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1.
水中苯酚—间甲酚的竞争吸附   总被引:4,自引:0,他引:4  
对水中苯酚—间甲酚在NKA树脂上的竞争吸附性能做了实验测定,并用IAS和LAC两种模型对竞争吸附性能数据进行预测,较好地反映了其竞争吸附的规律。  相似文献   

2.
含水率和流速变化对土壤吸附规律影响的实验研究   总被引:1,自引:0,他引:1  
通过重铬酸钾溶液的静态吸附实验和动态吸附实验分别研究了含水量变化及流速变化对土壤中吸附作用的影响,得到以下结论:①饱和土壤的吸附量大于非饱和土壤中的吸附量,且具有土壤含水量越低,吸附量越小的趋势;②动态流场中溶质的吸附量比在静态不动水体中溶质的吸附量要大  相似文献   

3.
天然气吸附过程的热效应严重影响天然气的吸附量,是吸附储存天然气汽车走向应用的一大障碍.为减小热效应的影响,建立车用天然气储罐吸附过程的数学模型并用SIMPLER算法进行求解,以充气60s和180s为条件进行计算,得到以下结论:60s和180s充气对应的充气质量分别为2.1389kg和2.1723kg;充气效率分别比等温充气减少45.15%和44.29%;吸附剂平均温度分别升高74.76K和72.72K.可见,吸附放热对充气效率有很大影响,必须采取适当的措施减小热效应的不利影响.  相似文献   

4.
Polanyi吸附势理论的热力学推导   总被引:3,自引:0,他引:3  
运用热力学理论和溶液理论,在不受经验性假设限制的条件下,分析了Polanyi吸附垫的热力学含义,指导出固液界面吸附的基本条件、凝聚吸附条件、混合溶液竞争凝聚吸附以及顶替吸附的基本条件,是出与Polanyi吸附势理论及其在溶液中吸附的应用相一致的结果。  相似文献   

5.
铵态氮在土壤中吸附性能探讨   总被引:12,自引:0,他引:12  
在介绍土壤常见几种理论吸附模型的基础上,以关中河漫滩、阶地、山前洪积扇和黄土台塬这些地区浅部土壤为例,在室内同等条件下,对不同土壤进行吸附实验,探讨不同土壤对NH4^ -N的吸附特征和吸附能力。结果表明,NH4^ -N吸附作用符合兰缪尔(Langmuir)等温吸附模型。土壤对NH4^ -N的吸附性的强弱与土壤颗粒大小百分含量有关。土壤中粘粒百分含量越高,吸附性就越强。这些土壤对NH4^ -N吸附的最大容量在0.2~0.9g/kg之间。  相似文献   

6.
据统计,世界上85%的化学制品要依靠催化反应制得,而催化与吸附关系密切,其中固体表面的吸附是多相催化的必经步骤,应用的最为广泛的是气固相的催化作用.笔者在本文中运用严谨的数学逻辑推理方法,论证中通过归纳、比较,指出吸附对于催化的重要意义,着力于BET公式的理论推导,同时进行了大量的理论上的证明与阐述,论述了气固相的吸附及其规律性.  相似文献   

7.
比较了活性炭纤维间歇系统当吸附等温方程为Langmuir型时表面扩散模型与孔扩散模型,获得了两模型扩散系数可相互转换的条件,分析了用间歇吸附实验研究溶质在活性炭纤维内扩散机理的可行性,同时给出当吸附等温方程为矩型时两模型的解析解。通过实验验证了部分结论。  相似文献   

8.
吸附床的传热传质性能的优化是提高吸附式制冷系统制冷效率的重要方法。利用FLUENT软件对使用CaCl2-NH3为吸附工质对的化学吸附制冷系统中的吸附床进行了数值模拟研究,分析了吸附床解吸过程中温度场和单位质量吸附剂制冷量(SCP)的变化规律,并对不同填充直径和每层填充厚度的吸附床进行了性能分析,结果显示在填充总量一定时,吸附床的填充直径越小,系统的制冷效率越高。  相似文献   

9.
测定了七种吸附树脂对模拟水溶液中游离胆红素的静态吸附能力,研究了试液pH和温度的影响。结果显示,NKA-21和CKA树脂对胆红素具有较强的吸附能力,其平衡吸附效率为64-72%,吸附量为13.3-16.8mg/g,最佳吸附温度为20-35℃,最佳吸附pH分别为7.30和7.75。  相似文献   

