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Removal of heavy metal ions in water by starch esters
Author(s) -
Soto Diana,
Urdaneta José,
Pernía Kelly,
León Orietta,
MuñozBonilla Alexandra,
FernandezGarcía Marta
Publication year - 2016
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.201500155
Subject(s) - itaconic acid , maleic acid , aqueous solution , adsorption , starch , thermogravimetric analysis , chemistry , fourier transform infrared spectroscopy , metal ions in aqueous solution , nuclear chemistry , solubility , acrylic acid , polyelectrolyte , polymer chemistry , organic chemistry , inorganic chemistry , metal , polymer , chemical engineering , engineering , copolymer , monomer
Corn starch has been modified with naturally occurring compounds, maleic acid (MA) and itaconic acid (IA), by esterification in an aqueous medium catalyzed by NaOH to produce adsorbents for heavy metals removal in water. The ester formation has been confirmed by wide angle x‐ray scattering (WAXS), thermogravimetric analysis (TGA), Fourier Transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The effect of the mono and di‐substitution with both acids, on the solubility and the swelling capacity of the modified starch have been investigated. The materials modified with maleic acid exhibited high water solubility, fact that made difficult their characterization and thus their application as adsorbents. In contrast, itaconate esters derivatives demonstrated superabsorbent characteristics and a typical polyelectrolyte behavior. Semiester derivative with greater content of carboxylic acid groups underwent the highest water uptake ( H ∞ = 1292%). Additionally, the capability of the modified starches with itaconic acid to adsorb aqueous metal cations such as Ni 2+ , Zn 2+ , Cd 2+ , and Pb 2+ was investigated and the results were compared with the native corn starch. The modified and native starches exhibited reasonable adsorption capacity for all the cations. It was demonstrated that the native starch does not exhibit selectivity for any of the cations, whereas the itaconate starches remove higher content of Pb 2+ with the lowest hydration radius in comparison with other ions.