DK型纳滤膜对水中微量邻苯二甲酸酯的吸附及截留特性

邻苯二甲酸酯(PAEs)是一类典型的环境激素,对人体健康具有较大的危害。本文采用DK型纳滤膜去除水中微量邻苯二甲酸酯,分析了水中微量邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸正二丁酯(DNBP)和邻苯二甲酸异二丁酯(DIBP)等在DK型纳滤膜表面的吸附行为,考察了4种邻苯二甲酸酯的辛醇/水分配系数(logKow)和相对分子质量(Mw)对其在DK型纳滤膜表面的吸附和膜的截留特性的影响。结果表明Freundlich吸附方程能较好地描述4种邻苯二甲酸酯在DK型纳滤膜表面的动态吸附行为;DK型纳滤膜对水中微量邻苯二甲酸酯的截留特性表现为膜面吸附作用和膜孔筛分效应,吸附平衡后的截留机理取决于膜孔的筛分效应,DK型纳滤膜对DMP、DEP、DNBP、DIBP的截留率分别为55%、78%、96%和96.8%(0.5 MPa,30℃,DMP、DEP、DNBP、DIBP浓度均为300μg/L),表明DK型纳滤膜能高效去除水中的DNBP和DIBP。     

Study on adsorption refrigeration cycle utilizing activated carbon fibers. Part 2. Cycle performance evaluation

Thermal heat driven adsorption systems have been gained considerable attention on the recent energy utilization trend. However, the drawbacks of these adsorption systems are their poor performance. It is urgently necessary to improve the system performance of the adsorption cycles. There are two major ways for the system performance improvement. One is to develop new adsorbent material well suited to low temperature heat regeneration. The other is to enhance heat and mass transfer in the adsorber/desorber heat exchanger. The objective of the paper is to investigate the system performance of an adsorption cycle. The cycle utilizes activated carbon fiber (ACF)/methanol as adsorbent/refrigerant pair. In this paper, specific cooling effect SCE and COP of the system are numerically evaluated from the adsorption equilibrium theory with different hot, cooling and chilled fluid inlet temperatures. It is confirmed that the influences of hot, cooling and chilled fluid inlet temperatures on the system performance are qualitatively similar to those of silica gel/water pair. Even though, the driving temperature levels of ACF/methanol and silica gel/water are different. There is an optimum condition for COP to reach at maximum for ACF/methanol pair. Particularly, the ACF/methanol system shows better performance with lower chilled fluid inlet temperature between −20 and 20 °C.     

Removal of vanadium from wastewater by multi-walled carbon nanotubes

Nitric acid heating reflux modified multi-walled carbon nanotubes (HMWCNTs) were used for the removal of vanadium(V) in aqueous solution. The removal rate of vanadium(V) decreased with the increase of the initial vanadium(V) concentration and the solution pH, and increased with the increase of reaction time, HMWCNTs amount and solution temperature. The adsorption equilibrium and dynamic kinetics fitted the Langmuir adsorption isotherm and pseudo-second order models. The results obtained by scanning electron micrography and Fourier transform infrared spectroscopy analysis revealed that the hydroxyl and carboxyl functional groups are mainly responsible for the vanadium adsorption. This study showed that the HMWCNTs proved to be a considerable adsorbent for the removal of vanadium from wastewater.     

氢键抑制方法减少瓜尔胶压裂液对砂岩储层的吸附伤害

为了减轻瓜尔胶压裂液在砂岩多孔介质中产生的吸附伤害、降低其对致密砂岩储层渗透率的伤害,以四川盆地中侏罗统沙溪庙组砂岩为研究对象,根据热重实验确定瓜尔胶在砂岩表面的吸附量,并利用X射线电子能谱测试结合岩心流动实验,分析瓜尔胶压裂液在砂岩多孔介质中的吸附作用机理,再通过核磁共振和CT成像,研究压裂液吸附对砂岩孔喉结构变化和氢键抑制剂对压裂液综合性能的影响。研究结果表明:(1)压裂液会吸附在岩石多孔介质内部,导致岩石孔径变小、储层渗透性变差,吸附量约为3.9 mg/g;(2)砂岩表面的含氧基团与瓜尔胶分子形成的多重氢键作用是砂岩多孔介质与压裂液之间发生吸附的主要作用力,氢键抑制剂可以降低瓜尔胶在砂岩中的吸附量和对储层渗透率的伤害程度;(3)氢键抑制剂的加入对压裂液流变性影响不大,但却可以有效地降低破胶液的表面张力和残渣含量。结论认为,氢键抑制剂可以解除瓜尔胶与砂岩的吸附作用,有效地降低瓜尔胶压裂液对储层的伤害,并且不会影响压裂液的综合性能;该研究成果对于认识氢键抑制剂的性能、改进瓜尔胶压裂液体系、提高致密砂岩储层的增产改造效果等都具有重要的意义。     

