Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater

As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%—78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

Solid-Liquid Equilibrium of Terephthalic Acid in Several Solvents

Terephthalic acid(PTA) is practically one of the main materials of polyester. Its corresponding solid-liquid equilibrium data will provide essential support for industry design and further theoretical studies. In this work,solid-liquid equilibriums of terephthalic acid in four solvents, N,N-dimethylformamide, N,N-dimethylacetamide,dimethylsulphoxide and N-methyl-2-ketopyrrolidene, were determined in the temperature range from 293.15 K to 364.6 K by dynamic method. All these data were regressed by λh model, Wilson model and NRTL model, average absolute relative deviations of which are 1.25%, 15.02% and 7.22% respectively. It indicates that λh model is mostsuitable for description of the solid-liquid equilibrium containing PTA.

Anaerobic biodegradability of terephthalic acid and its inhibitory effect on anaerobic digestion

The behavior of terephthalic acid (TPA) in anaerobic system has been studied bysemicontinuous bioassays under mesophilic condition with artificial TPA production wastewater. Theeffect of different loading rate of TPA on anaerobic digestion was studied under certain CODloading rate. The results showed that the TPA could be degraded anaerobically within a relativelylow range. The degradable concentration of TPA was less than 500 mg/L in the digester, higherconcentration of TPA could not be degraded totally and the rate of degradation might decrease withthe increase of feed amount. The inhibition is related to both loading rate and accumulatedconcentration of TPA in the digesters.

Dynamic Simulation and Analysis of Industrial Purified Terephthalic Acid Solvent Dehydration Process

Dynamic model for dehydration process of industrial purified terephthalic acid solvent is investigated to understand and characterize the process.A temperature differential expression is presented,which ensures the equation to convergence and short computation time.The model is used to study the dynamic behavior of an azeotropic distillation column separating acetic acid and water using n-butyl acetate as the entrainer.Responses of the column to feed flow and aqueous reflux flow are simulated.The movement of temperature front is also simulated.The comparison between simulation and industrial values shows that the model and algorithm are effective.On the basis of simulation and analysis,control strategy,online optimization and so on can be implemented effectively in dehydration process of purified terephthalic acid solvent.

Purified terephthalic acid wastewater biodegradation and toxicity

The biodegradation and toxicity of the purified terephthalic acid（PTA） processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process（ CASP）. Sludge loading rate（SLR） for Fhhh to COD of the wastewater was 1.09 d^-1 and to PTA in the wastewater was 0.29 d^-1. The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 （median lethal concentration） to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were .5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

Kinetics of the Mono-esterification Between Terephthalic Acid and 1,4-Butanediol

The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out in the temperature range of 463-483 K,and butylhydroxyoxo-stannane(BuSnOOH)and tetrabutyl titanate[Ti(OBu)4]were used as catalyst respectively.The initial rates of the reaction catalyzed by BuSnOOH or Ti(OBu)4 were measured at a series of initial concentrations of BDO(or TPA)with the concentration of TPA(or BDO)kept constant.The reaction orders of reagents were determined by the initial rate method.The results indicate that the reaction order for TPA is related with the species of catalyst and it is 2 and 0.7 for BuSnOOH and Ti(OBu)4 respectively.However,the order for BDO is the same 0.9 for the two catalysts.Furthermore,the effects of temperature and catalyst concentration are investigated,and the activation energies and the reaction rate constants for the two catalysts were determined.

Multi-objective Optimization of Industrial Purified Terephthalic Acid Oxidation Process

Multi-objective optimization of a purified terephthalic acid (PTA) oxidation unit is carried out in this paper by using a process modei that has been proved to describe industrial process quite well. The modei is a semi-empirical structured into two series ideal continuously stirred tank reactor (CSTR) models. The optimal objectives include maximizing the yield or inlet rate and minimizing the concentration of 4-carboxy-benzaldhyde, which is the main undesirable intermediate product in the reaction process. The multi-objective optimization algorithra applied in this study is non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ). The performance of NSGA-Ⅱ is further illustrated by application to the title process.

