Sequestration of Sulfate Anions from Groundwater by Biopolymer-Metal Composite Materials

Abstract

<jats:p>Binary (Chitosan-Cu(II), CCu) and Ternary (Chitosan-Alginate-Cu(II), CACu) composite materials were synthesized at variable composition: CCu (1:1), CACu1 (1:1:1), CACu2 (1:2:1) and CACu3 (2:1:1). Characterization was carried out via spectroscopic (FTIR, solids C-13 NMR, XPS and Raman), thermal (differential scanning calorimetry (DSC) and TGA), XRD, point of zero charge and solvent swelling techniques. The materials’ characterization confirmed the successful preparation of the polymer-based composites, along with their variable physico-chemical and adsorption properties. Sulfate anion (sodium sulfate) adsorption from aqueous solution was demonstrated using C and CACu1 at pH 6.8 and 295 K, where the monolayer adsorption capacity (Qm) values were 288.1 and 371.4 mg/g, respectively, where the Sips isotherm model provided the “best-fit” for the adsorption data. Single-point sorption study on three types of groundwater samples (wells 1, 2 and 3) with variable sulfate concentration and matrix composition in the presence of composite materials reveal that CACu3 exhibited greater uptake of sulfate (Qe = 81.5 mg/g; 11.5% removal) from Well-1 and CACu2 showed the lowest sulfate uptake (Qe of 15.7 mg/g; 0.865% removal) from Well-3. Generally, for all groundwater samples, the binary composite material (CCu) exhibited attenuated sorption and removal efficiency relative to the ternary composite materials (CACu).</jats:p>

Microfibrillated cellulose films containing chitosan and tannic acid for wound healing applications

“…3.b-i); such as the region of 1593-1501 cm −1 , characteristic absorption bands of chitosan in 1556 and 1541 cm −1 which are assigned to the stretching vibrations of amino groups. In addition to another characteristic chitosan band assigned to CH 2 scissoring at 1418 cm −1 [29]. When tannic acid was incorporated into the films, a large region is modified by the presence of its groups (Fig.…”

An Overview of Modified Chitosan Adsorbents for the Removal of Precious Metals Species from Aqueous Media

“…Pethkar et al used X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS) to support that Au(III) ions can interact with the protonated carbonyl and carboxyl groups by a physical sorption mechanism [69]. Xue and Wilson have proposed the role of the -OH and -NHR (R = H or -COCH3) groups of chitosan participate in the formation of complexes with Cu(II) [13,70], shown in Figure 8. The relatively high binding affinity was confirmed due to the negligible levels of leaching in chitosan-based Cu(II) composites by Hassan et al [70] Figure 8.…”

“…Xue and Wilson have proposed the role of the -OH and -NHR (R = H or -COCH3) groups of chitosan participate in the formation of complexes with Cu(II) [13,70], shown in Figure 8. The relatively high binding affinity was confirmed due to the negligible levels of leaching in chitosan-based Cu(II) composites by Hassan et al [70] Figure 8. Proposed adsorption mechanism for SO4 2− anions by a ternary biopolymer composite that contains Cu(II).…”

“…Proposed adsorption mechanism for SO4 2− anions by a ternary biopolymer composite that contains Cu(II). Reprinted with permission from [70].…”

Adsorptive Removal of Heavy Metal Ions, Organic Dyes, and Pharmaceuticals by DNA–Chitosan Hydrogels

“…IPECs from natural and synthetic polyelectrolytes, including those of DNA and chitosan, have been studied intensively [18][19][20][22][23][24] and applied for the removal of environmental pollutants such as sulphates [25,26], phosphates and nitrates [27], heavy metal ions [28], bisphenol A [29], nanomaterials [30], and so on. However, the adsorption properties of IPEC hydrogels have not been fully explored and the idea of combining polyions as active adsorption components into a single hydrogel matrix has not been fully addressed in previous studies.…”