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Study on Magnetic Materials for Removal of Water Pollutants

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Manoj Sharma, Pankaj Kalita, Kula Kamal Senapati and Ankit Garg

Submitted: November 14th, 2017 Reviewed: February 20th, 2018 Published: July 4th, 2018

DOI: 10.5772/intechopen.75700

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Water is a primary element for all living things, and we need water for each and every day-to-day activity related to agricultural, industrial, and domestic cares and, thus, its quality influences all aspects of human life including energy, food, health, and economy. Safe drinking water is our primary need to protect our life and thus developing efficient and affordable techniques for water treatment to access potable water to the humanity. Water pollution is one of the severe environmental and health problems worldwide. Pollutants in water can be of organic, inorganic, heavy metals, microbial, and radioactive species, which may be in different forms viz. suspended, dissolved, or dispersed materials. The water quality is mainly affected by industrial discharges, agricultural activities, mismanagement of hazardous materials, etc. Nowadays, nanotechnology offers the possibility of an efficient removal of water pollutants including metals, organic dyes, bacteria, parasites, etc. Magnetic nanomaterials like iron oxide (Fe3O4) are very promising materials used in water decontamination particularly for heavy metals and dyestuffs because of their ease of separation through external magnet, high surface area, unique morphology as well as their high stability. These materials can be used as adsorbent, photocatalyst, and coagulating agents for water remediation based on their composite materials or surface functionalities.


  • magnetic nanomaterials
  • water treatment
  • water pollution

1. Introduction

Water, i.e., 2 mol of hydrogen and 1 mol of oxygen or simply called H2O plays a vital role in our everyday life. Without water no one can think of life on earth. About 71% of earth is covered with water. Of that 71% water about 97% resides in oceans and only 3% of water is fresh water (Figure 1a) and of that 3% about 68.7% of freshwater is locked up in icecaps and glaciers (Figure 1b), and it is quite a surprising fact that almost all the remaining fresh water is below the ground. Of all the freshwater on the surface of earth only 0.3% is contained in fresh lakes, and rivers [1].

Figure 1.

(a) Water distribution on the earth and (b) freshwater distribution on the earth.

As the population is increasing day by day the water availability per capita is decreasing. So the challenge of limited amount of freshwater and its decreasing per capita availability is an issue of concern but another major challenge is water pollution that has not only environmental impact but also have a major effect on human health. As per the statistics 783 million people do not have access to clean and safe water worldwide [2]. Around 319 million people in Sub-Saharan Africa are without the access to improved reliable drinking water sources. One in nine people worldwide do not have access to safe and clean drinking water. 443 million school days are lost each year due to water-related diseases [3]. In developing countries, as much as 80% of illnesses are linked to poor water and sanitation conditions [4]. 2.6 billion people in the world lack adequate sanitation and which contributes to about 10% of the global disease burden [5]. Half of the world’s hospitals beds are filled with people suffering from a water-related disease [6].

There are various type of illnesses due to water and are summarized in Table 1.

Type of diseasesSourceExampleReferences
Water borneHuman or animal wasteCholera, typhoid, and dysentery,[7]
Water washedLack of clean water for washingSkin and eye infections[8]
Water basedOrganism developed in water and then become parasiteSchistosomiasis[9]
Water-related insect vectorMosquitoes breed in waterMalaria and dengue[9]

Table 1.

Various types of illness due to water.

As we have seen that the contaminated water has a very bad impact on human health even some heavy metals that if taken for long time it can cause cancer such as arsenic is considered as one the carcinogenic contaminant in water. After understanding the health issues related to contaminant water there is need to understand the source of contamination and major contaminants that pollute the water.

In recent years, magnetic materials have been potentially used for removal of water pollutants, particularly organic contaminates (dyes, chlorinated hydrocarbons, aromatics), pesticides, as well as heavy metals [10]. There are a large number of techniques available for water treatment for safe drinking water including adsorption, precipitation, solvent extraction, ion exchange, reverse osmosis, membrane separation, evaporation, and photocatalysis. The development of nanoscience and nanotechnology shows their potentiality in removing toxic elements from water bodies with better water treatment process. The design and development of nanomaterials which belong to the size range of 1–100 nm exhibiting unique properties as compared to the bulk materials leads to the enormous improvements in many sectors including, health, manufacturing, electronics, environmental remediation as well. The magnetic nanomaterials (paramagnetic or ferromagnetic or superparamagnetic) with tailored surface chemistry have already expanded their scope of application in water treatment. In this chapter, various processes of drinking water treatment and waste water treatment using advanced magnetic materials in removing toxic metal ions, organic and inorganic solutes, bacteria and viruses has been discussed.

1.1. Major sources of water contamination

There are many sources of drinking water and the main sources are ground water, lakes, canals, reservoirs, rain water, fog water and sea water. These sources are contaminated in different ways and broadly the source of contamination can be divided in to two categories:

  • Direct sources or point sources

  • Indirect sources or non-point sources

Direct sources basically include effluent from industries, treatment plants, refineries, factories, etc. However, indirect sources or non-point sources include the water contamination entering to the water body through a number of processes, e.g., while putting the fertilizers and pesticides to the agricultural field, the elements presents in the chemical percolates down to the groundwater and ultimately pollute the water.

1.2. Different types of water contaminants

There are various types of water contaminants, however in the following subsections organic contaminants, inorganic contaminants and pathogens are briefly discussed.

