Biodegradation of phenol and m-cresol by mutated Candida tropicalis

The phenol and m-cresol biodegradations were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis. The results showed that C. tropicalis exhibited the increased capacity of phenolic compounds degradation after laser irradiation. It could degrade 2600 mg/L phenol and 300 mg/L m-cresol by 5% inoculum concentration, respectively. In the dual-substrate biodegradation system, 0-500 mg/L phenol could accelerate m-cresol biodegradation, and 300 mg/L m-cresol could be completely utilized within 46 hr at the presence of 350 mg/L phenol. Besides, the maximum biodegradation of m-cresol could reach 350 mg/L with 80 mg/L phenol within 61 hr. Obviously, phenol, as a growth substrate, could promote CTM 2 to degrade m-cresol, and was always preferentially utilized as carbon source. Comparatively, low-concentration m-cresol could result in a great inhibition on phenol degradation. In addition, the kinetic behaviors of cell growth and substrate biodegradation were described by kinetic model proposed in our laboratory.

Kinetics of phenol and m-cresol biodegradation by an indigenous mixed microbial culture isolated from a sewage treatment plant

An acclimatized mixed microbial culture,predominantly Pseudomonas sp.,was enriched from a sewage treatment plant,and its potential to simultaneously degrade mixtures of phenol and m-cresol was investigated during its growth in batch shake flasks.A 22 full factorial design with the two substrates at two different levels and different initial concentration ranges(low and high),was employed to carry out the biodegradation experiments.The substrates phenol and m-cresol were completely utilized within 21 h when ...

Separation of m-cresol from aromatic hydrocarbon and alkane using ionic liquids via hydrogen bond interaction

Low temperature coal tar contained a large amount of phenols, aromatic hydrocarbons and alkanes;the separation of phenols from coal tar has a great significance to the deep processing of coal tar. In this work, the separation of m-cresol from cumene and n-heptane by liquid–liquid extraction using ionic liquids(ILs) as extractants was studied. The suitable ILs were screened by conductor-like screening model for real solvents(COSMO-RS)model and the liquid–liquid phase equilibrium(LLE) experiments were to verify the accuracy of the screening results. The extraction conditions such as extraction time, extraction temperature and mass ratio of ILs to model oils were evaluated. An internal mechanism of the m-cresol extract by ILs was revealed by COSMO-RS calculation and FT-IR. The results showed that the selected ILs can extract m-cresol effectively from cumene and nheptane, 1-ethyl-3-methylimidazolium acetate(emim CH3 COO) was the best extraction solvent. A hydrogen bond between anion of ILs and phenolic hydroxyl groups was observed. M-cresol in model oils could be extracted with extraction efficiencies up to 98.85% at an emim CH3 COO: model oils mass ratio of 0.5 and 298.15 K,emim CH3 COO could be regenerated and reused for 4 cycles without obvious decreases in extraction efficiency and extractant mass.

Supercritical gasification for the treatment of o-cresol wastewater

The supercritical water gasification of phenolic wastewater without oxidant was performed to degrade pollutants and produce hydrogen-enriched gases. The simulated o-cresol wastewater was gasified at 440-650℃ and 27.6 MPa in a continuous Inconel 625 reactor with the residence time of 0.42-1.25 min. The influence of the reaction temperature, residence time, pressure, catalyst, oxidant and the pollutant concentration on the gasification efficiency was investigated. Higher temperature and longer residence time enhanced the o-cresol gasification. The TOC removal rate and hydrogen gasification rate were 90.6% and 194.6%, respectively, at the temperature of 650℃ and the residence time of 0.83 min. The product gas was mainly composed of H2, CO2, CFL and CO, among which the total molar percentage of H2 and CFL was higher than 50%. The gasification efficiency decreased with the pollutant concentration increasing. Both the catalyst and oxidant could accelerate the hydrocarbon gasification at a lower reaction temperature, in which the catalyst promoted H2 production and the oxidant enhanced CO2 generation. The intermediates of liquid effluents were analyzed and phenol was found to be the main composition. The results indicate that the supercritical gasification is a promising way for the treatment of hazardous organic wastewater.

