FTIR Analysis Research Articles

First-ever study uncovers microplastic contamination in Nepalese table salt

Despite numerous studies on microplastic contamination in table salt worldwide, research focusing on Nepalese table salts is remarkably lacking. This study aims to address this gap by investigating microplastic contamination in salt samples collected from all seven provincial zones of Nepal. Our objective is to comprehensively assess the presence and characteristics of microplastics in salt sold within local markets across the country. Five salt packaging companies utilized by Nepalese consumers were identified. The collected salt samples were digested with Fenton's reagent to extract microplastics, which were then observed under a digital microscope. Using an OMAX stereomicroscope at 30× magnification and an OMAX A3503S digital camera, each microplastic was carefully identified and quantified. FTIR analysis was conducted to identify the polymer types. All tested salt samples (100 %) from both Nepalese and Indian packaging companies contained microplastics. Microplastic abundance exhibits variability among the samples, ranging from 80 to 1040 microplastics per kilogram of salt. The average value stands at 381 ± 219 microplastics per kilogram of salt sample. The distribution of microplastic concentrations within the salt samples reveals that the majority fall within the 301–400 microplastics per kilogram salt range, constituting 33 % of the total samples. Color analysis showed diverse contamination sources, while microplastic shapes included fibers (56 %), films (17 %), fragments (16 %) and pellets (11 %). Polymer type analysis confirmed the presence of polyethylene and polypropylene in tested microplastics. The study estimated that Nepalese individuals ingest an average of 1853 microplastics annually, indicating significant exposure from salt consumption. Surprisingly, factors such as storage conditions, date of salt packaging and thickness of packaging material did not significantly affect microplastic presence in the samples, suspecting manufacturing processes as the primary contributors to contamination. Therefore, the raw materials and purification practices for salt need improvement, as existing methods are insufficient to eliminate microplastics. These findings emphasize the need for further research and mitigation efforts to address microplastic contamination in Nepalese salt and its potential health impacts.

Fabrication and evaluation of a plasmonic biosensor based on silica-coated gold nanorods for highly-sensitive detection of anti-Müllerian hormone

Anti-müllerian hormone is a crucial biomarker for reproductive potential, but current detection methods are not cost-effective or time-efficient. In this study, we set out to develop a biosensor using gold nanorods (Au-NRs) coated with a functionalized silica network. The biosensor structure was completed by covalently binding the anti-Müllerian hormone antibody to SiO2@Au-NRs. We confirmed the proper coating of the gold nanorods using HR-TEM, EDS/EDAX, zeta potential, and FT-IR analysis. To assess the sensitivity of SiO2@Au-NRs, we analyzed the LSPR peak position redshift in different concentrations of ethylene glycol. The biosensor was then used to recognize the AMH antigen and determine the limit of detection (LoD) and quantification (LoQ) for the biosensor. Our research has shown that the SiO2@Au-NRs have a suitable thickness. The SiO2@Au-NRs demonstrated impressive sensitivity as a nano biosensor. The AMH antigen identification results indicated that the nano biosensor was highly sensitive. The LoD and LoQ values were 0.086 and 0.262 ng ml−1, respectively, very close to the values obtained by the ELISA kit. Furthermore, LSPR biosensors have reduced detection costs and measurement time. Their high sensitivity makes them excellent candidates for use in diagnostic kits.

Development of biocompatible packaging material: starch/PVA-based bio-composite enhanced with hydroxypropyl methylcellulose

ABSTRACT Hydroxypropyl methylcellulose (HPMC) incorporated bio-composite films (unplasticized and plasticized) were prepared from pregelatinized maize starch/polyvinyl alcohol (PMS/PVA) blends by solution casting method. 10% boric acid (BA) was used as crosslinker. The physico-mechanical properties (tensile strength (TS), elongation at break (%EB), water solubility and moisture uptake) of the bio-composite films were studied. The thermo-chemical stability of the biofilms was studied by FT-IR, TGA and DSC analysis. TS, %EB, water solubility and moisture absorbency of 10% HPMC containing unplasticized films were found 38.1 MPa, 8.5%, 61% and 32.3%, respectively, however, the films were hard and brittle. On the contrary, TS, %EB, water solubility and moisture absorbency of 10% HPMC plasticized films were found 19.2 MPa, 28.5%, 62.2% and 57.3%. The biofilms exhibited relatively low water solubility and moisture uptake compared to higher HPMC containing composite. The thermo-chemical analysis revealed that the HPMC incorporated plasticized film was more thermally stable compared to pure PMS, PVA, HPMC and other bio composite films due to strong hydrogen bonding interaction with BA. The biodegradability of HPMC incorporated plasticized films was confirmed by soil burial test (anaerobic condition, RH 98%, 3 months). Therefore, the plasticized biofilm would be considered an alternative approach for biocompatible packaging material.

