High Molecular Weight Products Research Articles

Characterisation of Polycondensation Products from Amino Acids and Lipid Oxidation Products

The Maillard reaction, or nonenzymatic browning, includes a complex network of reactions initiated by the condensation reaction of a carbohydrate and an amino compound, and is of utmost importance for the formation of flavour and colour in thermally treated foods. Besides volatile flavour compounds, also brown-coloured polycondensation products, named melanoidins, are produced. In latest years, the interaction of lipid oxidation products in the classical Maillard reaction pathway and vice versa is of particular interest, since it has been shown that the course of both reactions can be modified by the reactants, intermediates and products of the other (ZAMORA & HIDALGO 2005). Therefore, in parallel with the formation of model melanoidins, polycondensation products resulting from the interaction of amino acids with lipid oxidation products were studied. For this purpose, various coloured water-soluble high molecular weight and water-nonsoluble reaction products were isolated from the model reactions of glycine or lysine with a lipid oxidation product (hexanal, (2E)-hexenal, (2E,4E)-decadienal) in the presence or absence of glucose. They were characterised by UV-visible absorbance measurements, elementary analysis, and thermal degradation followed by SPME-GC-MS analysis (ADAMSet al. 2003). The UV-visible absorbance spectra before and after dialysis indicated that the most important contributors to the formation of water-soluble coloured material were constituents of the low molecular fraction. Elementary analysis data showed that a higher amount of nitrogen was incorporated in the high molecular weight fractions as compared to the water-nonsoluble fractions, except for the water-nonsoluble reaction products from amino acid/(2E, 4E)-decadienal interactions, which demonstrated the lowest C/N ratio found. Volatile carbonyl compounds, furans, a liphatic compounds, pyridines, pyrroles and benzene derivatives were the main groups of compounds identified in the thermal degradation profile of each fraction tested. Aldol condensation reactions of the carbonyl compounds were very important in the initial reaction steps. Especially pyridines seem typical indicators of amino acid-lipid oxidation product interactions.

Protection Against Fowl Cholera Conferred by Vaccination with Recombinant Pasteurella multocida Filamentous Hemagglutinin Peptides

Three gene fragments, derived from Pasteurella multocida strain P-1059 (serotype A:3), encoding approximately the 5' one-third of fhaB2 were overexpressed individually in Escherichia coli. The recombinant peptides were purified, pooled, and administered to turkey poults to evaluate immunity. The results showed that turkeys immunized twice with the recombinant peptides were significantly protected against intranasal challenge with P. multocida strain P-1059. Vaccination elicited antibody responses, based on Western blotting, that were reactive with a wild-type P-1059 cellular product approximately 170 kDa in size and multiple high molecular weight products in culture supernatant. These antibodies did not react with cell or supernatant blots of a P-1059 fhaB2 isogenic mutant. Pasteurella multocida fhaB2 genes of a bovine strain (A:3) and an avian strain (F:3) are highly conserved as is the portion of P-1059 fhaB2 examined here (>99% identities). These findings suggest that broad cross-protection against this heterogeneous pathogen may be achievable through immunization with specific recombinant FHAB2 peptides.

In‐situ polymerization of polyamide 66 nanocomposites utilizing interfacial polycondensation, Part 1: Organoclay nanocomposites

AbstractEffective dispersion of organically modified montmorillonite‐layered silicates in nylon 66 is addressed by synthesizing nanocomposites in situ via interfacial polycondensation from a suspension of silicate platelets in one of the monomer phases using either a stirred or unstirred reactor, while avoiding the detrimental heat history associated with melt compounding of this high melting polymer system. The effects of mixing methodology, reaction conditions, concentration ratio, and clay content are evaluated to elucidate process mechanisms and produce high molecular weight product. Enhanced stiffness of the nanocomposites measured by tensile modulus is related to their nanoscale morphology as characterized by transmission electron microscopy and wide angle X‐ray diffraction. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Characterization of oligomeric compounds in secondary organic aerosol using liquid chromatography coupled to electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

