2016年7月21日星期四

Illegal Dumping Jailed in Yunnan, WO3 Photocatalyst Degrades Landfill Leachate

Not long ago, the first case of illegal dumping of landfill leachate and caused environmental pollution of Yunnan which has caused much concern has been adjudged; the defendant because of surrender and pleaded guilty with a good attitude, has jailed for 2 years and will respite for 2 years, also he was imposed a fine of 20,000 and do some service as a environment volunteer. It is reported that this case is because the defendant privately dumped his transportation of 29 cars which totaled 568.34 tons of pollutants into the environment, under the case of known the heavy metals, organic compounds should be transported to a special institution for professional treatment, and thus caused serious pollution to the surrounding environment. In this regard, the court verdict this case based on the principle of "spoiler repairs, polluter controls".

tungsten trioxide and landfill leachate
 
Landfill leachate is the high concentration of organic or inorganic ingredients liquid which generates from the landfill garbage piling up in the biochemical degradation process due to compaction, fermentation, etc., while in precipitation and groundwater seepage produces liquid comprising. In the biological pretreatment process, titanium dioxide photocatalyst has been used in the degradation of landfill leachate, and the experiments showed that this is a successful method for cleaning leachate. In addition, the experimental has derived the factors which influence photocatalytic oxidation process of landfill leachate, they are photocatalyst dosage, pH value, light intensity, illumination time and oxygen content dissolved in the water ect..
 
Tungsten trioxide (WO3), a yellow powder, the large number of it is used for the production of metal tungsten; in addition, WO3 has the property of semiconductor, with the band gap of 2.4eV ~ 2.8eV. WO3 as a photocatalyst can response to visible light, thus to fully use the solar energy, instead of relying on the ultraviolet light, such as titanium dioxide. Photocatalytic activity is a common decision of the ability of absorbing light, charge separation and the transferring efficiency to the substrate. WO3 has a wider spectral response capability, to this point of view, it should have a stronger catalytic oxidation than titanium dioxide, and can be used for landfill leachate degradation. In addition, studies have shown that yttrium (Y+) doped WO3 photocatalyst can improve the ability to absorb light, thus improve the photocatalytic activity of the system.

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Tungsten Trioxide Applicable in New Water Electrolyzing Catalyst

Recently, the Chinese Academy of Physical and Chemical Research Institute has successfully synthesized a highly efficient water electrolyzing catalyst to achieve high efficiency at a low voltage of activating water molecules, and offered the potential for solving the future energy crisis. Hydrogen is considered as the best source of energy, unlike the other new energy sources, like solar, nuclear, ocean, biomass and geothermal energy and so on, it belongs to the energy of energetic body which is available direct combustion. Among the hydrogen production technologies, the way of solar water photolysis or photo-assisted electrolysis of water is one of the most promising and efficient pathway, which is depending on the semiconductor electrode, and moreover, the water electrolyzing catalyst can greatly improve the efficiency of water electrolysis hydrogen.

Tungsten Oxide

Zhang Rui, one of the researchers led his team carried out a in-depth study on the nanostructure of "Hydrotalcite (LDH)" clay mineral, through precise regulation of the hydrotalcite precursor morphology, and synthesized the ultra-thin and ultra-small heterogeneous nanostructures of NiO / TiO2by calcination under a high temperature. Studies have shown that this structure exhibited a superior catalytic performance in terms of electro-catalytic decomposition for generating hydrogen and oxygen. At the same time, studies have shown that the catalyst synthesis method is simple, and used the abundant nature of non-precious metal as the raw material, the obtained product of ultra-thin and ultra-small material of NiO / TiOhas the application value in the respects of electro-catalytic decomposition of water, capacitors ect.; also, it is applicable to other metal oxides (such as tungsten trioxide) to prepare the nanosheets electro-catalyst.
Tungsten (W) , an element of the transition metal in ⅥB family; tungsten trioxide is an important oxide in the tungsten metallurgical industry, which has semiconductor property; because of its catalytic property, it is commonly used in the preparation of the denitration, hydrodesulfurization, photocatalyst and other catalysts. Study on catalyst of titanium dioxide has been more than 40 years, while the international research on tungsten trioxide applied on the photocatalyst, water electrolysis catalyst is just in the early phase, we believe that in the near future, researchers will slowly open the mystery of tungsten trioxide in this regard applications.

