Preparation of fused silica membrane with high performance for high temperature gas filtration by sealing and spray coating

In order to improve the gas permeability and thermal shock resistance of the ceramic membranes applied in high temperature gas-solid separation techniques, fused silica and graphite particles were used as the primary raw material and pore-former agent, and the spray coating based-on PVA sealing was applied to prepare the separation membrane. These approaches remarkably decreases filtration resistance by increasing support permeability and reducing the intrusion of ceramic membrane forming particles into the support as well as the thickness of the membrane. The fabricated membrane had an average pore diameter of 9.85?μm and a gas permeability value of 8.2?×?10⁴?m³/(m² h bar), its dust removal efficiency reached 98.6%.     

Ion Exchange of Selected Group II Metals and Lead by Crystalline Silicotitanate and Competition for Cs Exchange Sites

ABSTRACT

A series of batch contact tests were conducted to evaluate the exchange behavior of Ba, Ca, Pb, and Sr onto crystalline silicotitanate (CST) in support of an expedited Cs removal and pretreatment system at the Hanford site. Binary Na/M²⁺ and ternary Na/Cs/M²⁺ isotherms were generated to understand selectivity, capacity, and competitive impact of each analyte on Cs uptake from a simple 1 M NaOH/4.6 M NaNO₃ simulant. Analyte loading from a 0.1 M NaOH/5.5 M NaNO₃ simulant was assessed to determine the effect of hydroxide concentration on binary Na/M²⁺ isotherms. Results from binary and ternary isotherms indicated that Group II metals Ca, Sr, and Ba (and Pb) do not impact CST performance toward Cs removal at concentrations expected in Hanford tank-waste supernate.     

An Injectable Hydrogel for Simultaneous Photothermal Therapy and Photodynamic Therapy with Ultrahigh Efficiency Based on Carbon Dots and Modified Cellulose Nanocrystals

The convenience of injectable hydrogels that can provide high loading of diverse phototherapy agents and further long-time retention at the tumor site has attracted tremendous interest in simultaneous photothermal and photodynamic cancer therapies. However, to incorporate the phototherapy agents into hydrogels, complex modifications are generally unavoidable. Moreover, these phototherapy agents usually suffer from low efficiency and work at different irradiation wavelengths outside the near infrared windows. Hence, a method for the fabrication of an injectable hydrogel for simultaneous photothermal therapy and photodynamic therapy, through the Schiff-base reaction between amido modified carbon dots (NCDs) and aldehyde modified cellulose nanocrystals is proposed. The NCDs act as both phototherapy agents and crosslinkers to form hydrogels. Significantly, the NCDs demonstrate an extremely high photothermal conversion efficiency of 77.6% which is among the highest levels for photothermal agents and a high singlet quantum yield of 0.37 under a single 660 nm light-emitting diode irradiation. The hydrogels are examined through in vitro and in vivo animal experiments which show nontoxic and effectively tumor inhibition. Thus, the strategy of direct reaction of phototherapy agents and the matrix not only provides new strategies for injectable hydrogel fabrication but paves a new road for advanced tumor treatment.     

变频电源在铜冶炼除尘器中的应用分析

针对冶炼烟气的除尘效率的问题，在冶炼生产实际需求的基础上，通过对高压电源提效进行理论分析，对各种高压电源进行对比分析，结合试用的结果表明对于除尘器本体未进行改造的情况下，仅改造高压电源可以显著提升冶炼烟气的除尘效率^［1］。     

Effects of microstructure shape parameters on water removal in a PEMFC lotus-like flow channel

To improve the drag reduction performances of the proton exchange membrane fuel cell (PEMFC), a three dimensional numerical investigation about the water removal in a lotus-like PEMFC flow channel is carried out. The effects of the microstructure shape parameters (height, radius and spacing) are investigated. The investigation revealed that the liquid water can be effectively removed by the lotus-like flow channel from the channel wall surface. The appropriate height of lotus-like channel can effectively reduce the water coverage ratio on the top wall of the lotus-like flow channel. As height increases, the average drag reduction ratio increases firstly and decreases finally. When the radiuses are 25 μm and 50 μm, the average drag reduction ratios of these cases are higher than those of the other cases obviously. The spacing of the lotus-like channel has a few effects on the water removal and water coverage ratio. The lotus-like flow channel with the height of 50 μm, the radius of 50 μm and the spacing of 150 μm has a high drag reduction and anti-corrosion performance. The work in this study provides a new choice for the flow channel and has certain guiding significance for the design of the flow channel for anti-corrosion and drag reduction.     

Thiol-modified cellulose nanofibrous composite membranes for chromium (VI) and lead (II) adsorption

Oxidized cellulose nanofibers (CNF), embedded in an electrospun polyacrylonitrile (PAN) nanofibrous scaffold, were grafted with cysteine to increase the adsorption capability for chromium (VI) and lead (II). Thiol-modified cellulose nanofibers (m-CNF) were characterized by titration, FT-IR, energy dispersive spectroscopy (EDS) and SEM techniques. Static and dynamic Cr(VI) and Pb(II) adsorption studies of m-CNF nanofibrous composite membranes were carried out as a function of pH and of contact time. The results indicated these membranes exhibited high adsorption capacities for both Cr(VI) (87.5 mg/g) and Pb(II) (137.7 mg/g) due to the large surface area and high concentration of thiol groups (0.9 mmol of –SH/gram m-CNF). The morphology and property of m-CNF nanofibrous composite membranes was found to be stable, and they could be used and regenerated multiple times with high recovery efficiency.     

120kt/a磷铵装置除尘、洗涤系统技术改造提高装置运行效率

我公司120 kt/a磷酸二铵生产工艺由于尾气洗涤及除尘系统设计缺陷,长期存在粉尘及氨外溢严重,生产周期短等问题。通过对上述系统的改造:将造粒与干燥尾气分开洗涤,对部分设备尺寸及各级洗涤介质进行调整;在现场环境改善、氨回收率提高、生产周期延长等方面都取得了较好效果。     

BAF脱氮除磷工艺浅述

曝气生物滤池(BAF)是一种集生物氧化、过滤、吸附于一体的新型生物膜污水处理技术。文章较详细地介绍了BAF的发展沿革,综述了BAF在填料、生物膜、有机物、SS、氨氮去除、脱氮除磷、有毒有害物质降解方面的最新进展,拓宽了BAF组合工艺的研究和应用范围,指出BAF作为一种深度处理工艺是非常适合于我国国情的水处理技术,尤其对我国今后中水回用、企业污水闭路循环以及"零排放"具有重要意义,应加大研发和开发力度,推广其应用。     

工业磷化废水处理的实验研究及应用

文章介绍了目前工业磷化废水处理过程中常用的化学沉淀除磷法,研究了pH、PAM投加量的变化对除磷效率的影响。确定了除磷的最佳工艺条件为:pH为7.5~9之间,PAM投加量为300 mg/L。