Synthesis and identification of new thermostable polyamides containing xanthene units with antibacterial properties and relevant composite grafted with modified GO nanoparticles

Efficient adsorptive removal of used drugs during the COVID-19 pandemic from contaminated water by magnetic graphene oxide/MIL-88 metal-organic framework/alginate hydrogel beads

Currently, the presence of drugs used in the COVID-19 pandemic in water bodies is worrisome due to their high toxicity, which necessitates their critical removal by developing highly efficient adsorbents. Hence, in this study, alginate hydrogel beads of magnetic graphene oxide@MIL-88 metal-organic framework (GO@Fe3O4@MIL-88@Alg) were prepared for the first time and then utilized as a new absorption system for the removal of COVID-19 drugs such as doxycycline (DOX), hydroxychloroquine (HCQ), naproxen (NAP), and dipyrone (DIP) from aqueous solutions by batch adsorption manner. The effects of different experimental factors, such as adsorbent dosage, contact time, pH, drug concentration, temperature, ionic strength, presence of an external magnetic field (EMF), and magnet distance from the adsorption flask were optimized for the removal of COVID-19 drugs. The adsorption equilibrium isotherm proved that the adsorption process of DOX, HCQ, NAP, and DIP drugs on GO@Fe3O4@MIL-88@Alg hydrogel beads conformed to the Langmuir model and followed the pseudo-second-order adsorption kinetics. The maximum adsorption capacities of DOX, HCQ, NAP, and DIP drugs obtained for GO@Fe3O4@MIL-88@Alg hydrogel beads with the Langmuir model were 131.57, 79.92, 55.55, and 49.26 mg/g at 298 K, respectively. The thermodynamic study suggested a spontaneous endothermic adsorption process. Also, the conclusion from this study confirmed the validity of GO@Fe3O4@MIL-88@Alg hydrogel beads for excellent removal of COVID-19 drugs from water samples. It was also found that the GO@Fe3O4@MIL-88@Alg hydrogel beads could be reused with satisfactory removal efficiency in six cycles. Based on the study, the GO@Fe3O4@MIL-88@Alg hydrogel beads could be considered a sustainable, simple, economical, environmentally friendly absorption system for the removal of pharmaceutical contaminants from water.

Investigation of thermal, antibacterial and heavy metal ion removal behavior of polyamide/polyimide iron oxide nanocomposites

In this study, a newly-designed diamine (DA) containing pyridine and carbazole groups was synthesized and the relevant polyamides (PAs) and polyimides (PIs) were prepared by polymerization reaction between the DA monomer and terephthalic acid, adipic acid, and pyromellitic dianhydride. In addition, polymer nanocomposites were prepared through a combination of the synthesized polymers with modified magnetite iron oxide nanoparticles. The synthesized compounds were fully characterized by hydrogen nuclear magnetic resonance (1HNMR), fourier-transform infrared (FTIR), field emitting scanning electron microscopy (FESEM), energy dispersive X-Ray (EDX), Transmission electron microscopy (TEM), Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) analyses. All of the synthesized properties of compounds such as thermal stability, viscosity, elimination capability of heavy metals ions adsorption, and antibacterial activity were investigated. Polyamides and PI showed good solubility in aprotic solvents and the viscosity was in the range of 0.72–0.89 dL/g. Also, the glass-transition temperature (Tg) of synthetic polymers was in the range of 214–273°C and 10% weight loss temperatures (T10%) for the synthesized compounds were in the temperature range of 280–492°C in N2, and the percentage of residual ash between 61 and 74%. The adsorption rate of Hg2+, Co2+, Pb2+, Cr2+, and Cd2+ metal ions by PA containing terephthalic acid (PAT) and its nanocomposite (NCPAT) showed that nanocomposite has a better performance compared to PAT. The highest and lowest removal efficiency was related to Hg2+ and Pb2+ ion, respectively. Finally, antibacterial test results against Gram-positive and Gram-negative bacteria showed favorable inhibitory effects of all the synthesized polymers.

The preparation of novel poly(ether-amide)s based on spiro[fluorene-9,9′-xanthene] and a polyamide/polymer-coated ZnO nanocomposite: thermal, optical, biological, and methylene blue dye adsorption attributes

Novel thermostable, photoactive, and solvable polyamides containing fluorene and xanthene groups were synthesized, as was a ZnO-based composite. These compounds were used as antibacterial and anticancer agents and as absorbents to remove MB dye.