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Tungsten Trioxide Photocatalyst Solves Mercury Pollution

In June, a primary school of Huayuan County of Hunan Province, China, occurred a serious mercury poisoning (Minamata disease) of many students, which resulted in 147 students urine mercury exceeded; its cause is a fifth-grade student took 50 ml of the remaining mercury in the wok of a waste workshop in a mineral water bottle to school, and gave it to the other students for playing. According to the source, this workshop was illegal constructed and operated unauthorized without Environmental Impact Assessment (EIA) and related procedures. For this accident, I am showing my deep sadness, someone innocent was suffered a serious injury because some unscrupulous manufacturers do not manage their hazardous substances.

Hg and drinking water
 
China as the largest country which uses and emissions most  in global mercury, and has faced with the tremendous pressure to reduce emissions of mercury reductions in the "global mercury instrument" negotiations. This year, on June 18th to 19th, "the second national mercury pollution control and monitoring technology seminar" held in Yancheng, Jiangsu Province of China, the main focus of the meeting lies in deeply discussing the hot spots and focus issues of the policy standards mercury pollution control and monitoring in the field of technical support, solutions, industry trends, monitoring system and management system, and so on; furthermore, it provided decision supporting to in facing with the mercury pollution problems of socio-economic development process.
 
Mercury is a quite rare element in the earth's crust, which is the only kind of liquid metal. Mercury pollution (Hg2+) is one of the major heavy metal pollutions in the water, which has lethal hazards on the human nervous system. Studies have shown that, in the photocatalytic reduction experiment of Hg2+ of tungsten trioxide photocatalyst, Hg2+ was strongly adsorbed on surface of tungsten trioxide, and its adsorption amount increased as the increasing of pH value. In addition, experiments found that the adsorbed Hg2+ by tungsten trioxide still exist in the form of oxidation states which means it won’t occur reduction. Thus, Hg2+ in the wastewater has been taken by the photocatalyst, to eliminate mercury pollution. In addition, the recovery of Hg2+can be separated with the photocatalyst, and then through the certain supporting of technical to recycle the mercury, and to realize resources recycling.

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Halo Holographic Helmet Uses Tungsten Trioxide Electrochromic Film

Virtual Reality (VR) and Augmented Reality (AR) are now leading the forefront of technology, what the surprises will be by the further combination of AR and VR? Recently, source pointed out that Halo holographic helmet has opened the official website pre-sale, and will deliver to the customers after the International Consumer Electronics Show in January 2017. It is reported that this holographic helmet can switch in a key between AR and VR, using the most advanced processor, and based on a whole new generation customization system, can achieve low latency display in the sensor; at the same time, it supports gesture recognition, without any external testing equipment to achieve SLAM, and supports real-time 3D modeling space. In addition, the key to switch between AR and VR of this holographic helmet in a key lies in the eyepiece glass with a special chemical materials sandwich, after conductive of the special sandwich of film, a reversible color change of light will occur, such as the use of tungsten trioxide electrochromic film will turn blue after the light irradiation.
 Holographic Helmet
The original state of tungsten trioxide electrochromic film appears in pale blue, the color gradually deepened after power, and the reason lies in tungsten bronze compound (MxWO3) is produced. Tungsten bronze is a tungsten-containing nonstoichiometric compound, it appearance looks like copper and has the chemically property of inert, its properties changed with the variety of M and value of x, which can produce properties changing of color, conductor or semiconductor and so on, such as when M = Na , x = 0.2, MxWO3 shows blue.
 
Tungsten trioxide is the most classic non-organic electrochromic material, since WO3 electrochromic film phenomenon has been found in 1969, people have committed to its study and gradually deepen its research. Electrochromic phenomenon is the chemical composition and the valence of the electrochromic material shows a reversible change under the applied electric field, and ultimately reflecting in the color changing; with this property, electrochromic film can be widely used in construction, automotive, aerospace and other fields, also it plays a role in energy-saving thermal control and so on.

