Removal of oil spills by novel amphiphilic Chitosan-g-Octanal Schiff base polymer developed by click grafting technique

Ultrafiltration membrane based on chitosan/adipic acid: Synthesis, characterization and performance on separation of methylene blue and reactive yellow-145 from aqueous phase

Here, we report for the first time using of the nontoxic chitosan/adipic acid cross-linked membrane CS/AA in the separation of methylene blue and reactive yellow-145 from aqueous phase. The reason we chose adipic acid as a cross-linking agent is because it gives the cross-linked membrane moderate flexibility due to the presence of four methylene groups in its structure. The structure of the cross-linked membrane CS/AA and their properties were confirmed through, FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and BET analysis. The thermal properties of membrane indicated an improvement in its flexibility and hydrophobicity, but this improvement was accompanied by a decrease in its thermal stability. pHpzc value and porosity of the CS/AA were 7.88, and 73.95 % respectively. The average pore radius distribution ranged from 2 to 27 nm. The prepared cross-linked membrane provides spontaneous and continuous purification of water with a high efficiency. This is due to the membrane CS/AA ability to separate methylene blue and reactive yellow-145 from the aqueous phase almost completely. The results revealed that the removal efficiency and permeation flux for MB were 100 % and 1 L/m2.h respectively at initial dye concentration of (4,8) mg/L, at 1 bar, and the removal efficiency and permeation flux for RY-145 were (94,96) % and (1.06, 2.09) L/m2.h respectively at 100 mg/L and at (1,1.5) bar. Such cross-linked nanopore polymer membranes provide a new approach for emerging novel purification systems, principally in the field of environmental field.

Flame retardant and superoleophilic polydopamine/chitosan-graft (g)-octanal coated polyurethane foam for separation oil/water mixtures

The discharge of crude petroleum oils and their derivatives poses serious environmental challenges, which can be mitigated through oil/water separation. In this study, polyurethane (PU)/polydopamine (PDA)/chitosan-graft (g)-octanal foam was prepared by immersing of PU foam in PDA and chitosan-g-octanal solutions. The fabricated PU foam exhibited thermal stability, flame retardancy, and hydrophobicity/superoleophilicity. The coated PU foam can selectively absorb heavy and light oils from dynamic and static oil/water mixtures. The maximum sorption capacity for olive oil was found to be as high as 41.48 g/g. PU/PDA/chitosan-g-octanal foam also demonstrated excellent flame retardancy and the ability to quickly extinguish fire, as confirmed by the limiting oxygen index (LOI) test.

A review study on green synthesis of chitosan derived schiff bases and their applications

Chitosan is a bio-degradable, bio-compatible, non-toxic, and renewable biopolymer. The reactive amino group of chitosan has gained importance because using these amino groups can help achieve the different types of structural modification in chitosan. Chemical modification of chitosan via imine functionalization results in the formation of a chitosan Schiff base. The present review covers the green synthesis of chitosan Schiff bases using non-conventional green methods such as microwave irradiation, green solvent, ultrasound irradiation, and one-pot synthesis. These methods are energy-efficient and greener versions of the conventional condensation methods. Scientists have paid significant attention to the chitosan Schiff base because of its unique properties and versatility. These molecules display various biological applications, including antioxidant, antimicrobial, anticancer, antibacterial, and anti-fungal. In addition to biological applications, chitosan Schiff base also has other applications like corrosion inhibition, catalysis, metal ion adsorption, and as a sensor. Available literature particularly shows the different methods for the synthesis of chitosan Schiff bases and their different applications. This review gives detailed insight regarding sustainable approaches to the synthesis of chitosan derived Schiff bases and their applications in various emerging fields.

Characterization of an isolated lactase enzyme produced by Bacillus licheniformis ALSZ2 as a potential pharmaceutical supplement for lactose intolerance

Introduction

Lactose intolerance is a widespread problem that affects people of many different races all over the world. The following pharmacological supplements can improve the lives of those who suffer from this issue.

