Tag Archives: chromatographic processes

Activation of Catalysts for Carbon Nanomaterial Production

The most important stage of preparing heterogeneous catalysts for carbon nanomaterial (CNM) is their activation, which is understood as a complex of physical influence on the catalytic material, which allows to significantly increase the efficiency of nanostructure synthesis.

This can be achieved by researching mechanical (dispersion) and physical (electromagnetic and ultrasonic) activation methods.

One of the most important factors defining catalyst efficiency is its granulometric composition. It is known that reduction of the particle size (less than 3 nanometers) causes capsulation inside nanotubes, while increasing it above 25 nanometers leads to uneven size distribution and defects in nanotubes. This is due to the fact the using large catalyst particles (25 to 100 nanometers) prevents carbon scattering from the surfaces where hydrocarbon decay occurs to the surfaces where carbon is deposited; as a consequence, no CNM growth occurs on such particles. Therefore, it is important to define reasonable catalyst particle size, as well as dispersion and classification methods.

Note that dispersion of catalyst microparticles causes both the reduction of size and the changes in the microstructure, e.g. destruction and reduction of pore depth, increasing the boundary of nano-seeds, where graphitized carbon is deposited.

Catalyst was activated in a drum mill and an electromagnetic vortex layer device (AVS). The distinguishing characteristic of the vortex layer in electromagnetic units is the multitude of high frequency and strength shocks, as well as friction, which not only break solid particles, but significantly activate their surfaces due to the deformation of their crystalline lattice. Enormous energy is concentrated in a volume of this process, which direct influence on the material. The influence is so high that it changes the structure as deeply as the atom’s valency shells. The process causes deep changes in the structure of the material.

Mean energy conducted to a volume of the vortex layer reaches 103 kW/m3. This is several orders of magnitude higher than in vibration mills, for instance. Besides, the energy is localized in certain areas, e.g. in the locations where the ferromagnetic particles collide, where mean power reaches even higher.

The electromagnetic vortex layer unit consisted of a process section and a control section, connected by oil tubes and a power cable. The process section consisted of a support, an enclosure, an induction coil for the rotating electromagnetic field, and a detachable operating chamber.

The catalyst activation process was performed with 1…1.5 mm by 10…15 mm PVC encapsulated ferromagnetic particles.

The chamber was loaded with 0.120 kg of the catalyst and 0.060 kg of ferromagnetic particles; retention time varied from 5 to 60 seconds. The granulometric composition of the Ni/MgO catalyst after the dispersion was done by fractionating sieve analysis. The catalyst after activation was separated into fractions and used for CNM synthesis under a unified method of testing various catalyst samples.

The results of the experiment show that the optimal duration time for the finest grinding constitutes 10 seconds, with initial catalyst particle size of 500 micron.

The observed increase of catalyst particle size after 10 or more seconds of dispersion is apparently due to the fact that with time the particles accumulate sufficient energy for spontaneous aggregation.

The analysis of the influence of the catalyst size composition on the mean output of CNM leads to the conclusion: the output increases in inverse proportion to catalyst particle size. This is due to the increased active surface of the catalyst. The experiments demonstrated that the actual method of catalyst dispersion has no significant influence on nanomaterial output.

Modern Electroplating Wastewater Neutralization

Electroplating wastewater. Electroplating facilities and shops produce toxic solid waste in the form of ions of heavy metals, acids and alkalis that can cause water pollution. It is due to the electrochemical technology requiring large volumes of water.

Generally, the decontamination and neutralization of electroplating wastewater is performed by a special unit which uses reagent purification. Despite the mainstream use of this approach, it is not without flaws. Its drawback is ineffective wastewater treatment that leads to excess of unwanted substances in the water output. Other drawbacks of the reagent method are high reagent consumption and high salt content, which do not allow the water to return back into the cycle; it also requires large bulky equipment.