1.2.1. Organic contaminants

Organic contaminants present in drinking water create severe problem on human health. Pollution by organic chemicals in water bodies occurs by various mechanisms. Industrial waste containing various organic chemical contaminants pollutes the water bodies. Volatile organic compounds (VOCs), pesticides, phenolic compounds, phthalates, and nitrogen-containing compounds, are often detected in polluted water [11]. Many of these compounds have been found to be carcinogenic, even in very low concentrations. WHO Guidelines for drinking water quality, levels are set for 28 organic constituents (i.e., microcystin-LR, chlorinated alkanes, chlorinated benzenes and miscellaneous), 33 pesticides, and 9 disinfectant by-products, due to their health effects on humans [12]. It is noteworthy to mention that, occurrence of pharmaceutical and personal care products and perfluoroalkyl acids in aquatic environment has been recognized as emerging issue in environmental chemistry [13].

1.2.2. Inorganic contaminants

Inorganic contaminants include metals, salts and other compounds that do not contain carbon. Many of them are naturally occurring and should be considered as an integral part of those waters, e.g., calcium carbonate and bicarbonate in hard water. The metal ions such as Hg(II), Pb(II), Cr(III), Cr(VI), Ni(II), Co(II), Cu(II), Cd(II), Ag(I), As(V) and As(III) are toxic from eco toxicological point of view. Besides, the pollution by the radioactive elements is of major concern looking into their long-term hazardous impacts.

1.2.3. Pathogens

Pathogens such as bacteria, viruses and parasites may be present in very low concentration in drinking water; but cause many infectious diseases and are considered as one of the major risk factors with drinking water safety [14]. The pathogenic microorganisms enter in to water body through sewage discharge as a major source or through the wastewater from industries like slaughterhouses. Water-borne pathogens have been the causes of many disease outbreaks such as diarrhea, cholera, gastro-intestinal illness [15]. The recurrence of water-borne pathogens is due to a number of reasons like heavy water contamination, population explosion, change in potable water treatment methods, globalization of commerce and travel. It has been made possible to detect pathogen based water contamination to a large extent owing to the improved methods for detection and source tracking [16, 17]. The most serious health risk is related with ingestion of water which is contaminated with fecal matter and the discharge of wastewater into various ambient water bodies is what contributes to the multiplication of numbers of such pathogens (bacteria, viruses, protozoa and helminthes) [18].


2. Techniques for water treatment

Water treatment is defined as the removal of the above contaminants using some specific process. In most of the water treatment processes, conventional adsorption process with activated carbon is adopted and the adsorption capacity is substantially decreased in presence of high concentration of organic matters in water where the active sites are mostly occupied by these materials. In recent times, there are various technologies have been employed for the removal of water contaminants such as filtration (ceramic, bio sand, membrane, and activated carbon based filtration), heat and UV radiation, chemical treatment (coagulation-flocculation, chemical disinfection), and desalination (reverse osmosis, distillation). The various techniques in water treatment can categorized into following six classes [19]:

  • Adsorption

  • Biotechnology

  • Catalytic processes

  • Membrane processes

  • Ionizing radiation processes

  • Magnetically assisted processes.

There are specific advantages and disadvantages for a particular process. The nanotech based processes are promising option in current water treatment processes because of their target specificity, ease of separation, high adsorption per unit area, as well as less maintenance.


3. Magnetic materials for water treatment

There has been increased interest in using magnetic materials in water treatment which are basically composed of magnetic core of iron oxides organic compounds, carbon materials, etc. Recently, nanomaterials in different shapes, morphologies, forms, e.g., metal-containing nanoparticles, carbonaceous nanomaterials, zeolites, dendrimers, carbon nanotubes, nanofibers have been used for water purification [20]. However, the difficulty arises in using these materials is the separation of solid materials from liquid and which is more difficult as the particle size decreases in nanoscale. On the other hand, the using of magnetic, particularly the magnetic nanoparticles (MNPs) materials have the advantage of magnetic filtration in separation of solid from liquid and are more efficient [21].

However solid/liquid (S/L) separation is more difficult as the particle size decreases. On the other side, in case of magnetic sorbents based on Fe oxides, the magnetic filtration may be applied for S/L separation. Furthermore, the removal of particles from solution with the use of magnetic fields is more selective and efficient (and often much faster) than centrifugation or filtration (Yauvuz et al.) [21]. Here are the advantages of using MNPs adsorbent for water treatment processes:

  • Small size and thus high surface to volume ratio

  • Solid/liquid separation through magnetic filtration is selective, faster than centrifugation and filtration techniques

  • Reusability

  • Greater biocompatibility

  • Magnetic separation

3.1. Different types of magnetic materials for water treatment

Different types of magnetic materials have been synthesized and designed for development of advanced materials and applied effectively in widespread uses such as biomedicine, magnetic resonance imaging (MRI), catalysis, spintronics, robotics, engineering, environmental remediation, etc. [22] There are different synthesizing methods viz. co-precipitation, solvothermal, hydrothermal, microemulsion, sonochemical, etc. which determine their particle size, distribution, morphology, surface functionality, and magnetic properties and in turn of their various application [22]. Magnetic materials are made from mixtures of metals of iron, cobalt, nickel, and alloys and their oxides (of the type MFe2O4, where M is a metal). Out of these materials, iron (zero valent iron) and its oxides, i.e., usually γ-Fe2O3 (maghemite) and Fe3O4 (magnetite) nanoparticles have attained significant interest in recent years and have been used for water treatment processes. The various composite magnetic materials such as Fe3O4@C [23, 24], Fe@SiO2 [25], Fe3O4@TiO2 [26], Fe3O4@PPO (poly(propylene oxide)), PEO (poly(ethylene oxide) [27], Fe3O4@PDA (polydopamine) [28], Fe3O4@PNIPAM (poly(N-isopropylacrylamide)) [29], Fe3O4@MIPs (molecularly imprinted polymer-encapsulated particles) [30], Fe3O4@CNTs (multi-walled carbon nanotubes) [31], Fe@CS (carbon spheres) [32], Fe/iron oxide-oxyhydroxide/rGO (grapheme) [33], etc. have been used for environmental applications. Singh and his co-workers synthesized a series of magnetic nanocomposites such as CoFe2O4–ZnS [34], Fe3O4@GTPs (green tea polyphenols) [35], Fe3O4–Cr2O3 [36], CoFe2O4-Cr2O3-SiO2 [37] and applied for wastewater treatment.

