6. Conclusions

Shukla et al. [86] synthesized the iron oxide nanoparticles coated with chitosan oligosaccharide and used for the removal of pathogenic protozoan cysts, entamoeba cyst (which causes amebiasis) from water. They found that E. histolytica can be efficiently captured using the magnetic

Zhang et al. [87] synthesized Fe3O4 nanoparticles surrounded with polyethylenimine-derived

Zhan et al. [88] synthesized the amine-functionalized magnetic nanoparticle (Fe3O4-SiO2-NH2) and used for rapid removal of pathogenic bacteria and viruses. The magnetic materials can be effectively used to capture a wide range of pathogens including various bacteria such as S. aureus,

Park et al. [89] developed a novel magnetic hybrid colloid (MHC) decorated with varying sized Ag nanoparticles. The MHC was prepared as a cluster of superparamagnetic Fe3O4 coated with silica shell. The MHC decorated with the Ag nanoparticle of 30 nm size (Ag30@MHC) exhibited the highest antimicrobial efficacy toward E. coli CN13 (6-log reduc-

Magnetic water treatment (MWT) is a new technique which is promising in environmental remediation in addition to its increased application in the area of medicine, agriculture and industrial process. The water molecules acquire unique physicochemical characteristics under the influence of the magnetic fields (MFs). It is a non-chemical method and the water molecules undergo change from their cluster of many loosely bound water molecules into very small, uniform and hexagonally organized clusters of molecules under the magnetic treatment [90]. These features of the magnetized water prevent the polluting agents to enter in to its cluster and also make their easy passage through the cells of plant as well as of animals. Moreover, the MFs have antimicrobial activity on water. Therefore, the magnetized water molecules depict as bio-friendly and eco-friendly compounds to environmental management as well as to plant

While taking sustainability in to consideration there are various factors over which it depends. Important factors include environmental impact on use of MNPs, toxicity associated with the MNPs, reusability, reactivity, adsorption capacity, biocompatibility, stability, etc. For example, uncoated nanoparticles are associated with some toxicity while coating can help them to make non-toxic. Similarly, their regeneration and reusability are the main factors for making them

technically more viable and economically sustainable materials for commercial uses.

corona and found to be efficient in capturing the pathogens and heavy metals.

70 Emerging Pollutants - Some Strategies for the Quality Preservation of Our Environment

nanoparticles from contaminated water.

E. coli O157:H7, P. aeuginosa, Salmonella, and B. subtilis.

tion) and the bacteriophage MS2 (2–3 log reduction).

5. Sustainability of magnetic nanoparticles

4. Magnetic water treatment

and animal cells.

In this chapter the removal of water pollutants by using magnetic materials of zero valent iron, magnetite (Fe3O4), maghemite (γ-Fe2O3) as adsorbent, photocatalyst and coagulants have been described. The MNPs have been used in removal of water pollutants through their various surface functionalities (e.g., coating with polyphenols, amino acids, sugars, alkaloids, terpenoids, proteins, carbonyl, carboxyl, carbon, polysaccharides, and semiconductors) with desired size and shapes, and magnetic behavior. Looking in to the fast development of magnetic materials in different technological and scientific fields, magnetic nanomaterials appear to be extremely promising for water and wastewater treatment. The waste water treatment methods using these materials are fast, non-toxic, and eco-friendly as compared to the available physic-chemical treatments which make it attractive for materializing commercially. Their magnetic nature makes them attractive for waste water treatment because of their easy separation from aqueous medium after purification and can be reused in repeated treatment cycles. However, research for bulk production, controlling morphology, optimizing surface functionality and their stability, and biocompatibility should be essentially considered prior to commercial application from laboratory scale. Moreover, further studies needs to be addressed to detail mechanism of magnetic nanomaterials in water treatment. The magnetic nanoparticles and their composites with their high surface to volume ratio offer more surfaces for chemical as well as physical adsorption and thus show high reactivity which gives the prospects of using these materials in large scale removal of emerging water pollutants.