Simultaneous Biological Removal of p-Cresol, Sulfide and Nitrate by Denitrification

Biological removal of sulfide, nitrate, and p-cresol at a loading rate of 340 gS/(m^3 · d), 340 gN/(m^3 · d) and600 gC/(m^3 · d), respectively, was achieved in an upflow anaerobic sludge blanket(UASB) reactor. The ratio of C/S could affect the elemental sulfur(S^0) accumulation, and the C/S ratio of 1.75:1 was optimal for S^0 accumulation. Strains Pseudomonas sp., Simplicispira sp., and Rhizobium sp. could likely yield heterotrophs. Strains Arcobacter sp.,Sulfurimonas sp., Sulfurovum sp., and Sulfurospirillum sp. are the autotrophics required for the proposed UASB system. At high loading rate, the autotrophic denitrification pathway declined faster than the heterotrophic pathway.

Comparison of Photochemical Reactions of m-Cresol in Aqueous Solution and in Ice

We compared the photochemical reaction of m-cresol containing ·OH precursors such as H2O2, NO2 and NO3 in aqueous solution with those in ice. The results show that the conversion rate of m-cresol in aqueous solution was higher than that in ice. H2O2, NO2 and NO3 all accelerated the photoconversion of m-cresol in both aqueous solution and ice. The photochemical reactions of m-cresol obeys the first order kinetics equation. According to the photoproducts identified by GC-MS, we proposed that hydroxylation and nitration reactions occurred in both aqueous solution and ice. Coupling reaction was common in ice, however, in aqueous solution it was found only in UV system. Our results suggest that the photochemical reactions of m-cresol were different in aqueous solution and in ice.

Development and validation of RP-HPLC and RP-UPLC methods for quantification of parathyroid hormones (1-34) in medicinal product formulated with meta-cresol

Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of parathyroid hormone (PTH) in presence of meta-cresol as a stabilizer in a pharmaceutical formulation.Chromatography was performed with mobile phase containing 0.1% Trifluoroacetic acid (TFA) in MilliQ water and 0.1% TFA in acetonitrile with gradient program and flow rate at 0.3 mL/min for HPLC and 0.4 mL/min for UPLC.Quantification was accomplished with internal reference standard (qualified against innovator product and National Institute for Biological Standards and Control (NIBSC) standard).The methods were validated for linearity (correlation coefficient 0.99),range,accuracy,precision and robustness.Robustness was confirmed by considering three factors;mobile phase composition,column temperature and flow rate/age of mobile phase.Intermediate precision was confirmed on different equipments,different columns and on different days.The relative standard deviation (RSD) (<2% for RP-HPLC and <1% for UPLC,n=30) indicated a good precision.Retention time was found about 17 min and 2 min by HPLC and UPLC methods,respectively.Both methods are simple,highly sensitive,precise and accurate and have the potential of being useful for routine quality control.

HYDROGENATION OF PHENOL AND CRESOLS CATALYZED BY CHITOSAN SUPPORTED PALLADIUM COMPLEX AT MILD CONDITIONS

A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% selectivity at 70 degrees C and 1.01325 x 10(5) Pa mild conditions. N/Pd molar ratio in the complex, temperature and solvents have much influence on the reaction. The reactivity order of reactants was found to be: phenol >m->p->o- The catalyst is stable during the reaction and could be repeatedly used for several times without much decrease in its catalytic activity.

An Excellent Gas Chromatographic Stationary Phase for Separation of Phenol and Cresol Isomers--Heptakis(2,6-di-O-pentyl-3-O-allyl)-β-Cyclodextrin

Heptakis(2.6-di-O-pentyl-3-O-ally)-β-cyclodextrin as an excellent gas chromatographic stationary phase separating phenol and cresol isomers is described.