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WO3 Denitration Catalyst Devotes to Green Energy

With the whole society to improve air quality concerns, China in recent years regarded environmental protection as an important work and expanded, the emerging energy, chemical and other industries are required to must equipped with exhaust gas purification, waste water treatment equipment; also, the old coal enterprise are asked to carry out reforming and installing some equipments to the boiler, thus the ultra-low emissions has become the mainstream environmental topics. 

three forms of SCR denitration catalyst
 
Media recently reported that Power Plant of Tongliao, Inner Mongolia of China, has started a wide load denitrification renovation project on its No.5 Unit from late May this year and it has been completed with the ongoing production and other external insulation finishing work. According to the source, this transformation is due to the No.5 unit has the situations of lacking of steam and temperature under the high-load condition, denitration can not to be put into operation under the low-load. The reconstruction project team increased the flue gas temperature by the mean of increasing flue gas bypass under the premise of ensuring the thermal efficiency not to be reduced compared with that of before the transformation, mode of boiler operation and adjustment method meet the boiler stability and security operational requirements and also no to increase the total flue resistance. And thus achieve the goal of full unit load denitrification, and make contributions to the undertaken of green and clean energy.
 
Denitration catalyst is installed in the SCR denitration catalyst system, which can be divided into three forms of plate, honeycomb and corrugated plate from the appearance. The most commonly used SCR denitration catalyst, no matter what form the ingredients are, they are almost similar in the ingredient, which is taking vanadium pentoxide as main active substance, WO3 as a co-catalyst, titanium dioxide as a carrier. Vanadium pentoxide is very active and will oxidize sulfur dioxide to sulfur trioxide during the production of sulfuric acid. WO3 as the co-catalyst, its presence can reduce the catalytic oxidation of sulfur dioxide at maximum under the basis of catalytic reduction of NOx is to be guaranteed, and thus to improve the denitration catalyst thermal stability and resistant to the As and other toxic substances in the flue gas. In addition, on the presence of WO3, it can be avoid that catalyst carrier occurs changes in the crystalline structure which cause the carrier sintering during the operating process for long-term, to minimize the sintering of the catalyst, thus maintain the specific surface area not to be reduced and affect catalyst activity.

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WO3 May Be Catalyst of Black Tech Fuel Cell

Recently, Nissan release the automobile solid oxide fuel cell (SOFC): vehicles which equipped with solid oxide fuel cells will use bio-ethanol rather than the liquid hydrogen. Produce ethanol reformer hydrogen combines with oxygen in the air in a fuel cell to produce electricity, then discharging water. According to the source, this system is more efficient than the existing hydrogen fuel cell system, which the recharge mileage can reach about 600 km. what kind of black tech is SOFC? SOFC is the third generation of the fuel cell, a solid-state chemical mean which direct converted efficiently and environmentally friendly the chemical energy which is stored in the fuel and oxidizer to electric energy at high temperature, a fuel cell which is considered to be widely applied as the proton exchange membrane fuel cell (PEMFC) in the future.
SOFC System
 
SOFC does not require expensive platinum as a catalyst with both the anode and cathode materials are oxides. WO3 is a semiconductor-type transition metal oxide, to maintain stability in an acidic environment, also form catalytic effect together with the noble metal, as carrier it can partial substitute carbon to prepared composite catalyst which has been extensively studied. We guess that perhaps WO3 catalysts can be used in SOFC. The work environment of fuel cells has the properties of high voltage, humidity and low pH values, thus requiring an electrode material has good corrosion resistance. Pt / WO3 / C being the most studied of the fuel cell catalyst, the experimental results showed that the addition of WO3 in the catalyst will bring the significant improvement of oxidation catalytic activity and electrochemical oxidation stability; the same time, most of the fuel cells take methanol, ethanol as the energy source and thus there is inevitable to generate amount of CO in the reaction process, while the addition of WO3 in the catalyst of the CO stripping experiment found that Pt / WO3 / C exhibited good CO oxidation, that is, it has good resistance CO poisoning ability.

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