Some Well-Known Alginate and Chitosan Modifications Used in Adsorption: A Review

Abstract

Owing to environmental pollution and increasingly strict regulations, heavy metals have attracted the attention of many researchers in various disciplines. Alginate and chitosan derivatives have gained popularity as biosorbents for water treatment. An increase in the number of publications on modified biosorbents for the biosorption of toxic compounds reveals widespread interest in examining the requirements and positive contribution of each modification type. This paper reviews the advantages and disadvantages of using alginate and chitosan for adsorption. Well-known modifications based on chitosan and alginate, namely, grafting, functionalization, copolymerization and cross-linking, as well as applications in the field of adsorption processes, especially amino acid functionalization, are reviewed. The selection criteria for the best biosorbents and their effectiveness and proposed mechanism of adsorption are discussed critically. In the conclusion, the question of why these adsorbents need modification before use is addressed.

Biosorbents Based on Biopolymers from Natural Sources and Food Waste to Retain the Methylene Blue Dye from the Aqueous Medium

“…The challenges of using microbial cells for the production of biosorbents using natural and agricultural resources can be overcome by microbial immobilization using a natural polymer, as alginate or chitosan (biodegradable, biocompatible, economical, and environmentally friendly) for the sorption of various pollutants [11]. Alginate can be used as adsorbent for metal ion removal-Pb (II), Cu (II), Cd (II) [12], but its sorption capacity can be significantly improved by the addition of microbial polymers.…”

Chitosan Nanoparticles as Potential Nano-Sorbent for Removal of Toxic Environmental Pollutants

“…Adsorption technology is one of the most reliable strategies in wastewater treatment, and the use of a variety of nanosized adsorbents enables preferential surface adsorption [ 12 , 13 , 14 , 15 , 16 ]. The increase in surface area can increase the sorption capacity towards pollutants on the surface of NPs [ 6 , 17 , 18 , 19 , 20 ]. In addition to wastewater treatment, NPs are used as antimicrobial agents [ 21 ], as catalysts [ 22 ], in biomedicine, energy conversion [ 23 ], agriculture, electronics, and optoelectronics industries [ 24 ].…”

Recent Application Prospects of Chitosan Based Composites for the Metal Contaminated Wastewater Treatment

“…In this aspect, CS is widely studied as they exhibit a range of characteristics, including biodegradability, non-toxicity, biocompatibility, abundance in nature, low cost, hydrophilicity, high content of functional groups (–NH 2 , –OH) that can contribute to various chemical modifications, attractive adsorption capacity, and metal ion chelation potential [ 22 , 32 ]. However, drawbacks of CS, including poor mechanical properties, pH sensitivity, low thermal stability, variability of polymer characteristics, poor solubility, low surface area, non-porosity, low adsorption capacity, and lack of reusability, limit their application in wastewater treatment [ 22 , 32 , 33 , 34 ]. The physical modification (transform powder form into nanoparticle) and chemical modification (crosslinking, graft modification, etc.)…”