A STUDY OF SILICA-SUPPORTED CROSS-LINKED POLY (MALEIC ACID-CO-STYRENE)-PLATINUM COMPLEX IN THE HYDROGENATION OF p-CRESOL

A silica-supported cross-linked poly(maleic acid -co- styrene)-platinum complex (PMS-Pt) has been prepared and found to be active in the hydrogenation of p-cresol under mild conditions (303-323K, 1.01 x 10(5)Pa). In this hydrogenation system water serves as a solvent and p-cresol can be converted to 4-methylcyclohexanol quantitatively via 4-methylcyclohexanone as intermediate.

Alkylation of p-Cresol with tert-Butanol Catalyzed by Novel Multiple-SO_3H Functioned Ionic Liquid

有到新奇 multiple-SO3H 催化的 2-tert-butyl-p-cresol (TBC ) 的 tert-butanol (TBA ) 的 p 甲酚的完化工作了离子的液体(IL1 ) 被调查。同时，这新奇离子的液体的催化活动与另外的四传统的离子的液体相比。结果证明 IL1 与 85.3% 的变换和 95.2% 的选择举办优异催化活动到另外的四传统的离子的液体。另外，反应条件被调查获得最佳条件。运作的简洁，用法的小数量，高活动，可重用性和选择是这方法论的特色。

Experimental and Simulation Study on the Extraction of p-Cresol Using Centrifugal Extractors

In this study,extraction of p-cresol from the simulated wastewater has been studied using centrifugal extractors and QH-1 extractant.The distribution ratio of p-cresol was approximately 308.5 in the QH-1-p-cresol(pH=2.0)system.The extraction stage efficiency of the single-stage centrifugal extractor was higher than 92%,and the extraction rate of the three-stage cascade was higher than 99%.When 15% NaOH was used for the stripping of p-cresol in QH-1 solution,the stripping rate of the three-stage cascade reached 100%.A mathematical model of multistage countercurrent extraction process that considers the phase volume change,extraction stage efficiency,and phase entrainment was used to simulate the extraction of p-cresol using centrifugal extractors.The calculated results using this model were in good agreement with the experimental results.

Selective aerobic oxidation of p-cresol with co-catalysts between metalloporphyrins and metal salts

A green and efficient method for the selective aerobic oxidation of p-cresol to p-hydroxybenzaldehyde catalyzed by co-catalysts between metalloporphyrins and metal salts was investigated and developed. The relationship between the synergistic catalytic effects and the composition as well as amount of co-catalysts was investigated. Moreover, the influence of different reaction conditions was studied in details. A high p-cresol conversion(N 99%) and p-hydroxybenzaldehyde selectivity(83%) were obtained using only 1.125 × 10^(-5) mol T(p-CH_3 O)PPFe^(III)Cl-Co(OAc)_2 used under mild, optimized reaction conditions. A possible mechanism for the reaction was also proposed. This work would be meaningful and instructive for the further researches and applications of co-catalyst system on oxidation of cresols and could give some enlightenment on the selectively catalytic oxidation of the side-chain alkyls of aromatics.

尿液中蛋白结合毒素水平与上尿路结石的相关性研究

目的·探讨尿液中蛋白结合毒素(protein-bound uremic toxin,PBUT)水平与上尿路结石形成的关系。方法·以海南省儋州市海头镇社区18~80岁居民为研究对象。记录研究对象基本信息和近3 d饮食情况,收集空腹血清和24 h尿液标本,所有对象接受肾脏和输尿管B超检查。将B超检查发现有上尿路结石或有明确上尿路结石病史的对象作为结石组,其他作为非结石组。检测血、尿中结石形成相关的生化指标,通过高效液相色谱检测血、尿中的PBUT(硫酸吲哚酚、3-吲哚乙酸和硫酸对甲酚),以及尿草酸和尿枸橼酸水平。通过多因素Logistic回归分析上尿路结石形成的相关因素。采用Spearman相关性检验分析尿PBUT与尿尿酸、草酸和枸橼酸的相关性。结果·经筛选,共纳入117例研究对象,其中结石组54例,非结石组63例。2组的性别、年龄、血清指标,以及高血压、糖尿病、高尿酸血症/痛风等合并症比例方面差异均无统计学意义。结石组的24 h尿液pH值、钙、尿酸和氯均显著高于非结石组(均P<0.05),而硫酸吲哚酚显著低于非结石组(P<0.05)。多因素Logistic回归分析结果显示,除尿钙外,尿硫酸吲哚酚水平(OR=0.929,95%CI 0.875~0.986,P=0.016)也是上尿路结石形成的独立相关因素。Spearman相关性分析结果显示,24 h尿液中3-吲哚乙酸(r=0.420,P=0.000)和硫酸对甲酚(r=0.307,P=0.001)水平均与草酸呈正相关,硫酸对甲酚水平与尿酸呈正相关(r=0.297,P=0.002),硫酸吲哚酚水平与枸橼酸呈正相关(r=0.289,P=0.002)。结论·在该研究人群中,尿硫酸吲哚酚水平降低可能是上尿路结石形成的独立危险因素,且尿液中PBUT水平与尿酸、草酸、枸橼酸的水平相关。