10.
通过矿物浮选实验、吸附量测试以及红外光谱分析,研究CSU—A与黄铜矿和黄铁矿相互作用的规律.浮选实验结果表明,当CSU—A的质量浓度为6mg/L,溶液pH值为9.0~9.5时,CSU—A对黄铜矿捕收能力强,对黄铁矿捕收能力弱;红外光谱分析结果表明,捕收剂CSU—A与黄铜矿和黄铁矿作用前、后的红外光谱图明显不同,在黄铜矿与药剂作用后出现了6cm^-1的波数位移,而黄铁矿与捕收剂作用前、后的红外光谱图基本上没有变化.由此可以确定,捕收剂CSU—A在黄铜矿表面发生了化学吸附,而在黄铁矿表面仅是简单的物理吸附.捕收剂CSU—A具有选择性的主要原因是在黄铜矿和黄铁矿表面发生吸附的形式不同.  相似文献   

11.
The adsorption properties of a novel macroporous weak acid resin (D152) for Pb2+ were investigated with chemical methods. The optimal adsorption condition of D152 resin for Pb2+ is at pH 6.00 in HAc-NaAc medium. The statically saturated adsorption capacity is 527 mg/g at 298 K. Pb2+ adsorbed on D152 resin can be eluted with 0.05 mol/L HCl quantitatively. The adsorption rate constants determined under various temperatures are k 288 K=2.22×10−5 st-1, k 298 K=2.51×10−5 s−1, and k 308 K= 2.95×10−5 s−1, respectively. The apparent activation energy, E a is 10.5 kJ/mol, and the adsorption parameters of thermodynamics are ΔH Θ=13.3 kJ/mol, ΔS Θ=119 J/(mol·K), and ΔG Θ 298 K =−22.2 kJ/mol, respectively. The adsorption behavior of D152 resin for Pb2+ follows Langmuir model. Foundation item: Project(2008F70059) supported by the Scientific and Technological Research Planning of Zhejiang Province, China  相似文献   

12.
The adsorption behavior and mechanism of D113 resin for Dy(III) was investigated by using the method of resin adsorption. Experimental results show that the optimum medium pH of adsorption of D113 resin for Dy3+ is pH=6.00 in the HAc-NaAc medium. The static adsorption capacity of D113 resin for Dy3+ is 292.7 mg·g−1. The optimum eluant is 0.5 mol·L−1 HCl. The adsorption rate constant is k 298=6.8×10−6s−1. The apparent activation energy of D113 resin for Dy(III) is 14.79 kJ·mol−1. The adsorption behavior of D113 resin for Dy(III) obeys the Freundlich isotherm. The adsorption parameters of thermodynamic are ΔH=14.48 kJ·mol−1, ΔS=54.69 J·mol−1·K−1, ΔG=−1.82 kJ·mol−1.The adsorption mechanism of D113 resin for Dy3+ was confirmed by chemical analysis and IR spectra. Funded by the Natural Science Foundation of Zhejiang Province (No.201027), Foundation of Zhejiang Provincial Education Bureau (No.20040551) and Zhoushan Science Technology Bureau (No.04114)  相似文献   

13.
The biosorption mechanism of Cr (Ⅳ) ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr (Ⅳ) consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-LR spectra of K2Cr2O7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp show that the speciation of chromium that binds to the cells ofSynechococcus sp. is Cr (Ⅲ), instead of Cr (Ⅳ), and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr (Ⅲ). Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr (Ⅵ), and the results of FT-IR show that the biosorption of Cr (Ⅵ) follows two subsequent steps, biosorption of Cr2O7 ^2- by electrostatical force at the protonated active sites and reduction of Cr2O7^2- to Cr^3+ by the reductive groups on the surface of the biosorbents.  相似文献   

14.
Several 1,4-benzenedicarbonyl thiourea resins (BTR) were synthesized through interfacial polymerization between 1,4-benzenedicarbonyl diisothiocyanate and polyamine. Their structures were confirmed by FT-IR. The adsorption properties (including the effect of adsorption time, pH, initial concentrations and temperature) of BTR-1, BTR-2 and BTR-3 for Ag(I) were investigated by batch tests. The results show that the adsorption equilibria of BTR-1, BTR-2, BTR-3 for Ag(I) are achieved after about 10 h. Their equilibrium adsorption capacities are 7.11, 6.75 and 6.23, respectively, and the adsorption process accords with G. E. Boyd equation and Langmuir adsorption isotherm as well. The adsorption capacities increase with the increase of pH (the highest uptake values are observed at pH being about 6–7). The thermodynamic parameters of BTR-1 were calculated. The results show that ΔH Θ; and ΔS Θ are 6 958.8 J/mol and 64.28 J/(mol·K), respectively, and ΔG Θ at 20, 30, 40 and 50 °C are −11.79, −12.52, −13.16 and −13.8 kJ/mol, respectively. The silver-loaded resins can be quantitatively eluted by a solution containing 6% thiourea in 1 mol/L HNO3.  相似文献   

