Polyethylenimine functionalized Fe3O4/steam-exploded rice straw composite as an efficient adsorbent for Cr(VI) removal

Novel magnetically separable anhydride-functionalized Fe3O4@SiO2@PEI-NTDA nanoparticles as effective adsorbents: synthesis, stability and recyclable adsorption performance for heavy metal ions

“…Aer the gra reaction with PEI, two new peaks at 2919 and 2840 cm À1 may be assigned to aliphatic C-H bonds; the bands at 1450 and 1320 cm À1 may belong to the stretching vibrations of C-H and C-N bonds, respectively. 28 The characteristic adsorption peaks of primary amines (-NH) appear at 1656 cm À1 and 1612 cm À1 , and a broader adsorption peak in the region of 3300-3600 cm À1 may be ascribed to the overlapping of the N-H vibration of PEI with the O-H stretching of SiO 2 . All these results indicate the successful graing of PEI.…”

“…24 PEI has usually been graed to other matrices such as insoluble polymers, 25 biomass, 26 and cellulose 27 to prevent its dissociation from the surface of the matrices during adsorption operations; it has also been used to construct magnetic hybrid nanomaterials for environmental applications in heavy metal ion removal. [28][29][30] In this work, to synthesize a magnetically separable adsorbent with high stability and adsorption capacity, a new type of magnetic silica material with amine and anhydridefunctionalized layers was fabricated by covalently graing a PEI polymer, followed by anhydride functionalization with 1,4,5,8-naphthalenetetracarboxylic-dianhydride (NTDA) onto the surface of Fe 3 O 4 @SiO 2 , as shown in Scheme 1. The PEI-NTDA layer on Fe 3 O 4 @SiO 2 not only endowed the nal magnetic adsorbents with hydrophilicity, reducing nonspecic adsorption during wastewater treatments, but also provided numerous amine and anhydride groups, which may synergistically coordinate or chelate with heavy metal ions.…”

A Review on Heavy Metal Ions and Containing Dyes Removal Through Graphene Oxide‐Based Adsorption Strategies for Textile Wastewater Treatment

“…Furthermore, chromium is categorized as group 1 carcinogenic by the International Agency for Research on Cancer (IARC) for animals and humans. The toxicity of hexavalent chromium Cr (VI) is normally 1000 times higher than that of Cr (III) trivalent chromium [47] . Accordingly, the World Health Organization (WHO) recommends that the chromium content in drinking water must be <50 ppb or 0.05 mg L −1[48] and European Union require that the discharge of Cr (VI) to surface water should be below 50 μg L −1 [49] .…”

Fluoroquinolones Antibiotics Adsorption Onto Polymer Coated Magnetic Nanoparticular Activated Carbon

“…The application of modified activated carbon, containing iron particles, is the commonly used adsorbent to remove a varirty of environmental contaminats from various waste streams. For example, activated carbon (AC) containing iron components (FeO, Fe2O3 or Fe 3 O4) have been recently used for the treatment of food waste [20], effluent streams containing various organic compounds [21], Cr(VI) [22], antibiotics [23], different heavy metals and As(V) [24]. In addition, AC can also be used for different purposes after processing with certain polymeric materials.…”