Department Laboratories

Batch reactor for wastewater treatment

Batch treatment is the basic process for cleaning industrial effluent. The contents are determined analytically and a specific treatment strategy is designed on the basis of this analysis. Typical process steps are redox reactions to break down nitrites and chromates, as are frequently used in wastewater treatment in the metal industry. The progress of the reaction is measured by online measuring instruments such as pH or redox probes and visualised at a central point by the process control system. Finally, heavy metal precipitation, flocculation and filtration are carried out. The sludge containing the heavy metals is subsequently dewatered by means of a chamber filter-press.

Electrolysis

Electrochemical methods are advantageous for the treatment of industrial effluents for two reasons, and can be investigated experimentally in the Technical Center: On the one hand, dissolved metals can be precipitated by applying a voltage, thus allowing resource recovery, and on the other, problematic substances are broken down. A number of parameters can be varied here and the electric current yield determined. The exhaust air produced during the electrolysis is cleaned in a Venturi scrubber.

Ultra-filtration system

Ultra-filtration is a type of membrane filtration to separate oil/water mixtures. Long-chain oil molecules are kept back by a membrane, while water as the permeate diffuses through the pores. This method can be used to concentrate used coolant-lubricant emulsions without the addition of chemicals. The permeate is returned into the process as envisaged by production-integrated environmental protection. The installation has process visualisation and thus makes it possible to determine the optimum operating parameters for various effluents.

Head:             Prof. Dr. Barna Heidel          

Assistant:        Dipl. Ing (FH) Michaela Hammermann       

Laboratory:          F 02.207, F 02.218     

The range of topics involved in air quality management is considered from several perspectives in the Environment Engineering Laboratory. The adsorption of the corrosive gas sulphur dioxide from an exhaust gas is investigated experimentally using a gas scrubber by way of example, and the effect of physical, chemical and process-related parameters on the process is visualised. Dynamic operating conditions as well as stationary operation are considered. To determine the rate of removal, continuous gas analysers and wet-chemistry measurement techniques are used and the results assessed in comparison with each other. Immission measurements are conducted with the aid of portable measuring instruments to determine the concentration of air pollutants at the place where they take effect. The pollutants measured here include nitrogen oxides, ozone and mercury. The measurement techniques comprise absorption methods and continuous analysis. Miniature measurement systems for air pollutants are currently being developed on the basis of single-chip sensors for the mobile, long-term monitoring of the air quality.

Head              Prof. Dr. Barna Heidel          

Assistant:        Dipl. Ing (FH) Michaela Hammermann       

Laboratory:          F 02.207, F 02.218      

Typical applications of distribution and particle measurement engineering are to be found in sorption, spray, agglomeration and dosing technology, for example. In the Environmental Engineering Laboratory, these sub-fields of mechanical process engineering are implemented in practice using the example of a specific regulation of the particle size distribution of coffee powder. Powders with different particle size distributions can be produced using a ball mill. The particle size distribution is determined by laser diffraction analysis and sieve analysis. The laser diffraction analyser allows a number of measuring cells to be integrated. Work is currently being carried out to expand the measuring setup to include sprays and suspensions.

Head              Prof. Dr. Barna Heidel          

Assistant       Dipl. Ing (FH) Michaela Hammermann       

Laboratory          F 02.207, F 02.218    

Contents

The practical work aims to familiarise students with various important analytical methods in practice, while at the same time consolidating their theoretical knowledge of important analytical techniques.

The actual content is subject to continual change to meet the requirements of those working with the methods in practice. Apart from fundamental experiments on chromatography and spectroscopy, modern methods such as the analysis of formaldehyde by means of HPLC or DIN methods and cation determination by means of polarography are taught.

Head of Laboratory:   Prof. Dr. Constanze Stiefel
 

Assistant:                    Dipl.-Ing. (FH) Edda Binder
 

Laboratory:                             S 10.117

Laboratory phone:                -3549 

Contents

In the surface and nano-chemistry laboratory the focus here is on the characterization and chemical modification of surfaces and nano structures.  The objective of the laboratory courses is to show students the correlations between the chemistry, structure and function of surfaces. This is illustrated by way of an example:

The silanisation of glass surfaces involves the application of a molecular film of alkoxysilyl groups to the surface. The quality of the films obtained can be controlled via the reaction parameters. This is verified by contact angle measurement of water. When the surface is structured, too, the wetting angle can be increased compared to the smooth surface. In this way we optain unwettable superhydrophobic surfaces (see fig. 1).

Further experiments deal with thiolization, nanopowder syntheses, sol-gel coatings, photocatalytic boundary layers, electrochemical double layers.

The following experimental techniques are used: Dip coating, screen printing, hydrothermal synthesis, UV-Vis spectrometry, zeta potential measurements, X-ray diffraction (see fig. 2), contact angle measurements (see fig. 3).

Research activities in the surface and nano-chemistry laboratory include

• sorption equilibria of ions and polymers 
• electrokinetic powder characterisation (see fig. 4)
• characterization of electrode materials of electrochemical energy storages

Head of Laboratory:       Prof. Dr. Stephan Appel
 

Assistants:                         Dipl.-Ing. (FH) Denise App

Laboratory:                          S 13.-113

Laboratory phone:                -3246