References
  -  M.A.F. Garcı´a, J.R. Utrilla, I.B. Toledo, C.M. Castilla, Adsorption
    of humic substances on activated carbon from aqueous
    solutions and their effect on the removal of Cr (III) ions, Langmuir,
    14 (1998) 1880–1886. 
-  N.T. Tavengwa, L. Chimuka, L. Tichagwa, Equilibrium and
    kinetic studies on the adsorption of humic acid onto cellulose
    and powdered activated carbon, Desal. Water Treat., 57(36)
    (2016) 16843–16854. 
-  F. Hua-Jun, H. Li-Fang, M. Qaisar, L. Yan, S. Dong-Sheng,
    Study on biosorption of humic acid by activated sludge, Biochem.
    Eng. J., 39 (2008) 478–485. 
-  J. Lin, Y. Zhan, Adsorption of humic acid from aqueous solution
    onto unmodified and surfactant-modified chitosan/zeolite
    composites, Chem. Eng. J., 200–202 (2012) 202–213. 
-  B. Ma, Y. Ding, W. Li, C. Hu, M. Yang, H. Liu, J. Qu, Ultra filtration
    membrane fouling induced by humic acid with typical
    inorganic salts, Chemosphere, 197 (2018) 793–802. 
-  F. Ulu, S. Barışçī, M. Koby, H. Särkkä, M. Sillanpää, Removal
    of humic substances by electro coagulation (EC) process and
    characterization of floc size growth mechanism under optimum
    conditions, Sep. Purif. Technol., 133 (2014) 246–253. 
-  X. Wang, Z. Wu, Y. Wang, W. Wang, X. Wang, Y. Bu, J. Zhao,
    Adsorption-photo degradation of humic acid in water by using
    ZnO coupled TiO2/bamboo charcoal under visible light irradiation,
    J. Hazard. Mater., 262 (2013) 16–24. 
-  M.A. Zulfikar, D. Wahyuningrum, R. Mukti, H. Setiyanto,
    Molecularly imprinted polymers (MIPs): a functional material
    for removal of humic acid from peat water, Desal. Water Treat.,
    57(32) (2016) 15164–15175. 
-  M.A. Zulfikar, F.I. Suri, Rusnadi, H. Setiyanto, N. Mufti, M.
    Ledyastuti, D. Wahyuningrum, Fe3O4 nano-particles prepared
    by co-precipitation method using local sands as a raw material
    and their application for humic acid removal, Int. J. Environ.
    Stud., 73 (2016) 79–94. 
-  M.A. Zulfikar, S. Afrita, D. Wahyuningrum, M. Ledyastuti,
    Preparation of Fe3O4-chitosan hybrid nano-particles used for
    humic acid removal from aqueous solution, Environ. Nanotechnol.
    Monit. Manage., 6 (2016) 64–75. 
-  M.A. Zulfikar, I. Afrianingsih, M. Nasir, N. Handayani, Fabrication
    of nanofiber membrane functionalized with molecularly
    imprinted polymers for humic acid removal from peat
    water, Desal. Water Treat., 97 (2017) 203–212. 
-  M.A. Zulfikar, E. Novita, R. Hertadi, S.D. Djajanti, Removal of
    humic acid from peat water using untreated powdered eggshell
    as a low cost adsorbent, Int. J. Environ. Sci. Technol., 10
    (2013) 1357–1366. 
-  B. Seredynska-Sobecka, M. Tomaszewska, A.W. Morawski,
    Removal of humic acids by the ozonation-biofiltration process,
    Desalination, 198 (2006) 265–273. 
-  A. Mehrparvar, A. Rahimpour, M. Jahanshahi, Modified ultra
    filtration membranes for humic acid removal, J. Taiwan Inst.
    Chem. Eng., 45 (2014) 275–282. 
-  H. Baker, F. Khalili, Comparative study of binding strengths
    and thermodynamic aspects of Cu(II) and Ni(II) with humic
    acid by Schubert’s ion-exchange method, Anal. Chim. Acta,
    497 (2003) 235–248. 