In addition to their suitable magnetic properties, i.e., ferrimagnetic, ferromagnetic and superparamagnetic (nanoparticle size less than 10 nm), their synthesis procedure is simple and cost-effective and they can be easily functionalized as desired for many applications. The size and shape and magnetism of these magnetic materials can be easily controlled based on their application and thus they can be easily dispersed in liquid medium and their stability can be retained for multiple uses. Moreover, these materials are non-toxic or less toxic, chemically inert, thermally stable as well as biocompatible.

3.2. Use of magnetic materials for clean water technology

Appearance of water pollution as a global threat demands the development of low-cost and reliable materials for effective waste water remediation. The magnetic materials have been used for clean water technology for both in laboratory as well as field scale [38, 39]. In recent years, iron oxide nanomaterials have been used as adsorbent or immobilizing agent and photocatalyst or the both depending on nature of contaminants in water [40].

3.2.1. MNPs for the removal of metals

Heavy metal contamination in water such as cadmium, zinc, lead, chromium, nickel, copper, vanadium, platinum, silver and titanium due to industrial activities is significantly increasing which is detrimental to human beings and animals. Magnetic nanomaterial adsorbents have been potentially used for removal of metallic ions such as Cr(VI), Cu(II), Co(II),Cd(II), As(V), As(III) and Hg(II) in water [41, 42] which are more effective as compared to micron size particles. The magnetic chelating resin based materials have been used for effective removal of Cu(II), Co(II), and Ni(II) ions [43]. The magnetic hydrogels based on 2-acrylamine-2-methyl-1-propansulfonic acid can be used for removal of many heavy metal ions such Cd(II), Co(II), Fe(II), Pb(II), Ni(II), Cu(II) and Cr(III) from water in repeated cycles [44]. The Cu(II) can also be effectively removed by functionalized mesostructured silica containing magnetite [45]. The acrylate-based polymer composites with magnetite can be used in selective removal of heavy metals from water (selectivity: Cu > Cr > Zn > Ni) [46]. Layered double hydroxide (LDH) prepared from Fe3+ and Ni2+ shows good adsorption of As and subsequent magnetic separation [47]. The magnetic zeolite composites are used for decontamination of heavy metals from water [48]. The composite materials of mesoporous magnetic MCM-41 with aminopropyls are used for selective removal of As(V), and Cr(VI) in presence of Cu(II) [49].

3.2.2. MNPs for removal of organic contaminants

Magnetic nanoparticles are used as an adsorbent for the removal of various dyes and dyes stuff from aqueous solution. Removal of dyes from waste water has become a serious issue of concern because of its harmful impact on human. Dyes basically can be classified in to two categories, i.e., anionic dyes and cationic dyes.

3.2.3. MNPs for the removal of anionic dyes

Long et al. [50] synthesized Fe3O4@catechol/polyethylenimine (PEI) nanoparticles and tested for adsorption of three different kind of anionic dyes, i.e., methyl blue, orange G and amaranth and found the maximum adsorption capacities of 344.8, 192.3 and 146.2 mg/g, respectively. Saksornchai et al. [51] synthesized magnetite (Fe3O4) coated with cetyltrimethylammonium bromide (CTAB) and tested for the adsorption of anionic dye Congo red (CR) removal. They found maximum adsorption capacity for CR dye to be 93.46 mg/g. Faraji et al. [52] synthesized triazine-based nitrogen-rich network-modified magnetic nanoparticles were synthesized for the adsorption of methyl orange. Sahraei et al. [53] reported the synthesis of magnetic bio-sorbent hydrogel beads based on modified gum tragacanth/graphene oxide for the removal of heavy metals and dyes from water. They found the adsorption capacity of 101.7 mg/g for Congo red dye. Ge et al. [54] fabricated Fe@MgO magnetic nanocomposites for the removal of heavy metal ions and dye from water. They found that the synthesized nanocomposite showed excellent adsorption capacity of 6947.9 mg/g for methylene orange. Wu et al. [55] fabricated multi-functional magnetic nanoparticle core covered with polyethylenimine (PEI) derived quaternary ammonium compounds (QAC) corona through electrostatic attraction for the removal of dyes and metal ion adsorption. The adsorption results corresponding to synthesized nanoparticle showed the maximum adsorption capacity of 653 mg/g for AF as a representative of dyes. Konicki et al. [56] synthesized Fe@graphite core shell nanocomposite for the removal of anionic dyes from aqueous solution. The synthesized nanoparticles were tested for the adsorption of two anionic dyes namely acid red 88 (AR88) and direct orange 26 (DO26) and the maximum adsorption capacity was found to be 63.7 mg/g and 42.7 for AR88 and DO26, respectively. Zhang et al. [57] synthesized the Fe3O4 nanoparticle modified with 3-glycidoxypropyltrimethoxysilane (GPTMS) and poly-lysine (P-Lys). They found that the synthesized MNPs could effectively remove anionic dyes including methyl blue (MB), orange I (OR-I), amaranth (AM) and acid red 18 (AR-18) from water solution.

