Fabrication of Inexpensive Polyethylenimine-Functionalized Fly Ash for Highly Enhanced Adsorption of Both Cationic and Anionic Toxic Dyes from Water

Abstract

Polyethylenimine-based modified coal fly ash (CFA-PEI) is synthesized by the wet impregnation method. The material was found to be an excellent adsorbent for removal of cationic (Malachite Green; MG) and anionic (Reactive Red 2; RR2) dyes from aqueous solution. CFA-PEI was characterized by various sophisticated instruments such as FTIR spectroscopy, 13 C MAS NMR spectroscopy, XRD, elemental analysis, Brunauer−Emmett−Teller (BET) isotherm, TGA, FESEM, and HRTEM. The FTIR spectra reveal that the N-containing functional group is introduced on the surface of CFA-PEI, which plays a vital role in the removal of these dyes. The adsorption behavior of the CFA-PEI toward toxic dyes is evaluated by investigating the effect of solution pH, contact time, solution temperature, adsorbent dose, and concentration of dye solution. The obtained adsorption isotherm and the kinetics data of both MG and RR2 are in compliance with the Langmuir adsorption isotherm and pseudo-second-order kinetics, respectively. Moreover, excellent adsorption capacity on CFA-PEI of dyes (q m : 174.83 mg/g for MG and 316.75 mg/g for RR2) is attributed to various factors (H-bonding, electrostatic interaction). CFA-PEI also has high regeneration capacity toward these dyes from aqueous solution. Finally, the advantage of the adsorbent lies in its low cost.

Adsorption mechanism of polyethyleneimine modified magnetic core–shell Fe3O4@SiO2 nanoparticles for anionic dye removal

“…Moreover, absorption bands at 2947 and 2860 cm À1 were indicative of the symmetric and asymmetric stretching vibration of C-H bonds. 29 One additional peak at 1643 cm À1 is associated to the symmetric N-H band from the PEI, which gives strong evidence of Fe 3 O 4 @SiO 2 /PEI. 17 XRD pattern of Fe 3 O 4 , Fe 3 O 4 @SiO 2 and Fe 3 O 4 @SiO 2 /PEI were illustrated in Fig.…”

Fabrication and Application of Low-Cost Thiol Functionalized Coal Fly Ash for Selective Adsorption of Heavy Toxic Metal Ions from Water

“…First of all, the magnetic and nonmagnetic components of as-received CFA were separated by a Davies tube. The magnetic components, enriched with iron-bearing crystallites, were rejected . The chemical compositions of both CFA and surface modified CFA were measured by XRF and are given in Table .…”

“…The nonmagnetic part of CFA was further surface modified by the following steps. At first, it was calcined with NaOH (1:1.2 weight ratio) for 4 h at 550 °C . Then it was cooled to room temperature and washed with double distilled water to remove adhered alkali.…”

The preparation of organophosphorus ligand-modified SBA-15 for effective adsorption of Congo red and Reactive red 2

“…Among these methods, the adsorption technique, which offers the benets of wide sources of absorbents, economic feasibility, simplicity, rapidity, and ease of operation, [13][14][15] has been regarded as one of the most efficient methods for dye removal. Till now, various adsorbents have been reported for dye removal, including activated carbon, 16,17 MOF materials, 18,19 metal oxide nanoparticles, 20 mesoporous materials, [22][23][24] and hydroxides. 25,26 However, the adsorption performance parameters of these adsorbents such as adsorption capacity and adsorption efficiency are still limited.…”