Superoleophilic Magnetic Iron Oxide Nanoparticles for Effective Hydrocarbon Removal from Water

Abstract

Various hydrocarbons are efficiently extracted from water by using a new sorbent material based on covalently functionalized magnetic nanoparticles. The functionalization of the magnetite nanoparticles with a self‐assembled monolayer of hexadecylphosphonic acid renders the nanoparticles oleophilic and the magnetic nature of magnetite allows for simple extraction of the hydrocarbon‐soaked sorbent. The sorbent material is capable of extracting single contaminants such as alkanes and aromatics and complex hydrocarbon mixtures such as crude oils in high extraction rates of up to 14 times the sorbent volume. Experimental results are explained by molecular dynamics simulations on the adsorption of single components from a hydrocarbon‐water mixture to the alkylphosphonic acid layer on the nanoparticles. The core–shell sorbent material is highly stable and therefore, reusable over several successive extraction cycles without degradation. The extraction performance is determined at different water temperatures, different water sources, and different magnetic core materials and evaluated compared to heptadecanoic acid functionalized magnetite. The new sorbent material provides the opportunity for an efficient, reliable, inexpensive, and environmental friendly removal of hydrocarbons from water.

Shell‐by‐Shell Functionalization of Inorganic Nanoparticles

“…These measurements showed a varying affinity to different nonpolar molecules that ranged from 104 to 411 % of the weight of the NPs. According to the findings of Halik, [14b] we attributed this to the different densities and stacking properties of the molecules. In comparison with other methods for the NP‐based extraction of nonpolar molecules, this approach combines the outstanding aqueous dispersibility of the SbS‐coated NPs and a high loading capacity through a micelle‐like arrangement in between the two ligand shells with the intrinsic magnetic properties of Fe 3 O 4 NPs.…”

“…Through utilization of the intrinsic magnetic properties of first‐shell functionalized Fe 3 O 4 NPs, Halik demonstrated the adsorption of hydrocarbons in water, followed by magnetic collection of the NPs (Figure 19). [14b] …”

“…Upon magnetic removal of the previously formed NP–oil phase from water, the binding of the oil phase is no longer supported by hydrophobic interactions and solely depending on London forces. The molecular dynamics (MD) simulations revealed the strongest interactions in case of aromatic molecules and thus a compensation of the lower segregation energies by stronger binding to the NPs first ligand‐shell upon magnetic extraction from the water phase [14b] . The extraction rates (ER) data for Fe 3 O 4 ‐(PAC 16 ) with an average volumetric ER vol of 10.6 times the sorbent volume and a gravimetric ER mass of 2.5, show the competitiveness with other sorbent materials like foams and polymerically coated NPs.…”

Synthesis of Long‐Chain n‐Alkylphosphonic Acids by Phosphonylation of Alkyl Bromides with Red Phosphorus and Superbase under Micellar/Phase Transfer Catalysis

“…In recent years, there has been published an impressive series of works devoted to the successful use of long‐chain n ‐alkylphosphonic acids in the nanoindustry for the design of diverse nanomaterials such as NPs, [25] nanocrystals, [26] nanotubes, [15c,27] nanolayers, nanofibers, nanorods, [28] tetrapods, [28a] nanoplatelets, [29] nanoflakes, [19b] which find application in optoelectronics, [29b,30] high‐tech technologies, [26b,27,31] catalysis, [25a] water treatment processes [25b] …”

A nanocomposite paper comprising calcium silicate hydrate nanosheets and cellulose nanofibers for high-performance water purification

“…2 Therefore, it is of great importance to develop technologies to remove these contaminants from wastewater. In recent years, various advanced techniques have been adopted for water remediation, including adsorption, 3,4 coagulation, 5,6 oxidation, 7,8 photocatalysis, 9,10 membrane separation, 11,12 and so on. Among them, the membrane separation technologies have attracted much interest owing to their easy manipulation, low energy consumption, time costs, and high separation efficiency.…”