Removal of Cu²⁺Ions from Aqueous Solutions by Starch-Graft-Acrylic Acid Hydrogels

Abstract

Gelatinized starch was prepared by constantly stirring a mixture of starch and water at 95 C for 1 hour. Starch-graft-acrylic acid (S-g-AA) hydrogels were prepared by grafting acrylic acid (AA) [monomer=starch (w=w) 0.5-1.5] onto gelatinized starch with ceric ammonium nitrate as initiator under nitrogen atmosphere. The surface morphology of samples was studied using a scanning electron microscope (SEM). The hydrogels were evaluated for the removal of Cu 2þ ion from aqueous solutions at different pH. The concentration of Cu 2þ ion in aqueous solution was kept constant at 4 mmol=L. The metal ion removal capacities changed depending on treatment time, initial pH of the solution, and monomer=starch (w=w) ratio of the S-g-AA hydrogels. Cu 2þ ion removal capacities were determined by atomic absorption spectrometer (AAS).

Swelling, mechanical and mucoadhesion properties of Mt/starch-g-PMAA nanocomposite hydrogels

“…As observed in Table 1, the amount of the G% of S-g-PMAA was found to be 43.6. When this result was compared with previous studies (Athawale and Lele, 1998;Athawale and Rathi, 1999;Aravindakshan and Kumar, 2002;Güçlü et al, 2006), it was observed that this product has a higher value of G% than those studies. In the previous study (Güler, 2011), when the non-gelatinized starch used in the grafting reaction, the amount of G% was found to be 30.9.…”

Study on adsorption, regeneration, and reuse of crosslinked chitosan graft copolymers for Cu(II) ion removal from aqueous solutions

“…In these preliminary studies, it was observed that Cu(II) ions collapsed at higher pH values than 6. In addition, Chg-IA and Ch-g-CA beads have negative charges (ionized form) at natural pH value (approximately 6) of metal ion solution [4]. Therefore, lower pH values than 6 are not suitable for adsorption studies because carboxyl groups of these beads are non-ionized form and, the optimal pH value was determined as "6" according to the preliminary adsorption studies, which were carried out at different pH values.…”

“…Chitosan is obtained by deacetylation of chitin under alkaline conditions. Chitosan is a linear polysaccharide composed of glucosamine and N-acetyl glucosamine units linked by (1)(2)(3)(4) glycoside bonds. When the content of glucosamine (degree of deacetylation) of chitin is higher than about 50%, it is as named chitosan, and it becomes soluble in an aqueous acidic medium [16,17].…”

“…Since adsorption method is highly effective, inexpensive and easy to operate, it is widely preferred for water treatment processes [10]. In recent years, polymeric adsorbents have been used to remove heavy metal ions and basic dyes from waste waters [4][5][6][7][11][12][13][14][15]. In parallel, the use of natural polymers (e.g., cellulose, starch, chitosan, and alginate) and their derivatives for the removal of heavy metal ions from wastewater has become important by reason of their biodegradability [2].…”

“…Heavy metals can accumulate easily in living tissues. Therefore, the presence of Cu ions in natural waters causes toxic effects for humans and other living organism in the long term [3][4][5].…”