3.2.4. MNPs for the removal of cationic dyes

Cationic dyes are most toxic because they can easily interact with negatively charged cell membrane surfaces, and also they can enter in to the cells and can concentrate in cytoplasm (Bayramoglu et al.) [58]. Ge et al. [59] have studied the adsorption of cationic dyes such as crystal violet, methylene blue and alkali blue 6B from aqueous solutions by use of polymer-modified magnetic nanoparticles. The cationic dyes could be quickly removed from water solution with high efficiency at pH 5–12. More significantly, the MNP showed high efficiency as a reusable adsorbent for fast and convenient removal of cationic dyes from water solution. Yan et al. [60] have synthesized full biodegradable magnetic adsorbent based on glutamic acid modified chitosan and silica coated Fe3O4 nanoparticles for removal of three different kinds of cationic dyes, methylene blue, crystal violet and cationic light yellow 7GL, from aqueous solutions. Chen et al. [61] have prepared magnetic adsorbent by fabrication of chitosan/polyacrylic acid multilayer onto magnetic Fe3O4 microspheres for removal of adsorption of two cationic dyes, methylene blue and crystal violet from aqueous solution. Amiri et al. [62] synthesized cobalt ferrite silica magnetic nanocomposite for the adsorption of Malachite green dye and found the adsorption capacity of 75.5 mg/g for that dye. Li et al. [63] synthesized wettable magnetic hypercrosslinked microporous nanoparticle for the water treatment. The synthesized nanoparticle consists of microporous organic polymer which combine sodium acrylate functionalized hypercrosslinked polymer with magnetic Fe3O4 nanoparticle to form a hybrid. They tested the synthesized hybrid for the adsorption of Rhodamine B dye and found the maximum adsorption capacity of 216 mg/g. Singh et al. [64] had synthesized the superparamagnetic nanoparticles coated with green tea polyphenol by wet chemical method. They found that the particles have a very high adsorption capacity of (7.25 mg/g) for removal of methylene blue (MB) dye in wastewater treatment. Li et al. [65] synthesized magnetic peach gum bead bio-sorbent for the adsorption of MB dye and found the maximum adsorption capacity of 231.5 mg/g.

3.2.5. MNPs for the removal of pharmaceutical products

The presence of pharmaceuticals such as antibiotics, anticonvulsants, antipyretics drugs, hormones in surface and ground water possesses a major environmental challenge. Their contamination even at trace amount is a serious concern to the aquatic organisms as well.

Attia et al. [66] synthesized magnetic nanoparticles coated zeolite for the adsorption of pharmaceutical compounds from aqueous solution. They found that the synthesized magnetic nanoparticles can remove more that 95% of PPCPs in 10 min. Reddy et al. [67] reviewed spinal ferrite nanoparticles and found that SF and its derivatives can be used for remediation of various pollutants. Nadim et al. [68] Synthesized gallic acid coated magnetic nanoparticles (GA-MNP) and used as a photocatalyst for degradation of meloxicam; a commonly prescribed nonsteroidal anti-inflammatory drug.

Recently, M. Hayasi and his coworker described the use of magnetic poly (styrene-2-acrylamido-2-methyl propanesulfonic acid) (St-AMPS) as adsorbent for removal of the pharmaceuticals viz. ceftriaxone sodium, diclofenac sodium, and atenolol from water [69].

Liu [70] discussed the use of various magnetic nanoparticles (MNPs) in pharmaceutical removal from waste water their recent review which are outlined below (Table 2).

Magnetic materials usedPharmaceuticals present in waterProcesses involved for decontaminationReferences
Nano zero-valent iron (nZVI)CarbamazepineAdsorption, chemical degradation (Fenton oxidation)[71]
Nano zero-valent iron (nZVI) and PEG and zeolite supported nZVIAmoxicillin, ampicillinAdsorption[72]
Zero valent iron (ZVI)CarbamazepineChemical degradation[73]
DiazepamChemical degradation[74]
Maghemite (Fe2O3) core confined in a silica porous layerAtenolol, gemfibrozil, and sulfamethoxazoleAdsorption[75]
MFe2O4 (M = Fe, Mn, Co, Zn)Tetracycline, oxytetracycline, and chlortetracyclineAdsorbent[76]
MnFe2O4/(activated carbon)ACSulfamethoxazoleAdsorption[77]
Fe3O4 MNPs in ultrasound (US)/H2O2 systemSono-degradation[79]
Fe3O4@α-MnO2 microspheresCiprofloxacinCatalytic degradation[80]
Fe-ZnODiclofenacPhotocatalytic degradation[81]

Table 2.

Magnetic nanomaterials used for removal of pharmaceuticals.

3.2.6. MNPs for removal of pathogens

Xu et al. [82] demonstrated that poly-allylamine-hydrochloride (PAAH) stabilized magnetic nanoparticles are powerful tools to remove pathogenic bacteria from drinking water with high efficiency and no significant toxicity was observed in the MNPs treated water. Over 99.5% of the pathogens (four main pathogens viz. Escherichia, Acinetobacter, Pseudomonasand Bacillus) can be removed when the bacterial count was less than 105 CFU/mL.

Zhang et al. [83] synthesized magnetic nanoparticle coated with Cu doped MgO through a hydrophilic carbon layer (Fe3O4@C@MgO-Cu). They found its potential application as disinfectant in water purification by examining the antibacterial activity of the Fe3O4@C@MgO-Cu composite toward Gram-negative Escherichia coliand Gram-positive Staphylococcus aureus.