The components of secondary organic aerosols (SOAs) generated from the gas-phase ozonolysis of two C(10)H(16)-terpenes (alpha-pinene; sabinene) and a cyclic C(6)H(10) alkene (cyclohexene) were characterized by the use of a Fourier transform ion cyclotron mass spectrometer equipped with an electrospray ionization source operated in the negative ion mode. Reversed-phase high-performance liquid chromatography was used to achieve chromatographic separation of highly oxidized organic compounds. In addition to the well-known group of low molecular weight oxidation products (monomers; e.g. dicarboxylic acids), higher molecular weight compounds (dimers) were also detected and their exact elemental compositions were determined. In order to provide additional information for the structural elucidation of these compounds, collision-induced dissociation was applied. Based on the MS/MS spectra, two higher molecular weight products are proposed to be an ester and a peroxide. Molecular formulae calculated from the exact masses show that the SOA-compounds are heavily oxidized and this information creates the background to a discussion of potential reaction pathways for the formation of higher molecular weight compounds.

Formation of chlorinated biphenyls, diphenyl ethers and benzofurans as a result of Fenton-driven oxidation of 2-chlorophenol

Homogeneous catalytic Fenton oxidation proved to be very efficient in the degradation of high concentrations (3.9 mM) of 2-chlorophenol (2-CP) in aqueous matrices. When using [H 2O 2] 0/[2-CP] 0 substoichiometric molar ratios of 4 and 16, the detected aromatic intermediates included mainly chlorinated benzenediols, with the virtual absence of condensation products of higher molecular weight. At even lower substoichiometric ratios of [H 2O 2] 0/[2-CP] 0 (⩽2.2), hydroxylated chlorobiphenyls, hydroxylated chlorodiphenyl ethers and hydroxylated chlorinated dibenzofurans were formed in addition to chlorinated benzenediols. The aromatic intermediates were identified as trimethylsilyl ethers and dimethyl-t-butyl silyl ethers. A reaction scheme was proposed to describe the formation of aromatic intermediates based on coupling reactions of resonance-stabilized 2-CP radicals generated by electrophilic attack of reactive hydroxyl radicals. The pattern of aromatic intermediates identified in the Fenton solutions coincided well with that predicted on the basis of oxidative coupling reactions. In addition to coupling of stabilized radicals, aromatic intermediates can be formed by addition of organoradicals onto neutral analyte molecules. The findings presented in this contribution are considered crucial for the design and optimization of Fenton-based remediation devoted either to wastewater treatment under economically feasible conditions or to in situ groundwater treatment where poorly controlled reaction conditions prevail.

Formation and characterisation of melanoidin-like polycondensation products from amino acids and lipid oxidation products

Various coloured water-soluble high molecular weight and water-nonsoluble reaction products were isolated from model reactions of an amino acid (glycine or lysine) and a lipid oxidation product (hexanal, (2E)-hexenal, (2E, 4E)-decadienal) with or without glucose. They were characterised by UV–visible absorbance measurements, elementary analysis, and thermal degradation followed by SPME–GC–MS analysis. The UV–visible absorbance spectra before and after dialysis indicated that the most important contributors to the formation of water-soluble coloured material were constituents of the low molecular fraction. Elementary analysis data indicated that a higher amount of nitrogen was incorporated in the high molecular weight fractions as compared to the water-nonsoluble fractions, except for the water-nonsoluble reaction products from amino acid/(2E, 4E)-decadienal interactions, which showed the lowest C/N ratio found. Volatile carbonyl compounds, furans, aliphatic compounds, pyridines, pyrroles and benzene derivatives were the main groups identified in the thermal degradation profile of each fraction tested. Especially pyridines seem typical indicators of amino acid–lipid oxidation product interactions.

Effect of Mg, La and Ca promoters on the structure and catalytic behavior of iron-based catalysts in Fischer–Tropsch synthesis

Abstract The effects of Mg, La and Ca promoters on the structure, surface area, reduction, carburization and catalytic behavior of precipitated Fe/Cu/SiO2 Fischer–Tropsch synthesis (FTS) catalysts were investigated. The catalysts are characterized using X-ray diffraction (XRD), H2 and CO temperature-programmed reduction (TPR) techniques. The catalysts were assessed in terms of their FTS activity and product selectivity using two superimposed Anderson–Schulz–Flory (ASF) models. The performance of the catalysts was tested in a fixed-bed reactor at 563 K, 1.7 MPa and feed (syngas with H2/CO molar ratio of 1) flow rates of 4.9 and 13.3 nl h−1 g(Fe)−1. It was found that Mg, La and Ca promoters have negligible effects on the textural properties of the catalyst. Promoter addition enhanced the surface basicity of the catalyst in the order Ca > Mg > La. Addition of the promoters with the atomic ratio of X/Fe = 0.02 (X = Ca, Mg and La) improved the reduction and carburization during the reduction and FTS reaction in the order of Ca > Mg > La. The promoters suppressed the rate of hydrogenation reaction in the order of Ca > Mg > La. The results also indicate that Mg, La and Ca promoters can improve the CO conversion and WGS reaction, suppress the formation of methane, enhance the selectivities to olefin and higher molecular weight products, enhance the break in ASF distributions in the order of Ca > Mg > La due to increasing the catalyst surface basicity and dropping the reducibility.