15.
Adsorption of Macroporous Phosphonic Acid Resin for Nickel   总被引:2,自引:0,他引:2  
1Introduction Thesynthesischaracterizationandadsorptionproper tyofpolymericmaterialshavebeenresearchedinrecent years[110].Macroporousphosphonicacidresin[11](PAR)isanovelpolymericmaterialwhichcontainsafunctional groupof[PO(OH)2].Ithasalotofadvantagessuchas…  相似文献   

16.
A novel chelating resin with sulfonic group was synthesized by chemical modification of D401 resin with sulphonation reaction and characterized by FT-IR spectrometry. The adsorption properties of the novel chelating resin for Pb2+ were studied by batch adsorption, and the adsorption process was analyzed from thermodynamics and kinetics aspects. The adsorption mechanism of Pb2+ on the modified D401 chelating resin was discussed by FT-IR spectrometry. Experimental results show that in the Pb2+ concentration range of 200–400 mg/L, the adsorption capacities of the modified D401 chelating resin for Pb2+ increase by 77%–129%, and Langmuir isothermal adsorption model is more suitable for the equilibrium adsorption data. Adsorption is an endothermic process that runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best pH value under adsorption condition is 4–5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the adsorption capacity remains stable after five consecutive adsorption-desorption cycles. The maximal static saturated adsorption capacity of the resin is 206 mg/g at 333 K in the Pb2+ concentration range of 200–400 mg/L. The modified D401 chelating resin is an efficient adsorbent for the removal of Pb2+ from its single-metal ion solution. Foundation item: Project(708049) supported by the Important Item Cultivation Foundation of Scientific Innovation Project of Colleges and Universities of China  相似文献   

17.
The adsorbabilities of the unmodified and modified bauxite tailings for Cr(Ⅵ), As(Ⅴ) and F(Ⅰ) ions were investigated. Batch experiments were carried out to determine the removal rate as a function of adsorbent dosage, solution pH value and shaking time. The results show that the maximum removal rates of Cr(Ⅵ), As(Ⅴ) and F(Ⅰ ) are respectively 99%, 99% and 90% by using the modified bauxite tailings. The isoelectric point of the unmodified bauxite tailings is 3.6, and that of the modified bauxite tailings is 5.0, which shifts to lower pH values in Cr(Ⅵ) solution. This indicates a specific adsorption of the anionic species on the modified bauxite railings. A new band of Cr2O72 appears in the FTIR, showing that Cr(Ⅵ) is adsorbed on the modified bauxite railings in the form of chemistry adsorption. The adsorption data of Cr(Ⅵ) on the modified bauxite tailings are well described by Freundlich model. The investigations of kinetic models show that pseudo-second-order kinetic model provides the best correlation for the experimental data.  相似文献   

18.
The atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) employing ethyl 2-bromoisobutyrate (EBiB)/CuBr as the initiating system was analyzed at 30, 40, 50 and 60 ℃ in N-methylimidazolium formate ([Hmim][HCOO])/THF mixtures. The polymerization was performed in a well-controlled manner as evidenced by kinetic study and the chain extension result. The apparent activation energy and the enthalpy of equilibrium for the preequilibrium were also investigated. Results show that Ea(app)=47.86 kJ/mol, △H0eq=25.67 kJ/mol.  相似文献   

19.
A batch of column experiments was carried out to investigate the change of Cr(Ⅵ) concentration leached out from chromium-containing slag with HCI as leaching agent, and to study influences of pH, ratio of solid mass to solution volume, flow velocity and temperature on Cr(Ⅵ) leaching. The optimal parameters were obtained for Cr(Ⅵ) leaching and a fitting model was established to describe the procedure of Cr(Ⅵ) leaching. The results show that Cr(Ⅵ) concentration in leachate increases with decreasing pH and increasing flow velocity and temperature. Moreover, Cr(Ⅵ) leaching percentage increases with increasing ratio of solid mass to solution volume. The optimal parameters for Cr(Ⅵ) selective leaching are as follows: pH=3.0, 1:5 of ratio of solid mass to solution volume, 180 mL/min of flow velocity and 40 ℃ of temperature. The procedure of Cr(Ⅵ) leaching fits well with the model: v= 1.87t^-0.54, indicating that the leaching rate of Cr(Ⅵ) declines in an exponential order of-0.54.  相似文献   

20.
The mechanism of synergistic extraction of gold in HCl media was researched with tri-n-octyl amine(TOA) and tri-n-octyl phospine oxide(TOPO). It was determined that the composition of synergistic extract is (TOAHTOPO) AuCl4; the constant of synergistic extracting equilibrium is 109.20; and the synergistic reaction is exothermic with − 17.187 kJ/K· mol of ΔH 298. The extraction mechanism was also studied by the IR-spectra and UV-spectra. It is found that the extraction mechanism belongs to ion-association type. Synopsis of the first author Yang Tianzu, professor, born in April 1958, majoring in the metallurgy of precious metals and coordination chemistry in hydrometallurgy.  相似文献   

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