Zhang et al. [84] synthesized magnetic poly-N,N′-[(4,5-dihydroxy-1,2-phenylene)bis(methylene)]bisacrylamide) (POHABA)-based core-shell nanostructure on the Fe3O4 core surface (Fe3O4@POHABA). The magnetic nanocomposite, Fe3O4@POHABA can be used in domestic water treatment against bacterial pathogens.

Rana et al. [85] synthesized ferromagnetic Ni-doped ZnO nanoparticles and applied as an antibacterial agent to control the growth of bacterial pathogens. They found the as synthesized material to be very effective against water related bacteria such as E. coliand V. cholera.

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. histolyticacan be efficiently captured using the magnetic nanoparticles from contaminated water.

Zhang et al. [87] synthesized Fe3O4 nanoparticles surrounded with polyethylenimine-derived corona and found to be efficient in capturing the pathogens and heavy metals.

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, E. coliO157:H7, P. aeuginosa, Salmonella, and B. subtilis.

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. coliCN13 (6-log reduction) and the bacteriophage MS2 (2–3 log reduction).


4. Magnetic water treatment

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 and animal cells.


5. Sustainability of magnetic nanoparticles

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.


6. Conclusions

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.


  1. 1. Okun DA, Wang LK, Shammas NK. Water supply and distribution and wastewater collection. United States of America: John Wiley and Sons; 2010
  2. 2. WHO, UNICEF. Millennium Development Goals: Progress on Sanitation and Drinking-Water: 2010 Update Report, Geneva: WHO/UNICEF Joint Monitoring Programme for Water Supply; 2010. ISBN: 978 92 4 156395 6
  3. 3. Corcoran E, editor. Sick Water? The Central Role of Wastewater Management in Sustain-able Development: A Rapid Response Assessment. UNEP (United Nations Environment Programme). UN-HABITAT, Nairobi: Kenia publishing; 2010
  4. 4. United Nations. Statement by Secretary General Koffi Annan. June 2003. Available from:
  5. 5. Maral D, Lane J, Scott B, Trouba D. Sanitation and health. PLoS Medicine. 2010;7(11):e1000363
  6. 6. UNEP/UN-Habitat. Sick Water? The Central Role of Wastewater Management in Sustainable Development. Available from:
  7. 7. Ashbolt NJ. Microbial contamination of drinking water and disease outcomes in developing regions. Toxicology. 2004;198(1):229-238
  8. 8. Tebbutt THY. Principles of Water Quality Control. Great Britain: Butterworth-Heinemann; 1997
  9. 9. Gleick PH. Dirty-Water: Estimated Deaths from Water-Related Diseases 2000–2020. Oakland: Pacific Institute for Studies in Development, Environment, and Security; 2002
  10. 10. Mohammed L, Gomaa HG, Ragab D, Zhu J. Magnetic nanoparticles for environmental and biomedical applications: A review. Particuology. 2017;30:1-14
  11. 11. Tsuchiya Y. Organical chemicals as contaminants of water bodies and drinking water. Water Quality and Standards – Volume II. 2010;7:150
  12. 12. World Health Organization. Guidelines for Drinking-water Quality [electronic resource]: incorporating 1st and 2nd addenda, Vol. 1, Recommendations 3rd ed. Geneva; 2008. ISBN: 978 92 4 154761 1 (WEB version)
  13. 13. Kubota S, Tsuchiya Y, editors, Water Quality and Standard. Vol. II. Encyclopedia of Life Support Systems (EOLSS) Publishing; 2009. p. 151. ISBN: 978-1-84826-031-3 (eBook)
  14. 14. Park S, Park HH, Ko YS, Lee SJ, Woo K, Ko G. Disinfection of various bacterial pathogens using novel silver nanoparticle-decorated magnetic hybrid colloids. Science of the Total Environment. 2017;609:289-296
  15. 15. Craun GF, Fraun MF, Calderon RL, Beach MJ. Waterborne outbreaks reported in the United States. Journal of Water and Health. 2006;4:19-30
  16. 16. Ingerson-Mahar M, Reid A. Microbes in Pipes: The Microbiology of the Water Distribution System A Report on an American Academy of Microbiology Colloquium. Boulder, CO, USA: ASM Academy; 2012. p. 26
  17. 17. Pandey PK, Kass PH, Soupir ML, Biswas S, Singh VP. Contamination of water resources by pathogenic bacteria. AMB Express. 2014;4:51
  18. 18. Bitton G. Microbiology of Drinking Water Production and Distribution. 1st ed. Hoboken, NJ, USA: John Wiley & Sons, Inc.; 2014. p. 312
  19. 19. Ambashta RD, Sillanpaa M. Water purification using magnetic assistance: A review. Journal of Hazardous Materials. 2010;180:38-49
  20. 20. Tiwari DK, Behari J, Sen P. Application of nanoparticles in waste water treatment. World Applied Sciences Journal. 2008;3(3):417-433
  21. 21. Yauvuz CT, Mayo JT, Yu WW, Prakash A, Falkner JC, Yean S, Cong L, Shipley HJ, Kan A, Tomson M, Natelson D, Colvin VL. Low-field magnetic separation of monodisperse Fe3O4 nanocrystals. Science. 2006;314(5801):964-967
  22. 22. Li X, Xu G, Liu Y, He T. Magnetic Fe3O4 nanoparticles: Synthesis and application in water treatment. Nanoscience & Nanotechnology-Asia. 2011;1:14-24
