Читать книгу Polysaccharides - Группа авторов - Страница 135

Over the last years, the use of biocompatible and biodegradable renewable resources for the retaining of different pollutants from wastewaters has attracted the attention of many researchers [200]. Biosorbent abilities of natural polysaccharide matrices have been under investigation for an efficient and low-cost wastewater treatment.

Chitosan, chitosan derivatives, and chitosan composites have been extensively referred in the literature with their biosorbent properties for the desired pollutants, such as heavy metal ions, organochloride pesticides, suspended solids, organic pollutants such as organochloride pesticides, organic oxidized or fatty and oil impurities or textile wastewater dyes [200, 201]. Lessa et al. investigated the adsorption capacity of the composite beads obtained from cell wall polysaccharides pectin and cellulose for removal of multi-metal ions from water [202]. In another study, Elbedwehy et al. designed super adsorbent polymers for the removal of heavy metals Pb²⁺, Cd²⁺, and Cu²⁺ from wastewater by chemically modifying gum arabic [203]. Zhang and Chen were used crosslinked-starch graft copolymers containing amine groups as the sorbents for Pb²⁺ and Cu²⁺. In another study, starch crosslinked with POCl₃ and carboxymethylation has been proposed as sorbents for the removal of Cu²⁺, Pb²⁺, Cd²⁺ and Hg²⁺. Additionally, several crosslinked cyclodextrins gels were investigated for the removal of chloro and nitro phenols, benzoic acid derivatives, and dyes from aqueous solutions. For instance, cyclodextrin-epichlorohydrin copolymer was found to be successful in the removal of Bisphenol A [204]. In addition, carboxylated cellulose nanocrystal sodium alginate hydrogel beads have been investigated for the removal of pharmaceutical and personal care products from wastewater or other water bodies. Recently, another advanced polysaccharide matrix, the porous β-cyclodextrin polymers, claimed as an excellent adsorbent for the removal of pharmaceutical and personal care products from wastewater [201].

The use of polysaccharide-based materials as sorbents offers several advantages including low cost, versatility, abundance, high capacity and high rate of adsorption, and ease of modification. However, there are also limitations of using polysaccharides in wastewater treatment. For instance, the choice of the adsorbent depends on the nature of the pollutant, thus the extreme variability of industrial wastewater must be taken into account in the design of any polysaccharide-based platform [204]. Still, polysaccharide-based materials one of the most attractive biosorbents for wastewater treatment. Considerable efforts are now being made in the investigation and development of polysaccharides and their derivatives as the natural materials for the removal of pollutants with different structures.