Hydrophobizing polyether sulfone membrane by sol-gel for water desalination using air gap membrane distillation

ABSTRACT

The hydrophobic polyether sulfone membranes were prepared by the sol-gel method to be applied in an air gap membrane distillation setup for desalination. The surface modifications were carried out using Trimethylsilyl chloride (TMSCl) and Methyltrimethoxysilane (MTMS) solutions. The membranes were characterized using Attenuated Total Reflection Infrared (ATR-IR) spectroscopy, Scanning Electron Microscopy (SEM), and Optical Contact Angle (OCA) methods. The effects of membrane preparation as well as operating conditions such as temperature difference, salt concentration, feed rotation speed, and cold-side temperature on membrane performance were investigated using central composite design method. It was found that feed temperature has the largest effect among the parameters on the permeation flux. The flow rate and salt rejection of the membrane in the optimum conditions were 4.47 Kg m^?2 h^?1 and 99.37%, respectively.     

State-of-the-art technology: Recent investigations on laser-mediated synthesis of nanocomposites for environmental remediation

In both developing and industrialized/developed countries, various hazardous/toxic environmental pollutants are entering water bodies from organic and inorganic compounds (heavy metals and specifically dyes). The global population is growing whereas the accessibility of clean, potable and safe drinking water is decreasing, leading to world deterioration in human health and limitation of agricultural and/or economic development. Treatment of water/wastewater (mainly industrial water) via catalytic reduction/degradation of environmental pollutants is extremely critical and is a major concern/issue for public health. Light and/or laser ablation induced photocatalytic processes have attracted much attention during recent years for water treatment due to their good (photo)catalytic efficiencies in the reduction/degradation of organic/inorganic pollutants. Pulsed laser ablation (PLA) is a rather novel catalyst fabrication approach for the generation of nanostructures with special morphologies (nanoparticles (NPs), nanocrystals, nanocomposites, nanowires, etc.) and different compositions (metals, alloys, oxides, core-shell, etc.). Laser ablation in liquid (LAL) is generally considered a quickly growing approach for the synthesis and modification of nanomaterials for practical applications in diverse fields. LAL-synthesized nanomaterials have been identified as attractive nanocatalysts or valuable photocatalysts in (photo)catalytic reduction/degradation reactions. In this review, the laser ablation/irradiation strategies based on LAL are systematically described and the applications of LAL synthesized metal/metal oxide nanocatalysts with highly controlled nanostructures in the degradation/reduction of organic/inorganic water pollutants are highlighted along with their degradation/reduction mechanisms.     

对“垃圾衍生燃料”RDF之探析

当前,我国水泥工业在可燃废弃物应用技术方面都还处于一家一户、自制自用、效率极低的初级阶段。发达国家的替代燃料:“垃圾衍生燃料”RDF、“固体回收燃料”SRF、“次煤”Subcoal和“纸塑垃圾衍生燃料”RPF制成的原材料都是可燃废弃物,只是处理工艺技术不同或者由垃圾中分拣出的可燃废弃物不同,制成颗粒状衍生燃料的品质不同,这些都可以替代部分甚或替代全部化石燃料在水泥窑炉中应用。我国大力发展“替代燃料”产业,有助于水泥工业消纳更多的“可燃废弃物”,为改善环境尤其是城镇环境和面貌,为我国的节能减排和绿色高质量发展发挥更大的作用。     

氮含量及固溶温度对21-6-9奥氏体不锈钢组织和硬度的影响

为了探讨氮含量及固溶温度对21-6-9不锈钢组织和硬度的影响,分别在950、1000、1050和1100 ℃对3种不同氮含量的热轧态21-6-9不锈钢进行1 h固溶处理,通过光学显微镜观察其组织结构,结合Thermo-Calc热力学计算对试验钢的微观组织进行分析,并对其进行硬度测试。结果表明,0.20%~0.28%N的21-6-9不锈钢热轧后沿轧制方向析出铁素体,且钢中铁素体经950~1100 ℃固溶处理可消除,当N含量达到0.34%时,试验钢中不再出现铁素体。随着固溶处理温度的升高,21-6-9不锈钢的晶粒组织长大,硬度降低。N含量的增加可显著提高固溶态21-6-9不锈钢的硬度,其增加程度随固溶处理温度的升高而减弱。     

Sustainable optimization of waste management network over extended planning time horizon

This study proposes a multiperiod mixed integer linear programming model for the management of a single municipal solid waste (MSW) treatment plant with sustainability as the objective. Discrete and continuous variables define the capacity selections for diverse MSW technologies, and the operation of the MSW network, respectively. The economic target is considered to maximize the net present value. The environmental impact is the minimization of a normalized environmental objective function (NEOF). The social target is the maximization of jobs. An interesting feature about the research work is the requirement of biodrying technologies for MSW moisture content control. Due to the conflicted nature among the sustainability components, a multiobjective optimization (MO) is carried out to find the Pareto optimal solutions. The MO results show that the Pareto optimal solutions vary around profit range of $4.9–8.5 billion, NEOF impact range of 3.2–3.6 units, and social benefit range of 2700–4828 jobs.     