  23. 23. Bao X, Qiang Z, Chang JH, Ben W, Qu J. Synthesis of carbon-coated magnetic nanocomposite (Fe3O4@C) and its application for sulfonamide antibiotics removal from water. Journal of Environmental Sciences. 2014;26:962-969
  24. 24. Zhou L, Zhang G, Tian J, Wang D, Cai D, Wu Z. Functionalized Fe3O4@C nanospheres with adjustable structure for efficient hexavalent chromium removal. ACS Sustainable Chemistry & Engineering. 2017;5(11):11042-11050
  25. 25. Li Y, Jin Z, Li T, Xiu Z. One-step synthesis and characterization of core–shell Fe@SiO2 nanocomposite for Cr(VI) reduction. Science of the Total Environment. 421-422, 260-266
  26. 26. Xin T, Ma M, Zhang H, Gu J, Wang S, Liu M, Zhang Q. A facile approach for the synthesis of magnetic separable Fe3O4@TiO2, core shell nanocomposites as highly recyclable photocatalysts. Applied Surface Science. 2014;288:51-59
  27. 27. Moeser GD, Roach KA, Green WH, Laibinis PE, Hatton TA. Water-based magnetic fluids as extractants for synthetic organic compounds. Industrial & Engineering Chemistry Research. 2002;41:4739-4749
  28. 28. Wang Y, Wang S, Niu H, Ma Y, Zeng T, Cai Y, Meng Z. Preparation of polydopamine coated Fe3O4 nanoparticles and their application for enrichment of polycyclic aromatic hydrocarbons from environmental water samples. Journal of Chromatography. A. 2013
  29. 29. Dionigi C, Pineiro Y, Riminucci A, Banobre M, Rivas J, Dediu V. Regulating the thermal response of PNIPAM hydrogels by controlling the adsorption of magnetite nanoparticles. Applied Physics A. 2014;114:585-590
  30. 30. Xia X, Lai EPC, Ormeci B. Ultrasonication-assisted synthesis of molecularly imprinted polymer-encapsulated magnetic nanoparticles for rapid and selective removal of 17b-estradiol from aqueous environment. Polymer Engineering and Science. 2012;52:1775-1783
  31. 31. Luo YB, Yu QW, Yuan BF, Feng YQ. Fast microextraction of phthalate acid esters from beverage, environmental water and perfume samples by magnetic multi-walled carbon nanotubes. Talanta. 2012;90:123-131
  32. 32. Sun H, Zhou G, Liu S, Ang HM, Tad_e MO, Wang S. Nano-Fe0 encapsulated in microcarbon spheres: Synthesis, characterization, and environmental applications. ACS Applied Materials & Interfaces. 2012;4:6235-6241
  33. 33. Karamani AA, Douvalis AP, Stalikas CD. Zero-valent iron/iron oxide-oxyhydroxide/graphene as a magnetic sorbent for the enrichment of polychlorinated biphenyls, polyaromatic hydrocarbons and phthalates prior to gas chromatography mass spectrometry. Journal of Chromatography A. 2013;1271:1-9
  34. 34. Senapati KK, Borgohain C, Phukan P. CoFe2O4–ZnS nanocomposite: A magnetically recyclable photocatalyst. Catalysis Science & Technology. 2012;2:2361-2366
  35. 35. Singh KK, Senapati KK, Sarma KC. Synthesis of superparamagnetic Fe3O4 nanoparticles coated with green tea polyphenols and their use for removal of dye pollutant from aqueous solution. Journal of Environmental Chemical Engineering. 2017;5:2214-2221
  36. 36. Singh KK, Senapati KK, Sarma KC. Newly developed Fe3O4–Cr2O3 magnetic nanocomposite for photocatalytic decomposition of 4-chlorophenol in water. Journal of Environmental Sciences. 2017;52:333-340
  37. 37. Senapati KK, Borgohain C, Phukan P. Photocatalytic degradation of methylene blue in water using CoFe2O4–Cr2O3–SiO2 fluorescent magnetic nanocomposite. Journal of Molecular Catalysis A: Chemical. 2011;346:111-116
  38. 38. White BR, Stackhouse BT, Holcombe JA. Magnetic γ-Fe2O3 nanoparticles coated with poly-l-cysteine for chelation of As(III), Cu(II), Cd(II), Ni(II), Pb(II) and Zn(II). Journal of Hazardous Materials. 2009;161(2–3):848-853
  39. 39. Girginova PI, Daniel-da-Silva AL, Lopes CB, Figueira P, Otero M, Amaral VS, et al. Silica coated magnetite particles for magnetic removal of Hg2+ from water. Journal of Colloid and Interface Science. 2010;345(2):234-240
  40. 40. Xu P, Zeng GM, Huang DL, Feng CL, Hu S, Zhao MH, Lai C, Wei Z, Huang C, Xie GX, Liu ZF. Use of iron oxide nanomaterials in wastewater treatment: A review. Science of the Total Environment. 2012;424:1-10
  41. 41. Tuutijarvi T, Lu J, Sillanpaa M, Chen G. As(V) adsorption on maghemite nanoparticles. Journal of Hazardous Materials. 2009;166(2–3):1415-1420
  42. 42. Sharma YC, Srivastava V, Singh VK, Kaul SN, Weng CH. Nano adsorbents for the removal of metallic pollutants from water and wastewater. Environmental Technology. 2009;30(6):583-609
  43. 43. Monier M, Ayad DM, Wei Y, Sarhan AA. Preparation and characterization of magnetic chelating resin based on chitosan for adsorption of Cu(II), Co(II), and Ni(II) ions. Reactive and Functional Polymers. 2010;70(4):257-266
  44. 44. Ozay O, Ekici S, Baran Y, Aktas N, Sahiner N. Removal of toxic metal ions with magnetic hydrogels. Water Research. 2009;43(17):4403-4411