Efficient synthesis of some [1,3]-oxazine derivatives in the presence of solid acid nano catalyst based on ferrierite and study on their activity against breast cancer through molecular docking calculation

In this research, the magnetic solid acid nanocatalyst based on ferrierite has been prepared and used as catalyst for the green synthesis of some [1,3]-oxazine derivatives in water at room temperature. The synthesized compounds were obtained in high to excellent yields after short reaction times and the structure of synthesized products were investigated by spectroscopic methods such as: FT-IR, 1H NMR and 13C NMR. The prepared magnetic solid acid catalyst was characterized using XRD, FT-IR, FE-SEM, EDX, elemental mapping, TGA and VSM analysis methods. Magnetic catalyst has easy separation ability, which leads to better and easier recycling. The preparation and synthesis of [1,3]-oxazine derivatives were carried out at room temperature in the presence of M-FER/TEPA/SO3H. Easy workup, green solvent (water) and also short reaction times with high to excellent yield of products, are some of advantageous of presented method. Docking calculations on the structure of the synthesized compounds proved their medicinal properties against breast cancer cells.

Delineating acetaminophen biodegradation kinetics and metabolomics using bacterial community.

Acetaminophen [N-(4-hydroxyphenyl) acetamide, APAP]is an extensively and frequently consumed over-the-counter analgesic and antiphlogistic medication. It is being regarded as an emerging pollutant due to its continuous increment in the environment instigating inimical impacts on humans and the ecosystem. Considering its wide prevalence in the environment, there is an immense need of appropriate methods for the removal of APAP. The present study indulged screening and isolation of APAP degrading bacterial strains from pharmaceuticals-contaminated sites, followed by their molecular characterization via 16SrRNA sequencing. The phylogenetic analyses assigned the isolates to the genera Pseudomonas, Bacillus, Paracoccus, Agrobacterium, Brucella, Escherichia, and Enterobacter based on genetic relatedness. The efficacy of these strains in batch cultures tested through High-performance Liquid Chromatography (HPLC) revealed Paracoccus sp. and Enterobacter sp. as the most promising bacterial isolates degrading up to 88.96 and 85.92%, respectively of 300mg L-1 of APAP within 8days of incubation. Michaelis-Menten kinetics model parameters also elucidated the high degradation potential of these isolates. The major metabolites identified through FTIR and GC-MS analyses were 4-aminophenol, hydroquinone, and 3-hydroxy-2,4-hexadienedioic. Therefore, the outcomes of this comprehensive investigation will be of paramount significance in formulating strategies for the bioremediation of acetaminophen-contaminated sites through a natural augmentation process via native bacterial strains.

A comparative study of in vivo toxicity in zebrafish embryos synthesized CuO nanoparticles characterized from Salacia reticulata.

The Salacia reticulata, a medicinal woody climbing shrub, was utilized for our study, the green synthesis of CuO nanoparticles, which were analyzed through SEM, EDX, FTIR, XRD, and UV‒Vis spectroscopy. This study assessed the toxicity to zebrafish embryos and explored the antibacterial, cytotoxic, antidiabetic, and anti-inflammatory properties of the synthesized nanoparticles. In results, the UV absorption of the CuO NPs showed that the intensity of nanoparticle green colloidal suspension changed from blue to green, which also confirmed that the spectrum of the green CuO NPs changed from colorless to black. in FT-IR and XRD spectral analysis to identify functional groups and determine the particle size of CuO NPs prepared by green and chemical methods. Its showed that CuO NPs (green) had a size of approximately 42.2nm, while CuO NPs (chemical) had a size of approximately 84nm. The morphology of these NPs was analyzed using SEM-EDX. Compared with their chemically prepared counterparts, the green-synthesized CuO nanoparticles demonstrated superior dispersion. Additionally, both green and chemical CuO nanoparticles at a concentration of 200 µL/mL caused developmental anomalies and increased mortality in zebrafish embryos and larvae. The green and chemical CuO NPs inhibited α-glucosidase enzyme activity at concentrations between 10 and 50 µL/mL, with IC50 values of 22 µL/mL and 26 µL/mL, respectively. The extract exhibited anti-inflammatory activity, with IC50 values of 274 and 109 µL/mL. The authors concluded that this green nanoparticle method has potential as a more eco-friendly and cost-effective alternative to traditional synthetic methods. NPs are widely used in human contact fields (medicine and agriculture), hence synthesis methods that do not involve toxic substances are becoming increasingly important.

