含酚废水处理的吸附和臭氧氧化动力学模型

A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min1,respectively.The phenolic treatment results in seven cases were compared:(a)O3 only,(b)fresh granular activated carbon(GAC),(c) 1st reused GAC,(d)2nd reused GAC,(e)fresh GAC enhanced with O3,(f)1st reused GAC enhanced with O3,and (g)2nd reused GAC enhanced with O3.The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time.The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result.The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone.Fresh GAC could adsorb phenol better than reused GAC.All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics.Finally,a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3.The calculated results agree reasonably well with the experimental results.     

ZL50活性炭吸附脱除二氧化硫的吸附动力学模型(英文)

A semi-empirical adsorption kinetic model was proposed with the time compensation method to describe the chemisorption of SO2 in flue gas by carbon adsorbents for flue gas purification. The change in adsorption capacity and adsorption rate with time at different water vapor concentrations and different SO2 concentrations was studied. The model was in good agreement with experimental data. The surface reaction was probably the rate controlling step in the early stage for SO2 adsorption by ZL50 activated carbon. The parameters m and n in the nth order adsorption kinetic model were related to the magnitude of the time compensation and adsorption driving force, respectively. The change of parameter n with water vapor concentrations and sulfur dioxide concentrations was studied and some physical implications were given. The sum of square errors was less than 1.0 and the average absolute percentage deviations ranged from 0.5 to 3.2. The kinetic model was compared with other models in the literature.     

Fe2(SO4)3/C催化餐饮废油脂中游离脂肪酸酯化反应的动力学

The esterification of free fatty acids(FFA) in waste cooking oil with methanol in the presence of Fe₂(SO₄)₃/C(ferric sulfate/active carbon) catalyst was studied.The effects of different temperature,methanol/FFA mole ratio and amount of catalyst on the conversion of FFA were investigated.The results demonstrated that under optimal esterification conditions the final acid value of the resultant system can be reduced to ～1(mg KOH)·g^-1,which met fully the requirements in post-treatment for efficient separation of glycerin and biodiesel.The kinetics of the esterification were also investigated under different temperatures.The results indicated that the rate-control step could be attributed to the surface reaction and the esterification processes can be well-depicted by the as-calculated kinetic formula in the range of the experimental conditions.     

表面活性剂在气/液界面上扩散控制的吸附动力学(英文)

For the diffusion-controlled adsorption, the expression of dynamic surface adsorption P（t） was ob- tained by solving the diffusion equation. Two cases, i.e. the short and long time limits, were mainly discussed in this paper. From the measured dynamic surface tension of aqueous surfactant sodium dodecyl sulfate （SDS） solutions at 25 ℃, the adsorption kinetics of SDS at air/solution interface was studied. It was proved that for both of the short and long time limits, the adsorption process of SDS was controlled by diffusion.     

杜仲全叶综合利用中叶绿素和β-胡萝卜素提取分离的研究

在杜仲叶综合利用过程中,首次提取分离出叶绿素和β-胡萝卜素,并将叶绿素制成相对较稳定的叶绿素铜盐。产品经GC、IR、UV检测鉴定,与文献相符。实验操作简便、投资少,可充分发挥原料的经济价值。     

杜仲全叶综合利用中叶绿素和β-胡萝卜素提取分离的研究

在杜仲叶综合利用过程中，首次提取分离出叶绿素和β-胡萝卜素，并将叶绿素制成相对较稳定的叶绿素铜盐。产品经GC、IR、UV检测鉴定，与文献相符。实验操作简便、投资少，可充分发挥原料的经济价值。     

AB-8树脂吸附反式1,2环己二醇热力学和动力学(英文)

AB-8 resin was used as an adsorbent for the removal of trans-1,2-cyclohexandiol(CHD) from aqueous solutions.Batch experiments were carried out to investigate the effect of contact time and temperature on sorption efficiency.The adsorptive thermodynamic properties and kinetics of CHD from water onto AB-8 resin were studied.The Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior.Thermodynamic parameters such as G,H and S were calculated.The results indicate that the equilibrium data are perfectly represented by Langmuir isotherm model.Thermodynamic study reveals that it is an exothermic process in nature and mainly physical adsorption enhanced by chemisorption with a decrease of entropy process.The kinetics of CHD adsorption is well described by the pseudo second-order model.The adsorbed CHD can be eluted from AB-8 resin by 5% ethanol aqueous solution with 100% elution percentage.     

