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1.
Environ Res ; 229: 115932, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37076029

RESUMO

Diffusion dialysis (DD) process utilizing anion exchange membranes (AEMs) is an environmentally-friendly and energy-efficient technology. From acidic wastewater, DD is needed for acid recovery. This research reports the development of a series of dense tropinium-functionalized AEMs via solution casting method. Fourier Infrared transform (FTIR) spectroscopy verified the successful preparation of AEMs. The developed AEMs exhibited a dense morphology, featuring 0.98-2.42 mmol/g of ion exchange capacity (IEC), 30-81% of water uptake (WR) and 7-32% of linear swelling ratio (LSR). They displayed exceptional mechanical, thermal and chemical stability and were employed for acid waste treatment from HCl/FeCl2 mixtures via DD process. AEMs possessed 20 to 59 (10-3 m/h) and 166 to 362 of acid diffusion dialysis coefficient (UH+) and separation factor (S) respectively at 25 °C. Compared to DF-120 commercial membrane (UH+ = 0.004 m/h, S = 24.3), their DD efficiency was improved under identical experimental conditions.


Assuntos
Águas Residuárias , Diálise/métodos , Ânions , Difusão
2.
Photodermatol Photoimmunol Photomed ; 37(1): 39-48, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32969087

RESUMO

BACKGROUND: Sunlight exposure causes several types of health issues to humans, and in particular, it affects especially the skin. Among the most common harmful issues developed by UV exposure are erythema, pigmentation, and lesions in DNA, which may lead to cancer. These long-term effects can be minimized with the use of sunscreen. OBJECTIVE: The use of commercial UV filters causes severe side effects such as skin allergy and whitening of the skin. Therefore, in this study the effectiveness of Ca2 SiO4 , a compound abundantly present in the soils of certain South Asian regions, has been the first time explored as UV filter. This compound leaves a low amount of white residue on the skin and is highly stable. METHOD: The comparative study of a cosmetic formulation having 5% Ca2 SiO4 , and other formulations containing 5% TiO2 and 5% ZnO as inorganic UV filters, was performed to evaluate the physical and chemical stability. RESULT: The zeta potential and chemical stability of formulations containing these different UV filters were investigated by using UV-Vis spectroscopy, FTIR-ATR, and X-ray diffraction. Results indicated Ca2 SiO4 as a promising innovative UV filter with an SPF value of 37.94. One of the reasons is its low interaction with organic filter, that is, PABA, as compared to commercial ZnO and TiO2 inorganic UV filters. Biological absorption in organs was studied by ICP-MS on model mice. CONCLUSION: It also has a low photocatalytic activity; thus, formation of radicals is minimum. Moreover, Ca2 SiO4 showed a recognized ability to leave a low amount of white residue on the skin combined with great stability.


Assuntos
Compostos de Cálcio/química , Silicatos/química , Protetores Solares/síntese química , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/química , Difração de Raios X , Óxido de Zinco/química
3.
Phytochem Anal ; 29(1): 16-22, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28741853