Study on efficient extraction of saponins from Polygonatum sibiricum by enzyme assisted cold isostatic pressing technology

Saponin is one of the main active ingredients of Polygonatum sibiricum. In this study, the method of enzyme-assisted cold isostatic pressure extraction (EACIP) of Polygonatum sibiricum saponins was established. The effects of different cold isostatic extraction pressures, pressure-maintaining time times, enzymatic temperatures and enzymatic pH on the yield of saponin were investigated, and the factors were simplified by single factor experiments and Box-benhken design (BBD). Under the best extraction conditions, the EACIP method achieved the best possible results and extraction rate was 11.45 % ± 0.017. In addition, SEM-Mapping, XRD analysis and FTIR analysis proved that EACIP treatment increased the extent of cell deformation and improved the mass transfer system between solvent and active substance. Furthermore, by comparing different extraction methods, EACIP was found to have a higher extraction rate due to the synergistic effect of cold isostatic pressure extraction (CIP) and enzymatic hydrolysis extraction (EH). In vitro antioxidant and anti-inflammatory assays demonstrated that EACIP extracts have good antioxidant and anti-inflammatory capacity. Therefore, EACIP is a method to extract natural products from plants with increased extraction rate.

Transformation of As and Cd associated with Fe-Mn-modified biochar during simultaneous remediation on the contaminated soil.

Here, Fe- and Mn-modified biochar (BC-Fe-Mn) was applied to simultaneously stabilize As and Cd in the contaminated soil. The removal efficiencies for NaHCO3-extractable As and DTPA-extractable Cd by BC-Fe-Mn were 60.8% and 49.6%, respectively. The speciation analyses showed that the transformation to low-crystallinity Fe-bound (F3) As, Fe-Mn oxide-bound (OX) of Cd, and residual As and Cd was primarily attributed to stabilizing the two metal(loid)s. Moreover, the correlation analyses showed that the increase of As in F3 fraction was significantly and positively associated with the increase of OX fraction Mn (r = 0.64). Similarly, OX fraction Cd was increased notably with increasing OX fraction Fe (r = 0.91) and OX fraction Mn (r = 0.76). In addition, a novel dialysis experiment was performed to separate the reacted BC-Fe-Mn from the soil for intensively investigating the stabilization mechanisms for As and Cd by BC-Fe-Mn. The characteristic crystalline compounds of (Fe0.67Mn0.33)OOH and Fe2O3 on the surface of BC-Fe-Mn were revealed by SEM-EDS and XRD. And FTIR analyses showed that α-FeOOH, R-COOFe/Mn+, and O-H on BC-Fe-Mn potentially served as the reaction sites for As and Cd. A crystalline compound of MnAsO4 was found in the soil treated by BC-Fe-Mn in the dialysis experiment. Thus, our results are beneficial to deeper understand the mechanisms of simultaneous stabilization of As and Cd by BC-Fe-Mn in soil and support the application of the materials on a large scale.

Synthesis, characterization and evaluation of in vitro potential antimicrobial efficiency of new chitosan hydrogels and their CuO nanocomposites

The phenomenon of microbial resistance and its resulting biofilms to traditional antibiotics is worsening over time. Therefore, the discovery of alternative substances that inhibit microbial activities through mechanisms different from those of known antibiotics requires attention. So, chitosan was crosslinked using different amounts of oxalyl dihydrazide yielding four novel hydrogels; ODHCs-I, ODHCs-II, ODHCs-III, and ODHCs-IV of crosslinking degree 12.17, 20.67, 31.67, and 43.17, respectively. Different amounts of CuO nanoparticles were impregnated into ODHCs-IV, obtaining ODHCs-IV/CuONPs-1 %, ODHCs-IV/CuONPs-3 % and ODHCs-IV/CuONPs-5 % composites. Their structure was emphasized using FTIR, SEM, XRD, TEM, EDX and elemental analysis. Their in vitro antimicrobial and anti-biofilm activities improved with increasing ODH and CuONPs content. ODHCs-IV exhibited minimal inhibition concentration (2 μg/mL) against S. pyogenes that was much lower than Vancomycin (3.9 μg/mL). ODHCs-IV/CuONPs-5 % displayed better inhibition performance than Vancomycin and Amphotericin B against Gram-positive-bacteria and fungi, respectively, and comparable one to that of Vancomycin against Gram-negative-bacteria. ODHCs-IV/CuONPs-5 % displayed much lower minimal biofilm inhibition concentrations (1.95 to 3.9 μg/mL) as compared with those of ODHCs-IV (7.81 and 15.63 μg/mL), against C. albicans, S. pyogenes, and K. pneumonia. ODHCs-IV/CuONPs-5 % composite is safe on normal human cells. Oxalyl dihydrazide and CuONPs amalgamated into chitosan in one formulation promoted its antimicrobial efficiency.

