysulfide cure that is too rapid for normal application when added at 10 pph polysulfide. The curing behavior of sodium birnessite added as 5 pph, 4 pph, and as a 5 : 5 pph mixture with an inert natural manganese dioxide was compared with that of a readily available manganese‐based commercial curing agent. The rate of cure at 5 and 4 pph was slower than the commercial agent at 10 pph and led to products with lower tensile strength. The cure with the 5 : 5 pph mixture gave a more rapid reproducible cure than that of the commercial agent, making a product with a higher tensile strength and lower elongation, which indicates better curing and higher crosslinking. The improved performance of sodium birnessite as a curing agent is consistent with the presence of Mn²⁺ in the lattice, creating vacancies in the Mn⁴⁺ O²⁻ lattice and increasing the mobility of Mn⁴⁺ and its transport to the surface of the solid to oxidize the polysulfide. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1177–1181, 2000     

Some observations in the aqueous and emulsion polymerizations of common vinyl monomers initiated by sodium metabisulfite (Na2S2O5) at 50°C

Analytical grade sodium metabisulfite (Na₂S₂O₅) has been found to initiate the polymerizations of methyl methacrylate (MMA) and ethyl methacrylate (EMA) in the aqueous media in the presence and absence of detergents, and of styrene in the presence of detergents only, but it fails to initiate the polymerization of methylacrylate (MA) at low concentrations of the initiator and of acrylonitrile (AN) in the absence of cationic detergent micelles. If a mixture of AN (2.0%, v/v) and metabisulfite (1.60%, w/v) is kept for 16 h at 50°C in the presence of nitrogen, no polymerization occurs, but if a little ferric chloride (0.001%, w/v) is added to this mixture in nitrogen atmosphere, the initiation of AN polymerization is found to occur. MA can be polymerized partly by adding metabisulfite to an aqueous solution of MA and a cationic detergent (above CMC) in the presence and absence of air. Very little polymer is found under similar conditions with AN. No polymerizations were found to occur with any of the above-mentioned monomers if hydroquinone was present in the system. In the Na₂S₂O₅—MMA and Na₂S₂O₅—EMA systems, the average rates of the aqueous polymerizations were found to decrease with the increase of the initiator concentrations (from 1.316 × 10^?3 to 2.63 × 10^?1 m/L) at 50°C in the presence of nitrogen, and to be approximately inversely proportional to the sqare root of the initiator concentrations. It is suggested that the bisulfite (produced by the reaction of S₂O^2?₅ ions with water) adds to vinyl monomers as well as initiaing polymerization reactions by the reduction activation of the monomers in the presence of nitrogen. The presence of bulky groups such as methyl, phenyl, etc., at the β-position of the ethylenic double bond of the monomer, probably prevents or slows down the bisulfite addition reactions due to the steric hindrance, and so the polymerization reactions will predominate in the system of MMA, EMA, and styrene-like monomers. The complex species formed due to the interactions of the cetyltrimethyl ammonium bromide (CTAB) micelles and free CTAB cations with HSO and S₂O ions initiate the polymerizations of MA and of AN in the presence of nitrogen or air. Cationic detergent micelles protect the monomers from the direct attack of the HSO/S₂O ions.     

Photopolymerization of methyl methacrylate with the triethylamine-bromine charge transfer complex as photoinitiator

The triethylamine-bromine (TEA-Br₂) charge transfer complex was employed as photoinitiator in the photopolymerization of methyl methacrylate under light of 440 nm. The initial rate of conversion was 0.418%/min with an induction period of 56 min. The initiator and monomer exponents were 0.5 and 1.0, respectively. The polymerization was inhibited in the presence of hydroquinone but oxygen had a very little inhibitory effect. The value of k/k_t was 5.13 · 10^?2 l/mol · s and the activation energy was 19.18 kJ/mol. The rate constant for the decomposition of the charge transfer complex (k_ε) was 4.61 · 10^?6 1/s. Kinetic data and other evidence indicate that the overall polymerization takes place by a radical mechanism.     

Influence of cations and borate on the alkaline extraction of xylan and glucomannan from pine pulps

Southern pine pulp fibers were extracted with Na, K, and Li hydroxides at several concentrations from 0.5 to 4.0 m (molal). The amounts of extracted xylan and glucomannan increased with the swelling of the cellulose structure up to 2.0–2.5 m. The addition of H₃BO₃ to alkaline solutions produced the B(OH) anion, which had less swelling power than OH^?. It was not effective for removal of xylan except for some very accessible xylan of holocellulose. Removal of xylan from chemical pulps depended upon OH^? in molar excess over H₃BO₃. In the same extractions, glucomannan removal was enhanced by B(OH) alone and further increased by additional OH^?. The formation of anions (carboxylate in xylan and borate complex of glucomannan) appeared to be important for the release of polymer from within the cellulose structure. Some glucomannan was more accessible in oxygen pulp than in holocellulose. The resorbed xylan of kraft pulp was less accessible than the xylans of either holocellulose or oxygen pulp.     

Anaerobic biodegradability and toxicity of eucalyptus fiber board manufacturing wastewater

Wastewater from eucalyptus fiber board manufacturing (EFBM) was characterized and studied for its treatability by anaerobic digestion. The characteristics of the wastewater (in mg dm^?3), are as follows: COD (42 000), SS (550), SO (1200), PO.P (50), NH.N (15), VFA (710), phenol (20), p-cresol (125), tannin COD (1460) and pH 2.8. Approximately 60% of the COD is composed of carbohydrates. The continuous treatment of EFBM wastewater resulted in 93% COD removal and 78% COD methanogenized, with influent COD values of 20 g dm^?3 and OLR of 17 kg COD m^?3 d^?1. The biodegradation reached 94% of influent COD and 74% of influent ultraviolet absorbance (215 nm). EFBM wastewater supplied at 20 g COD dm^?3 (1:1 tap water diluted) caused 50% methanogenic toxicity, which did not disappear when tannins were removed by adsorption on PVP (polyvinylpyrrolidone). The toxicity decreased to 25% once the wastewater was autoxidized with air at high pH values. However, the effluent of the continuously fed column didn't show methanogenic toxicity, therefore the main toxic compounds in the wastewater were removed during anaerobic treatment.