Low-dimensional models for describing mixing effects in reactive extrusion of polypropylene

Spatially averaged low-dimensional models based on Liapunov–Schmidt technique of bifurcation theory have been developed to study mixing effects in peroxide-induced reactive extrusion of polypropylene degradation. The two-dimensional convection–diffusion-reaction equations for each species and the energy balance equation have been averaged in the transverse direction to obtain low-dimensional models that describe transverse (local) mixing effects on conversion, average molecular weight and temperature distribution in a reactive extruder channel with asymmetric thermal boundaries. Our models predict that incomplete local mixing due to velocity distribution, backflow and transverse diffusion may significantly reduce the conversion (by more than 50%) in a reactive extruder, compared to a plug-flow case. Our analysis further reveals that beyond a transition value of Damköhler number ( Da), the overall reaction occurs in the mixing-limited regime, where the conversion and the average molecular weight of the polymer melt are determined only by the dimensionless local mixing time (which, in turn, depends on the screw speed) and are independent of Da. Increased Graetz number (i.e. slow transverse thermal diffusion) decreases the polymer-melt temperature and reduces conversion, while increase in screw speed increases viscous heat generation resulting in higher exit temperature accompanied by reduced conversion and produces off grade high molecular weight (low melt flow index) product when the mixing effect dominates the temperature effect.

Synthesis of high molecular weight alkylketenes on silica monoliths functionalized with TEOS

In this work, the catalytic synthesis of alkylketenes over functionalized silica monoliths at short contact times was extended to high molecular weight products such as decylketene, hexadecylketene and 7-hexadecenylketene. The reactor was coupled with a derivatization system with methanol to obtain the corresponding esters in high yields, allowing the ketene identification. It was found that it is possible to maintain the activity that the silica catalyst has shown for the synthesis of low molecular weight ketenes, in the temperature range between 700 and 830 K, obtaining selectivities in the order of 75–90% for the decylketene and the hexadecylketene, and near to 43% for 7-hexadecenylketene. The results showed that the control of contact time is a valid strategy to increase the yield in the catalytic synthesis of high molecular weight ketenes.

Anthocyanin condensation reactions under high hydrostatic pressure

The effects of temperature and/or high hydrostatic pressure on anthocyanin condensation reactions were studied. For this purpose, model solutions containing cyanidin-3- O-glucoside (Cy3gl) and pyruvate, in excess, were subjected to different combined temperature/pressure treatments. After a high hydrostatic pressure treatment of 600 MPa, at 70 °C during 30 min, about 25% of Cy3gl was degraded. Parallel to this decrease, a vitisin A-type derivative was formed. By contrast, the rate of condensation was only 5% when samples were heated (70 °C, 30 min). In both cases, the degradation kinetics fitted well to a first order reaction ( R 2 = 0.99). The decrease in Cy3gl was correlated with a decrease in the antioxidant activity. Moreover, the chemical stability of wine subjected to a temperature/pressure treatment of 600 MPa, at 70 °C during 1 h was investigated. After this treatment, a decrease in the concentration of malvidin-3- O-glucoside (Mv3glu) was found. As a consequence, an increase in the concentration of several products of high molecular weight at 370 nm was observed. When wine was subjected to pasteurization conditions (600 MPa, 70 °C, 10 min), no significant changes in the chemical composition were found ( P < 0.05).

