Adsorber Particles with Magnetically‐Supported Improved Electrochemical Conversion Behavior for Waste Water Treatment Processes

Micron‐sized supraparticles, consisting of a plurality of discrete nano‐ and microscale functional units, are assembled and fused by means of a droplet extrusion process. By combining nano magnetite, activated carbon, and conductive carbon with a polymeric binder matrix, particles are obtained which unite good magnetic properties, electrical conductivity, and adsorber activity through the high accessible surface area of the incorporated activated carbon of about 570 m2 g−1, thereby enabling a new approach toward sustainable water treatment processes. Due to the interplay of the components, it is possible to adsorb target substances, dissolved in the water which is demonstrated by the adsorption of the model dye methylene blue. A very fast adsorption kinetic and an adsorption capacity of about 400 mg g−1 is determined. By using the developed composite particles, it is also possible to electrochemically alter substances flowing through a magnetically‐stabilized fluidized‐bed reactor by electrochemically charging/discharging, significantly supported by the magnetic field enabling alternatingly optimum mobility/adsorption phases with contact/charging intervals. The electrochemical conversion can be increased up to 151% depending on the applied flow‐rate and electrical voltage. By applying an external magnetic field, a further increase of electrochemical conversion of up to 70% can be observed

Coatings with a mole-hill structure of nanoparticle-raspberry containers for surfaces with abrasion-refreshable reservoir functionality

Active silica nanoparticle-based raspberry-like container depots for agents such as antimicrobial substances are presented. The nano raspberry-containers are integrated into coatings in a way that they form a mole-hill structure; i.e., they are partly standing out of the coating. As an application example, it is demonstrated that the containers can be filled with antimicrobially active agents such as nano ZnO or Ag or organic molecules such as thymol. It is demonstrated that the containers can be partly chopped-off via abrasion by rubbing over the surface. This mechanism proves to be an attractive approach to render surfaces refreshable. A first proof of principle for antimicrobial activity of the intact containers in the coatings and the abrasion treated, chopped-off (and thereby reactivated) containers is demonstrated

Technologien für die Zukunft - Anorganische Rohstoffbasis im Wandel

It will not be long until the peak oil problem will spread onto a number of metals. Profitable sources of many inorganic raw materials have already been exhausted. In primary raw materials, the ore content of metals is beginning to be very low, so that the exploitation is increasingly time- and energy consuming. By way of application examples, it will be demonstrated that many raw materials have a tremendous influence on our day-to-day life even though their actual content in a final product may appear to be negligible. The recovery of precious raw materials and their recycling back into the substance cycle will remain one of the main head topics on society's agenda for decades to come. Development of novel recovery processes is in full swing as will be shown by the examples chosen for this article

Polishing of secondary wastewater effluents through elimination and recovery of dissolved phosphorus with reusable magnetic microsorbents

The proposed innovative technology combines nanocomposite magnetic particles with a tailored adsorbent material for the selective removal of dissolved phosphorus from pretreated wastewater and concentrating it in a purer liquid matrix as a source for further phosphorus recovery. The adsorbent deposited on the carrier magnetic particles was carefully preselected among many other options, showing high adsorption capacity, good selectivity, stability and recovery potential. The engineered composite particles can be magnetically extracted from water, regenerated in an alkaline solution, where phosphorus desorption takes place, and reused again. Their reusability is demonstrated for 55 adsorption/desorption cycles in municipal wastewater by adjusting the process parameters, without detecting any drop in performance. Important advantage of the developed technology is the dual benefit of phosphorus elimination down to concentrations < 5 μg/L PO4-P and < 50 μg/L Ptotal, which do not pose any eutrophication risk, and the option for subsequent recovery of the valuable nutrient, thus having the potential to be an attractive alternative to the conventional P-removal methods in wastewater treatment

Effect of ph on the synthesis and properties of luminescent sio2/calcium phosphate:eu3+ core-shell nanoparticles

A novel method for the synthesis of luminescent SiO(2)/calcium phosphate (CaP):Eu(3+) core-shell nanoparticles (NPs) was developed via a sol-gel route followed by annealing at a temperature of 800 degrees C. The object of this study was the investigation of the effect of pH on the formation of a CaP shell around the silica core. The resulting annealed NPs exhibited an amorphous SiO(2) core and a crystalline luminescent shell. The formation of a CaP layer was possible at pH below 4.5 and above 6.5 during the coating step. The crystal structure of the shell was studied by X-ray diffraction analysis. Hydroxyapatite (HAp) and alpha-tricalcium phosphate were detected as crystal phases of the surrounding layer. However, NPs produced under basic conditions exhibited a higher crystallinity of the CaP layer than did samples coated at pH below 4.5. In the pH interval between 4.5 and 6.5, no shell growth but the formation of secondary NPs containing CaO and Ca(OH)(2) was observed. Furthermore, SiO(2)/CP:Eu(3+) core-shell NPs were investigated by transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, inductively coupled plasma optical emission spectrometry, and photoluminescence spectroscopy. The resulting HAp-coated NPs were successfully tested by a cell-culture-based viability assay with respect to a later application as a luminescent marker for biomedical applications