A novel terpolymer nanocomposite (carboxymethyl β-cyclodextrin-nano chitosan-glutaraldehyde) for the potential removal of a textile dye acid red 37 from water

Development of a Novel Cyclodextrin-Chitosan Polymer for an Efficient Removal of Pharmaceutical Contaminants in Aqueous Solution

A novel polymer synthesized by grafting three cyclodextrins onto chitosan was characterized and evaluated for its potential to adsorb two pharmaceutical residues: ibuprofen and progesterone. The influence of various operational parameters, including contact time, initial molecule concentration, pH, ionic strength, and temperature, was investigated. The synthesized polymer exhibits an amorphous and porous structure with a remarkable swelling capacity of 9.5 mmol/g. It demonstrates remarkable adsorption capacities for progesterone and ibuprofen, reaching 90% and 75%, respectively. Kinetic studies reveal that the adsorption of both molecules follows a pseudo-second-order model. A DSC analysis elucidated the adsorption mechanism, which is governed by the formation of inclusion complexes and electrostatic interactions within the polymer network. The polymer's regeneration after 23 cycles demonstrates its sustainable adsorption efficiency. The combination of chitosan with three cyclodextrins opens up promising new avenues for water treatment and the removal of specific pollutants. This approach significantly improves the material's selectivity towards target pollutants, offering a significant advantage in pollution remediation applications.

Ahmed A, M. Fadhil F, R. Kuot S, S Alsubaie M, L.Alazmi M, Fetouh H. New approach for processing chitosan as low cost protective hybrid coating for C-steel in acid media

The novelty of this study is that it the first time blending and formulation of chitosan as a new hybrid (organometallic) protective coatings for achieving synergistic protection for carbon steel alloy during acid pickling. The role of coated silica (by 0.1 wt % stearic acid lubricant) in the improvement of coating performance was highlighted. Variable weight percentage of chitosan and silica in addition to a fixed weight percentage (35 %) of guar gum natural plant resin, 5 × 10-6 mmol (2-Hydrazinyl-6-methyl (or phenyl) -4, 5-di-H pyrimidinone) as organic corrosion inhibitors were compounding as hot melt in the presence of a low cost surfactant as an emulsifying agent improved compatibility between coating constituents. Guar gum increased coating flow during application and grafted chitosan into high molecular copolymer resin insoluble in acid media. Phosphorous acid improved coating flexibility during application by hot dipping. Hybrid coating decreased corrosion potential of carbon steel and retarded both redox reactions of corrosion acting as adsorbed mixed-type inhibitor. Percentages protection (%P) approached hundred percentage as confirmed from the agreement between impedance and polarization parameters. Guar gum plant resin and slice powder increased gloss of coating. The coated silica filled the pores and increased stiffness of coating. Super hydrophobicity of coating was confirmed by the measured contact angle above 150oC indicating good spreading of coating sample as insulating adherent surface film.

Bacterial cellulose microfilament biochar-architectured chitosan/polyethyleneimine beads for enhanced tetracycline and metronidazole adsorption

This study investigates the potential applications of incorporating 2D bacterial cellulose microfibers (BCM) biochar into chitosan/polyethyleneimine beads as a semi-natural sorbent for the efficient removal of tetracycline (TET) and metronidazole (MET) antibiotics. Batch adsorption experiments and characterization techniques evaluate removal performance and synthesized adsorbent properties. The adsorbent eliminated 99.13 % and 90 % of TET and MET at a 10 mg.L-1 concentration with optimal pH values of 8 and 6, respectively, for 90 min. Under optimum conditions and a 400 mg.L-1 concentration, MET and TET have possessed the maximum adsorption capacities of 691.325 and 960.778 mg.g-1, respectively. According to the isothermal analysis, the adsorption of TET fundamentally follows the Temkin (R2 = 0.997), Redlich-Peterson (R2 = 0.996), and Langmuir (R2 = 0.996) models. In contrast, the MET adsorption can be described by the Langmuir (R2 = 0.997), and Toth (R2 = 0.991) models. The pseudo-second-order (R2 = 0.998, 0.992) and Avrami (R2 = 0.999, 0.999) kinetic models were well-fitted with the kinetic results for MET and TET respectively. Diffusion models recommend that pore, liquid-film, and intraparticle diffusion govern the rate of the adsorption process. The developed semi-natural sorbent demonstrated exceptional adsorption capacity over eleven cycles due to its porous bead structure, making it a potential candidate for wastewater remediation.

Preparation and characterization of ternary polysaccharide hydrogels based on carboxymethyl cellulose, carboxymethyl chitosan, and carboxymethyl β-cyclodextrin

A series of ternary polysaccharide hydrogels were facile prepared by incorporating carboxymethyl cellulose (CMC) into the carboxymethyl chitosan/carboxymethyl β-cyclodextrin (CMCS/CMCD) complex solution based on multiple physical interactions. Structure properties of the CMC/CMCS/CMCD hydrogels were revealed by FTIR, XRD, SEM, and TG. The rheological and texture properties, temperature/pH-response behaviors, biocompatablity, and antimicrobial activity of the hydrogels were determined in detail. These results showed that the existence of electron force and hydrogen bond among three components leading to formation of the hydrogels, displaying good mechanical characteristic, stable solid-like rheological properties, controllable swelling and degradation behaviors, and excellent biocompatibility. Additionally, the swelling kinetics can be well described by the Schott's pseudo second order model. Moreover, the hydrogels loaded with cinnamic acid (CA) exhibited good antimicrobial activity against both Staphylococcus aureus and Escherichia coli, and the antimicrobial activity was related to the composition of the prepared hydrogels. The novel ternary polysaccharide hydrogels may have good application prospects in food and bio-medicine.