Chicken lung lectin is a functional C-type lectin and inhibits haemagglutination by influenza A virus

Many proteins of the calcium-dependent (C-type) lectin family have been shown to play an important role in innate immunity. They can bind to a broad range of carbohydrates, which enables them to interact with ligands present on the surface of micro-organisms. We previously reported the finding of a new putative chicken lectin, which was predominantly localized to the respiratory tract, and thus termed chicken lung lectin (cLL). In order to investigate the biochemical and biophysical properties of cLL, the recombinant protein was expressed, affinity purified and characterized. Recombinant cLL was expressed as four differently sized peptides, which is most likely due to post-translational modification. Crosslinking of the protein led to the formation of two high-molecular weight products, indicating that cLL forms trimeric and possibly even multimeric subunits. cLL was shown to have lectin activity, preferentially binding to α-mannose in a calcium-dependent manner. Furthermore, cLL was shown to inhibit the haemagglutination-activity of human isolates of influenza A virus, subtype H3N2 and H1N1. These result show that cLL is a true C-type lectin with a very distinct sugar specificity, and that this chicken lectin could play an important role in innate immunity.

Syntheses of high molecular weight aliphatic polyesters in 1-alkyl-3-methylimidazolium ionic liquids

High molecular weight aliphatic polyesters were synthesized, for the first time, in 1-alkyl-3-methylimidazolium ionic liquids via two-step polycondensation. An oligoester with diol/diacid ratio higher than unity was essential for achieving high molecular weight product. Moreover, the molecular weight of the resulting polyesters was found to depend on the activity of the catalyst in the ionic liquids and the miscibility of aliphatic polyester/ionic liquid. The former factor was dominated by the anion of the ionic liquids. The latter factor could readily be tuned by varying the anion and/or the cation of the ionic liquids. A clear correlation was found between the miscibility of aliphatic polyester/ionic liquid and the extent to which their solubility parameters matched.

Rubber Vulcanizates Degradation and Stabilization

Abstract Degradation of rubber vulcanizates in the presence and absence of air as well as in presence of ozone is reviewed in this paper. The paper also outlines the means to overcome this undesirable phenomenon. Under anaerobic aging conditions, which is termed as reversion, the vulcanizates are exposed to elevated temperature in the absence of oxygen. The consequence of this process is reflected in a decline in physical properties and performance characteristics. These changes are directly related to modifications of the original crosslink structure. Decomposition reactions tend to predominate and thus leading to a reduction in crosslink density and physical properties as observed during extended cure or when using higher curing temperatures. The decrease in network density is common when vulcanizates are subject to an anaerobic aging process. However, in the presence of oxygen, the network density is increased with the main chain modifications playing a vital role. Over the years the rubber industry has developed several compounding approaches to address the changes in crosslink structure during thermal aging. This paper gives a review of these compounding approaches. As with many formulation changes in rubber compounding, there is a compromise that must be made when attempting to improve one performance characteristic. For example, improving the thermal stability of vulcanized natural rubber compounds by reducing the sulfur content of the crosslink through the use of the more efficient vulcanization systems will reduce dynamic performance properties such as fatigue resistance. The challenge is to define a way to improve thermal stability while maintaining dynamic performance characteristics. In the second part, the protection against aerobic ageing as well as in ozone environment is reviewed. The anti-degradant effects are summarized and means to counteract are outlined. The most commonly used antidegradants are N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD) and N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD). Although conventional antidegradants such as IPPD and 6PPD are still the most widely used antidegradants in rubber, there is a trend and demand for longer-lasting and non-staining products. The relatively low molecular weight (MW) antioxidants have undergone an evolutionary change towards higher molecular weight products with the objective to achieve permanence in the rubber polymer, without loss of antioxidant activity. In the last two decades, several approaches have been evaluated in order to achieve this objective: attachment of hydrocarbon chains to conventional antioxidants in order to increase the MW and compatibility with the rubber matrix; oligomeric or polymeric antioxidants; and polymer bound or covulcanizable antioxidants. The disadvantage of polymer bound antioxidants was tackled by grafting antioxidants onto low MW polysiloxanes, which are compatible with many polymers. New developments on antiozonants have focused on non-staining and slow migrating products, which last longer in rubber compounds. Several new types of non-staining antiozonants have been developed, but none of them appeared to be as efficient as the chemically substituted p-phenylenediamines. The most prevalent approach to achieve non-staining ozone protection of rubber compounds is to use an inherently ozone-resistant, saturated backbone polymer in blends with a diene rubber. The disadvantage of this approach however, is the complicated mixing procedure needed to ensure that the required small polymer domain size is obtained