A two-stage anaerobic system for biodegrading wastewater containing terephthalic acid and high strength easily degradable pollutants

The high strength easily biodegradable pollutants (represented by COD E) are strong inhibitors of terephthalic acid (TA) anaerobic biodegradation. At the same time, TA can inhibit easily biodegradable pollutants removal under anaerobic conditions to a limited extent. This mutual inhibition could happen and cause a low removal efficiency of both TA and COD E, when the effluent from TA workshops containing TA and easily biodegradable pollutants are treated by a single anaerobic reactor system. Based upon the treatment kinetics analysis of both TA degradation and COD E removal, a two stage up flow anaerobic sludge blanket and up flow fixed film reactor(UASB UAFF) system for dealing with this kind of wastewater was developed and run successfully at laboratory scale. An UASB reactor with the methanogenic consortium as the first stage removes the easily biodegradable pollutants(COD E). An UAFF reactor as the second stage is mainly in charge of TA degradation. At a COD E loading of 15.3 g/(L\5d) and a TA loading of 1.4 g/(L\5d), HRT 18.5h, the COD E and TA removal rate of the system reached 89.2% and 71.6%, respectively.

Synthesis and identification of dinitro- and diaminoterephthalic acid

Dinitroterephthalic acid （DNTPA） and diaminoterephthalic acid （DATPA） were prepared in 85% and 75% yields, respectively. These compounds were characterized by using FTIR and ^1HNMR. DATPA can be used as a monomer for the preparation of polyesters and polyamides. 2009 H. Migbani. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Fuzzy Neural Network Model of 4-CBA Concentration for Industrial Purified Terephthalic Acid Oxidation Process

A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeling.First,a set of preliminary input variables is selected according to prior knowledge and experience. Secondly,a method based on the maximum correlation coefficient is proposed to detect the dead time between the process variables and response variables. Finally, the fuzzy curve method is used to reduce the unimportant input variables.The simulation results based on industrial data show that the relative error range of the FNN model is narrower than that of the American Oil Company (AMOCO) model. Furthermore, the FNN model can predict the trend of the 4-CBA concentration more accurately.

Research and Implementation of Decreasing the Acetic Acid Consumption in Purified Terephthalic Acid Solvent System

Decreasing the acetic acid consumption in purified terephthalic acid （PTA） solvent system has become a hot issue with common concern. In accordance with the technical features, the electrical conductivity is in direct proportion to the acetic acid content. General regression neural network （GRNN） is used to establish the model of electrical conductivity on the basis of mechanism analysis, and then particle swarm optimization （PSO） algorithm with the improvement of inertia weight and population diversity is proposed to regulate the operating conditions. Thus, the method of decreasing the acid loss is derived and applied to PTA solvent system in a chemical plant. Cases studies show that the precision of modeling and optimization are higher. The results also provide the optimal operating conditions, which decrease the cost and improve the profit.

Towards recycling purpose:Converting PET plastic waste back to terephthalic acid using pH-responsive phase transfer catalyst

Converting polyethylene terephthalate(PET)wastes to its monomer and valuable chemicals via ecofriendly chemical method is still a challenge task.Previously,phase transfer catalysts used for alkaline hydrolysis were soluble in reaction media and hardly separated after reaction.Here,we reported several pH-responsive catalysts combined alkyl quaternary ammonium units with heteropolyacid anion for achieving stepwise product/catalyst separation and catalyst recycling.The properties of homogeneous/heterogeneous transfer behavior allow catalyst to be easily separated from reaction media by adjusting of pH value.Among them,[C_(16)H_(33)N(CH_(3))_(3)]_(3)PW_(12)O_(40)(abbreviated as[CTA]_(3)PW)exhibits the highest activity and the most suitable pH responsive values.Such a pH triggered switchable catalytic system not only shows good performance for depolymerization of pure PET,but also some real PET wastes such as coloured trays and PE/PET complex films could be completely degraded into terephthalic acid.Additionally,the reaction kinetics and activation energy of PET alkaline hydrolysis also studied with and without pH-responsive[CTA]_(3)PW.

Spectrofluorimetric determination of terbium with terephthalic acid

A Spectrofluorimetric method has been developed for the determination ofterbium(Ⅲ) based on the formation of a complex with terephthalic acid [benzene-1, 4-dicarboxylicacid (TPA)] in slightly acidic aqueous solution in the presence of gelatin. Terbium ion can form astable complex with TPA with the stoichiometry of 1:2. The best excitation and maximum emissionwavelengths are observed at 260 nm and 545 nm, respectively. The fluorescence intensity of terbiumcomplex gets the strongest within 20 min and remains stable up to 10 h, and it is proportional toterbium(Ⅲ) concentration in the range of 4.0x10^(-5)-1.6x10^(-7) mol·L^(-1) under the optimumconditions. The fluorescence system has good selectivity, sensitivity and stability. The relativestandard deviation is still within +-4% in the presence of 1200-fold amounts of the other lanthanideions when the concentration of terbium(Ⅲ) is 1.0x10^(-6) mol·L^(-1) and common co-existing ionshardly interfere the determination. It has been applied to the direct fluorimetric determination oftrace terbium (Ⅲ) in rare earth ores and oxides.