  45. 45. Kim Y, Lee B, Yi J. Preparation of functionalized mesostructured silica containing magnetite (MSM) for the removal of copper ions in aqueous solutions and its magnetic separation. Separation Science and Technology. 2003;38(11):2533-2548
  46. 46. Phanapavudhikul P, Waters JA, de Ortiz ESP. Design and performance of magnetic composite particles for the separation of heavy metals from water. Journal of Environmental Science and Health, Part A. 2003;38(10):2277-2285
  47. 47. Nakahira A, Kubo T, Murase H. Synthesis of LDH-type clay substituted with Fe and Ni ion for arsenic removal and its application to magnetic separation. IEEE Transactions on Magnetics. 2007;43(6):2442-2444
  48. 48. Oliveira LCA, Petkowicz DI, Smaniotto A, Pergher SBC. Magnetic zeolites: A new adsorbent for removal of metallic contaminants from water. Water Research. 2004;38:3699-3704
  49. 49. Chen XQ, Lam KF, Zhang QJ, Pan BC, Arruebo M, Yeung KL. Synthesis of highly selective magnetic mesoporous adsorbent. Journal of Physical Chemistry C. 2009;113(22):9804-9813
  50. 50. Long Y, Xiao L, Cao Q. Co-polymerization of catechol and polyethylenimine on magnetic nanoparticles for efficient selective removal of anionic dyes from water. Powder Technology. 2017;310:24-34
  51. 51. Saksornchai E, Kavinchan J, Thongtem S, Thongtem T. Simple wet-chemical synthesis of superparamagnetic CTAB-modified magnetite nanoparticles using as adsorbents for anionic dye Congo red removal. Materials Letters. 2018;213:138-142
  52. 52. Faraji M, Shabanian M, Aryanasab F. Efficient removal of anionic dyes from aqueous media using newly in situ synthesized triazine-based nitrogen-rich network-modified magnetic nanoparticles. Journal of the Iranian Chemical Society. 2018;15:733-741
  53. 53. Sahraei R, Pour ZS, Ghaemy M. Novel magnetic bio-sorbent hydrogel beads based on modified gum tragacanth/graphene oxide: Removal of heavy metals and dyes from water. Journal of Cleaner Production. 2017;142:2973-2984
  54. 54. Ge L, Wang W, Peng Z, Tan F, Wang X, Chen J, Qiao X. Facile fabrication of Fe@MgO magnetic nanocomposites for efficient removal of heavy metal ion and dye from water. In: Powder Technology. 2017
  55. 55. Wu Y, Chen L, Long X, Zhang X, Pan B, Qian J. Multi-functional magnetic water purifier for disinfection and removal of dyes and metal ions with superior reusability. Journal of hazardous materials. 2018;347:160-167
  56. 56. Konicki W, Hełminiak A, Arabczyk W, Mijowska E. Removal of anionic dyes using magnetic Fe@graphite core-shell nanocomposite as an adsorbent from aqueous solutions. Journal of Colloid and Interface Science. 2017;497:155-164
  57. 57. Zhang YR, Su P, Huang J, Wang QR, Zhao BX. A magnetic nanomaterial modified with poly-lysine for efficient removal of anionic dyes from water. Chemical Engineering Journal. 2015;262:313-318
  58. 58. Bayramoglu G, Altintas B, Arica MY. Adsorption kinetics and thermodynamic parameters of cationic dyes from aqueous solutions by using a new strong cation-exchange resin. Chemical Engineering Journal. 2009;152(2):339-346
  59. 59. Ge F, Ye H, Li MM, Zhao BX. Efficient removal of cationic dyes from aqueous solution by polymer-modified magnetic nanoparticles. Chemical Engineering Journal. 2012;198:11-17
  60. 60. Yan H, Li H, Yang H, Li A, Cheng R. Removal of various cationic dyes from aqueous solutions using a kind of fully biodegradable magnetic composite microsphere. Chemical Engineering Journal. 2013;223:402-411
  61. 61. Chen Y, He F, Ren Y, Peng H, Huang K. Fabrication of chitosan/PAA multilayer onto magnetic microspheres by LbL method for removal of dyes. Chemical Engineering Journal. 2014;249:79-92
  62. 62. Amiri M, Salavati-Niasari M, Akbari A, Gholami T. Removal of malachite green (a toxic dye) from water by cobalt ferrite silica magnetic nanocomposite: Herbal and green sol-gel autocombustion synthesis. International Journal of Hydrogen Energy. 2017;42(39):24846-24860
  63. 63. Li Q, Zhan Z, Jin S, Tan B. Wettable magnetic hypercrosslinked microporous nanoparticle as an efficient adsorbent for water treatment. Chemical Engineering Journal. 2017;326:109-116
  64. 64. Singh KK, Senapati KK, Sarma, KC. Synthesis of superparamagnetic Fe3O4 nanoparticles coated with green tea polyphenols and their use for removal of dye pollutant from aqueous solution. Journal of environmental chemical engineering. 2017;5(3):2214-2221
  65. 65. Li C, Wang X, Meng D, Zhou L. Facile synthesis of low-cost magnetic biosorbent from peach gum polysaccharide for selective and efficient removal of cationic dyes. International journal of biological macromolecules. 2018;107:1871-1878
  66. 66. Attia TMS, Hu XL, Yin DQ. Synthesized magnetic nanoparticles coated zeolite for the adsorption of pharmaceutical compounds from aqueous solution using batch and column studies. Chemosphere. 2013;93(9):2076-2085
  67. 67. Reddy DHK, Yun YS. Spinel ferrite magnetic adsorbents: Alternative future materials for water purification? Coordination Chemistry Reviews. 2016;315:90-111