RESUMO

INTRODUCTION: Citrullus colocynthis (L.) Schrad is extensively used to treat diabetes, obesity, fever, cancer, amenorrhea, jaundice, leukemia, rheumatism, and respiratory diseases. Chemical studies have indicated the presence of several cucurbitacins, flavones, and other polyphenols in this plant. These phytochemical constituents are responsible for the interesting antioxidant and other biological activities of C. colocynthis. OBJECTIVE: In the present study, for the first time, near infrared (NIR) spectroscopy coupled with partial least square (PLS) regression analysis was used to quantify the polyphenolic phytochemicals of C. colocynthis. METHODOLOGY: The fruit and aerial parts of the C. colocynthis were extracted individually in methanol followed by fractionation in n-hexane, chloroform, ethyl acetate, n-butanol, and water. Near infrared (NIR) spectra were obtained in absorption mode in the wavelength range 700-2500 nm. The PLS regression model was then built from the obtained spectral data to quantify the total polyphenol contents in the selected plant samples. RESULTS: The PLS regression model obtained had a R2 value of 99% with a 0.98 correlationship value and a good prediction with a root mean square error of prediction (RMSEP) value of 1.89% and correlation of 0.98. These results were further confirmed through UV-vis spectroscopy and it is found that the ethyl acetate fraction has the maximum value for polyphenol contents (101.7 mg/100 g; NIR, 100.4 mg/100 g; UV-vis). CONCLUSIONS: The polyphenolic phytochemicals of the fruit and aerial parts of C. colocynthis have been quantified successfully by using multivariate analysis in a non-destructive, economical, precise, and highly sensitive method, which uses very simple sample preparation. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Citrullus colocynthis/química , Frutas/química , Componentes Aéreos da Planta/química , Polifenóis/química , Análise dos Mínimos Quadrados , Análise Multivariada , Compostos Fitoquímicos/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos
4.
ACS Omega ; 9(2): 2422-2431, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38250400

RESUMO

This research describes the fabrication of the porous trimethylamine (TMA)-grafted anion exchange membrane (AEM) over a phase inversion process. The synthesis of the generated AEM was verified using Fourier transform infrared (FTIR) spectroscopy. The fabricated porous AEM showed 240% water uptake (WR), 1.45 mg/g ion exchange capacity (IEC), and a 9.0% linear expansion ratio (LER) at 25 °C. It exhibited a porous structure and higher thermal stability. It was utilized to remove eosin B (EB) from wastewater via the process of adsorption. The adsorption capacity of EB increased with time and the starting concentration of EB while decreasing with temperature and the AEM dosage. Adsorption isotherm investigation results showed that EB adsorption onto the porous AEM followed the Langmuir isotherm because the value of correlation coefficient (R2 = 0.992) was close to unity. Because the correlation coefficient was close to one, it was determined through adsorption kinetic experiments that the adsorption of EB on the produced porous AEM was suitable for a pseudo-second-order model. Thermodynamic study about process of EB adsorption on the porous AEM revealed that there was an exothermic (ΔH° = -16.60 kJ/mol) and spontaneous process.

5.
ACS Omega ; 9(1): 1143-1155, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38222658

RESUMO

The present study was carried out to investigate the antioxidant effect of ascorbic acid on omeprazole (O.P.)-induced acute kidney infection (AKI). Design of experiment (DoE) was employed to fabricate formulations (P1-P8) by the extrusion spheronization technique, and they were evaluated using various analytical techniques. P1-P8 formulations have % drug loading ranging from 56.34 ± 1.10 to 98.67 ± 1.05%, encapsulation efficiency from 70.98 ± 0.96 to 98.67 ± 1.05%, percentage drug release varying from 36.56 ± 1.34 to 93.45 ± 1.45%, Hausner's ratio ranging from 1.026 ± 0.05 to 1.065 ± 0.02%, and Carr's index varying from 2.3 ± 0.07 to 6.1 ± 0.06 g/mL. The optimized formulation (P6) was dual-coated with Eudragit L-100 (5% w/v) and ascorbic acid (2% w/v). A smooth uniform morphology was found after coating, and particle size nonsignificantly changed from 85.31 ± 77.43 to 101.99 ± 65.56 µm. IR spectra showed omeprazole characteristic peaks confirming drug loading, and peaks at 1747.40 and 1611.51 cm-1 confirmed ascorbic acid and Eudragit L-100 coating. X-ray diffraction (XRD) analysis confirmed the crystalline nature, and thermal degradation studies until 500 °C demonstrated increased stability after coating. Cytotoxicity analysis with 97% cell viability revealed the nontoxic behavior of pellets. In vitro dissolution studies of coated pellets showed <20% drug release at pH 1.2 and 99.54% at pH 6.8. Animal studies showed that pure omeprazole showed a nonsignificant decrease in weight, urine output, and fecal output compared to rodents on ascorbic acid pellets. Increased uric acid and creatinine levels in the group on pure omeprazole indicated AKI. Histopathological studies of renal cells also supported these results. The integration of experimental pellet formulation with molecular docking simulations has unveiled the potential of ascorbic acid and omeprazole as highly promising therapeutic agents for addressing oxidative stress and inflammation.