Induction of Bladder Lesion by Terephthalic Acid and Its Mechanism

To provide more information for rational evaluation of potential risks of terephthalic acid （TPA）, we studied the effects of TPA on rats＇ bladders in 90 days after TPA exposure. Methods Sprague Dawley rats were subdivided into five groups, ingesting 0 %, 0.04 %, 0.2 %, 1%, and 5 % TPA respectively for a sub-chronic feeding study lasting for 90 days. Urine, serum and samples of brain, liver, lung, kidney, bladder, etc. were collected and analyzed. Results TPA ingesting decreased the value of urinary pH, and increased the contents of Ca^2＋, Zn^2＋, Mg^2＋, Na^＋, K^＋ in urine. The volume of 24 h urine was significantly increased in male rats in the 1% and 5 % TPA groups. Urinary white sediment was found in both sexes, and its formation in male rats seemed more susceptible than that in female rats. Alpha 2u-globulin （AUG） in serum and urine of male rats was markedly increased in a dose-dependent manner. Fifteen cases of hyperplasia （simple or atypical） were determined in the 5 % TPA ingesting group, 14/52 in male rats and 1/23 in female rats. Among them 3 male rats had no stone or calculus. Those with either bladder stones or hyperplasia were accompanied with urinary white sediments. Conclusion White sediment accompanied with elevated urine AUG is the basis of TPA induced urolith formation, and is also associated with TPA induced bladder epithelial cell proliferation. It can act as an early biomarker for the potential toxic effect of TPA.

Synthesis and Characterization of Poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) Copolyester

Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified as PEOT-x,where x is the mole fraction of furandicarboxylic acid in the samples,were synthesized by direct esterification.The molecular structure of the copolyesters was characterized by FTIR and 1H NMR spectroscopy.Gel permeation chromatography (GPC),differential scanning calorimetry (DSC),and thermogravimetric analysis (TGA) were used to characterize the molecular weight,molar mass dispersity,glass transition temperature,and thermal stability of the copolyesters,respectively.The mechanical properties of the samples were also investigated.The number-average molecular weight (M_(n)) of the samples varies from 9 700-18 800 g/mol,and molar mass dispersity (■=M_(w)/M_(n)) from 2.15-3.34.The initial decomposition temperature of the copolyesters is in the 332-356 ℃ range,with maximum decomposition rates at 390-410 ℃,while the glass transition temperature (Tg) varies from 0-33 ℃.Mechanical test shows that PEOT-10 has the highest tensile strength,while PEOT-90 has the largest tensile modulus and elongation at break.The experimental results show that these copolyesters can be synthesized with relatively high molecular weights,good thermal stability,and fair mechanical properties,which makes them excellent replacements for commercial polyesters,such as PET,and these properties can be tuned through the relative amounts of biomass monomer 2,5-furandicarboxylic acid used in the reactions.

Syntheses and applications of Eu(Ⅲ) complexes of 2-thienyltrifluoroacetonate, terephthalic acid and phenanthroline as light conversion agents

A series of europium（Ⅲ） complexes of 2-thienyltrifluoroacetonate （HTTA）, terephthalic acid （TPA） and phenanthroline （Phen） were synthesized. The new complexes Eu（TPA）（TTA）Phen and EUE（TPA）（TTA）4Phen2 were characterized by elemental analysis, IR spectrum, scanning electron microscope and thermal stability analysis. The results show that the thermal stability of the Eu（Ⅲ） complexes increases in the following order： the mononuclear complex Eu（TTA）3Phen, the binuclear complex EUE（TPA）（TTA）4Phen2, the chain polynuclear complex Eu（TPA）（TTA）Phen. And the formation of the binuclear/polynuclear structure of the new complexes appears to be responsible for the enhancement of their thermal and optical stability. In addition, The fluorescence excitation spectra of these new complexes show more broad excitation bands than that of the complex Eu（TTA）3Phen corresponding to their formation. The enhancement of Eu^3＋ fluorescence in the new complexes can be observed by the addition of Gd^3＋. The bright red luminescent plastics can be obtained when the complex EuGd（TPA）（TTA）4Phen2 is added above 0.5% （mass fraction）.

