Development of functionalized carrageenan, chitosan and alginate as polymeric chelating ligands for water softening

Abstract

Chitosan, carrageenan and alginate are among the most abundant biopolymers in nature. They were prepared in uniform beads shape with a diameter of 2 mm ± 10%, using the encapsulator for removal of calcium, magnesium and iron cations from hard water. Solutions of 100-500 mg/L were prepared from each cation, and the detection of cations was carried out using atomic absorption spectrometer. Carrageenan and chitosan were able to chelate the three cations without further modification. However, alginate beads succeeded to chelate iron and magnesium and failed to chelate any calcium ions; in contrast, it increased the initial calcium concentration! That could be due to the pre-cross-linking of alginate beads using calcium chloride solution, which may be leaked back to the solution. However, grafting the alginate beads with polyethyleneimine and bromoacetic acid rectified this problem and the new functional group, -COOH, has been proved using the FT-IR. Optimization of the results in terms of beads weight (0.25-3.0 g) and cations concentrations (100-500 mg/L) has shown that most biopolymeric beads can chelate 85-100% of the cations in concentrations up to 500 mg/L. According to our finding, we came up with the recommendation to use chitosan for chelation of calcium and iron as it showed 100% chelation efficiency of both cations, whereas carrageenan is highly recommended for chelation of iron and magnesium, as it showed 100 and 98% chelation efficiency, respectively. Further work can be done on the reusability of the beads and scale up for the industrial use.

Polysaccharides as the Sensing Material for Metal Ion Detection-Based Optical Sensor Applications

“…According to their discoveries, the electrostatic interaction between Li + and the carboxylic groups of carboxymethyl carrageenan is more favorable than for the sulfate group. This On the other hand, for carrageenan, sulfates are accountable for ion chelation [35]. A recent study by Cao and co-workers [36] shows that the chelation of carrageenan with a metal ion is affected by several factors, including valency and the hydration size of the metal ion.…”

“…On the other hand, for carrageenan, sulfates are accountable for ion chelation [ 35 ]. A recent study by Cao and co-workers [ 36 ] shows that the chelation of carrageenan with a metal ion is affected by several factors, including valency and the hydration size of the metal ion.…”

Adsorption of Methylene Blue on A Polymeric Matrix of Poly Lactic Acid/Sodium Alginate/Carbon Nanoparticles (PLA/SA/CNP)

“…The activation is split into two parts procedure. The rst is raw material charring, and the second is activation, which can be done chemically, thermally, or with steam to drive extremely porous material 17 . Biomaterials, particularly bio-polymers derived from renewable sources, can be used as an alternative to traditional adsorbents because of their biodegradability, low cost, and availability 15 .…”

“…In this research, the polymer matrix as PLA was chosen because it generated beads easily using the phase inversion method. 17 PLA is biodegradable because it is made up of thermoplastic aliphatic polyesters made from renewable resources including tapioca roots, maize starch, chips, and starch 18 . Its structure is shown in Figure (1).…”

Chelate coupling with pineapple leaves as a modified bio-sorbent for lead ions (II) removal

“…For example, integrating a chelating group into an adsorbent could add a great advantage in capturing heavy metals in particular. The ability of such functional groups to bind with heavy metal ions by forming two or more coordinate bonds can significantly improve the sequestering process in many aspects, such as removal rate, uptake capacity, and selectivity (Ali et al 2017;Mosekiemang and Dikinya 2012).…”