  68. 68. Nadim AH, Al-Ghobashy MA, Nebsen M, Shehata MA. Gallic acid magnetic nanoparticles for photocatalytic degradation of meloxicam: synthesis, characterization and application to pharmaceutical wastewater treatment. RSC Advances. 2015;5(127):104981-104990
  69. 69. Hayasi M, Saadatjo N. Preparation of magnetic nanoparticles functionalized with poly (styrene-2-acrylamido-2-methyl propanesulfonic acid) as novel adsorbents for removal of pharmaceuticals from aqueous solutions. Advances in Polymer Technology. 2017:1-13
  70. 70. Liu WT. Nanoparticles and their biological and environmental applications. Journal of Bioscience and Bioengineering. 2006;102(1):1-7
  71. 71. Shirazi E, Torabian A, Nabi-Bidhendi G. Carbamazepine removal from groundwater: Effectiveness of the TiO2/UV, nanoparticulate zero-valent iron, and Fenton (nZVI/H2O2) processes. CLEAN – Soil, Air, Water. 2013;41:1062-1072
  72. 72. Ghauch A, Tuqan A, Assi HA. Antibiotic removal from water: Elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles. Environmental Pollution. 2009;157:1626-1635
  73. 73. Segura Y, Martinez F, Melero JA. Effective pharmaceutical wastewater degradation by Fenton oxidation with zero-valent iron. Applied Catalysis B: Environmental. 2013;136:64-69
  74. 74. Bautitz IR, Velosa AC, Nogueira RF. Zero valent iron mediated degradation of the pharmaceutical diazepam. Chemosphere. 2012;88:688-692
  75. 75. Huang YX, Keller AA. Magnetic nanoparticle adsorbents for emerging organic contaminants. ACS Sustainable Chemistry & Engineering. 2013;1:731-736
  76. 76. Bao X, Qiang Z, Ling W, Chang JH. Sonohydrothermal synthesis of MFe2O4 magnetic nanoparticles for adsorptive removal of tetracyclines from water. Separation and Purification Technology. 2013;117:104-110
  77. 77. Wan J, Deng HP, Shi J, Zhou L, Su T. Synthesized magnetic manganese ferrite nanoparticles on activated carbon for sulfamethoxazole removal. CLEAN – Soil, Air, Water. 2014;42:1199-1207
  78. 78. Lu L, Li J, Yu J, Song P, Ng DHL. A hierarchically porous MgFe2O4/γ-Fe2O3 magnetic microspheres for efficient removals of dye and pharmaceutical from water. Chemical Engineering Journal. 2016;283:524-534
  79. 79. Wei H, Hu D, Su J, Li KB. Intensification of levofloxacin sono-degradation in a US/H2O2 system with Fe3O4 magnetic nanoparticles. Chinese Journal of Chemical Engineering. 2015;23:296-302
  80. 80. Zhao H, Cui H-J, Fu M-L. Synthesis of core-shell structured Fe3O4@α-MnO2 microspheres for efficient catalytic degradation of ciprofloxacin. RSC Advances. 2014;4:39472
  81. 81. Madhavan J, Kumar PS, Anandan S, Zhou M, Grieser F, Ashokkumar M. Ultrasound assisted photocatalytic degradation of diclofenac in an aqueous environment. Chemosphere. 2010;80:747-752
  82. 82. Xu Y, Li C, Zhu X, HuangWE, Zhang D. Application of magnetic nanoparticles in drinking water purification. Environmental Engineering and Management Journal (EEMJ). 2014;13(8): 2023-2029
  83. 83. Zhang X, Wang W, Zhang Y, Zeng T, Jia C, Chang L. Loading Cu-doped magnesium oxide onto surface of magnetic nanoparticles to prepare magnetic disinfectant with enhanced antibacterial activity. Colloids and Surfaces B: Biointerfaces. 2018;161:433-441
  84. 84. Zhang Z, Xing D, Zhao X, Han X. Controllable synthesis Fe3O4@POHABA core-shell nanostructure as high-performance recyclable bifunctional magnetic antimicrobial agent. Environmental Science and Pollution Research. 2017;24(23):19011-19020
  85. 85. Rana SB, Singh RP. Investigation of structural, optical, magnetic properties and antibacterial activity of Ni-doped zinc oxide nanoparticles. Journal of Materials Science: Materials in Electronics. 2016;27(9):9346-9355
  86. 86. Shukla S, Arora V, Jadaun A, Kumar J, Singh N, Jain VK. Magnetic removal of Entamoeba cysts from water using chitosan oligosaccharide-coated iron oxide nanoparticles. International Journal of Nanomedicine. 2015;10:4901
  87. 87. Zhang X, Qian J, Pan B. Fabrication of novel magnetic nanoparticles of multifunctionality for water decontamination. Environmental Science & Technology. 2016;50(2):881-889
  88. 88. Zhan S, Yang Y, Shen Z, Shan J, Li Y, Yang S, Zhu D. Efficient removal of pathogenic bacteria and viruses by multifunctional amine-modified magnetic nanoparticles. Journal of Hazardous Materials. 2014;274:115-123
  89. 89. Park HH, Park S, Ko G, Woo K. Magnetic hybrid colloids decorated with Ag nanoparticles bite away bacteria and chemisorb viruses. Journal of Materials Chemistry B. 2013;1(21):2701-2709
  90. 90. Ali Y, Samaneh R, Zohre R, Mostafa J. Magnetic water treatment in environmental management a review of the recent advances and future perspectives. Current World Environment. 2014;9(3):1008-1016

Written By

Manoj Sharma, Pankaj Kalita, Kula Kamal Senapati and Ankit Garg

Submitted: November 14th, 2017 Reviewed: February 20th, 2018 Published: July 4th, 2018