Tannin-coated PVA/PVP/PEI nanofibrous membrane as a highly effective adsorbent and detoxifier for Cr(VI) contamination in water

Electrospinning PVA/PEI/rGO Fibrous Membrane and Its Adsorption of Cr(VI) and Congo Red in Water

“…The influence of the initial pH mainly arose from the surface charge of the membrane and the ion charge of Cr­(VI). In order to obtain information on the surface charge, the membrane’s zero charge point (pH PZC ) was determined according to our previous work Figure S6 shows that the pH PZC was 7.4; thus, the surface of the membrane was positively charged under pH below 7.4 and negatively charged under pH above 7.4.…”

“…Various heavy metal and dye removal methods have been reported. , Among these methods, adsorption possesses vast development potential due to its cost-effectiveness, easy manipulation, high efficiency, and good selectivity. , Developing highly efficient and facile separation adsorbents is essential for adsorption and is always a research hotspot. Branched polyethylenimine (PEI) has abundant amine and imine groups, which makes it advantageous for capturing metal ions, especially the Cr­(VI) ion. , Graphene and graphene oxide (GO)-based composites are the most promising materials for heavy metal ions and dye adsorption due to their large specific surface area, oxygenous functional groups, high chemical reactivity, and good mechanical strength. Liu et al prepared the PEI/GO composites through a self-assembly method for U­(VI) adsorption.…”

Research Progress of Water Treatment Technology Based on Nanofiber Membranes

“…Moreover, the amine groups in PEI acted as reduction sites after Cr(VI) was adsorbed to reduce Cr(VI) to harmless and chemically stable Cr(III), resulting in the formation of insoluble octahedral Cr(III) oxide [ 136 , 141 ]. Furthermore, the membrane prepared by coating PVA/PVP/PEI ENM with tannic acid had a stronger adsorption capacity for Cr(VI), with the maximum value of 695.04 mg·g −1 [ 142 ]. The membrane could be calcined into high-purity and harmless CrO 2 after completing the adsorption of Cr(VI).…”

Waste organic acid treatment with polyethyleneimine grafted polystyrene resin

“…15 First, DMF with high boiling point and good solubility of PEI was selected as the best solvent to mediate both substitution reactions. More solvent was required to better disperse the larger PEI-1800 (entries [16][17][18][19][20][21][22][23][24][25][26][27]. Second, the reactions were more efficient under 363 K for a duration of 6 h. Further elevating the temperature or prolonging the reaction time did not result in a better acid uptake (entries 5-12 and 16-23).…”

“…Splitting the N 1 s peak resulted in two distinct fitting signals at 398.5 and 399.4 eV, corresponding to tertiary and primary, secondary amines, respectively. 20 The higher ratio of tertiary amine in PSPEI-1800 is again due to the more significant extra grafting. As primary and secondary amines are more reactive toward acids, this also contributed to the higher adsorption capacity of PSPEI-600.…”