Methods

This work focused on lactase producer isolation and statistical design (Plackett-Burman, and BOX-Behnken) to maximize the effectiveness of environmental factors. A lactase-producing bacterium was chosen from a discovery of 100 strains in soil that had previously been polluted with dairy products. Plackett-Burman investigated fifteen variables.

Results

The most critical variables that lead to increased lactase synthesis are glucose, peptone, and magnesium sulfate (MgSO4). The ideal process conditions for the creation of lactase yield among the stated variables were then determined using a BOX-Benken design. To establish a polynomial quadratic relationship between the three variables and lactase activity, the Box-Behnken design level was used. The EXCEL-solver nonlinear optimization technique was used to predict the best form for lactase production. The ideal temperature and pH levels have been determined, both before and after the lactase purification process, to achieve the highest performance of isolated lactase.

Conclusion

According to this study, Bacillus licheniformis is a perfect supply of the lactase enzyme (β -Galactosidase), It can be used as a product to assist people who have health issues due to lactose intolerance.

Functionalization of chitosan with poly aromatic hydroxyl molecules for improving its antibacterial and antioxidant properties: Practical and theoretical studies

In this study, the chitosan backbone was functionalized with 2,2',4,4'-tetrahydroxybenzophenone by Schiff base, bonding the molecules into the repeating amine groups. The use of ¹H NMR, FT-IR, and UV-Vis analyses provided compelling evidence of the structure of the newly developed derivatives. The deacetylation degree was calculated to be 75.35 %, and the degree of substitution was 5.53 % according to elemental analysis. The thermal analysis of samples using TGA demonstrated that CS-THB derivatives are more stable than chitosan itself. SEM was used to investigate the change in surface morphology. The improvement of the biological properties of chitosan was investigated in terms of its antibacterial activity against pathogenic antibiotic-resistant bacteria. The antioxidant properties showed an improvement in activity compared to chitosan by two times against ABTS radicals and four times against DPPH radicals. Furthermore, the cytotoxicity and anti-inflammatory properties were investigated using normal skin cells (HBF4) and WBCs. Quantum chemistry calculations revealed that combining polyphenol with chitosan makes it more effective as an antioxidant than either chitosan or polyphenol alone. Our findings suggest that the new chitosan Schiff base derivative could be utilized for tissue regeneration applications.

Synthesis and physicochemical properties of an aromatic chitosan derivative: In vitro antibacterial, antioxidant, and anticancer evaluations, and in silico studies

This study was designed to synthesize a functionalized chitosan by coupling the amine groups of chitosan with 2,4,6-Trimethoxybenzaldehyde, producing a chitosan Schiff base (Cs-TMB). The development of Cs-TMB was verified employing FT-IR, ¹H NMR, the electronic spectrum, and elemental analysis. Antioxidant assays exhibited significant ameliorations of Cs-TMB, reporting scavenging activities of 69.67 ± 3.48 % and 39.65 ± 1.98 % for ABTS^•+ and DPPH, respectively, while native chitosan showed scavenging ratios of 22.69 ± 1.13 % and 8.24 ± 0.4.1 % toward ABTS^•+ and DPPH, respectively. Besides, Cs-TMB exerted significant antibacterial activity up to 90 % with remarkable bactericidal capacity against virulent gram-negative and gram-positive bacteria compared to the original chitosan. Furthermore, Cs-TMB exhibited a safe profile against normal fibroblast cells (HFB4). Interestingly, flow cytometric analysis showed that Cs-TMB demonstrated prominent anticancer properties of 52.35 ± 2.99 % against human skin cancer cells (A375), compared to 10.66 ± 0.55 % for Cs-treated cells. Moreover, Python and PyMOL in-house scripts were used to predict the interaction of Cs-TMB with the adenosine A1 receptor and visualized as a protein-ligand system submerged in a lipid membrane. Overall, these findings accentuate that Cs-TMB could be a favorable representative for wound dressing formulations and skin cancer treatment.