Therefore, scientists continue to search for new methods to improve the efficiency of existing technologies. A solution was found by GlobeCore in its magnetic mill (AVS). These devices were developed in the last century by Logvinenko. In his book “The Intensification of Technological Processes in a Vortex Layer Unit” he demonstrated the positive results obtained with the AVS in wastewater treatment. But the low capacity of the device precluded its mass introduction into the wastewater treatment industry, because a large industrial enterprise required many AVS units for neutralization of wastewater, until recently. The newly developed high-performance devices cover the necessary volumes of wastewater treatment.

The GlobeCore design department studied the effectiveness of the AVS for cleaning and neutralizing wastewater from electroplating facilities. The data is shown in the table below.

Heavy metal wastewater treatment from galvanizing plant using AVS 100



Maximum concentration level (European Union legislation)

Before treatment

After treatment







Fe, mg/l





Cu, mg/l





Ni, mg/l


<0,02 (not detected)



Cr+6, mg/l


<0,005 (not detected)


The use of the AVS-100 magnetic mill in wastewater treatment from electroplating plants reduces the concentration of heavy metals to values ​​not exceeding the maximum permissible concentration accepted in the European Union. It achieves complete absence of nickel and hexavalent chromium in the treated water and shows the possibilities of future use of the vortex layer devices in countries with more stringent demands for hexavalent chromium and nickel concentrations.

Wastewater treatment is immediate and does not require high expenditure of reagents. The sedimentation with the AVS occurs much faster than with a stirrer.

Wastewater treatment technology

Development of wasteless technology is an important measure to protect the environment from anthropogenic loads by separating contaminants from water, and possibly to recycle the contaminants for use in technology processes.

This can be achieved by using modern efficient technologies. However, wastewater has several types of contaminants and so using only technology process in real conditions might be economically problematic or too cumbersome.

Wastewater is most often processed using traditional treatment methods. However, if wastewater contains several organic substances, similar in physical and chemical properties, the technology process becomes complicated.

The amount of wastewater, including that containing hazardous organic materials, grows every year. To prevent further increase of wastewater amount in the industry, a promising approach is to develop wasteless technology processes and implementation of closed loop water supply systems. That is why comprehensive purification processes are being developed. Also, new methods of chemical removal, such as iron, fluoride, manganese, pesticides and other chemicals, petroleum products etc.

Hexane is used in many industries. For instance, hexane solvent is widely used in vegetable oil extraction. Such solvents as benzol, toluene, ethyl acetate, isopropanol and cyclopentane.

Reduction of organic substances in wastewater can be achieved by local purification. The processes involved adsorption, reverse osmosis, ultra-fitration, electrodialysis and ion exchange. Oxidation by atmospheric oxygen and ozone allows to remove up to 99% and 75% mercaptans. Resinous materials are removed by filtration through activated charcoal or coke.

Activated charcoal can easily adsorb acrylonitrile, aniline, benzene, chlorobenzene, cyclohexane, cresol, mercaptan, naphthalene and phenol. These substances can be extracted from activated charcoal by chloroform, ethanol, acetone, while reverse osmosis removes up to 90% of organic substances from wastewater.

In sulfate cellulose factories, the local purification methods include purification of wastewater with chlorine, lime, ozone and oxygen, which oxidize hydrogen sulfide and hydrosulfide. To oxidize organic substances in wastewater and for disinfection, chlorine is used, to remove odor, apart from ozone and chlorine, hypochlorite and manganese dioxide are used; unpleasant smell of sediment is neutralized at 730ºС.

As a rule, organic substances in wastewater are biologically oxidized in local or factory facilities. However, many are resistant to biological oxidation, and in such cases, thermal decontamination (incineration) is often used. Organic wastewater materials are incinerated at 800-1000ºС. Incineration is often used for such substances as benzol, toluene, resins, aldehydes and paraffins.

Using natural sorbents is treatment does not require their regeneration, while contaminated sorbents may be used in other chemical, construction or agricultural processes. Therefore adsorption is a promising and relatively inexpensive method of wastewater purification.

Chromatographic processes, especially adsorption, are often used in chemical and pharmaceutical industries, in biotechnology for breaking chemical and physical bonds. Many types of adsorbents with various structure and chemistry found use in adsorptive chromatography.