6.
Chemosphere ; 321: 138006, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36731668

RESUMO

Commercially available QPPO/PVA based anion exchange membrane (AEM) BIII was to inquire the percentage discharge of anionic dye Eosin-B (EB) at terrain temperature from wastewater. The impact of EB initial concentration, membrane dosage, ionic strength, contact time and temperature on EB percentage removal was contemplated. The EB percentage removal was increased from 22 to 99.56% and 38.15-99.56% with contact time and membrane dosage respectively while decreased from 99.56 to 29%, 99.56 to 54.61% and 99.56 to 92.22% with enhancing initial concentration of EB, ionic strength and temperature respectively. Nonlinear isotherm models were utilized to demonstrate EB adsorption onto AEM BIII. Attained results exhibited that nonliner Freundlich isotherm model best fitted to EB adsorption onto AEM BIII. For EB adsorption onto AEM BIII, adsorption kinetics were inquired in detail by using several kinetic models but EB adsorption nicely fitted to pseudo-second-order kinetics. Similarly thermodynamic analysis was performed and results pointed to an exothermic adsorption of EB onto AEM BIII. The membrane could be reused for four concecutive cycles with loosing its efficiency.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Corantes , Amarelo de Eosina-(YS) , Concentração de Íons de Hidrogênio , Termodinâmica , Adsorção , Cinética , Ânions
7.
Chemosphere ; 320: 137835, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36702413

RESUMO

Novel molecularly imprinted organically modified silica was prepared by reacting acrylamide and 3-(tri-methoxysilyl) propyl methacrylate followed by condensation and hydrolysis with tetraethyl ortho-silicate for the determination of pyriproxyfen. The sorbent proved to be highly selective for the template molecule, pyriproxyfen. The characterization of sorbent was carried out using SEM, BET and TGA. The prominent peaks in FTIR at 3700 cm-1 and 1071 cm-1 confirmed the stretching of amide group's N-H and Si-O-Si bond linkage of MIOrmosil. The pseudo-first-order model (R2 0.99) described the adsorption kinetics of the MIOrmosil, whereas among adsorption isotherms, Freundlich model showed the best fit (R2 0.99). The molecularly imprinted silica was applied for the determination of target analytes from strawberries sample using dispersive solid-phase micro extraction (DSPME) followed by high-performance liquid chromatography (HPLC). The LOD (4.93 x10-5 µg mL-1) and LOQ (1.49 x10-4 µg m-1) values were calculated by signal to noise ratio through HPLC. Results show that the maximum binding capacity and percentage recovery values of MIOrmosil were 13 mg g-1 (n = 5) and 97.3% respectively.


Assuntos
Fragaria , Impressão Molecular , Polímeros/química , Impressão Molecular/métodos , Extração em Fase Sólida/métodos , Dióxido de Silício/química , Adsorção , Cromatografia Líquida de Alta Pressão/métodos
8.
Chemosphere ; 313: 137332, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36427576

