Marwa. M. Abd El-Hady

A significant amount of interest in Schiff bases (SBs) produced from metal-based hydrogels and chitosan has recently been garnered for their biological applications. We successfully synthesised a new hydrogel by crosslinking chitosan with 2,3,4-trihydroxybenzaldehyde (THB) to produce chitosan Schiff base (CSB) and subsequently created its Zn(II) metal composite and ZnO nanoparticles. Two different concentrations of Zn(II) ions (1% w/v and 1.5% w/v) and mass ratio of (CS: THB) of 1.0:0.25, 1.0:0.5, 1.0:1.0 and 1.0: 1.5 were studied. The structure and characteristics of the composite hydrogels are characterised using various techniques. The synthesised CSB and its nanocomposites were confirmed using XRD analysis, UV–Vis spectroscopy, and FTIR. The interactions among chitosan and metals, thermal stability, surface shape, and the elemental presence of metal ions in the hydrogels were analysed using FTIR, TGA, SEM, NMR, and EDX techniques. The synthesized CSB hydrogels were tested for their swelling manners at different temperatures ( 30, 45, and 60 °C) and pH ( 4, 7, 10). The antimicrobial applications were also investigated. The results indicate that the most significant degree of swelling occurs at low pH levels. The ZnO@CSB nanocomposite hydrogel has a swelling degree of 267%, whereas the Zn(II)@CSB nanocomposite hydrogel has a swelling degree of 260%. The antimicrobial tests demonstrated that all hydrogels and their nanocomposites possess potential antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. From the results, all samples demonstrate higher antimicrobial activity against Candida albicans than against bacterial strains. The ZnO@CSB nanocomposite hydrogel exhibited the maximum inhibition rate at 19 mm, compared with the Zn(II)@CSB nanocomposite hydrogel at 15 mm. Furthermore, the hydrogel that was synthesized displayed significant values of tensile strength as well as elongation at break. Finally, these innovative hydrogels can be promising candidates for sustainable biomedical applications and wound dressing materials.

Due to the lack of UV-protective properties for cotton textiles and the potential of cotton textiles to cause microbes to their users, we synthesized benzimidazole Schiff base derivative (BZI) namely N-((1H-benzo[d]imidazol-2-yl)methyl)-1-(4-fluorophenyl)methanimine and their V(III), Fe(III), Co(II), Ni(II), and Cu(II) complexes as UV protection and antimicrobial agents for cotton textile. Several techniques investigated these compounds: ¹H, ¹³C NMR, IR, UV–Vis, elemental analysis, DTA, and TGA. The Schiff base ligand behaved as a bidentate ligand. The prepared ligand and its complexes are used to treat the cotton fabrics (CFs) by immersing the fabric in the solution of the samples under ultrasonic. The treated cotton fabrics were investigated using IR and SEM-EDX analysis. The UPF values of the treated cotton fabric were obtained. The results showed that the cotton fabric treated with Fe(III) and Cu(II) complexes had excellent UV protection with UPF values of 50+. The disc diffusion method evaluated the treated cotton fabric’s antimicrobial activity. The antifungal activities of the treated CFs demonstrated that the Co(II)-BZI-CF was active on C. albicans with an inhibition zone of 12 mm, while the other samples were inactive on C. albicans and A. flavus. The V(III)-BZI-CF and Fe(III)-BZI-CF had no activity against S. aureus and E. coli bacteria while the other samples gave an inhibition zone of between 10 to 17 mm. Unlike previous studies that primarily focused on either UV protection or antimicrobial properties of metal complexes separately, this research integrates both functionalities by synthesizing benzimidazole Schiff base metal complexes and applying them to cotton textiles, demonstrating enhanced UV protection and selective antimicrobial activity.