Uncovering the role of free lanthanum (La3+) ions and La oligomer on the surface of La (oxy)hydroxide particles for phosphate removal

La (oxy)hydroxide-based materials have been recognized as promising adsorbents for aqueous phosphate (P) removal. However, comprehending the adsorption behavior of P onto La (oxy)hydroxide particles remains challenging, given the heterogeneous low-crystalline surface encompassing La oligomers and free La3+ ions. In this study, a hydrogen (H) bond capping method was developed to construct La (oxy)hydroxide oligomers (LHOs) to simulate the low-crystalline La on the surface of La (oxy)hydroxide particles. The P uptake capacity was compared among free La3+ ions, LHOs, and La nanoparticle (La-NP) with maximum capacities of 1967.3 ± 30.8 mg/g, 461.1 ± 53.7 mg/g and 62.5 ± 6.0 mg/g, respectively. The FT-IR, Raman, in situ-XRD and XPS deconvolution analyses revealed that the removal of P by free La3+ ions mainly involve the process of chemical precipitation to form LaPO4·0.5H2O. Conversely, the elimination of P by LHOs is primarily attributed to inner-sphere complexation and hydroxyl exchange effect between LaOOH and P. Based on this study, the free La3+ ions and La oligomers on the surface of La (oxy)hydroxide particles play a primary role in P adsorption. These results also suggest that the successively decreased adsorption capacity of La (oxy)hydroxide-based adsorbents in the continuously adsorption/desorption cycles might be due to the irreversible inactivation and recrystallization of free La3+ ions and La oligomers on the surface.

Ultra-efficient peroxymonosulfate utilization and trichloroethylene degradation in heterogeneous catalytic system guided by sheet-like Cu2MnO4 nanoparticles: The role of Cu(III)–O species and free radicals

Synthesizing cubic spinel Cu2MnO4 with nanosheet structure (SCMO) aimed to construct a “non-radical-mediated radical-oxidative reaction”, for increasing PMS utilization efficiency, and solving the defects of SO4•− and •OH through indirect PMS activation by electron transfer process. Compared with box-like Cu2MnO4 (11.1%, 0.0035 min−1) and ordinary Cu2MnO4 nanoparticles (21.3%, 0.0070 min−1), SCMO/PMS showed excellent trichloroethylene removal (98.8%, 0.1577 min−1). The pivotal role of Cu(III) was determined based on EPR analysis, quenching experiments, chemical probe experiments, hydrogen temperature-programmed reduction and Raman spectroscopy analysis, in-situ FTIR and Raman analyses. In brief, the interaction between PMS and SCMO could produce surface-bonded reactive complexes and the subsequent breaking of O–O bond in the sub-stable structure allowed the conversion of Cu(II) to Cu(III), which in turn facilitates the generation of •OH and SO4•−. The density functional theory (DFT) calculations provided supporting evidence for the electron donor role of SCMO and the increase of the electron acceptance capacity of PMS. SCMO/PMS system showed good resistance and degradation efficiency to complex composition and combined pollutants in actually contaminated groundwater, respectively. However, the coexistence of high concentrations of arsenic could significantly affect SCMO performance due to their adsorption on –OH groups, which still need in-depth study.