Facile synthesis of Zn-based metal-organic framework in the presence of carboxymethyl cellulose: A safe carrier for ibuprofen

Fabrication of porous materials with a high surface area affords a great interest to achieve a system with a prolonged drug release manner. In this context, the subject of this work is to describe a novel green one-pot synthesis route for the growth of metal-organic framework (MOF) from zinc metal (Zn) and 1, 4-benzene dicarboxylic acid (BDC) in the vicinity of the carboxymethyl cellulose (CMC), which homogeneously confined in the biopolymeric chains. The synthesized Zn (BDC)@CMC was characterized and confirmed using different analyses. N₂ adsorption/desorption isotherms determined the mean diameter of pore size of about 2.3993 nm. Ibuprofen (IBU) as a model drug was highly loaded to the Zn(BDC)@CMC by immersing in the drug solution; 50.95%. The in vitro IBU release study indicated that the Zn(BDC)@CMC has more attractive performances than pristine Zn(BDC). The IBU release occurred via the Fickian mechanism. Isotherm studies showed that the IBU adsorption on obeys from Langmuir isotherm; R² 0.9623. The MTT results revealed the HEK 293A cell viability of higher than 90% for Zn(BDC)@CMC that confirms its cytocompatibility. Overall, obtained results confirm the functionality of CMC biopolymer for in situ growth of MOF in the presence of it due to having the reactive nature.

Chitosan coated Fe3O4@Cd-MOF microspheres as an effective adsorbent for the removal of the amoxicillin from aqueous solution

In this work, for the first time, a new magnetic cadmium-based MOFs (Fe₃O₄@Cd-MOF) was successfully synthesized in a green way and then modified with chitosan (CS) in the microsphere form (Fe₃O₄@Cd-MOF@CS). The obtained materials were fully characterized by several techniques. In the following, the efficiency of Fe₃O₄@Cd-MOF@CS was explored for the removal of amoxicillin (AMX). The outcome of the adsorption study showed that the removal efficiency is affected by CS and reaches its optimum at pH 8 and contact time of 240 min. Under optimized conditions, over 75% of AMX was removed. The kinetic and the isotherm of the adsorption were fit with the pseudo-second-order model and the Langmuir adsorption isotherm respectively. Eventually, the maximum adsorption capacity was obtained ~103.09 mg/g. Interestingly, these findings convince that the newly prepared Fe₃O₄@Cd-MOF@CS could be proposed as a promising magnetically separable adsorbent for antibiotic contaminants removal from the aqueous solution.

Design and fabrication of photoactive imidazole-based poly(ether-imide)s and a polyimide/HBP-modified SiO2 composite: toward high heat-resistance, antimicrobial activity and removal of heavy metal ions

This article describes the synthesis and properties of novel imidazole-based aromatic polyimides (PIs) containing bulky groups from direct polycondensation of two diamines with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and (hexafluoroisopropylidene)diphthalic anhydride (6FDA). The structure–property relationship of the prepared samples was fully determined via FT-IR, ¹H and ¹³C NMR and elemental analysis (CHN) techniques. The inherent viscosity values of the polyimides ranged from 0.51 to 0.73 dL g⁻¹. These PIs showed glass transition temperatures ranging from 273 to 306 °C, and 10% mass loss temperatures within the range of 478–504 °C in a N₂ atmosphere. High transparency with a UV-visible absorption cut-off wavelength was found to range between 285 and 300 nm. Good antimicrobial activity can be correlated with the presence of xanthene and imidazole units into the main structure of PIs. Next, SiO₂ nanoparticles as inorganic nanoparticles were added to one of the synthesized polyimides (BTDA-PIb), causing changes in the attributes of both the nanoparticles and PI. The data obtained from examining the properties of the prepared BTDA-PIb/HBP@SiO₂ demonstrated increased heat resistance, photoluminescence intensity, and antimicrobial inhibition compared to pure PI. Also, in this article, the polymeric samples as adsorbents were evaluated for extraction of heavy metal ions (Hg²⁺ and Co²⁺) from water sources.

Novel thermostable, photoactive, and solvable poly(ether-imide)s containing imidazole-based pendant groups and a BTDA-PIb/HBP@SiO₂ composite were synthesized and used due to their antimicrobial activity and as an adsorbent to remove heavy metal ions.