Preparation of chitosan/MCM-41-PAA nanocomposites and the adsorption behaviour of Hg(II) ions

Abstract

A novel functional hybrid mesoporous composite material (CMP) based on chitosan and MCM-41-PAA was reported and its application as an excellent adsorbent for Hg(II) ions was also investigated. Innovatively, MCM-41-PAA was prepared by using diatomite and polyacrylic acid (PAA) with integrated polymer–silica hybrid frameworks, and then CMP was fabricated by introducing MCM-41-PAA to chitosan using glutaraldehyde as a cross-linking agent. The structure and morphology of CMP were characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy and Brunauer–Emmett–Teller measurements. The results showed that the CMP possessed multifunctional groups such as –OH, –COOH and –NH2 with large specific surface area. Adsorption behaviour of Hg(II) ions onto CMP was fitted better by the pseudo-second-order kinetic model and the Langmuir model when the initial Hg(II) concentration, pH, adsorption temperature and time were 200 mg l−1, 4, 298 K and 120 min, respectively, as the optimum conditions. The corresponding maximum adsorption capacity could reach 164 mg g−1. According to the thermodynamic parameters determined such as free energy, enthalpy and entropy, the adsorption process of Hg(II) ions was spontaneous endothermic adsorption.

Adsorption of Anionic Dyes by Polypyrrole‐Grafted Mesoporous SBA‐15 Composite: Isotherms, Kinetics, Thermodynamics, Interaction Mechanism and Recycling

“…This occurs through the exchange or sharing of electrons between sunset yellow, indigo carmine, titan yellow, and orange G dye, and the functional groups present in the SBA-15/polypyrrole composite. [25][26][27] This is also in accordance with the results from 3.8.1 (ii) in the work, which suggests that the possible mechanism of dyes involves electrostatic interactions between the SBA-15/polypyrrole composite and dye molecules.…”

Synthesis of cross-linked poly(acrylic acid) nanogels in an aqueous environment using precipitation polymerization: unusually high volume change

“…Cross-linked poly(acrylic acid)—p(AA) particles are examples of nanogels sensitive to pH. Due to the presence of a high amount of carboxylic groups, pAA gels undergo a big-volume transition in response to appropriate pH changes [18]. At pH smaller than p K a of pAA (4.5) [19], they exist in the shrunken state (carboxylic groups are protonated), while at pH higher than p K a they are swollen (carboxylic groups are dissociated).…”

Synthesis of chitosan-iron keplerate composite as an adsorbent for removal of toxic ions from water

“…have many applications in drug release [8][9][10][11][12][13][14][15][16][17] (for more details regarding the application of chitosan and its derivatives in drug release, see review, [18] and references therein), biological activity [19][20][21][22][23][24] (for more details regarding the biological activity of chitosan and its derivatives, see review, [25] and references therein)), beverages and food industry [26][27][28][29] (also see [30] and references therein, an extensive review reporting the application of chitosan and its derivatives in beverages and food industry) as well as membranes for the removal of various pollutants such as metals, ions, dyes, pharmaceuticals/drugs, phenols, pesticides, herbicides, etc. [31][32][33][34][35][36][37][38][39][40][41][42][43][44] (references [31] and [44] are extensive reviews).…”