微电解-Fenton氧化法去除垃圾渗滤液中有机物

采用Fe/C微电解和Fe/C微电解-Fenton氧化联合工艺对垃圾渗滤液进行处理,研究了废水初始pH、药剂投加量、药剂投加比例和反应时间等对处理效果的影响,获得Fe/C微电解处理垃圾渗滤液的最佳工艺条件:初始pH=3、m(Fe)/m(C)为4、ρ(Fe/C)为0.6 g/L、反应时间为60 min,处理后COD降至5 960 mg/L,COD去除率达51.8%。Fe/C微电解-Fenton氧化处理垃圾渗滤液的最佳工艺条件:在Fe/C微电解最佳条件下,H2 O2投加量为11 mL/L,反应时间为100 min,出水COD为4 480 mg/L,COD总去除率为63.8%。垃圾渗滤液中的腐殖酸类有机质经过Fe/C微电解或微电解-Fenton氧化处理后变成小分子产物,与Fe/C微电解相比,Fenton氧化对腐殖酸等大分子有机质有更强的氧化降解效果。     

Removal of selected persistent organic pollutants by heterogeneous photocatalysis in water

Environmentally relevant polar persistent organic pollutants (pharmaceuticals and diagnostic agents) were chosen according to human consumption and occurrence in the aquatic environment (sewage plant effluents, rivers and groundwater) to investigate their behavior during photocatalytic oxidation. From data compilation in the literature, the active metabolite clofibric acid of some lipid lowering agents, the anti-epileptic drug carbamazepine and the X-ray contrast media iomeprol were selected. The degradation of the persistent pollutant was monitored by HPLC/DAD/FLD. The study also focuses on the identification and quantification of possible degradation products by HPLC/DAD/FLD and HPLC/MS/MS. The degradation process was also monitored by determination of sum parameters and inorganic ions. Various aromatic and aliphatic degradation products have been identified and quantified. From analytical data, a possible degradation scheme for carbamazepine was proposed. Kinetic studies showed that the TiO₂ photocatalyst P25 was more active in clofibric acid degradation than Hombikat UV100. For photocatalytic degradation of iomeprol Hombikat UV100 was more suitable than P25. In general the presence of NOM and carbamazepine retarded the photocatalysis of clofibric acid. Radiation attenuation, competition for active sites and surface deactivation of the catalyst by adsorption are the reason for that. The results of this work proof that photocatalysis is a promising technology to reduce persistent substances even if they are present in low concentrations or in a complex matrix.     

Fine-structured patterns of porous alumina material fabricated by a replication method

Porous alumina materials with three-dimensional fine-patterning over multiple length scales were fabricated from mixed slurry of polyvinyl alcohol (PVA) and alumina nanosized particles in water by a replication method. The mixed slurry was then filled in a silicon mold with different pattern sizes and dried at room temperature. After the drying, the PVA and alumina dried film were detached from the mold. Through burn-out at various sintering temperatures, alumina porous materials with dot, hole and line and space patterns as small as sub-micrometer in size were successfully fabricated. The results demonstrated possibilities to produce porous inorganic materials with various compositions and structures with a facile approach and a simple method.     

Significance of microhardness of porous inorganic materials

Microhardness was measured of porous and nonporous samples of halite and selenite and it has been shown that the relationship between microhardness and porosity may be expressed by the emperical relation H = H_oe^−bp. The significance of the microhardness measurements as applied to porous materials is discussed from the standpoint of the disturbed zone of crystals or micro-units, including the problem of “work hardening” when powdered samples are compacted. The effect of morphology on microhardness is also discussed with regard to a series of gypsum samples. Reference is made to the effect of humidity on microhardness of porous glass and the conclusion drawn that the micromechanics of failure in microhardness are similar to flexure strength.     

Removal of inorganic mercury from mine waste water by ion exchange

The present study has been undertaken to investigate a process that might remove inorganic mercury from mine waste water streams by use an ion exchange resin system. A number of commercial resins have been evaluated as ion exchangers and the mercury content of the waste water, ranging from 70 to 90 ppm, is reduced to a permitted level of 34 ppb. Dowex XZS‐1, a strong cationic ion exchanger in a gel Form, has the most pronounced selectivity for mercury. The loaded resin was regenerated efficiently using HCl solutions, due to increased competition between Hg and hydronium ions and formation of an HgCl ₄ ²⁻ ionic complex. © 2000 Society of Chemical Industry     

Removal of aerosols by bubbling through porous media submerged in organic liquid

Aerosols can be filtered by passing the carrier gas through a fibrous filter immersed in water (Agranovski, I. E., Myojo, T., & Braddock, R. D. (1999a). Bubble filtering through porous media. Aerosol Science and Technology, 31, 249-257. Using water as the irrigating fluid significantly increases the efficiency of filtration of particles and adds the possibility for simultaneous removal of alien gases from the carrier. Organic compounds (gaseous and particulate) form a significant proportion of pollutants in the atmosphere, and effective purification is needed for ambient air as well as for cleaning exhaust streams. Water does not have a high level of solubility for gaseous organic compounds, and alternative irrigating liquids need to be considered. Experiments were conducted using sunflower oil as the irrigating fluid. The filtration efficiencies of the oil are better than for water, for liquid di-ethyl-hexyl-sebacate particles. As the solubility of organic vapours is much higher in oil compared with the one in water, oil provides an excellent opportunity for utilizing as the irrigating liquid for high-efficient simultaneous removal of organic particles and vapours from air carrier.     

