EDTA functionalized magnetic nanoparticle sorbents for cadmium and lead contaminated water treatment

Isothermal titration microcalorimetry to determine the thermodynamics of metal ion removal by magnetic nanoparticle sorbents

“…61 Interestingly these results do not follow the sequence in conventional formation constants for metal-EDTA complexes 62 (log K, 298 K) strictly, which are 23.40 for Cr 3+ and 18.04 for Pb 2+ , and the order of magnitude of the affinity constants we obtained in the current study are much lower. As indicated in our previous study, 10 EDTA was covalently attached to the APTES coated maghemite nanoparticles by the formation of amide bonds between the carboxylic acid groups of the complexing agent and amino groups provided by the APTES coating. This covalent attachment requires that at isotherms fit at pH 7, symbols represent experimental data, error bars represent standard deviation from the mean (n = 3), and red line represents model prediction.…”

“…range of pH and water hardness) as well as shown good regenerability and reusability. Though magnetic nanoparticle sorbents have successfully been applied to remove heavy metal ions, 10,[18][19][20][21][22] hydrophobic compounds, [23][24][25] pesticides, 26,27 natural organic matter, 22,28,29 oxyanions 30,31 and emerging organic contaminants, 25,32,33 those studies focused on the synthesis and characterization of physicochemical properties of these engineered nanomaterials, as well as their environmental application. However, the key quantitative thermodynamic data (e.g.…”

“…10 The metals can also enter the food supply chain via pesticides or fertilizers where they are found as impurities, with gradual accumulation in living organisms over their life span causing progressive toxic effects.…”

Heteroaggregation of nanoparticles with biocolloids and geocolloids

“…Typical applications include multi-walled carbon nanotubes (MWNTs) for reinforcing the strength of baseball bats [6], and single-walled carbon nanotubes (SWNTs) for biomedical applications, sensors, and electronics [7]; and (3) magnetic particles: magnetic particles have been extensively considered as adsorbents for the removal of various pollutants from water because their inherent superparamagnetic properties result in easy separation by a magnetic field [8][9][10]. Typical magnetic iron oxides are Fe 3 O 4 , and pristine and modified nanoscale zerovalent iron (nZVI) [11][12][13].…”

Optimization of porous structure of superparamagnetic nanoparticle adsorbents for higher and faster removal of emerging organic contaminants and PAHs

“…1,8,[11][12][13] With the superparamagnetic feature, these nanoparticle sorbents could be extracted and recycled from wastewater system by applying an external magnetic field. 13,14 In previous studies, we synthesized magnetic permanently confined micelle arrays (Mag-PCMAs) with a maghemite core and a silica porous layer that permanently confines cationic surfactant micelles within the mesopores, and had been successfully applied to remove hydrophobic compounds, 14 pesticides, 15 natural organic matter, 16 oxyanions 17 and emerging organic contaminants. 1 However, since the cationic surfactant is permanently anchored on the silica framework through -Si-O-Si-covalent bonding, 14 the surfactant micelles occupy most of the pore space, reducing the adsorption capacity and hindering the kinetics.…”