Kinetics and Mechanism of Cyanobacteria Cell Removal Using Biowaste-Derived Activated Carbons with Assessment of Potential Human Health Impacts

Harmful cyanobacteria blooms and the escalating impact of cyanotoxins necessitates the effective removal of cyanobacteria from water ecosystems before they release cyanotoxins. In this study, cyanobacteria removal from water samples taken from the eutrophic Aleksandrovac Lake (southern Serbia) was investigated. For that purpose, novel activated carbons derived from waste biomass—date palm leaf stalk (P_AC), black alder cone-like flowers (A_AC), and commercial activated carbon from coconut shell (C_AC) as a reference were used. To define the best adsorption conditions and explain the adsorption mechanism, the influence of contact time, reaction volume, and adsorbent mass, as well as FTIR analysis of the adsorbents before and after cyanobacteria removal, were studied. The removal efficiency of P_AC and A_AC achieved for the applied concentration of 10 mg/mL after 15 min was ~99%, while for C_AC after 24 h was only ~92% for the same concentration. To check the safety of the applied materials for human health and the environment, the concentrations of potentially toxic elements (PTEs), the health impact (HI) after water purification, and the toxicity (MTT and Comet assay) of the materials were evaluated. Although the P_AC and A_AC achieved much better removal properties in comparison with the C_AC, considering the demonstrated genotoxicity and cytotoxicity of the P_AC and the higher HI value for the C_AC, only the A_AC was further investigated. Results of the kinetics, FTIR analysis, and examination of the A_AC mass influence on removal efficiency indicated dominance of the physisorption mechanism. Initially, the findings highlighted the superior performance of A_AC, with great potential to be globally commercialized as an effective cyanobacteria cell adsorbent.

Kinetics and Mechanism of Cyanobacteria Cell Removal Using Biowaste-Derived Activated Carbons with Assessment of Potential Human Health Impacts

Harmful cyanobacteria blooms and the escalating impact of cyanotoxins necessitates the effective removal of cyanobacteria from water ecosystems before they release cyanotoxins. In this study, cyanobacteria removal from water samples taken from the eutrophic Aleksandrovac Lake (southern Serbia) was investigated. For that purpose, novel activated carbons derived from waste biomass—date palm leaf stalk (P_AC), black alder cone-like flowers (A_AC), and commercial activated carbon from coconut shell (C_AC) as a reference were used. To define the best adsorption conditions and explain the adsorption mechanism, the influence of contact time, reaction volume, and adsorbent mass, as well as FTIR analysis of the adsorbents before and after cyanobacteria removal, were studied. The removal efficiency of P_AC and A_AC achieved for the applied concentration of 10 mg/mL after 15 min was ~99%, while for C_AC after 24 h was only ~92% for the same concentration. To check the safety of the applied materials for human health and the environment, the concentrations of potentially toxic elements (PTEs), the health impact (HI) after water purification, and the toxicity (MTT and Comet assay) of the materials were evaluated. Although the P_AC and A_AC achieved much better removal properties in comparison with the C_AC, considering the demonstrated genotoxicity and cytotoxicity of the P_AC and the higher HI value for the C_AC, only the A_AC was further investigated. Results of the kinetics, FTIR analysis, and examination of the A_AC mass influence on removal efficiency indicated dominance of the physisorption mechanism. Initially, the findings highlighted the superior performance of A_AC, with great potential to be globally commercialized as an effective cyanobacteria cell adsorbent.

Formulation and characterization of antibiotic drug loaded aquasome for the topical application.

Aim: This study aimed to develop a topical antibiotic drug delivery system using aquasomes for enhanced treatment of skin and soft tissue infections (SSTIs). Materials & methods: Cephalothin was loaded into aquasomes using a multi-step process and optimized using design of experiment. The aquasomes were characterized for FT-IR, SEM and zeta potential analysis. Entrapment efficacy, In vitro drug release studies, antibacterial assays and stability study was performed to evaluate the efficacy of the formulated aquasomes. Results & conclusion: The formulated cephalothin-loaded aquasomes exhibited stable properties, controlled drug release and significant antibacterial activity against bacteria. This proves that the developed aquasome-based delivery system has the potential for sustained treatment of SSTIs.