Effects of upholstery materials on the burning behavior of real‐scale residential upholstered furniture mock‐ups

Fire spread and growth on real‐scale four cushion mock‐ups of residential upholstered furniture (RUF) were investigated with the goal of identifying whether changes in five classes of materials (barrier, flexible polyurethane foam, polyester fiber wrap, upholstery fabric, and sewing thread), referred to as factors, resulted in statistically significant changes in burning behavior. A fractional factorial experimental design plus practical considerations yielded a test matrix with 20 material combinations. Experiments were repeated a minimum of two times. Measurements included fire spread rates derived from video recordings and heat release rates (HRRs). A total of 13 experimental parameters (3 based on the videos and 10 on the HRR results), referred to as responses, characterized the measurements. Statistical analyses based on Main Effects Plots (main effects) and Block Plots (main effects and factor interactions) were used. The results showed that three of the factors resulted in statistically significant effects on varying numbers of the 13 responses. The Barrier and Fabric factors had the strongest main effects with roughly comparable magnitudes. Foam was statistically significant for fewer of the responses and its overall strength was weaker than for Barrier and Fabric. No statistically significant main effects were identified for Wrap or Thread. Multiple two‐term interactions between factors were identified as being statistically significant. The Barrier*Fabric interaction resulted in the highest number of and strongest statistically significant effects. The existence of two‐term interactions means that it will be necessary to consider their effects in approaches designed to predict the burning behavior of RUF.     

一起发电机定子接地故障的分析与处理

文章介绍了海外某大型火力发电厂发生的一起发电机定子接地故障的分析和处理过程,对发电厂类似故障的处理和海外发电厂的运行和维护提供了参考。     

Ir(III) and Ru(II) Complexes in Photoredox Catalysis and Photodynamic Therapy: A New Paradigm towards Anticancer Applications

Individually, photoredox catalysis (PC) and photodynamic therapy (PDT) are well-established concepts that have experienced a remarkable resurgence in recent years, leading to significant progress in organic synthesis for PC and clinical approval of anticancer drugs for PDT. But, very recently, new photoredox catalyst systems based on Ir(III) and Ru(II) complexes have garnered significant interest because they can simultaneously be used as PDT agents apart from their demonstrated PC activity. This highlight discusses the unique PC behavior of emerging Ir(III)- and Ru(II)-based systems while also examining their potential PDT activity in cancer treatment.     

Kinetic analysis of crystallization of zeolite beta synthesized by direct heating

To quantitatively investigate the initial crystallization of zeolite beta synthesized by direct heating, the extent of the reaction was precisely evaluated by X-ray diffraction measurements and Rietveld structural refinement, and a kinetic analysis of crystallization was performed using the Avrami-Erofe'ev equation. The activation energy for crystallization was lower than that for hydrothermal synthesis. Reaction and synthesis time curves revealed that the initial zeolite beta crystallization consisted of three stages. The first was an induction period with nucleation by the generation of building units and the formation of an initial coordinated structure. The second stage was crystal growth by a diffusion-controlled reaction, and the third stage involved slowing down of crystallization by the limitation of dehydrocondensation. These stages could be analyzed by calculation of the rate constant and Avrami exponent for each stage.     

Inter-Sample and Intra-Sample Variability in Electronic Properties of Methylammonium Lead Iodide

While the challenges associated with the stability of metal halide perovskites are well known and intensely studied, variability in electronic properties represents an equally significant, yet seldom studied, challenge that could potentially slow or inhibit the commercial viability of these systems. In this work, the contactless characterization technique time-resolved microwave conductivity (TRMC) is used to quantify the variability in electronic properties of the prototypical perovskite, methylammonium lead iodide (MAPbI₃) both between different samples, and at different locations within the same sample. Using scanning electron microscopy (SEM) and a quasi-automated image-analysis strategy, it is possible to evaluate the metrics of heterogeneity in surface microstructure and correlate them with the electronic properties as obtained by TRMC. Substantial intra-sample and inter-sample variation is observed in the mobility-yield product in samples prepared following differing protocols, and in samples prepared following identical protocols.