离子交换法脱除己内酰胺产品中的无机盐

采用不同的阴阳离子交换树脂,对己内酰胺产品进行了精制研究,脱除了产品中微量的硫酸铵等无机杂质。通过静态和动态实验对比考察了不同树脂对硫酸铵的吸附性能。结果表明,离子交换反应是吸热的过程,树脂的吸附量随温度、初始浓度和接触时间的增加而增加。动态穿透曲线能很好地符合Adams-Bohart和Thomas模型,并得到树脂的最大交换容量,阳离子交换树脂D001对NH_4~+的最大交换容量为61.51 mg/g,阴离子交换树脂717对SO_4~(2-)的最大交换容量为7 640.4 mg/g。在吸附过程中,己内酰胺的含量稳定不变,且电导率的测定可用于检测实际己内酰胺溶液中硫酸铵的浓度变化。     

离子交换法脱除己内酰胺产品中的无机盐

采用不同的阴阳离子交换树脂,对己内酰胺产品进行了精制研究,脱除了产品中微量的硫酸铵等无机杂质。通过静态和动态实验对比考察了不同树脂对硫酸铵的吸附性能。结果表明,离子交换反应是吸热的过程,树脂的吸附量随温度、初始浓度和接触时间的增加而增加。动态穿透曲线能很好地符合Adams-Bohart和Thomas模型,并得到树脂的最大交换容量,阳离子交换树脂D001对NH_4⁺的最大交换容量为61.51 mg/g,阴离子交换树脂717对SO_4+的最大交换容量为61.51 mg/g,阴离子交换树脂717对SO_4^(2-)的最大交换容量为7 640.4 mg/g。在吸附过程中,己内酰胺的含量稳定不变,且电导率的测定可用于检测实际己内酰胺溶液中硫酸铵的浓度变化。     

The pressure drop in a porous material layer during combustion

During the combustion of a porous material layer, a manometer, which is attached to the cold end of the charge, records at the bottom of the layer a pressure reduction, which was discovered more than 20 years ago but which remains essentially unexplained up to the present. It is experimentally shown that this effect is similar to the pressure change in the cavities when a light gas (helium, hydrogen) diffuses from (or to) them under isothermal conditions and that it increases during the combustion mainly due to the accompanying Stefan type flow, and probably also as a result of the thermal diffusion. A pressure drop in the cavities is evidently made possible also by the pressure reduction in the flame which follows from the Hugoniot adiabatic theory.D. I. Mendeleev Mosk. Khim.-Tekhnol Inst. 125190, Moscow. Translated from Fizika Goreniya i Vzryva, No. 1, pp. 57–60, January–February, 1995.     

Synthesis of polymer/inorganic nanocomposite films using highly porous inorganic scaffolds

Polymeric/inorganic nanocomposite films have been fabricated through a combination of flame-spray-pyrolysis (FSP) made inorganic scaffold and surface initiated polymerization of cyanoacrylate. The highly porous structure of pristine SnO(2) films allows the uptake of cyanoacrylate and the polymerization is surface initiated by the water adsorbed onto the SnO(2) surface. Scanning electron microscopy study reveals a nonlinear increase in the composite particle size and the film thickness with polymerization time. The structural change is rather homogeneous throughout the whole layer. The composite is formed mainly by an increase of the particle size and not by just filling the existing pores. High-resolution transmission electron microscopy imaging shows SnO(2) nanoparticles embedded in the polymeric matrix, constituting the nanocomposite material. Thermogravimetric analysis indicates that the porosity of the nanocomposite films decreases from 98% to 75%, resulting in a significant enhancement of the hardness of the films. DC conductivity measurements conducted in situ on the nanocomposite layer suggest a gradual increase in the layer resistance, pointing to a loss of connectivity between the SnO(2) primary particles as the polymerization proceeds.     

Determination of Darcian permeability of porous material by infrared spectrometry