Highly Adsorptive Organic Xerogels for Efficient Removal of Metformin from Aqueous Solutions: Experimental and Theoretical Approach

Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with molar ratios ranging from 0.05 to 0.40. These xerogels were thoroughly characterized using FT-IR, SEM, TGA, and TEM analyses. Batch adsorption experiments were performed with standard metformin solutions at concentrations of 50 and 500 mg/L, varying pH, and temperature to determine the adsorption isotherms of the synthesized xerogels. The adsorption data revealed a maximum adsorption capacity of 325 mg/g at pH 11 and 25 °C. Quantum chemical calculations revealed that electrostatic interactions govern metformin adsorption onto xerogels. The xerogels’ adsorption capacity was evaluated in competitive systems with CaCl2, NaCl, MgCl2, and synthetic urines. Reuse cycles demonstrated that xerogels could be reused for up to three cycles without any loss in adsorptive efficiency. The adsorption mechanisms of metformin in the adsorption process highlight the strong electrostatic interactions and hydrogen bonds between the adsorbate and the adsorbent material. Xerogels synthesized show promise as efficient adsorbents to remove metformin from aqueous solutions, helping to mitigate its environmental impact.

Preparation of 6-Amino-N-Hydroxyhexanamide-Modified Porous Chelating Resin for Adsorption of Heavy Metal Ions

Abstract: The pollution of water bodies by heavy metal ions has recently become a global concern. In this experiment, a novel chelating resin, D851-6-AHHA, was synthesized by grafting 6-amino-N-hydroxyhexanamide (6-AHHA) onto the (-CH2N-(CH2COOH)2) group of the D851 resin, which contained a hydroxamic acid group, amide group, and some carboxyl groups. This resin was developed for the purpose of removing heavy metal ions, such as Cr(III) and Pb(II), from water. The findings from static adsorption experiments demonstrated the remarkable adsorption effectiveness of D851-6-AHHA resin towards Cr(III) and Pb(II). Specifically, the maximum adsorption capacities for Cr(III) and Pb(II) were determined to be 91.50 mg/g and 611.92 mg/g, respectively. Furthermore, the adsorption kinetics of heavy metal ions by D851-6-AHHA resin followed the quasi-second-order kinetic model, while the adsorption isotherms followed the Langmuir model. These findings suggest that the adsorption process was characterized by monolayer chemisorption. The adsorption mechanism of D851-6-AHHA resin was comprehensively investigated through SEM, XRD, FT-IR, and XPS analyses, revealing a high efficiency of D851-6-AHHA resin in adsorbing Cr(III) and Pb(II). Specifically, the (-C(=O)NHOH) group exhibited a notable affinity for Cr(III) and Pb(II), forming stable multi-elemental ring structures with them. Additionally, dynamic adsorption experiments conducted using fixed-bed setups further validated the effectiveness of D851-6-AHHA resin in removing heavy metal ions from aqueous solutions. In conclusion, the experimental findings underscored the efficacy of D851-6-AHHA resin as a highly efficient adsorbent for remediating water bodies contaminated by heavy metal ions.

Highly Adsorptive Organic Xerogels for Efficient Removal of Metformin from Aqueous Solutions: Experimental and Theoretical Approach

Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with molar ratios ranging from 0.05 to 0.40. These xerogels were thoroughly characterized using FT-IR, SEM, TGA, and TEM analyses. Batch adsorption experiments were performed with standard metformin solutions at concentrations of 50 and 500 mg/L, varying pH, and temperature to determine the adsorption isotherms of the synthesized xerogels. The adsorption data revealed a maximum adsorption capacity of 325 mg/g at pH 11 and 25 °C. Quantum chemical calculations revealed that electrostatic interactions govern metformin adsorption onto xerogels. The xerogels’ adsorption capacity was evaluated in competitive systems with CaCl2, NaCl, MgCl2, and synthetic urines. Reuse cycles demonstrated that xerogels could be reused for up to three cycles without any loss in adsorptive efficiency. The adsorption mechanisms of metformin in the adsorption process highlight the strong electrostatic interactions and hydrogen bonds between the adsorbate and the adsorbent material. Xerogels synthesized show promise as efficient adsorbents to remove metformin from aqueous solutions, helping to mitigate its environmental impact.

Preparation of PVP-BiOBr Adsorbent for Efficient Indigo Carmine Dye Removal Using Flow-Circulation Systems.

