Electron beam induced purification of dilute off gases from industrial processes and automobile tunnels

The electron beam process has proved to be an efficient method for the removal of inorganic pollutants from flue gas. Since it simulates natural processes which occur in the atmospheric photochemistry, it appeared attractive to investigate the potential of the e-beam process to clean off-gases which contain hydrocarbon and inorganic trace components. Such emissions arise from industrial processes and from automobile tunnels. Commercial solvents were vaporized in air and irradiated with energetic electrons (300 keV). CO, CO₂ and aerosol particles were found as products and were determined quantitatively. The aerosol particles can be collected by a gravel bed filter and can be removed by combustion or biological degradation. From experiments and model calculations it was found that the e-beam process is a very economic tool to remove hydrocarbons from large off-gas volumes at initial concentrations of 50–100 mg C/m³, and that NO_x can be removed very efficiently from tunnel off-gas.     

Fluoride and lead adsorption on carbon nanotubes

The properties and applications of CNT have been studied extensively since Iijima discovered them in 1991[1,2]. They have exceptional mechanical properties and unique electrical property, highly chemical stability and large specific surface area. Thus far, they have widely potential applications in many fields. They can be used as reinforcing materials in composites[3], field emissions[4], hydrogen storage[5], nanoelectronic components[6], catalyst supports[7], adsorption material and so on.…     

DeNOx催化剂FeZSM-5/Raney Fe的制备

用原位晶化法合成了FeZSM-5/RFe(RFeRaney Fe)催化剂. 合成液的组成为5Na2O*100SiO2*10TPABr*7 000H2O,pH＞11.5. 合成液中不含Al,ZSM-5分子筛的骨架Al只来源于Raney Fe的表面. 此法提高了ZSM-5分子筛中骨架Al的稳定性和分子筛上Fe离子的负载量. FeZSM-5/RFe用作DeNOx催化剂时具有较高的活性和水热稳定性.     

Blood cell separation using crosslinkable copolymers containing N,N‐dimethylacrylamide

Amphiphilic copolymers using hydrophilic N,N‐dimethylacrylamide (DMA), hydrophobic methyl methacrylate (MMA) and a crosslinkable monomer, 3‐methacryloyloxypropyl trimethoxysilane (MTSi), were synthesized and evaluated as coating materials for leukocyte removal filters for whole blood. When filters composed of non‐woven fabrics were coated with crosslinked synthesized copolymers, the elution ratios of the copolymers to water were adequately low because of the crosslinking with trimethoxysilane groups of MTSi units in the copolymers. Filters coated with crosslinked poly(DMA‐co‐MTSi) having a 0.96 mole fraction of DMA units showed a 0.35 ± 0.44% platelet permeation ratio and a logarithmic reduction of 4.0 ± 0.68 for leukocytes. On the other hand, an increase in the content of MMA units in the DMA‐containing copolymers improved the permeation ratio of the platelets dramatically. Filters coated with crosslinked poly(DMA‐co‐MMA‐co‐MTSi) containing a 0.39 mole fraction of MMA units and a 0.58 mole fraction of DMA units showed an 86 ± 3.0% platelet permeation ratio and a logarithmic reduction of 2.1 ± 1.2 for leukocytes. This indicates that an adequate content of hydrophobic monomer units, such as MMA units, is necessary for effective platelet permeation. Copyright © 2007 John Wiley & Sons, Ltd.     

A novel and simple pathway to synthesis of porous polyurea absorbent and its tests on dye adsorption and desorption

A novel one-step protocol for the preparation of porous polyurea material (PPU) through precipitation polymerization of toluene diisocynate (TDI) is presented. The process is based on step polymerization of one singlemonomer, TDI, with water in water-acetonemixed solvent. PPU is obtained without need for any porogen or additives, and no any chemical modification on the outcome polymer is necessary. The morphology, pore size and size distribution of PPU are characterized by scanning electron microscope and BET nitrogen adsorption. Taking acid fuchsine (AF) and Congo Red as dye examples in wastewaters, their adsorption on, desorption from PPU and the reusability of PPU were tested. Experimental conditions for AF adsorption were optimized with regard to pH, adsorption time, AF concentration and amount of PPU. Results demonstrate that the as-prepared PPU is of high performance in dyes adsorption and recycled use. This work presents therefore a novel and attractive candidate for removal of anionic dyes from wastewaters.     

