Structural and hydrogen sorption properties of SmNi5−xGax system – an experimental and theoretical study

A series of ternary alloys of general formula SmNi_5−xGa_x (x = 0.25, 0.5, 1.5, 2, 2.5) was prepared by melting mixtures of Sm, Ni and Ga in arc furnace under argon. From X-ray powder diffraction lattice parameters are determined and it is found that hexagonal structure of P6/mmm space group is retained for all considered values of x. Hydrogen absorption ability and thermodynamic quantities of the systems are determined by pressure-composition desorption isotherms. The obtained properties are compared with those of previously reported SmNi₅ and SmNi₄Ga. DFT calculations were performed for selected members of the system and the results are discussed with regard to experiment.     

Removal of phenol from aqueous solutions by adsorption onto activated carbon prepared from biomass material

Activated carbon derived from rattan sawdust (ACR) was evaluated for its ability to remove phenol from an aqueous solution in a batch process. Equilibrium studies were conducted in the range of 25–200 mg/L initial phenol concentrations, 3–10 solution pH and at temperature of 30 °C. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Equilibrium data fitted well to the Langmuir model with a maximum adsorption capacity of 149.25 mg/g. The dimensionless separation factor R_L revealed the favorable nature of the isotherm of the phenol-activated carbon system. The pseudo-second-order kinetic model best described the adsorption process. The results proved that the prepared activated carbon was an effective adsorbent for removal of phenol from aqueous solution.     

生物表面活性剂作为牺牲剂在三元复合驱中的应用研究

界面活性研究表明，在一定NaOH浓度下，鼠李糖脂发酵液和表面活性剂按不同比例复配后，可以改善界面活性，界面张力代于表面活性剂为主剂形成的三元复合体系与原油的界面张力。说明生物表面活性剂与表面活性剂复配后存在着明显的协同效应。生物表面活性剂中作为牺牲剂，用其对油砂预吸附后可以降低表面活性剂附损失30％左右。在用生物表面活性剂的三元复合驱矿场试验中，表面活性剂用量减少一半情况下，采出井流出物中表面活性剂相对浓度高于未使用生物表面活性剂的三元复合驱矿场试验中流动出物表面活性剂的相对浓度。化学驱原油采收率平均提高16．64％以上。     

胡萝卜渣对Cr6+的吸附作用及吸附机理的研究

研究了胡萝卜渣对Cr6+的吸附作用及吸附过程的影响因素、热力学和动力学行为,结果表明:吸附率随胡萝卜渣粒径的减少而增大;Cr6+初始质量浓度相同时,吸附率随加入胡萝卜渣量的增加而增大,胡萝卜渣加入量相同时,吸附率均出现两次极小值且初始质量浓度为15 mg/L时吸附率最佳;正交试验结果表明:3个因素影响程度依次为温度>pH>时间,最佳吸附条件为溶液pH2、温度60℃、浸泡时间10 h;吸附等温线结果表明:胡萝卜渣对Cr6+的吸附以单分子层吸附占优势,Freundlich吸附等温式吸附热力学行为,吸附为吸热过程,胡萝卜渣对Cr6+的吸附热为53.6 kJ/mol;吸附动力曲线结果表明:二级动力学模型能较好地描述胡萝卜渣对Cr6+的吸附动力学行为.     

GAC对水中内分泌干扰物双酚A的吸附特性及动力学研究

研究了颗粒活性炭(GAC)对水中内分泌干扰物双酚A(BPA)的吸附容量、吸附动力学及其影响因素.结果表明,GAC吸附容量大,吸附等温线符合Langmuir和Freundlich模型;吸附容量受GAC粒径的变化影响较大.Langmuir模型的最大吸附容量qm与粒径dp关系为:ln(qm)=-0.507 5×ln(dp) 14.07;Freundlich模型Kf与dp关系为:ln(kf)=-1.078 ln(dp) 18.307.GAC对BPA为单分子层吸附,400 min基本可达到平衡,且吸附速率变化符合拟二级动力学模型,dp与速率常数k2之间符合ln(k2)=-1.039 ln(dp)-9.014;BPA初始浓度C0与k2关系式为1/k2=529.7 C0-35 979.     