新型氧化钯在高真空多层绝热设备中不同数量级真空度下吸氢特性实验研究

氧化钯被公认为性能优良的吸氢剂之一。常应用于高真空多层绝热设备中维持真空。本文通过搭建实验台系统地研究新型氧化钯在不同数量级的真空度下吸氢性能、吸附速率、吸氢效率、吸附量以及平衡压强之间的关系。实验结果表明新型氧化钯最优维持的真空度为0.016 Pa,饱和吸附量为197.238 mL/g,吸附系数为60.473。并通过31组在1、10^-1和10^-2Pa不同数量级上反复加注氢气,观察其吸氢动态。结果表明初始加气压强2.7 Pa以下,吸氢动态曲线均呈现\     

Electrochemical and thermodynamic studies to evaluate inhibition effect of 2-[(4-phenoxy-phenylimino)methyl]-phenol in 1 M HCl on mild steel

Inhibition of the corrosion of mild steel in 1.0 M HCl solution by a Schiff base compound named 2-[(4-phenoxy-phenylimino)methyl]-phenol (APS) was investigated at different temperatures (25–55 °C) using electrochemical measurements. The inhibition efficiency increased as APS concentration and temperature increased. It was found that adsorption for APS on mild steel complies with the Langmuir adsorption isotherm in all studied temperature. Thermodynamic parameters (ΔG_ads, ΔH_ads and ΔS_ads) for APS adsorption on mild steel were found out and discussed at each temperature. Time dependency of mild steel in 1.0 M HCl solution in the absence and presence of APS was also studied. The surface morphology of mild steel was examined via SEM analysis.     

Study on phenol adsorption from aqueous solutions on exfoliated graphitic nanoplatelets

In this study we report first data on exfoliated graphitic nanoplatelets (xGnPs) as a sorbent for phenol removal and preliminary evaluated the ability of different type of natural organic matter (NOM) to effectively disperse exfoliated graphitic nanoplatelets.     

膜分离和吸附技术的教学改革与思考

本文阐述了吸附和膜分离技术在化工原理教学中的重要性,以材料科学的发展成就作为吸附和膜分离技术教学的内容,对化工原理中这两个新的单元操作进行了阐述。学生们通过学习可以掌握最新的单元操作的进展和发展方向。     

Receptor function of small semiconductor crystals with clean and electron-traps dispersed surfaces

Theoretical exploration has been conducted to formulate the receptor function and response of a semiconductor gas sensor using thin plate-like crystals. The receptor function can be formulated over a wide range of depletion from conventional one (regional depletion) to new type one (volume depletion) by focusing attention on how the surface density of adsorbed oxygen ions (O⁻) is related with chemical moiety outside the crystals and physical moiety inside. The responses to gases thus derived are inversely proportional to the thickness of the plates used in the range of volume depletion. Electron-traps, if dispersed on the crystals, are shown to exert drastic effects in promoting sensitivity to gases.     

改性粉煤灰吸附处理含铜废水的试验研究

分别用碱、酸、高温、超声波和助溶剂对粉煤灰进行改性,对每种改性粉煤灰吸附处理含铜废水进行研究。试验结果表明:其中碱、高温、助熔剂都可改性粉煤灰,碳酸钠助熔剂改性效果最好,其最佳反应时间是30min,最适宜反应温度是20℃,最适宜p H值是10。吸附过程符合Temkin和Langmuir吸附等温式。