Optimized mercapto-modified resorcinol formaldehyde xerogel for adsorption of lead and copper ions from aqueous solutions
Resorcinol formaldehyde (RF) xerogel was modified by mercapto functional groups for removal of Pb(II) and Cu(II) ions from aqueous solutions. The chemical structure of the mercapto-modified resorcinol formaldehyde xerogel (MRFX) was compared with the RF xerogel via Fourier transform infrared spectra (FTIR), X-ray photoelectric spectroscopy (XPS), and energy dispersive X-ray (EDX) mapping to characterize the functional groups and their dispersion in the xerogel. The results showed that the MRFX included not only thiol groups, but also sulfonic groups with higher adsorption affinity sites. The functional groups were fully dispersed in the xerogel and made a homogeneous composition. X-ray diffraction (XRD) patterns were also employed to show the effect of modifier on the phase structure of the xerogels. Moreover, the morphologies of the xerogels were observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques. According to the TEM micrographs, the MRFX included more nanopores than the unmodified xerogel. The MRFX was studied for adsorption tests. According to the results, the optimal pH to adsorb maximum Pb(II) and Cu(II) ions was 6. Adsorption kinetics study revealed that the adsorption process followed the pseudo-second-order kinetic equations and the adsorption equilibrium agreed much more with Langmuir rather than Freundlich model.
MRFX was used in the removal of Pb(II) and Cu(II) ions from aqueous solutions.
MRFX included not only thiol groups, but also sulfonic groups with higher adsorption affinity sites.
Adsorption isotherms and kinetics were used to address the adsorption mechanism.
The adsorption capacities of Pb(II) and Cu(II) are 84 and 120 mg g−1, respectively.
KeywordsSol–gel synthesis Heavy metal adsorption Xerogel Surface modification
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 6.Javadian H, Taghavi M (2014) Application of novel polypyrrole/thiol-functionalized zeolite Beta/MCM-41 type mesoporous silica nanocomposite for adsorption of Hg 2 + from aqueous solution and industrial wastewater: kinetic, isotherm and thermodynamic studies. Appl Surf Sci 289:487–494CrossRefGoogle Scholar
- 14.Motahari S, Nodeh M, Maghsoudi K (2016) Absorption of heavy metals using resorcinol formaldehyde aerogel modified with amine groups. Desalin Water Treat 57(36):16886–16897Google Scholar
- 22.Jafari M, Davachi SM, Mohammadi-Rovshandeh J, Pouresmaeel-Selakjani P (2017) Preparation and characterization of bionanocomposites based on benzylated wheat straw and nanoclay. J Polym Environ 17:(9)1–13Google Scholar
- 24.Gwon JG, Lee SY, Doh GH, Kim JH (2010) Characterization of chemically modified wood fibers using FTIR spectroscopy for biocomposites. J Appl Polym Sci 116(6):3212–3219Google Scholar
- 40.Oyedoh EA, Albadarin A, Walker G, Mirzaeian M, Ahmad M (2013) Preparation of controlled porosity resorcinol formaldehyde xerogels for adsorption applications. Chem Eng Trans 32:1651–1656Google Scholar