Liquid-phase thiophene adsorption on MCM-22 zeolite and activated carbon

The liquid-phase adsorption of thiophene from thiophene/ iso-octane and toluene-rich thiophene/toluene/ iso-octane solutions has been investigated in batch conditions at room temperature and atmospheric pressure on MCM-22 zeolite and activated carbon. The adsorption of toluene from toluene/ iso-octane solutions has also been investigated on both the adsorbents. These were characterised by X-ray diffraction, nitrogen physisorption, scanning electron microscopy and adsorption microcalorimetry of ammonia. Both MCM-22 and activated carbon were able to adsorb thiophene and toluene from the corresponding single-adsorptive iso-octane solutions. MCM-22 appeared superior to activated carbon for the adsorption of thiophene from toluene-rich thiophene/toluene/ iso-octane mixtures. The adsorption data for MCM-22 were correlated with the acid sites and silanol groups concentrations, as determined by microcalorimetric experiments. No such correlation was found for activated carbon. Apparently, on MCM-22 thiophene adsorption occurs first on the acid sites until they are saturated and then continues on the silanol groups. Toluene adsorption also occurs on the acid sites of MCM-22 until saturation, but no further adsorption by interaction of toluene with the silanol groups takes place. GC/MS investigation of the nature of the organosulphur material retained by the adsorbent revealed that the tiophene adsorbed on MCM-22 undergoes transformation into heavy products. Besides thiophene trimers and tetramers, these include other compounds formed by two and three thiophenic rings linked by alkyl groups, as well as a rather high molecular weight product where a trimer is linked to thiophenic ring by a cyclohexadienic ring. Reaction pathways leading to these products have been tentatively outlined.

Investigative modeling of new pathways for secondary organic aerosol formation

Abstract. Recent advances in secondary organic aerosol (SOA) research are reviewed and the status of current understanding is investigated using a box model of SOA formation. Benzene and isoprene are newly identified precursors that are included in this SOA model; these precursors form SOA via secondary products. The model is also extended to include some representation of aqueous partitioning and the formation of high molecular weight products via oligomerization. Experimental data and empirical relationships are used where possible, because a detailed representation of SOA formation is not supported by the current state of information. Sensitivity studies are conducted with the SOA model and SOA predictions are found to be very sensitive to the treatment of the interactions between particulate water and organic compounds. While uncertainties due to model formulation are significant, influential model parameters include the aerosol partitioning ratios for several small products of isoprene and the partitioning constants for unidentified products (currently, the partitioning constants are derived by fitting experimental data). The pH value used as the reference for the activation of oligomerization is also a critical parameter. Recommendations for future work needed to improve SOA models include the elucidation of the water-organic relationship, the extent of phase separation, and laboratory experiments conducted under conditions more relevant to ambient studies (e.g., lower concentrations, higher relative humidity).

Multisegmented Block Copolymers by 'Click' Coupling of Polymers Prepared by ATRP

Multisegmented block copolymers were prepared by the step-growth click coupling of well-defined block copolymers synthesized by atom transfer radical polymerization (ATRP). α,ω-Diazido-terminated polystyrene-block-poly(ethylene oxide)-block-polystyrene was coupled with propargyl ether in N,N-dimethylformamide in the presence of a CuBr/N,N,N´,N´´,N´´-pentamethyldiethylenetriamine catalyst. The preparation of multisegmented block copolymers was also demonstrated by the click coupling of propargyl ether with another diazido-terminated triblock copolymer, poly(n-butyl acrylate)-block-poly(methyl methacrylate)-block-poly(n-butyl acrylate), and a diazido-terminated pentablock copolymer, polystyrene-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-polystyrene. The formation of a product of higher molecular weight and broader molecular weight distribution was verified by triple-detection size exclusion chromatography, which revealed that typically five to seven block copolymers were linked together during the click reaction. Differential scanning calorimetry and dynamic mechanical analysis revealed that the amphiphilic block copolymer behaves as a viscoelastic fluid, while its corresponding multiblock copolymer is an elastic material. The multisegmented block copolymers with partially miscible segments exhibit higher glass transition temperatures than their precursors.