RESUMO

Conventional chemotherapy poses toxic effects to healthy tissues. A therapeutic system is thus required that can administer, distribute, metabolize, and excrete medicine from human body without damaging healthy cells. This is possible by designing a therapeutic system that can release drug at specific target tissue. In current work, novel chitosan (CS) based polymeric nanoparticles (PNPs) containing N-isopropyl acrylamide (NIPAAM) and 2-(di-isopropyl amino) ethyl methacrylate (DPA) are designed. The presence of available functional groups i.e. OH- (3262 cm-1), -NH2 (1542 cm-1), and CO (1642 cm-1), was confirmed by Fourier Transform Infra-red Spectrophotometry (FTIR). The surface morphology and average particle size (175 nm) was determined through Scanning Electron Microscope (SEM). X-Ray Diffractometry (XRD) studies confirmed the amorphous nature and excellent thermal stability of PNPs up to 100 °C with only 2.69% mass loss was confirmed by Thermogravimetric analysis (TGA). The pH sensitivity of such PNPs for release of encapsulated doxorubicin at malignant site was investigated. The encapsulation efficiency of PNPs was 89% (4.45 mg/5 mg) for doxorubicin (a chemotherapeutic) measured by using UV-Vis Spectrophotometer. The drug release profile of loaded PNPs was 88% (3.92 mg/4.45 mg) at pH 5.3, in 96 h. PNPs with varying DPA concentration can effectively be used to deliver chemotherapeutic agents with high efficacy.


Assuntos
Quitosana , Nanopartículas , Neoplasias , Humanos , Polímeros , Doxorrubicina , Liberação Controlada de Fármacos , Portadores de Fármacos , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Microambiente Tumoral
9.
Chemosphere ; 311(Pt 2): 137103, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36347346

RESUMO

The excessive use of antibiotics and their ultimate routes to the environment have prompted the drug resistance, which is becoming a major ecological issue. In this work, we have evaluated the performance of quaternary ammonium poly (2, 6-dimethyl-1,4-phenylene oxide) and polyvinyl alcohol (QPPO/PVA) based anion exchange membrane against cefixime (a third generation cephalosporin antibiotic) present in hospital effluents. The membrane's surface morphology was studied through scanning electron microscopy. The optimization of experimental parameters through Response Surface Methodology helped to evaluate the inter parameter dependence and predict maximum uptake capacity (qe). The speculated value of qe (6.72 mg g-1) obtained through central composite design was close to the experimental value of 7.01 mg g-1 with percent relative error of 4.31%. Further, the evaluation of experimental data using isotherms (Langmuir and Freundlich) and kinetic models (pseudo-first-order and second-order) proposed that the interactions between cefixime and the membrane were physisorptive in nature. The intra-day and inter-day assays exhibited lower %RSD values of 0.4% (n = 5) and 0.3% (n = 5). Furthermore, a percentage recovery of 98.2% (n = 9) and limit of detection 1 × 10-5 µg mL-1 was observed. The chromatogram of the treated water samples presented only negligible amount of cefixime indicating a great potential of QPPO/PVA membrane for the removal of cefixime from real water samples. The membrane could be regenerated for three consecutive cycles without any prominent loss in efficiency.


Assuntos
Antibacterianos , Projetos de Pesquisa , Cefixima , Cinética , Ânions , Água , Adsorção
10.
ACS Omega ; 8(51): 48966-48974, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38162758

RESUMO

A magnetic nanocomposite of tungsten and vanadium was employed as a catalyst for the mitigation of water contaminants, including a carcinogenic dye (Congo red, CR), a widely used pesticide (glyphosate), and the bacterial strain Escherichia coli. Additionally, it was subjected to several characterization techniques. X-ray diffraction spectroscopy examination validated the synthesized nanoparticles' crystalline nature, and scanning electron microscopy and energy-dispersive X-ray analysis were employed to examine the morphology and elemental composition of the catalyst. The use of thermogravimetric analysis enabled the elaboration of the thermal behavior of tungsten sulfide-vanadium decorated with Fe2O3 nanoparticles. The experiments were conducted under visible light conditions. The highest levels of photodegradation of 96.24 ± 2.5% for CR and 98 ± 1.8% for glyphosate were observed following a 180 min exposure to visible light at pH values of 6 and 8, respectively. The quantum yields for CR and Gly were calculated to be 9.2 × 10-3 and 4.9 × 10-4 molecules photon-1, respectively. The findings from the scavenger analysis suggest the involvement of hydroxyl radicals in the degradation mechanism. The study evaluated the inhibition of E. coli growth when exposed to a concentration of 0.1 g/10 mL of the photocatalyst, utilizing a 1 mL sample of the bacterial strain. The successful elimination of CR and glyphosate from water-based solutions, along with the subsequent antibacterial experiments, has substantiated the efficacy of the photocatalyst in the field of environmental remediation.