蚕沙中β-胡萝卜素提取的研究

蚕沙所含丰富β-胡萝卜素对人体具有重要的生理作用。用柱层析和重结晶的方法分离得到了该物质,分析结果显示和文献报道一致。并且得到类似三十烷醇的固体物质。     

蚕沙中β-胡萝卜素提取的研究

蚕沙所含丰富β-胡萝卜素对人体具有重要的生理作用。用柱层析和重结晶的方法分离得到了该物质，分析结果显示和文献报道一致。并且得到类似三十烷醇的固体物质。     

β-胡萝卜素-β-环糊精包合物的研究

以β胡萝卜素包埋率为指标,采用超声法用β-环糊精包合β-胡萝卜素。通过单因素和正交实验确定的最佳工艺条件为:超声功率为300W、n(β胡萝卜素)∶n(β-环糊精)=1∶4,超声时间为40min。用显微镜观察和X射线衍射分析对包合物进行了验证,并对包合前后的保留率进行了比较测定,结果表明β-胡萝卜素的保留率提高了25.5%。     

改性膨润土对刚果红的吸附动力学及热力学研究

制备了十六烷基三甲基溴化铵(CTAB)改性膨润土,利用红外光谱和XRD对其结构进行了表征,考察了投加量和pH值对吸附性能的影响.结果表明: CTAB能插入膨润土层间;当投加量为4 g/L,pH值为4时,去除率最高达97.15%.改性膨润土对刚果红的吸附符合准二级动力学方程和Langmuir等温吸附方程,由吸附热力学方程计算得到的吸附焓变(ΔH)<0,吸附自由能变(ΔG)<0,吸附熵变(ΔS)<0,表明吸附为放热和熵减少的自发过程.     

Aqueous Phase Adsorption of Cephalexin onto Bentonite and Activated Carbon

The adsorption of cephalexin in aqueous solution has been investigated using bentonite and activated carbon as the adsorbents. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, adsorbent dosage, pH, particle size, and temperature. Adsorption equilibrium data were well represented by the Langmuir and Freundlich isotherm models. The adsorption intensity was found to be increased as the aqueous phase pH increased, and had a maximum at pH = 6.1. The pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to describe the kinetic data. The experimental data fitted very well with the pseudo-second-order kinetic model and also followed the simple external and intraparticle model.     

阴离子交换树脂对茶氨酸的吸附动力学和热力学

以酶法制备茶氨酸,研究了碱性条件下阴离子交换树脂对茶氨酸的吸附与分离. 结果表明,强碱性树脂对茶氨酸的吸附性能优于弱碱性树脂,且其吸附容量受pH值的影响较小,pH=9.0时凝胶型强碱性树脂HZ202对茶氨酸的平衡吸附量可达96.3 mg/g. 对HZ202吸附茶氨酸的吸附等温模型及动力学、热力学参数进行了分析,结果表明,茶氨酸在HZ202树脂表面为非均一分布,Spis模型可较好模拟其吸附等温线数据;热力学参数计算结果显示,不同温度下吸附过程的吉布斯自由能变DG均为负值,表明吸附为自发的放热过程;吸附过程的焓变DH=20.9~418.4 kJ/mol,可判断其为化学吸附. 茶氨酸吸附过程符合准二级动力学方程,吸附过程受化学反应控制,提高茶氨酸初始浓度可提高吸附速率.     

Adsorption Kinetics of Fluroxypyr Herbicide in Aqueous Solution onto Granular Activated Carbon

Fluroxypyr is a widely used herbicide whose presence in natural waters has prompted research into its removal by adsorption. This article reports a kinetics study of fluroxypyr adsorption on a commercial activated carbon. The experimental study used a micro differential column batch reactor operated at three solution flow rates and two initial fluroxypyr concentrations, establishing a differential regime in order to obtain correct experimental data. Initial rates at zero coverage permitted the external transfer coefficient k _L to be calculated. Internal surface diffusion coefficients D _S were determined by using the Homogeneous Surface Diffusion Model running the FAST software and taking advantage of tabulated user-oriented solutions. This model satisfactorily fits the experimental data. D _S values were 2.5 × 10^?14 and 4.2 × 10^?14 m² s^?1 for initial concentrations of 30 and 50 mg/L, respectively. These values were confirmed by experiments in a widely used shaken batch reactor with a determined k _L value.     

酸改性膨润土对含铅废水的吸附性能研究

以硫酸为改性剂,对钙基膨润土进行活化改性,考察了改性剂用量、改性膨润土加入量、吸附时间以及pH值等因素对改性膨润土去除模拟水样中重金属离子Ph^2＋的影响。结果表明,用体积浓度为20％的硫酸溶液改性后的膨润土的除铅效果最好,在常温下,当改性膨润土用量为15g／L,吸附时间为30min,pH值为6-9时废水中铅的去除率最大,超过99.5％,处理后铅的剩余浓度小于1mg/L,达到国家第一类污染物排放标准。     

Complexation of Surfactant/β‐Cyclodextrin to Inhibit Surfactant Adsorption onto Sand,Kaolin, and Shale for Applications in Enhanced Oil Recovery Processes. Part II: Dynamic Adsorption Analysis

