Study: Zeolite for Hydrogen Energy August 16th, 2010
Our Important Source Of Storing Hydrogen: The Natural Zeolite
ABSRACT
It is very necessary to find an alternative resource to fossil ones. Such kind of fuel must be improvable, friendly with natural and found with huge amounts. The production, storage and usage of the fuel are also important points when choosing the fuel. It must be easy reachable, carriage of it must not be dangerious. more…
Study: Zeolite Minerals for Uptake of Mercury Solutes September 8th, 2009
The uptake of inorganic Hg2+ and organometallic CH3Hg+ from aqueous solutions by 11 different natural zeolites has been investigated using a batch distribution coefficient (Kd) method and supported by a preliminary voltammetric study. The effect of mercury concentration on the Kd response is shown over an environmentally appropriate concentration range of 0.1–5 ppm inorganic and organometallic Hg using a batch factor of 100 ml g–1 and 20 h equilibration. Analcime and a Na-chabazite displayed the greatest methylmercury uptakes (Kd values at 1.5 ppm of 4023 and 3456, respectively), with mordenite as the smallest at 578. All uptake responses were greater for methylmercury than for the inorganic mercuric nitrate solutions, suggesting a distinctive sensitivity of zeolites to reaction with different types of solute species. It is likely that this sensitivity is attributable to the precise nature of the resultant Hg-zeolite bonds. Additionally, both the Si-Al ratio and the Na content of the initial natural zeolite samples are shown to influence the Kd responses, with positive correlations between Kd and Na content for all zeolites excluding mordenite.
Zeolite in Soil Amendments September 8th, 2009
Natural Zeolites
Natural zeolites were formed by the chemical reaction of volcanic ash and alkaline salt water. This chemical reaction gives natural zeolites an open three-dimensional honeycomb and porous structure. The mined zeolite ore is dried, crushed, and screened to meet USGA particle size specifications. Different natural zeolite deposits can have quite different chemical and physical characteristics. A high quality natural zeolite has a high CEC, low clay, low sodium, and high potassium.
Zeolites, Natural and Synthetic September 8th, 2009
Two Kinds of Zeolites: Natural and Synthetic
Synthetic and natural zeolites are hydrated aluminosilicates with symmetrically stacked alumina and silica tetrahedra which result in an open and stable three-dimensional honeycomb structure with a negative charge. The negative charge within the pores is neutralized by positively charged ions (cations) such as sodium. Over 150 zeolite structural types have been identified.
Study: Biosorption of Chromium Using a Bacterial Biofilm with Zeolite September 2nd, 2009
Two mini-columns partially filled with granular activated carbon (GAC) and/or a natural zeolite, covered by a bacterial biofilm of Arthrobacter viscosus, were used in a continuous flow system to remove Cr (VI) from solutions with initial concentration of 70mg/l and a working pH ranging between 4.5 and 5.5. Three different set-up’s were used: two columns in series filled GAC covered with a biofilm, two columns in series filled with zeolite covered with a biofilm and a column filled with GAC followed by another column filled with zeolite, both supports covered with biofilm. Comparatively, the biosorption system supported on GAC reaches similar removal values, 19%, as the one supported on the zeolite, 18%, but when these two beds are used in combination better performances are reached, i.e. 42% removal. The maximum uptake values ranged from 0.57mg(Cr)/g(Support) to 3.58mg(Cr)/g(Support). The interactions between metal ions and functional groups on the cell wall surface of the biomass were confirmed by FTIR. GAC was regenerated with steam draughting and reused twice. The first regeneration caused a decrease in the removal capacity of 38% and the second regeneration caused a total decrease in the removal capacity of 76%.
Zeolite Mineral History & Properties September 2nd, 2009
Historically, mineral zeolite was discovered in 1756 by a Swedish mineralogist named Freiherr Axel Fredrick Cronstedt, who derived the name from the Greek words zein and lithos meaning “boiling stones”. Over the next 200 years chemists and mineralogists studied zeolites and discovered the dehydration, adsorption, and cation exchange properties of this mineral.