This work presents an adsorptive removal of indigo carmine (IC) dye using a polyvinylpyrrolidone capped bismuth oxybromide (PVP-BiOBr) adsorbent. PVP-BiOBr was synthesized via a simple precipitation method. The morphology and surface chemical structure of the adsorbent were characterized using XRD, SEM, FTIR, and BET analyses. The adsorption isotherm and kinetics were investigated to reveal the mechanism of dye removal. Prepared PVP-BiOBr has a crystallite size of 19.7 nm, with a mean particle size of ∼2 μm and a surface area of 5.14 m2 g-1. The optimum pH for this adsorptive process spanned the range of 4 to 9. Experimental data indicated applicability of the Langmuir isotherm model, and the study confirms a pseudo-second-order kinetics model. The maximum adsorption capacity for IC dye was 208.3 mg g-1. A flow-circulation system was developed for the treatment of IC dye contaminated water samples. PVP-BiOBr was packed inside a column and did not spill into the water sample after treatment. The removal efficiency was ≥90% after 25 min. The PVP-BiOBr adsorbent could be reused for three cycles. This work demonstrates that PVP-BiOBr is a promising candidate as an adsorbent for IC dye removal. Additionally, the flow-based system establishes an automated operation in continuous mode, which is viable for large scale applications.

Preparation of 6-Amino-N-Hydroxyhexanamide-Modified Porous Chelating Resin for Adsorption of Heavy Metal Ions

Abstract: The pollution of water bodies by heavy metal ions has recently become a global concern. In this experiment, a novel chelating resin, D851-6-AHHA, was synthesized by grafting 6-amino-N-hydroxyhexanamide (6-AHHA) onto the (-CH2N-(CH2COOH)2) group of the D851 resin, which contained a hydroxamic acid group, amide group, and some carboxyl groups. This resin was developed for the purpose of removing heavy metal ions, such as Cr(III) and Pb(II), from water. The findings from static adsorption experiments demonstrated the remarkable adsorption effectiveness of D851-6-AHHA resin towards Cr(III) and Pb(II). Specifically, the maximum adsorption capacities for Cr(III) and Pb(II) were determined to be 91.50 mg/g and 611.92 mg/g, respectively. Furthermore, the adsorption kinetics of heavy metal ions by D851-6-AHHA resin followed the quasi-second-order kinetic model, while the adsorption isotherms followed the Langmuir model. These findings suggest that the adsorption process was characterized by monolayer chemisorption. The adsorption mechanism of D851-6-AHHA resin was comprehensively investigated through SEM, XRD, FT-IR, and XPS analyses, revealing a high efficiency of D851-6-AHHA resin in adsorbing Cr(III) and Pb(II). Specifically, the (-C(=O)NHOH) group exhibited a notable affinity for Cr(III) and Pb(II), forming stable multi-elemental ring structures with them. Additionally, dynamic adsorption experiments conducted using fixed-bed setups further validated the effectiveness of D851-6-AHHA resin in removing heavy metal ions from aqueous solutions. In conclusion, the experimental findings underscored the efficacy of D851-6-AHHA resin as a highly efficient adsorbent for remediating water bodies contaminated by heavy metal ions.

Cationic Imidazolium-Urethane-Based Poly(Ionic Liquids) Membranes for Enhanced CO2/CH4 Separation: Synthesis, Characterization, and Performance Evaluation

The escalating emissions of CO2 into the atmosphere require the urgent development of technologies aimed at mitigating environmental impacts. Among these, aqueous amine solutions and polymeric membranes, such as cellulose acetate and polyimide are commercial technologies requiring improvement or substitution to enhance the economic and energetic efficiency of CO2 separation processes. Ionic liquids and poly(ionic liquids) (PILs) are candidates to replace conventional CO2 separation technologies. PILs are a class of materials capable of combining the favorable gas affinity exhibited by ionic liquids (ILs) with the processability inherent in polymeric materials. In this context, the synthesis of the IL GLYMIM[Cl] was performed, followed by ion exchange processes to achieve GLYMIM variants with diverse counter anions (NTf2−, PF6−, and BF4). Subsequently, PIL membranes were fabricated from these tailored ILs and subjected to characterization, employing techniques such as SEC, FTIR, DSC, TGA, DMA, FEG-SEM, and CO2 sorption analysis using the pressure decay method. Furthermore, permeability and ideal selectivity assessments of CO2/CH4 mixture were performed to derive the diffusion and solubility coefficients for both CO2 and CH4. PIL membranes exhibited adequate thermal and mechanical properties. The PIL-BF4 demonstrated CO2 sorption capacities of 33.5 mg CO2/g at 1 bar and 104.8 mg CO2/g at 10 bar. Furthermore, the PIL-BF4 membrane exhibited permeability and ideal (CO2/CH4) selectivity values of 41 barrer and 44, respectively, surpassing those of a commercial cellulose acetate membrane as reported in the existing literature. This study underscores the potential of PIL-based membranes as promising candidates for enhanced CO2 capture technologies.