Arsenic Removal from Water by Green Synthesized Magnetic Nanoparticles

Abstract

Magnetite nanoparticles were synthesized by a simple and ecofriendly method using onion peel (MNp-OP) and corn silk extract (MNp-CS), in order to develop new low-cost adsorbents for arsenic removal from groundwater. As a point of comparison, magnetite nanoparticles were also synthesized with a conventional chemical process (MNp-CO). The antioxidant potential of onion peel and corn silk extracts was determined using ferric reducing antioxidant power (FRAP) and free radical (DPPH) scavenging assays, including the total phenolics, flavonoids and tannins contents. The synthesized magnetite nanoparticles were characterised using different techniques (Scanning electron microscope/Energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) surface area analyzer). The adsorption capacity of MNp-OP and MNp-CS and the arsenic removal mechanism of these novel adsorbents was investigated through kinetic and equilibrium experiments and their corresponding mathematical models. Characterisation of MNp-OP and MNp-CS shows high BET specific surface areas of 243 m2/g and 261 m2/g, respectively. XRD and FTIR analysis confirmed the formation and presence of magnetite nanoparticles. The arsenic adsorption mechanism on MNp-OP, MNp-CS and MNp-CO involves chemisorption, intraparticle and external diffusion. Maximal adsorption capacities of MNp-OP, MNp-CS and MNp-CO were 1.86, 2.79, and 1.30 mg/g respectively. The green synthesis applied using onion peel and corn silk extracts was cost effective and environmentally friendly, and results in adsorbents with a high capacity for arsenic and magnetic properties, making them a very promising alternative approach in the treatment of arsenic contaminated groundwater.

Differentiating Nanomaghemite and Nanomagnetite and Discussing Their Importance in Arsenic and Lead Removal from Contaminated Effluents: A Critical Review

“…Indeed, many magnetic Fe-oxide NP composites have been tested as As adsorbents in recent years [ 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 ]. Their adsorbent properties and experimental conditions are exposed and a comparison of their removal efficiency and an analysis of the experimental condition effects (pH, temperature, adsorbent dose, initial concentration, particle size and shape, surface area, and saturation magnetization, equilibrium time, kinetic and isothermal adsorption parameters) [ 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ,…”

“…For these reasons, it can be indirectly inferred that the monolayer adsorption mechanism is used more often than the multilayer adsorption. However, it must be noticed that Nisticò et al [ 73 ] and Yu et al [ 47 ] obtained better Langmuir model R 2 values for As(III) adsorption, whereas a better fitting with the Freundlich model for As(V) adsorption was reported by Nikić et al [ 74 ] and Zeng et al [ 76 ]. The above results suggest that multilayer adsorption is dominant in the case of As(V) ions as compared to As(III).…”

“…Moreover, they also observed that the adsorption capacity increased due to the high driving force to transfer the mass of elevated concentrations of As(V) in the solution, as observed in the adsorption isotherms. Briefly, considering the As adsorption process, the adsorbents that exhibited the best performances and their maximum adsorption capacities in mg g −1 according to the Langmuir adsorption model, presented for both As species, and compared to other systems [ 58 , 59 , 60 , 61 , 62 , 63 , 65 , 66 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 ], were FeO X -GO-80 with 147 mg g −1 (arsenite) and 113 mg g −1 (arsenate) [ 64 ], γ-Fe 2 O 3 @CTF-1 with 198 mg g −1 (arsenite) and 102.3 mg g −1 (arsenate) [ …”

Recent Advances in Magnetic Nanoparticles and Nanocomposites for the Remediation of Water Resources

“…In a report by Agbaba et al [162] extracts from onion peels and corn-silk husks were used for the synthesis of magnetite nanoparticles (size range, 26-28 nm) through a green synthesis. They were then tested for the adsorption of arsenic species in water.…”

Removal of Phenolic Compounds from Olive Mill Wastewater by a Polydimethylsiloxane/oxMWCNTs Porous Nanocomposite

“…For all these reasons, there is an urgent need to develop alternative methods for the removal and recovery of PCs from OMW. In this view, adsorption techniques can be an attractive alternative [20][21][22][23][24][25]. Different adsorbents have been developed, such as granular activated carbon [20], zeolites [26], agricultural wastes [3], and amberlite [27].…”