Chromate ion removal by water‐soluble functionalized chitosan

Abstract

Hexavalent chromium (Cr(VI)) is a highly toxic metal that has been accused to be carcinogen with prolonged inhalation by humans and is toxic to aquatic life even at low concentrations. The objective of this work was to use water‐soluble functionalized chitosan in the removal of chromate ions in aqueous solution. Functionalized chitosan was obtained by grafting molecules with quaternary ammonium groups in a heterogeneous process under alkaline conditions. Chitosan modified was characterized by FTIR, 1H‐NMR spectroscopy, and TGA. The retention tests were carried out using the liquid‐phase polymer‐based retention technique (LPR) by means of the washing method, studying the effects of the variation of pH, interfering ions, and variations of hydrodynamic flow. The results showed 94.0% retention with regard to the modification of chitosan. For the removal studies, a trend in the retention percentages was presented as the pH increased, obtaining a maximum retention of 92.0% at pH 9.0. In studies of interfering ions, a decrease was found as the concentrations of interferent increased, obtaining the highest retention >70.0%. In conclusion, the functionalization of chitosan with quaternary ammonium groups in conjunction with the LPR technique is a great alternative in the removal of chromate ions and is friendly to the environment.

Removing Calcium Ions from Remelt Syrup with Rosin-Based Macroporous Cationic Resin

“…When the pH > 4.0, the adsorption capacity was basically constant, as confirmed by the pHpzc (zero charge points) and zeta potential of RMCRs. At pH 8.0, the adsorption capacity of RMCRs de creased because the system could present molecular agglomeration due to the number o intermolecular interactions and induced precipitation processes or an increase in viscosi ty [21]. The supreme adsorptivity for calcium ions was obtained at pH 7.0.…”

Synthesis of Magnesium hydroxide Whisker‐encapsulated Carbonized Chitosan and Basic Magnesium Carbonate Composite for Efficient Pb(II) Removal

“…Rachid [21] synthesized a novel chitosan‐loaded MgAl‐LDH nanocomposite, and its performance in As(V) removal and antimicrobial activity was evaluated. Palacio [22] studied the adsorption behavior of water‐soluble functionalized chitosan for chromate ions. Carbon materials are also excellent adsorbents.…”

Influence of 2‐hydroxypropyltrimethyl ammonium chloride chitosan on sedimentation and volume change behavior of cohesive soil sediments

“…37,38 Quaternary ammonium (QA)-based materials introduce the QA groups to the Nitrogen-atoms position, resulting in a stable cationic charge. [39][40][41] HACC has good solubility and stable cationic charges, promoting the strong adsorption effect. The performance research of QA-functionalized Chitosan to solve soil problems is significant.…”

“…For example, carboxymethyl chitosan has a significant anti‐swelling effect on Na‐bentonite, and 2‐hydroxypropyltrimethyl ammonium chloride chitosan (HACC) also significantly controls the expansion of Na‐ bentonite 37,38 . Quaternary ammonium (QA)‐based materials introduce the QA groups to the Nitrogen‐atoms position, resulting in a stable cationic charge 39–41 . HACC has good solubility and stable cationic charges, promoting the strong adsorption effect.…”