Solvothermal Synthesis,Crystal Structure and Photoluminescence Property of a 3D Lead(Ⅱ)Coordination Polymer Based on Terephthalic Acid

Solvothermal reaction of Pb（NO3）2·6H2O with rigid linear ligand terephthalic acid（H2pta） in N,N-dimethylformamide（DMF） produced a new three-dimensional（3D） lead（Ⅱ）coordination polymer[Pb2（pta）1.5（μ4-OH）（DMF）]n 1,and its structure was characterized by single-crystal X-ray diffraction analyses.In polymer 1,the μ4-OH bridges the nearby lead（Ⅱ） ions into an infinite one-dimensional（1D） chain,and then the organic ligand pta^2- joins the neighbored chains into a 3D structure by two similar connection modes in different configurations.The solid-state photoluminescent studies revealed that 1 exhibits a strong greenish emission mainly originating from ligand-to-metal charge transfer between the delocalized π bonds of the aromatic carboxylate ligand pta^2- and the p orbitals of the Pb^2＋ centers.

PREPARATION AND PROPERTIES OF POLY(LACTIC ACID-CO-GLYCOL TEREPHTHALIC ACID)COPOLYESTER

To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly（lactic acid-co-glycol terephthalate） （PETA）, was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, ^1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the Tins and Tas of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.

Syntheses and cofluorescence of complexes of Eu(Ⅲ)/Y(Ⅲ) with terephthalic acid, 2-thenoyltrifluoroacetone and trioctylphosphine oxide

A series of Eu( Ⅲ )/Y( Ⅲ ) complexes of terephthalic acid(TPA) with 2-thenoyltrifluoroacetone(HTTA) and trioctylphosphine oxide(TPPO) were synthesized. Compositions of these complexes are revealed to be Eu2(1-x)Y2x(TPA)(TTA)4- (TPPO)4 or Eu1-xYx(TPA)(TTA)(TPPO)2. Their IR spectra, fluorescent spectra and the thermal and optical stability were studied. The fluorescent excitation spectra of these complexes show more broad excitation bands than those of Eu2(TPA)3(TPPO)4 and Eu(TTA)3(TPPO)2 corresponding to their formations. In addition, both the binuclear complex EuY(TPA)(TTA)4(TPPO)4 and the chain complex Eu0.4Y0.6(TPA)(TTA)(TPPO)2 present higher thermal stability and better optical stability than the mononuclear complex Eu(TTA)3(TPPO)2 does. And their thermal and optical stabilities are preferably interpreted from the binuclear structure together with the chain polynuclear structure of the complexes. The fluorescence enhancement of cofluorescence Y3+ ions to the Eu(Ⅲ) complexes is clear. The optimum content of Y3+ is 0.6 (molar fraction) for the chain complexes Eu1-xYx(TPA)(TTA)- (TPPO)2 and 0.5 for the binuclear complexes Eu2(1-x)Y2x(TPA)(TTA)4(TPPO)4. The formation of polynuclear structure of the complex Eu1-xYx(TPA)(TTA)(TPPO)2 appears to be responsible for the good cofluorescence effect of Y3+ ions.

Effects of Terephthalic Acid on Rat Lipid Metabolism

Objective To study the effect of terephthalic acid （TPA） on lipid metabolism in Sprague-Dawley （SD） rats. Methods Five groups of SD rats that ingested 0%, 0.04%, 0.2%, 1%, and 5% TPA, respectively, were included in a 90-day subchronic feeding study. Effects of TPA on levels of serum protein, total cholesterol （TC）, triglycerides （TG）, high-density lipoprotein cholesterol （HDL）, total antioxidative capability （T-AOC）, superoxide dismutase （SOD） and malondialdehyde （MDA） were observed. Urine samples were collected and analyzed for concentration of ion. Results TPA decreased the level of serum T-AOC in a dose dependent manner. The contents of serum and bladder MDA significantly decreased in 1% and 5% TPA ingestion groups. Serum CuZn superoxide dismutase （CuZnSOD） lowered in groups of 0.2%, 1%, and 5% TPA. TPA subchronic feeding had no significant influences on serum TC, LDL or HDL, but increased serum TG, TP and ALB after administration of 0.04% and/or 0.2% TPA. Concentrations of urinary Ca^2＋, Mg^2＋, Na^＋, and K^＋ were elevated in 1% and 5% TPA groups. Conclusion Antioxidative potential decreased after TPA exposure. MDAincrease in serum and bladder tissues was one of the most important reactions in rats which could protect themselves against TPA impairment. The decrease of serum CuZnSOD was related to the excretion of Zn^2＋.