11.
Sci Rep ; 13(1): 13425, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37591923

RESUMO

The present study aimed to fabricate a novel polymeric spongy composite to enhance skin regeneration composed of Nystatin (antifungal agent) and Silver Nanoparticles (AgNps). Different formulations (F1-F8) were developed & characterized by using various analytical techniques. AgNps synthesized by chemical reduction method showed spherical morphology 2 µm in size showed by SEM and XRD. A fine porous structure of gel embedded with AgNps having an amorphous structure with 10 % crystallinity due to AgNps was found. IR spectra revealed no chemical interaction between polymers and Nystatin. An increase in thermal stability of formulation was observed till 700 â„ƒ analyzed by Differential Scanning Calorimetry. Cytotoxic analysis on L929 mouse skin fibroblast cells showed a decrease in cell viability as Ag concentration increased (inactivating Fibroblast and keratinocytes) while 10 mg composition was found safest concentration (94%). Optimized formulation (F2) presented in-vitro drug release up to 90.59% ± 0.76 at pH 7.4, swelling studies (87.5% ± 0.57), water retention (26.60 ± 0.34), pH (5.31 ± 0.03). In the animal burn model, the group that received CHG/Ag/Nystatin healed the wound significantly (p < 0.05). These results suggested that optimized carrier can be used for other anti-fungal drugs facilitating the early healing of the wound.


Assuntos
Ácido Hialurônico , Nanopartículas Metálicas , Animais , Camundongos , Nistatina , Prata , Cicatrização , Sistemas de Liberação de Medicamentos
13.
Membranes (Basel) ; 12(3)2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35323739

RESUMO

In fuel cell applications, the proton exchange membrane (PEM) is the major component where the balance among dimensional stability, proton conductivity, and durability is a long-term trail. In this research, a series of blended SPEEK/SPPO membranes were designed by varying the amounts of sulfonated poly(ether ether ketone) (SPEEK) into sulfonated poly(phenylene) oxide (SPPO) for fuel cell application. Fourier transform infrared spectroscopy (FTIR) was used to confirm the successful synthesis of the blended membranes. Morphological features of the fabricated membranes were characterized by using scanning electron microscopy (SEM). Results showed that these membranes exhibited homogeneous structures. The fabricated blended membranes SPEEK/SPPO showed ion exchange capacity (IEC) of 1.23 to 2.0 mmol/g, water uptake (WR) of 22.92 to 64.57% and membrane swelling (MS) of 7.53 to 25.49%. The proton conductivity of these blended membranes was measured at different temperature. The proton conductivity and chemical stability of the prepared membranes were compared with commercial membrane Nafion 117 (Sigma-Aldrich, St. Louis, Missouri, United States) under same experimental conditions. The proton conductivity of the fabricated membranes increased by enhancing the amount of SPPO into the membrane matrix. Moreover, the proton conductivity of the fabricated membranes was investigated as a function of temperature. Results demonstrated that these membranes are good for applications in proton exchange membrane fuel cell (PEMFC).