Surfactant adsorption onto solid surfaces is problematic in some industrial processes, such as in surfactant flooding for enhanced oil recovery. In this work, it was hypothesized that the use of a surfactant delivery system could prevent surfactant adsorption onto solid surfaces. Therefore, the encapsulation of sodium dodecyl sulfate (SDS) into the hydrophobic core of β‐cyclodextrin (β‐CD) to generate a surfactant delivery system (SDS/β‐CD) was evaluated in this work. This complexation was characterized using optical and scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT‐IR). Dynamic adsorption evaluation was applied to determine the effectiveness of the complexation in inhibiting surfactant adsorption onto a variety of solid adsorbents including sand, and mixtures of sand–kaolin and sand–shale. Surfactant adsorption was also evaluated applying the quartz crystal microbalance technology (QCM‐D). The formation and morphology of the complexation was confirmed by optical microscopy, SEM, and FT‐IR. Dynamic adsorption tests demonstrated the effectiveness of the surfactant delivery approach in preventing the adsorption of surfactant (up to 74 % adsorption reduction). The QCM‐D technology confirmed these observations. Several mechanisms were proposed to explain the inhibition of surfactant adsorption including steric hindrance, self‐association of inclusion complexes, hydrophilicity increase, and disruption of hemimicelles formation.     

高温焙烧底泥吸附重金属Mn2+和Ni2+的动力学与热力学研究

制备了高温焙烧底泥作为吸附剂,并对底泥焙烧前后的表征(SEM、FTRI、XRD、BET)进行研究与分析.采用静态吸附试验来研究高温焙烧底泥吸附废水中重金属Mn2+和Ni2+的吸附动力学与热力学的特性并确定吸附机理.结果表明:对高温焙烧底泥吸附的数据进行拟合且符合Langrnuir和Freundlich吸附等温方程,但拟合效果更好的符合Freundlich吸附等温方程,表明吸附介于单层与多层之间.在高温焙烧底泥对Mn2和Ni2的吸附阶段用Lagergren伪一级吸附动力学方程和Lagergren伪二级吸附动力学方程进行拟合,其结果表明吸附过程遵循Lagergren伪二级吸附动力学方程,表明以化学吸附为主,对Mn2、Ni2+的平衡吸附量分别为5.2083、3.6563 mg/g.由热力学参数(△S、△H和△G)表明:高温焙烧底泥对Mn2+和Ni2+的吸附均为吸热过程.     

Enhanced hydrogen sorption kinetics of magnesium by destabilized MgH2−δ

The kinetics of the reversible reaction of hydrogen gas with magnesium forming MgH₂ is enhanced significantly by the addition of transition metals oxide catalysts and by using nanostructured powders. Hydrogen absorption and desorption properties of such systems were studied by differential scanning calorimetry (DSC) under hydrogen atmosphere, from which the heat of hydride formation and decomposition is determined. Apart from Mg and stoichiometric MgH₂, we find an additional, slightly destabilized phase, which is formed prior to MgH₂ upon hydrogenation. The amount of this phase depends on the degree of nanostructuring and the used additive. X-ray diffraction measurements confirm the compared to MgH₂ slightly different lattice parameters of the intermediate phase. The results correspond to recent neutron diffraction measurements, by which a new MgH_2−δ phase was found. We propose that this destabilized phase acts as a gateway for de-hydrogenation of MgH₂.     

Kinetic Study of Black Fe2O3-Cr2O3 Pigment Synthesis: I, Influence of Synthesis Time and Temperature

A study was undertaken of the kinetics of the black Fe-Cr oxide pigment synthesis process based on the oxide constituents (Fe₂O₃ and Cr₂O₃). A kinetic model is proposed which enables correlating the degree of transformation advance, expressed as the mass fraction of the arising solid solution (of the same composition as the starting oxide mixture), with synthesis time and temperature. The model is valid for raw materials, range of starting compositions, and operating conditions similar to those used in black Fe-Cr oxide pigment processing in industry.     

Equilibria,Kinetics, and Mechanisms for the Adsorption of Four Classes of Phenolic Compounds onto Synthetic Resins

The adsorption of five phenolic compounds of four different classes from aqueous batch solutions onto four styrene-divinylbenzene and acrylic resins (EXA 90, EXA 118, XAD 7, and XAD 16) was investigated regarding their equilibria, kinetics and surface-energy heterogeneity, and mechanisms of adsorption. The experimental equilibrium data were very well fitted to Langmuir and Freundlich models (R ² > 0.900). Three kinetic models (pseudo-first-order, pseudo-second-order, and an intra-particle diffusion model) were suitable for describing the experimental data, the pseudo-second-order kinetic model being the best one (p < 0.001). The adsorption energy values were low (<19.00 kJ/mol), suggesting a physical adsorption process. Driving forces involved in the adsorption of the phenolic compounds onto the resins were hydrogen bonding, π ? π stacking and hydrophobic interactions.