An increase in textile resistance to antimicrobial agents has posed a pressing need for the development of new antimicrobials. Therefore, the antimicrobial characteristics of thiophene and pyridine acetohydrazide derivatives have been developed as novel textile-modified complexes exhibiting antibacterial agents. Synthesis and characterization of pyridyl-thienyl acetohydrazide derivative (AHZ) using NMR (¹³C and ¹H) and FTIR. Modification of cotton fabric (CF) with acetohydrazide (AHZ) and metal chlorides of divalent Cr, Mn, Co, Ni, Cu, and Zn and trivalent Fe, and Cr. SEM-EDX and Fourier-transform infrared were utilized to characterize cellulose-based cotton fabric (CF) attached to AHZ and their metal (M) complexes. Antimicrobial activity was examined against two types of bacteria, namely S. aureus and E. coli, and two types of fungi, namely C. albicans and A. flavus. All modified samples exhibited higher efficiency towards bacterial strains than fungal strains. In addition, cellulose modified with Ni (II) confers the most antibacterial protection efficiency.

Ultraviolet (UV)-protective and antimicrobial cotton fabrics are necessary for the protection of our skin. In this article, a pyrimidinethione hydrazide (PTH) derivative ligand was complexed with Mn, Co, Ni, Cu, Zn, and Cd as divalent metals and Fe and Cr as trivalent metals to prepare highly antimicrobial and UV-blocking metal–pyrimidinethione hydrazide-modified cotton fabrics (M-PTH-C). The cotton sample treated (M-PTH) was found to show improved efficiency over pyrimidinethione hydrazide-modified cotton (PTH-C). Cadmium-PTH-C showed the highest performance of antimicrobial action against Staphylococcus aureus (Gram-positive bacteria), Escherichia Coli (Gram-negative bacteria), and Candida albicans (fungi) with zones of inhibition 31 mm, 18 mm, and 27 mm, respectively. Furthermore, all M-PTH-C samples showed no effect against Candida albicans, except Co, Ni, and Cd pyrimidinethione hydrazide-modified cotton with inhibition zones of 16 mm, 27 mm, and 22 mm. In addition, no compounds showed any activity against Aspergillus flavus except Cd-PTH-C, which gave an excellent performance, with a 33 mm inhibition zone. Furthermore, most modified cotton fabrics have excellent UV protection. Fe-PTH-C showed 113.3 as the highest Ultraviolet protection factor (UPF) compared to the other modified samples. The tensile strength test of all samples was also investigated. The values of tensile strength for the treated cotton samples are slightly affected compared to the untreated ones.

Phosphorus input with excessive use of fertilizers and manure as one of the main sources of nutrient pollution has increased recently in the wastewater as result of intensive farming and industrialized and densely populated areas. The novelty of the current work lies in improving a Vertical Aerated Rock Filter (VARF) using steel slag and limestone media to enhance the efficiency of a rock filter (RF) to eliminate total phosphorus (TP) from domestic wastewater. RF was designed with steel slag and limestone (calcium hydroxide) as a pilot scale called vertical aerated steel slag filter (VASSF) and optimized based on hydraulic loading rates (HLR) (0.16 to 5.44 m³/m³ day) and airflow rates ranging from 3 to 10 L/min. The highest removal for the design of the laboratory scale steel slag filter (LSSSF) was achieved by approximately 58%, while for the laboratory-scale limestone filter (LSLSF), it was 64%. The VASSF achieved a removal percentage at 30% of TP, biological oxygen demand (BOD; 89%), chemical oxygen demand (COD; 75%), total suspended solids (TSS; 73%), and total coliforms (TC; 96%), recorded with 7 L/min of an airflow rate and 1.04 m³/m³.day of hydraulic loading rate (HLR) at potential of hydrogen (pH) 7.3 and 5.09 mg/L of dissolved oxygen (DO). These findings indicated that the steel slag is higher than limestone in TP removal, because of ion exchange between phosphorus hydrolysis and the adsorption process. Moreover, in the pilot study, the removal efficiency needs more investigation to determine the best conditions for TP considering the temperature, which is unstable, and presence of other pollutants, which might negatively affect the removal efficiency under unstable conditions.