-  H. Baker, F. Khalili, A study of complexation thermodynamic
    of humic acid with cadmium (II) and zinc (II) by Schubert’s
    ion-exchange method, Anal. Chim. Acta, 542 (2005) 240–248. 
-  L. Wang, C. Han, M.N. Nadagouda, D.D. Dionysiou, An innovative
    zinc oxide coated zeolite adsorbent for removal of humic
    acid. J. Hazard. Mater., 313 (2016) 283–290. 
-  C. Leodopoulos, D. Doulia, K. Gimouhopoulos, T. Triantis, Single
    and simultaneous adsorption of methyl orange and humic
    acid onto bentonite. Appl. Clay Sci., 70 (2012) 84–90. 
-  L. Liang, L. Luo, S. Zhang, Adsorption and desorption of
    humic and fulvic acids on SiO2 particles at nano- and microscales,
    Colloid Surf. A., 384 (2011) 126–130. 
-  D.D. Sun, P.F. Lee, TiO2 microsphere for the removal of humic
    acid from water: Complex surface adsorption mechanisms,
    Sep. Purif. Technol., 91 (2012) 30–37. 
-  S.P. Moussavi, M.H. Ehrampoush, A.H. Mahvi, M. Ahmadian,
    S. Rahimi, Adsorption of humic acid from aqueous solution
    on single-walled carbon nanotubes, Asian J. Chem., 25 (2013)
    5319–5324. 
-  Y. Lu, Z. Wu, M. Li, Q. Liu, D. Wang, Hydrophilic PVA-co-PE
    nanofiber membrane functionalized with iminodiacetic acid
    by solid-phase synthesis for heavy metal ions removal, React.
    Funct. Polym., 82 (2014) 98–102. 
-  R. Xu, M. Jia, Y. Zhang, F. Li, Sorption of malachite green on
    vinyl-modified mesoporous poly(acrylic acid)/SiO2 composite
    nanofiber membranes, Microporous Mesoporous Mater., 149
    (2012) 111–118. 
-  S. Abbasizadeh, A.R. Keshtkar, M.A. Mousavian, Preparation
    of a novel electro spun polyvinyl alcohol/titanium oxide nanofiber
    adsorbent modified with mercapto groups for uranium
    (VI) and thorium (IV) removal from aqueous solution, Chem.
    Eng. J., 220 (2013) 161–171. 
-  A.R. Keshtkar, M. Irani, M.A. Moosavian, Removal of uranium
    (VI) from aqueous solutions by adsorption using a novel
    electro spun PVA/TEOS/APTES hybrid nanofiber membrane:
    comparison with casting PVA/TEOS/APTES hybrid membrane,
    J. Radioanal. Nucl. Chem., 295 (2013) 563–571. 
-  Y.J. Qiu, J. Yu, J. Rafique, J. Yin, X.D. Bai, E.G. Wang, Largescale
    production of aligned long boron nitride nanofibers by
    multi jet/multi collector electro spinning, J. Phys. Chem. C.,
    113 (2009) 11228–11234. 
-  R. Ostermann, D. Li, Y.D. Yin, J.T. McCann, Y.N. Xia, V2O5
    nanorods on TiO2 nanofibers: a new class of hierarchical nanostructures
    enabled by electro spinning and calcination, Nano
    Lett., 6 (2006) 1297–1302. 
-  S. Wu, F. Li, H. Wang, L. Fu, B. Zhang, G. Li, Effects of poly
    (vinyl alcohol) (PVA) content on preparation of novel thiol-functionalized mesoporous PVA/SiO2 composite nanofiber
    membranes and their application for adsorption of heavy
    metal ions from aqueous solution, Polymer., 51 (2010) 6203–6211. 
-  X. Xue, F. Li, Removal of Cu(II) from aqueous solution by
    adsorption onto functionalized SBA-16 mesoporous silica,
    Microporous Mesoporous Mater., 116 (2008) 116–122. 
-  M. Irani, A.R. Keshtkar, M.A. Mousavian, Removal of Cd(II)
    and Ni(II) from aqueous solution by PVA/TEOS/TMPTMS
    hybrid membrane, Chem. Eng. J., 175 (2011) 251–259.