The active cooling of aerospace structures can be performed by the use of porous materials. It requires characterizing its permeability to predict the cooling efficiency by means of Computational Fluid Dynamics codes. The Darcian term is generally deduced experimentally from a relationship between the mass flow rate and the pressure drop through the porous media. Due to thermo-chemical process involved in the cooling, the permeability can change. It is currently not possible with common techniques to determine these variations during the flight. This paper presents a novel approach taking advantage of well known flow behaviour in chemical reactor engineering in order to propose a real-time in situ quantification of the Darcian permeability. The residence time distribution is analyzed thanks to tracer injection and to associated experimental measures of Infra-Red signals. The IR peak characteristics (height, width, surface, rising and falling gradients) and time delays are analyzed and correlated to physical parameters (mass flow rate, injected mass of tracer, properties of fluids). The peak height and surface and the rising gradient vary linearly in the same sense as the injected tracer mass while the falling gradient varies in the opposite sense. Both gradients decrease with a mass flow rate increase. The time delay between injection and detection of the tracer is quite constant except when changing the fluid nature. A design of experiments allowed estimating quantitatively the influence of each physical parameter on the optical one of the IR signal. Thanks to this first understanding, the Darcian permeability is linked to the observed IR signal. A linear regression is proposed with the peak width which is judged to be the most relevant parameter. Finally, an analytical approach is developed to fit ordinary differential equations to IR peak measures and to correlate the parameters of the law to the Darcian permeability. Several laws (linear, logarithmic and power) are proposed depending on the parameter but the linear regression involving the coefficient noted ?? ₁ is the most promising. One of the advantages of this method is to be able measuring the permeability during the flight and not only on-ground with specific test facility.     

Adsorption of bovine serum albumin to a polymer brush prepared by atom-transfer radical polymerization in a porous inorganic membrane

Protein adsorption was performed by a polymer brush prepared by atom-transfer radical polymerization (ATRP) to a porous inorganic membrane. The porous inorganic membrane, Shirasu Porous Glass made from silica, was modified with a halogen-containing compound to bind the active species for the polymerization. Glycidyl methacrylate was polymerized from the halogen compound by ATRP for a prescribed time, and subsequently chemically modified. The progression of the chemical modification allowed the membrane to lower the phosphate-buffer flux of the porous membrane due to the attachment of the polymer brush. Bovine serum albumin (BSA), as a model protein, was adsorbed at 12 mg per gram of the membrane in permeating BSA solution through the polymer-brush-attached porous membrane.     

Removal of mineral material from solvent-refined coal by solvent extractions

Solvent refined coal (SRC), a coal extract which is highly polyaromatic in character and relatively high in N, O and S content, is derived from the direct liquefaction of coal. SRC contains mineral matter in the form of soluble organometallic compounds which can not be removed by filtration. These soluble species can be detrimental to the hydrocracking catalyst used in the upgrading of the SRC to high-value liquid fuels. These species, however, can be separated from the SRC by extraction with benzene or tetralin as solvents so that the mineral matter is mainly concentrated in the solvent-insoluble fraction, the other fraction are then readily hydrocracked, as demonstrated in this work.     

Dispersion states of porous inorganic materials in polymer blends observed by inverse gas chromatography

Inverse gas chromatography (i.g.c.) of columns prepared with a polymer blend of poly(ethylene oxide) (PEO) and polystyrene (PS) in the presence of pulverized porous inorganic materials has been studied. Information on the inorganics-polymer interaction was obtained from the change in the Z-shaped curve observed in the retention diagram. Inorganic materials except active carbon selectively incorporated PEO into their pores. The incorporation ability increased with increasing surface area of inorganic material. Molecular sieve 5A was scarcely able to incorporate PEO into its pores in spite of its large surface area, and this was ascribed to its small pore diameter. Active carbon selectively incorporated PS into its pores. Irreversible adsorption of a solute on active carbon was a dominant process in i.g.c. measurement for the column prepared with polymer and active carbon.     

Drying characteristics of porous material immersed in a bed of hygroscopic porous particles fluidized under reduced pressure

A relatively large wet material was immersed in a fluidized bed of hygroscopic porous particle (silica gel beads) under reduced pressure. And then the drying characteristics were compared with those in the case of inert particle (glass beads). The comparison of drying characteristics is performed experimentally and theoretically. In calculation, the water transfer from the sample to the fluidized bed was considered. The calculation results are in good agreement with the experimental data. The effects of the operational conditions (the pressure in the drying chamber and the temperature of the drying gas) on the drying characteristics were also examined in both fluidizing particles.The drying finishes earlier in the case of hygroscopic porous particle than in the case of inert particle regardless of pressure in the drying chamber, since the water transfer from the sample facilitates the drying in the case of hygroscopic porous particles. The temperature decrement in drying appears in the case of inert particle. This phenomenon is also observed in the case of hygroscopic porous particle, but the decrement degree of the temperature is much smaller than that in the case of inert particle. The difference of the minimum temperature in the sample in drying between the cases of hygroscopic porous particle and inert particle is very slight for different pressures in the drying chamber.     

Enhancement of the rate of solar photocatalytic mineralization of organic pollutants by inorganic oxidizing species

Particulate suspensions of TiO₂ irradiated with natural solar light in a large experimental plant catalyze the oxidation of a typical organic contaminant: pentachlorophenol (PCP). The addition of oxidants, concentration of which is kept constant during treatment, such as hydrogen peroxide, peroxymonosulphate (oxone) and peroxydisulphate increases the rate of photodegradation of PCP in the following order: . Peroxydisulphate (10 mM), selected as the best oxidant studied, has been applied to the development of a solar photocatalytic plant for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant, which includes the correct treatment of this highly contaminating effluent. The first results, without process or hardware optimisation, show that peroxydisulphate enhances the photocatalytic mineralization rate at least five times.