The effect of pH and temperature on the dye sorption of wool powders

The sorption behavior of wool powders for three acid dyes (C. I. Acid Red 88, C. I. Acid Red 13 and C. I. Acid Red 18) and a basic dye (methylene blue) was investigated as a function of pH and temperature. The sorption capacity of wool powders depends on the pH of dye solution. The maximum uptake of acid dyes and methylene blue by wool powders occurred at pH 2.5 and pH 7.5, respectively. The effect of pH on the sorption of the hydrophilic dyes (C. I. Acid Red 13 and C. I. Acid Red 18) was more significant than that of the uptake of the hydrophobic dye (C. I. Acid Red 88). Increasing temperature enhanced the dye sorption ability of coarse wool powders, but did not impact that of fine wool powders. The dye‐absorption models of wool powders agree with the Langmuir isotherm. Comparison to activated charcoal and other sorbents indicates that fine wool powders have excellent dye sorption capacity even at room temperature, and may be used as a potential sorbent. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Application of Acid Treated Almond Peel for Removal and Recovery of Brilliant Green from Industrial Wastewater by Column Operation

Abstract

The treated almond peels (TAP) have been employed as adsorbents for the removal of Brilliant green dye from waste water. The nature of possible adsorbent and dye interaction was examined by the FTIR and SEM technique. The adsorption of BG was found to be maximum (93%) at pH 8. The extent of removal of BG was found to be dependent on the adsorbent dose, the temperatures, and the times. The equilibrium data for adsorption was best represented by the Langmuir isotherm. Thermodynamic parameters (ΔH⁰ and ΔG⁰) suggest endothermic and spontaneous process. Kinetic studies show better applicability of second-order kinetic model. The practical utility of TAP was demonstrated by removing BG from pure solution and industrial effluent system by column process. It was found that the removal effficiency of TAP was better by pure solution. The breakthrough capacities of pure solution and industrial effluent systems on TAP are found to be 30 and 17 mg/g, respectively.     

Thermodynamic and Adsorption Behaviour of Medicinal Nitramine as a Corrosion Inhibitor for AISI Steel Alloy in HCl Solution

The inhibition ability of 2-amino-5-nitrothiazole(Nitramine) against the corrosion of AISI steel 4130 in 1 mol/L HCl solution was evaluated by polarization,electrochemical impedance spectroscopy(EIS) and chronoamperometry.Polarization studies indicated that nitramine retards both the cathodic and anodic reactions through chemical adsorption and blocks the active corrosion sites.The adsorption of this compound obeyed the Temkin’s adsorption isotherm.The inhibition efficiency was increased with inhibitor concentration as well as temperature.EIS data were analysed by equivalent circuit model shows that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased.Kinetic and thermodynamic parameters such as activation energy,enthalpy,entropy and free energy of activation and adsorption were calculated.Atomic force microscopy and optical microscopy were used to study the steel surface with and without inhibitor.     

一类可降解的生物表面活性剂(Ⅰ)-芦丁脂肪酸酯在弱碱性水溶液中表面活性的研究

研究了3种可降解的生物表面活性剂-芦丁脂肪酸酯,在弱碱性水溶液中的表面吸附性质。芦丁硬脂酸酯(RS)、芦丁月桂酸酯(RL)和芦丁正己酸酯(RC)弱碱性水溶液的表面饱和吸附量分别为:1·71×10-11、1·35×10-11和1·41×10-11mol/cm2,它们的临界胶束浓度(CMC)分别是3×10-3、1·65×10-3和1·3×10-3mg/mL。其吸附等温线都属于Langmuir型。3种芦丁脂肪酸酯弱碱性水溶液的表面吸附,在标准状态下均能自发进行。     

基于吸附等温线及玻璃化转变的夹心海苔贮藏稳定性研究

为了解夹心海苔在贮藏期间水分活度、含水率、玻璃化转变温度与贮藏温度之间的关系,该研究探讨了夹心海苔吸附等温线和玻璃化转变曲线并用数学模型进行拟合,分析夹心海苔绝对安全含水率和临界含水量,并探讨热力学性质。结果表明：GAB模型能较好地反映出夹心海苔水分吸附特性,并得出在20、30、40 ℃条件下夹心海苔的绝对安全含水率分别为5.19%、4.69%、3.72%,作为预测夹心海苔加工及贮藏过程中最佳含水率的依据;同理可得20、30、40 ℃的临界含水量分别为0.98、0.84、0.71 g/g,作为判断贮藏稳定性的依据。当夹心海苔的平衡含水率高于0.08%时,水同物质的结合能较小,易失水。夹心海苔水分吸附过程中等温速率为0.62 K,吉布斯自由能为2.61 kJ/mol,为一种熵驱动的自发的吸热过程。综合分析,随着温度降低夹心海苔安全含水率升高,不易使玻璃化结构发生崩塌,对其加工工艺及干制品贮藏等方面具一定的参考意义,该研究结果可为夹心海苔产业提供科学依据。