Bilayer rGO-Based Photothermal Evaporator for Efficient Solar-Driven Water Purification[]**

Interfacial evaporation has emerged as a promising approach to produce freshwater. However, an urgent concern is that, due to the illegal discharge of industrial wastewater, most water bodies are polluted by trace volatile organic compounds (VOCs), which are easily volatilized and enriched in the collected water during the interfacial evaporation process. Herein, a bilayer photothermal evaporator was reasonably designed for contaminated water purification. The bottom hydrophilic rGO-sodium alginate (SA) sheets purposefully disintegrate water transport channels, thus quickly removing VOCs through physical adsorption. The rGO-SA-TiO₂ upper layer sufficiently absorbs incident light and therefore persistently generates reactive oxidizing species to degrade upward VOCs. Notably, the oriented microchannels inside the evaporator allow sustained light reflections to improve the utilization of solar energy. The evaporation rate can reach 1.63 kg m⁻² h⁻¹ with a considerably high VOC removal efficiency of up to 96 %. Such an integrated bilayer evaporator provides an effective strategy to obtain clean water via solar distillation.     

Examination of the Degreasing of Metal Surfaces by the Use of a Plasma Torch

Metal surfaces can be degreased via a combustion reaction upon the metal surface by the use of a plasma torch jet. The required energy and the reaction rate of the combustion reaction are examined here. It turns out that the reaction rate can limit the cleaning performance. In such case, the cleaning performance is not improved at higher powers. It is suggested to increase the temperature at which combustion takes place such that the cleaning performance can improve again at higher powers. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

溶剂去除速度对于溶剂退火薄膜相形貌的影响

以聚苯乙烯-聚4-乙烯基吡啶(PS-b-P4VP)嵌段共聚物作为研究对象,采用DMF作为退火溶剂,以原子力显微镜(AFM)和透射电子显微镜(TEM)为表征手段,研究了溶剂退火后期溶胀薄膜中溶剂的去除速度对于薄膜相形貌的影响,发现通过改变溶剂去除速度可以有效的调控薄膜中的形貌.当薄膜厚度为35 nm时,DMF的快速挥发会导致薄膜中形成以PS为分散相的反转柱状相结构,当降低溶剂的挥发速度时,薄膜中形成了以PS为分散相的环状形貌,当进一步减缓挥发速度时,薄膜中将形成台阶状的片层结构;然而当薄膜厚度为55 nm时,溶剂退火后期薄膜中形成的是以P4VP为分散相的正常柱状相结构,在相同溶剂去除速度条件下薄膜相形貌变化较小.     

Optimization of cadmium adsorption from aqueous solutions by functionalized graphene and the reversible magnetic recovery of the adsorbent using response surface methodology

Novel functionalized graphene adsorbent was prepared and characterized using different techniques. The prepared adsorbent was applied for the removal of cadmium ions from aqueous solution. A response surface methodology was used to evaluate the simple and combined effects of the various parameters, including adsorbent dosage, pH, and initial concentration. Under the optimal conditions, the cadmium removal performance of 70% was achieved. A good agreement between experimental and predicted data in this study was observed. The experimental results revealed of cadmium adsorption with high linearity follow Langmuir isotherm model with maximum adsorption capacity of 502 mg g^?1, and the adsorption data fitted well into pseudo‐second order model. Thermodynamic studies showed that adsorption process has exothermic and spontaneous nature. The recommended optimum conditions are: cadmium concentration of 970 mg L^?1, adsorbent dosage of 1 g L^?1, pH of 6.18, and T = 25 °C. The magnetic recovery of the adsorbent was performed using a magnetic surfactant to form a noncovalent magnetic functionalized graphene. After magnetic recovery of the adsorbent both components (adsorbent and magnetic surfactant) were recycled by tuning the surface charges through changing the pH of the solution. Desorption behavior studied using HNO₃ solution indicated that the adsorbent had the potential for reusability.