Magnetic Nanoparticles

-

In many parts of the world, access to clean drinking water is far from certain. Filtration of large volumes of water, however, is slow and impractical. As a consequence, scientists have introduced a new water purification method based on magnetic nanoparticles coated with a so-called “ionic liquid” that simultaneously remove organic, inorganic, and microbial contaminants, as well as microplastics. The nanoparticles are then easily removed with magnets. The surfaces of the nanoparticles were coated with a layer of an ionic liquid. An ionic liquid is a salt that is in its molten state at room temperature, making it a liquid without use of a solvent. The ionic liquid used by the researchers were based on polyoxometallates (POMs)—metal atoms bound into a three-dimensional network by oxygen atoms. 



In this case the metal of choice was tungsten because the polyoxotungstate anions can bind to heavy metals. As counterions, the researchers used bulky tetraalkylammonium cations with antimicrobial properties. The resulting ionic liquids form stable thin layers (supported ionic liquid phases) on the porous silicon dioxide surface of the nanoparticles. Once loaded with contaminants, the nanoparticles can simply be extracted from water with magnets.

Adjustment of the components of the nanoparticles should allow for further optimization of their properties, making the magnetic nanoparticles a highly promising starting point for both central and decentralized water purification systems. This would allow for easy purification of large amounts of water, even without extensive infrastructure.

Additionally, new magnetic nanoparticle recovery devices are being developed such as magNERD was developed and operated to separate, capture, and reuse superparamagnetic Fe3O4 from treated water in-line under continuous flow conditions. Experimental data and computational modeling demonstrate how the MagNERD’s efficiency to recover nanoparticles depends upon reactor configuration, including the integration of stainless-steel wool around permanent magnets, hydraulic flow conditions, and magnetic NP uptake. The MagNERD efficiently removes Fe3O4 in the form of a nanopowder, up to > 95% at high concentrations (500 ppm), under scalable and process-relevant flow rates (1 L/min through a 1.11-L MagNERD reactor), and in varying water matrices (e.g., ultrapure water, brackish water). The captured nanoparticles were recoverable from the device using a simple hydraulic backwashing protocol. Additionally, the MagNERD removed ≥ 94% of arsenic-bound Fe3O4, after contacting As-containing simulated drinking water with the nanopowder. The MagNERD emerges as an efficient, versatile, and robust system that will enable the use of magnetic nanoparticles in larger scale water treatment applications.

Magnetic nanoparticles is a growing technology and it will continue to develop well into the future as we continue our quest to find the best method to treat waste water.


References:

https://www.nanowerk.com/nanotechnology-news2/newsid=54136.php

https://link.springer.com/article/10.1007/s11051-020-4770-4

Comments

Post a Comment

Popular posts from this blog

SLUDGE REDUCTION POTENTIAL OF METAZOA

-
Image
 A way to reduce excess sludge production and enhance mineralization is to retain the sludge completely in a treatment plant, which can be achieved by a membrane separation process. There the sludge concentration is expected to stabilize at the level at which energy supplied is fully utilized for maintenance purpose. Another way to enhance mineralization and reduce the sludge production is to exploit the organism in the process that predate on bacteria (sludge), by promoting their growth in an extra “grazing stage”. During energy transfer from bacteria to higher trophic level organisms, energy is lost due to inefficient biomass conversion and thus the predator may make a large contribution to biomass replacement. A long sludge retention period in membrane bioreactors (MBR) is very suitable for the abundant growth of these higher organisms. This predatory population in the system can be exploited to enhance mineralization and reduce sludge production.  High metazoa density lead...
Read more

Pseudomonas in wastewater treatment

-
Image
Pseudomonas in wastewater treatment-  Source- Céline Slekovec, Julie Plantin, and Didier Hocquet  Pseudomonas is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 validly described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches. Pseudomonas aeruginosa was isolated consistently from domestic and hospital sewage. In domestic sewage the numbers were usually less than 30,000 per 100 ml whereas counts above 500,000 per 100 ml were frequently obtained in hospital sewage. Correspondingly high counts of Escherichia coli were not found in hospital sewage and the ratio of E. coli to P. aeruginosa was usually less than 25 compared to ratios of over 500 often found in ordinary domestic sewage. During passage through sewage treatment plants the numbers of both bacteria were reduced by about 90% so that their ratio in the effluent remained...
Read more

ANAEROBIC FERMENTATION

-
Image
  Most of the organics in the sewage sludge were transformed into useful energy by the anaerobic fermentation of microorganism. Plenty of nitrogen, phosphate, potassium could be separated from the leachate produced in this fermentation which makes the recycling of sewage sludge much easier. This method could also help stabilize and decrease the amount of sewage sludge and make it harmless.  Here is a brief account on the mechanism of this process. The sewage sludge samples are taken in conical flasks; the flasks were sealed and kept in an airtight and anaerobic condition. Then the conical flasks were kept in thermostatic water bath box, controlling the temperature at 95°C to improve the efficiency of the anaerobic fermentation of the sewage sludge. The conical flasks were taken out and put into a container with oxygen at the 2th, 7th, 10th, 14th, 17th, 21th, and 28th day after the beginning of the anaerobic fermentation, respectively. When the flasks were taken out, a little o...
Read more