沉淀法回收对甲酚模拟废水中酚的研究

用离子沉淀法回收对甲酚模拟废水中的酚,考察了不同的金属离子沉淀剂、沉淀剂加量、温度与pH值对酚去除率的影响。结果表明,最优的沉淀剂为BaCl_(2);对于50 mL、5000 mg/L的对甲酚模拟废水,当温度为25℃,pH值为14,BaCl_(2)溶液加量为18 mL,酚去除率可达52.3%。将收集的酚钡盐沉淀用稀HCl中和,用乙酸丁酯为萃取剂进行萃取,对甲酚的萃取回收率达到99.69%,为高含酚废水的资源化利用提供了思路和方法。

焦化污泥基生物炭在氯介质下催化降解间甲酚的性能

以焦化污泥制备生物炭,并在硝酸溶液中低温条件下进行改性,研究其在氯介质下对间甲酚降解的效率与机理.焦化污泥(CSS)具有较大的比表面积和丰富的官能团,其吸附作用较强,对间甲酚的吸附去除率为27.1%.而通过炭化和改性的焦化污泥炭的比表面积显著降低,官能团数量减少,吸附作用极弱.在催化降解过程中,改性焦化污泥炭(CSSC-N)对间甲酚和总有机碳(TOC)的去除率分别为98.1%和80.1%,远高于未改性的焦化污泥炭(CSSC-0),主要归因于CSSC-N中具有多种含铁物质,有利于铁循环,且表面铁含量高达60.10%,能提供丰富的催化活性组分.Cl-对间甲酚和TOC的去除率有抑制作用,随着Cl-浓度的升高,去除率降低.当废水中的NaCl为5%wt时,在催化重复实验中间甲酚的去除率均高于70%.CSSC-N具有一定的抗氯性能,在氯介质下具有较高的催化活性和稳定性.三维荧光光谱分析和中间产物鉴定结果表明Cl-的存在影响了间甲酚的降解过程,生成了难降解的氯代副产物.

慢性肾衰竭患者并发心血管疾病相关危险因素分析

目的:探究慢性肾衰竭(CRF)患者并发心血管疾病(CVD)的相关危险因素。方法:选取111例CRF维持性血液透析患者作为研究对象,调查CVD发生情况。将其分为CVD组(n=54)、非CVD组(n=57),收集两组一般临床资料,采用Logistic单因素和多因素回归分析,探究CRF患者并发CVD的独立危险因素。结果:两组患者年龄、性别、体重指数(BMI)、合并糖尿病情况、心血管疾病史及原发病差异比较无统计学意义(均P>0.05);CVD组血红蛋白、Klotho蛋白水平均低于非CVD组(均P<0.05),低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)/高密度脂蛋白胆固醇(HDL-C)、血清磷酸盐、甲状旁腺激素(PTH)、白细胞介素-6(IL-6)、基质金属蛋白酶-9(MMP-9)、硫酸对甲酚水平均高于非CVD组(均P<0.05);Logistic多因素回归分析显示,血红蛋白、Klotho蛋白下降及TG/HDL-C、IL-6、硫酸对甲酚升高均为CRF连续性血液透析患者发生CVD的独立危险因素(均P<0.05)。结论:血红蛋白和Klotho蛋白的下降以及TG/HDL-C、IL-6和硫酸对甲酚的升高均可增加CRF维持性血液透析患者CVD的风险,血液透析治疗期间应加强对上述危险因素的评估和管理。