Catalytic vapour phase epoxidation of propene with nitrous oxide as an oxidant

The vapour phase epoxidation of propene with nitrous oxide (N 2 O) was experimentally investigated in a fixed bed reactor using a CsO x /FeO y /SiO 2 catalyst in a broad range of residence times. A complex reaction network was derived from the trends of product selectivities as function of the conversion. For the determination of the reaction paths, not only propene but also its oxidation products, propylene oxide (PO) and propionaldehyde (PA), were used as reactants. The selectivity to PO was found to be limited due to fast side reactions, like PO isomerisation reactions and, in particular, the formation of higher molecular weight products (HMP) mainly present as carbonaceous deposits (coke) on the catalyst. The amount of HMP and coke was quantified through several methods and both were identified as the major byproducts. Although PO is formed with more than 60% selectivity among the directly identified vapour phase products, the maximum selectivity is only about 30% when taking the HMP into account. A complex reaction network was derived from experiments using propene, propylene oxide (PO), and propionaldehyde as reactants. Fast side reactions, especially to higher molecular weight products (HMP) limit the selectivity to PO. Although PO is formed with more than 60% selectivity among the directly identified vapour phase products, the maximum selectivity is only about 30% when taking the HMP into account.

Negative Regulation of Osteoclastogenesis by Ectodomain Shedding of Receptor Activator of NF-κB Ligand

Receptor activator of NF-kappaB ligand (RANKL) is a transmembrane glycoprotein that has an essential role in the development of osteoclasts. The extracellular portion of RANKL is cleaved proteolytically to produce soluble RANKL, but definite RANKL sheddase(s) and the physiologic function of RANKL shedding have not yet been determined. In the present study, we found that matrix metalloproteinase (MMP) 14 and a disintegrin and metalloproteinase (ADAM) 10 have strong RANKL shedding activity. In Western blot analysis, soluble RANKL was detected as two different molecular weight products, and RNA interference of MMP14 and ADAM10 resulted in a reduction of both the lower and higher molecular weight products. Suppression of MMP14 in primary osteoblasts increased membrane-bound RANKL and promoted osteoclastogenesis in cocultures with macrophages. Soluble RANKL produced by osteoblasts from MMP14-deficient mice was markedly reduced, and their osteoclastogenic activity was promoted, consistent with the findings of increased osteoclastogenesis in vivo. RANKL shedding is an important process that down-regulates local osteoclastogenesis.

Urokinase separation from cell culture broth of a human kidney cell line.

A single step ion-exchange chromatography on a sulfo-propyl (SP)- Sepharose column was performed to separate both the high molecular weight (HMW)- and low molecular weight (LMW)- forms of enzymatically active urokinase type plasminogen activator from human kidney (HT1080) cell culture media. The level of urokinase secreted by the cell line reached to about 145 Plough units/ml culture broth within 48 h of cultivation. The conditioned cell culture media was applied directly to the column without any prior concentration steps. Polyacrylamide gel electrophoresis of the column eluates in the presence of sodium dodecyl sulphate showed that the cell line secretes three forms of two-chain high molecular weight (HMW) urokinase of molecular weights (M(r)) 64,000, 60,900 and 55,000. In addition, two low molecular weight (LMW) forms of M(r) 22,000 and 20,000; proteolytic cleavage products of HMW, were also found. The HMW and LMW forms had intrinsic plasminogen dependent proteolytic activity as judged by zymographic analysis. The specific activity of the pooled peak fractions increased (approximately 93-fold) to values as high as 1481 Plough units/ mg protein. Both HMW as well as LMW forms were obtained in significantly high yields.

Calcium enhanced COD removal for the ozonation of phenol solution

In order to improve the chemical oxygen demand (COD) removal rate for the ozonation of phenol solution, ozonation combined with calcium binding was investigated. The results show that the addition of Ca 2+ can effectively enhance the COD removal rate. During the ozonation, calcium ion can bind with some of the intermediate products of phenol, including high molecular weight products, maleic acid and oxalic acid, to form insoluble precipitates. These calcium binding effects are responsible for the enhancement of COD removal. The variations of ADMI value during ozonation are similar for solutions with and without Ca 2+. However, the peak ADMI value in calcium-contained solution is lower than that without Ca 2+. As the phenol was completely decomposed, the ozone gas outlet concentration rapidly increases. The increasing rate of the ozone gas outlet concentration for ozonation with the presence of Ca 2+ is faster than that without Ca 2+. The optimal initial calcium dosage shows linear relationship with the initial phenol concentration, which is useful for practical application.