Essential oils (EO_S), which naturally come from plants, have significant antibacterial properties against a variety of pathogens, but their high volatility and poor water solubility severely restrict their use in the textile industry. In this study, an inclusion complex based on β-cyclodextrin (β-CD)/EO_S was prepared by two different simple methods: pad dry cure (method 1) and pad batch (method 2). A glyoxal crosslinking agent was used for the fixation of the inclusion complexes on the surface of the fabric. Lavender, rosemary, salvia, and lemon essential oils were applied. The structure of the β-CD/EOs inclusion complex was investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and weight gain (%), which indicated that the β-CD/EOs were successfully deposited on cellulose-based fabric. The results demonstrated that β-CD enhanced the oils’ scent stability, with the advantage of exhibiting no major change in the tensile strength or permeability of cotton. Lavender oil had the highest stability scent with a value of 3.25, even after 30 days of evaluation. The antibacterial activity showed that EO_S/βCD-impregnated fabrics for method 1 had an inhibition zone ranging from 33 to 23 mm, while the inhibition zone for method 2 ranged from 39 mm to 29 mm, indicating that our treatment was able to control the growth of bacteria, even after five washing cycles. This study confirmed that the EOs/βCD inclusion-complex-deposited cotton fabric might hold further promise for medical and hospital use.

In the search for ultraviolet radiation exposure protective textile to minimize risk factors for skin cancer, we synthesized a Schiff base ligand from the condensation reaction 2,4‐dihyroxybenzaldehyde with p‐amino aniline. Also, the Schiff base complexes with Fe (III), Mn (II), and Cr (III) were synthesized. The ligand and the complexes were characterized by ultraviolet (UV)‐visible, Fourier transform infrared spectroscopy, ¹H ¹³C NMR, X‐ray diffraction, and elemental analysis. We treated cotton fabric (CF) with the complexes to achieve the conventional fabric materials with highly efficient and durable UV protection properties. The modified CF is also characterized via different techniques. UV protection properties of coated fabrics are investigated by measuring UV protection factor values. Excellent UV protection even after 10 washing cycles can be used in protective textiles. In contrast to fungal activity, modified CF demonstrated strong antibacterial activity. We used the density functional theory to compute the reactivity indices and the binding energy of the complexes with the cellulosic fiber. The theoretical results favor binding the Fe (III) complex with the cellulose fiber. Also, Fe (III) metal complexes gave the highest antibacterial and UV protection. The modified fabrics' antibacterial and excellent UV protection make the studied complexes potential candidates for applying UV protective (ultraviolet protection factor) textiles.

Antimicrobial textiles have played an increasingly important protection role in the medical field. With this aim, Schiff bases and nanometal complexes on the cotton fabric were in situ synthesized for achieving the conventional cotton fabric’s highly efficient and durable UV protection and antibacterial properties. Herein, a new Schiff base derived from the condensation reaction of 2,4-dihyroxybenzaldehyde with p-amino aniline was synthesized. Co, Ni, Cu, and Zn complexes of the Schiff base were also prepared and characterized by UV-Vis, Fourier-transform infrared spectroscopy, ¹HNMR, ¹³CNMR, elemental analysis, and thermal analysis. The modified cotton fabric was also characterized via X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transition electron microscope (TEM), and Energy Dispersive X-Ray Analysis (EDX). Moreover, the microbial, UV protection, and tensile strength of the samples were investigated. The antimicrobial was studied against Gram-positive bacteria, Gram-negative bacteria, and fungal strains. Modified cotton fabric exhibited highly antibacterial activity in contrast with fungal activity. These results depended on the Schiff base and the type of metal complex. The results also show that the cotton fabric modified by in situ nanometal complexes provides excellent UV protection.