Performance study and kinetic modeling of hybrid bioreactor for treatment of bi-substrate mixture of phenol-m-cresol in wastewater:Process optimization with response surface methodology

Performance of a hybrid reactor comprising of trickling filter （TF） and aeration tank （AT） unit was studied for biological treatment of wastewater containing mixture of phenol and m-cresol, using mixed microbial culture. The reactor was operated with hydraulic loading rates （HLR） and phenolics loading rates （PLR） between 0.222-1.078 m3/（m2-day） and 0.900-3.456 kg/（m3.day）, respectively. The efficiency of substrate removal varied between 71%-100% for the range of HLR and PLR studied. The fixed film unit showed better substrate removal efficiency than the aeration tank and was more resistant to substrate inhibition. The kinetic parameters related to both units of the reactor were evaluated and their variation with HLR and PLR were monitored. It revealed the presence of substrate inhibition at high PLR both in TF and AT unit. The biofilm model established the substrate concentration profile within the film by solving differential equation of substrate mass transfer using boundary problem solver tool ＇bvp4c＇ of MATLAB 7. 1 software. Response surface methodology was used to design and optimize the biodegradation process using Design Expert 8 software, where phenol and m-cresol concentrations, residence time were chosen as input variables and percentage of removal was the response. The design of experiment showed that a quadratic model could be fitted best for the present experimental study. Significant interaction of the residence time with the substrate concentrations was observed. The optimized condition for operating the reactor as predicted by the model was 230 mg/L of phenol, 190 mg/L of m-cresol with residence time of 24.82 hr to achieve 99.92% substrate removal.

Biodegradation of p-cresol by aerobic granules in sequencing batch reactor

The cultivation of aerobic granules in sequencing batch reactor for the biodegradation of p-cresol was studied. The reactor was started with 100 mg/L of p-cresol. Aerobic granules first appeared within one month of start up. The granules were large and strong and had a compact structure. The diameter of stable granules was in the range of 1-5 mm. The integrity coefficient and granules density was found to be 96% and 1046 kg/m3, raspectively, The settling velocity of granules was found to be in the range of 2×10^-2-6×10^-7 m/sec. The aerobic granules were able to degrade p-cresol upto 800 mg/L at a removal efficiency of 88%. Specific p-cresol degradation rate in aerobic granules followed Haldane model for substrate inhibition, High specific p-cresol degradation rate up to 0,96 g pcresol/（g VSS.day） were sustained upto p-cresol concentration of 400 mg/L, Higher removal efficiency, good settling characteristics of aerobic granules, makes sequencing batch reactor suitable for erLhaneing the microorganism potential for biodegradation of inhibitory compounds.

Synthesis ofp-Hydroxybenzaldehyde by Liquid-phase Catalytic Oxidation of p-Cresol over PVDF Modified Cobalt Pyrophosphate

The influence of the wettability of a catalyst on the performance of the liquid phase oxidation of p-cresol was investigated. It was found that the surface hydrophobicity of a catalyst, which can be changed by modification with various loadings of polyvinylidene fluoride（PVDF）, has a promotion effect on the catalytic performance. At the same time, the reaction parameters such as oxygen pressure, molar ratio of NaOH to p-cresol, reaction temperature and time on the catalytic performance in the liquid-phase oxidation of p-cresol were optimized. As a result, 10%（mass fraction） PVDF modified cobalt pyrophosphate gave the highest conversion of 94.2% of p-cresol with a selectivity of 94.4% for p-hydroxybenzaldehyde at 348 K and a molar ratio of4：l of NaOH/p-cresol and an oxygen pressure of 1.0 MPa for 3 h.