A Strategy of Liquid-Grafted Slippery Sponges with Simultaneously Enhanced Absorption and Desorption Performances for Crude Oil Spill Remediation

Crude oil spill accidents pose a worldwide environmental threat. Oleophilic and hydrophobic absorbents that can selectively absorb oil from water have shown promising application potential in oil spill remediation. Simultaneous optimization of the absorption and desorption speed of absorbents towards oil is highly desirable for their recyclable usage, but remains a great challenge, because these two properties are generally conflicting. Here, a facile and ingenious strategy is proposed to tackle the above challenge via surface modification of porous sponges with highly flexible linear polydimethylsiloxane (LPDMS) brushes. The LPDMS brushes feature liquid-like properties at room temperature owing to its extremely low glass transition temperature, and act as a covalently-grafted lubrication layer throughout the 3D network channels of the sponge, which can minimize contact angle hysteresis and reduce friction between oil and sponge channel. Compared to the prevalent cross-linked polydimethylsiloxane (CPDMS) modification strategy, sponges modified with LPDMS brushes not only shows significantly enhanced absorption speed, but also exhibits superior desorption dynamics towards viscous crude oils. The design strategy of slippery sponges with liquid-like molecules may open a new avenue for developing advanced absorbents with simultaneously enhanced absorption and desorption performances for liquid separation and purification applications.     

Gas-liquid mass transfer in three-phase fluidized beds with viscous pseudoplastic liquids

Liquid phase volumetric mass transfer coefficients for oxygen were determined in three-phase fluidized beds of 8 mm glass spheres fluidized by a cocurrent flow of air and pseudoplastic polysaccharide solutions (carboxymethyl cellulose, xanthan). A semi-theoretical relation for the effective shear rate was suggested. The mass transfer coefficients could be correlated, together with literature data for particle diameters of 3 mm and 5 mm in other liquids, using the terminal velocity as the particle-specific property.     

高吸水性树脂AA/DMAEMA的常温合成研究

以丙烯酸(AA)和甲基丙烯酸-N,N’-二甲氨基乙酯(DMAEMA)为原料,N,N’--亚甲基双丙烯酰胺为交联剂,采用常温水溶液聚合法合成了耐盐性能良好的高吸水性树脂。研究了合成的有关工艺条件对产物吸水性能的影响。在AA/HEMA为95/5(摩尔比),交联剂质量分数0．0002％,引发剂质量分数为0．46％,还原剂用量为0．23％时,合成树脂的吸水率700 g/g,吸收1％的氯化钠溶液能力大于80g/g。     

A novel efficient RhB absorbent of Mo2N/MoO2 composite nanofibers for wastewater treatment

Mo₂N/MoO₂ composite nanofibers have been prepared via an electrospinning and controlled nitridation process. The composite nanofibers exhibit a highly efficient Rhodamine B (RhB) absorption behavior with a rate constant of 0.153 g min⁻¹ mg⁻¹, which is about 20 times of the commercial-activated carbon material. Furthermore, the nanofibers show stable absorption activity after recycled by an environmental friendly procedure for four times. The excellent absorption performance of Mo₂N/MoO₂ composite nanofibers demonstrates a promising application of Mo₂N-related materials as an absorbent for wastewater treatment.     

Piperazine and methyldiethanolamine interrelationships in CO2 absorption by aqueous amine mixtures. Part II—Saturation rates of mixed reagent solutions

This work is a companion to a previous article, Part I, published in The Canadian Journal of Chemical Engineering, dealing with CO₂ absorption in aqueous solutions containing a single aminic reagent (specifically methyldiethanolamine (MDEA) or piperazine (PZ)). In this second part, different PZ/MDEA mixtures are experimentally studied and their performances are compared with that of the single reagents. It is indeed well known that small quantities of PZ added to MDEA aqueous solutions are sufficient to obtain a significant improvement in the kinetics of the process. PZ is considered an activator or promoter for MDEA, but the mechanism of this synergy has still not been clearly demonstrated. The aim of this study is an attempt to understand how PZ and MDEA can interact by experimentally analyzing this beneficial mutual effect and by explaining it with the help of a suitable yet not complex model. We believe that the involved chemistry is not more complex than that reported in Part I for the single reagents. According to our findings, it is MDEA that enhances the action of PZ, as opposed to what many authors claim. Moreover, our results seem to rule out the existence of any PZ shuttle effect.     

新型多功能腐植酸基农林保水生态治理剂

论述了新型多功能腐植酸基农林保水生态治理剂研制开发的意义,提出了保水剂在农林业应用中存在的问题及目前的研究方向,并介绍了新型多功能腐植酸基农林保水生态治理剂的特点、效果及项目实施的可行性。     

吸收法处理苯系VOCs气体的应用

溶剂吸收法是一种高效实用的废气处理方法。文章介绍了VOCs气体的概念、来源及危害,阐述了苯系VOCs气体吸收剂的选择,分析了适用吸收剂的特点,并对比了几种常用的吸收剂的具体性能,讨论了近年来一些新型的苯系VOCs吸收剂的应用前景。     

A THREE-PHASE MODEL FOR SORPTION ISOTHERM IN ZEOLITE ADSORBENTS

A three-phase model for adsorption in zeolite cavities is proposed. The adsorbed molecules are taken to be distributed between a surface layer and a dense phase filling the rest of the cavity volume. This model is a more realistic representation of molecules in zeolite cages especially at high pressures. The equation for the adsorption isotherm, based on this model, has two contributions: a surface term and a dense phase term. The dense phase contribution was estimated from a simple equation that obeys the limiting values at low and high pressures. The surface contribution can be estimated from the existing surface adsorption models. When all model parameters are estimated from molecular and literature data, the combination of the two terms was found to be an improvement over traditional treatment of adsorption data of a number of gases in zeolite-A for a wide range of pressures. However, new models for the adsorbed phase that account for sorbate-sorbate repulsive forces correctly are needed for accurate prediction of adsorption data.     

丙烯酸系高吸水聚合物的结构表征

高吸水聚合物 (SAP)是一类不溶不熔的低交联高分子聚合物 ,常规的色谱法无法进行分析鉴定。本文介绍了红外光谱 (IR)、核磁共振法、热分析及电镜法在表征SAP中的应用