Hydrogels Based on Chitosan and Nanoparticles and Their Suitability for Dyes Adsorption from Aqueous Media: Assessment of the Last-Decade Progresses

Water is one of the fundamental resources for the existence of humans and the environment. Throughout time, due to urbanization, expanding population, increased agricultural production, and intense industrialization, significant pollution with persistent contaminants has been noted, placing the water quality in danger. As a consequence, different procedures and various technologies have been tested and used in order to ensure that water sources are safe for use. The adsorption process is often considered for wastewater treatment due to its straightforward design, low investment cost, availability, avoidance of additional chemicals, lack of undesirable byproducts, and demonstrated significant efficacious potential for treating and eliminating organic contaminants. To accomplish its application, the need to develop innovative materials has become an essential goal. In this context, an overview of recent advances in hydrogels based on chitosan and nanocomposites and their application for the depollution of wastewater contaminated with dyes is reported herein. The present review focuses on (i) the challenges raised by the synthesis process and characterization of the different hydrogels; (ii) the discussion of the impact of the main parameters affecting the adsorption process; (iii) the understanding of the adsorption isotherms, kinetics, and thermodynamic behavior; and (iv) the examination of the possibility of recycling and reusing the hydrogels.

Beetroot extract@chitosan nanocomposite as a promising approach towards cancer therapy

The exceptional antioxidant properties of beetroot (BR) and the cancer antiproliferative effects of chitosan nanoparticles (CS NP) have led to the synthesis of a BR@CS nanocomposite (NC) in this study. The novel BR@CS NC was applied to human epithelial colorectal adenocarcinoma (Caco-2), human epithelial ductal breast carcinoma (T-47D), and human epithelial lung carcinoma (A549) cells. SEM characterization of CS NP revealed a variety of particle shapes ranging from 20 to 58 nm in diameter. UV-VIS analysis confirmed the formation of the BR@CS NC, while FTIR analysis demonstrated strong hydrogen bonds between CS NP and BR. These bonds reduced the positive surface charge of CS NP, as indicated by zeta potential analysis. When applied to cancer cell lines at a concentration of 250 μg/mL, the BR@CS NC successfully eradicated 89 % of A549, 88 % of T-47D, and 83 % of Caco-2 cell lines. The cell death mode exhibited extensive, apoptotic, and massive necrotic changes in all cell lines treated with BR@CS NC. Caspase 3 (CasP3) and P53 levels were elevated in BR@CS NC-treated cells. This study merges BR's antioxidant and anti-inflammatory properties with the antiangiogenic mechanism and inhibition of tumors by CS NP, resulting in a unique and innovative strategy for cancer treatment.

Cyclodextrin Polymer-Loaded Micro-Ceramic Balls for Solid-Phase Extraction of Triazole Pesticides from Water

A citric acid cross-linked β-cyclodextrin (β-CD) polymer was synthesized and loaded on micro-ceramic balls to fabricate the solid-phase adsorbents (P-MCB) for adsorption and extraction of triazole pesticides from water. The stability of β-CD polymer and P-MCB was investigated in solutions with different pH values at different temperatures. The adsorption properties and the influence of kinetics, sorbent amount, pesticide concentration, and temperature on the adsorption capacity were evaluated. The results showed P-MCB had favorable adsorption of 15.98 mg/g flutriafol in 3.5 h. The equilibrium data followed the Freundlich equation, and the adsorption of flutriafol and diniconazole followed the second-order kinetics. The recovery rate of P-MCB for triazole pesticides in water was satisfactory, and the recovery rate was still 80.1%, even at the 10th cycle. The P-MCB had good stability, with a degradation rate of 0.2% ± 0.08 within 10 days, which could ensure extraction and recycling.

Graphene oxide@Fe3O4-decorated iota-carrageenan composite for ultra-fast and highly efficient adsorption of lead (II) from water

The aggravated problem of lead pollution, especially in aquatic environments, necessitates the development of eminent adsorbents that could radically solve this environmental problem. Hence, a new composite was constructed based on iota carrageenan (i.Carr), graphene oxide (GO) and magnetite (Fe3O4) for removing noxious Pb2+ ions. The GO@Fe3O4-i.Carr composite was characterized by VSM, SEM, XPS, XRD, FTIR and Zeta potential. The removal of Pb2+ ions attained a quick equilibrium of almost 30 min with a removal efficiency reaching 93.68 %. The removal of Pb2+ was boosted significantly, in the order of GO@Fe3O4-i.Carr(1:1) > GO@Fe3O4-i.Carr(1:3) > GO@Fe3O4-i.Carr(3:1). Moreover, acquired experimental data fitted the pseudo 2nd order kinetic model and Freundlich isotherm model with a maximal monolayer adsorption capacity reached 440.05 mg/g. Notably, after five adsorption runs, the composite maintained its removal efficiency exceeding 74 %. The assumed adsorption mechanisms of Pb2+ onto GO@Fe3O4-i.Carr were complexation, precipitation, Lewis acid-base, and electrostatic attraction forces. Overall, the GO@Fe3O4-i.Carr composite elucidated the auspicious adsorbent criteria, comprising fast adsorption with high performance, ease-separation and tolerable recyclability, advising its feasible use to decontaminate water bodies from hazardous heavy metals.