Preparation of Chitosan Stacking Membranes for Adsorption of Copper Ions

Abstract

Chitosan (CS) stacking mats with excellent performance for adsorption of copper ions (Cu(II)) in wastewater were fabricated by alternating electrospinning/electrospraying. The hierarchical structure of the stacking membranes was designed by CS micro-hemispheres sandwiched between CS fibers. The CS stack membranes prepared by the electrospinning technology could effectively increase the specific surface area, and thus, facilitate the adsorption of copper ions. CS stacking membranes with three layers reached adsorption equilibrium within 60 min, and had a maximum absorbance of 276.2 mg/g. The absorbance performance was superior to most of the reported CS adsorbents. Compared with CS fiber mats which were dominated by CS chemical structure during adsorption, the stacking structure of CS membranes contributed to the high efficient capability, and exhibited the multilayer adsorption behavior. This study may develop a promising method for the design of environmentally-friendly natural polymer adsorbents to remove Cu(II) in wastewater.

Electrosprayed Chitosan–Copper Complex Microspheres with Uniform Size

“…Although Zhang et al [ 20 ] observed the appearance of new absorption bands after the adsorption of Cu (II) ions, the formation of new absorption bands was not detected in this work. It can be concluded that electrostatic forces between chitosan and cupric ions are the only bond formed in CHT–Cu 2+ complex microspheres.…”

“…The addition of Cu 2+ ions at the lowest concentration (CHT85–Cu0.5) creates a rough, wrinkled surface. Furthermore, the concavity of some microspheres can be observed, which has been previously reported in the literature [ 20 ]. The same effect was also described as “hollow” particles [ 15 ] or “cavities” [ 1 , 10 ].…”

“…As can be seen from Figure 2 and data in Table 2 , the absorption bands characteristic for chitosan were found at 3362 and 3290 cm −1 for CHT85 and at 3359 and 3292 cm −1 for CHT95, which correspond to the stretching vibration of the hydroxyl group (–OH) and the extension vibration of the amino group (–NH 2 ) and their interactions through hydrogen bonds [ 7 , 20 ]. Two bands observed in the range of 2950–2850 cm −1 are associated with the symmetric and asymmetric stretching of C–H in –CH– and –CH 2 [ 8 , 13 ].…”

“…Chitosan macromolecules, containing a large number of amino and hydroxyl groups, could form complexes with transition metal ions through various mechanisms such as chelation, electrostatic attraction or ion exchange, depending on the metal ion and the pH of the solution. The main complex sites are nitrogen and oxygen atoms owing to electron pairs that could be combined with metal ions [ 9 , 13 , 20 ]. One of the transition metals that possess strong chelation with amine is copper.…”

Fly Ash Coated with Magnetic Materials: Improved Adsorbent for Cu (II) Removal from Wastewater

“…A variety of technologies have been applied for the treatment of waters contaminated with copper ions, among which the adsorption process is considered the most favorable alternative [ 10 , 11 , 12 , 13 , 14 ]. A series of materials were involved in Cu (II) adsorption, such as fly ash (FA) and modified fly ash [ 15 , 16 ], manganese ore [ 17 ], LSX zeolite [ 18 ], zeolite 4A [ 19 ], mesoporous silica [ 20 ], macro algae [ 21 ], and chitosan-based biodegradable composite [ 22 ].…”