14.
Chemosphere ; 308(Pt 3): 136330, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36087733

RESUMO

The design of conductive, improved durable and selective anion exchange membranes (AEMs) for desalination application via electrodialysis (ED) process is critical for a more sustainable future. This work reports the design of a series of homogeneous trimethylphosphine (TMP)-functionalized anion exchange membranes (AEMs) for desalination application via electrodialysis (ED) process. Physico-chemical characterization and electrochemical performance of the trimethylphosphine-functionalized anion exchange membranes was conducted and the activity found to be tuned by varying the quantity of trimethylphosphine into the membrane architecture. For anion exchange membranes M1 to M4, the ion exchange capacity (IEC) was increased from 1.35 to 2.16 mmol/g, water uptake (WR) from 4.30 to 17.72%, linear expansion ratio (LER) from 3.70 to 12.50% with enhancing the quantity of trimethylphosphine into the polymer architecture. The ionic resistance decreased from 15.14 to 2.61 Ω cm2 with increasing quantities of trimethylphosphine whereas transport number increased from 0.98 to 0.99. The performance of synthesized trimethylphosphine-functionalized anion exchange membranes in desalination of NaCl was evaluated via electrodialysis process (flux of 3.42 mol/m2. h and current efficiency of 64.30%). Results showed that the prepared trimethylphosphine-functionalized membrane (optimum M4) possess improved desalination performance as compared to commercial membrane Neosepta AMX under identical experimental conditions.


Assuntos
Membranas Artificiais , Cloreto de Sódio , Ânions , Polímeros/química , Sulfonas , Água/química
15.
Front Plant Sci ; 13: 925451, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36247569

RESUMO

Aspergillus parasiticus (A. parasiticus) is known for producing aflatoxins and is a major threat to the food industry. Green synthesis of nanoparticles (NPs) is a cost-effective and environment-friendly approach. A variety of NPs have been explored as antifungal agents; however, their antifungal characteristics need to be further enhanced to compete with traditional fungicides. The present work describes the green synthesis of ZnO and CuO NPs by precipitation method using aqueous leaf extract of Manilkara zapota and their surface modification through polyaniline (PANI). Still, there is no published study on the application of PANI-coated particles as antifungal agents against A. parasiticus and hence was the focus of this work. The polymer-coated NPs were synthesized, characterized, and investigated for their antifungal properties against A. parasiticus. Textural and structural characterization of PANI-coated and non-coated ZnO and CuO NPs were confirmed through FT-IR, SEM, and XRD techniques. The PANI-coated NPs presented higher fungal growth inhibition (%) as compared to the non-coated ones. The maximum inhibition of 77 ± 2% (n = 3) was shown by PANI/ZnO NPs at a concentration of 12 mmol L-1 and 72 h of incubation. The non-coated NPs presented a lower inhibition rate with respect to their coated NPs, thus justifying the role of polymeric coating in improving antifungal efficiency.

16.
ACS Omega ; 7(32): 28516-28524, 2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-35990493

RESUMO

Molecularly imprinted biodegradable polymers are receiving considerable attention in drug delivery due to their ability of targeted recognition and biocompatibility. This study reports the synthesis of a novel fluorescence-active magnetic molecularly imprinted drug carrier (MIDC) using a glucose-based biodegradable cross-linking agent for the delivery of anticancer drug docetaxel. The magnetic molecularly imprinted polymer (MMIP) was characterized through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy, and vibrating sample magnetometry (VSM). The MMIP presented a magnetization value of 0.0059 emu g-1 and binding capacity of 72 mg g-1 with docetaxel. In vitro and in vivo studies were performed to observe the effectiveness of the MIDC for drug delivery. The cell viability assay suggested that the MMIP did not present toxic effects on healthy cells. The magnetic property of the MMIP allowed quick identification of the drug carrier at the target site by applying the external magnetic field to mice (after 20 min of loading) and taking X-ray images. The novel MMIP-based drug carrier could thus deliver the drug at the target site without affecting the healthy cells.

17.
ACS Omega ; 7(30): 26788-26799, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35936400

RESUMO

In this research, the development of a novel brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO)-based homogeneous anion exchange membrane (AEM) via the solution casting method was reported. Fourier transform infrared spectroscopy was used to confirm the successful development of the BPPO-based AEM. The prepared AEM showed excellent thermal stability. It exhibited an ion exchange capacity of 2.66 mg/g, a water uptake (W R) of 68%, and a linear swelling ratio of 31%. Methyl orange (MO), an anionic dye, was used as a model pollutant to evaluate the ion exchange ability of the membrane. The adsorption capacity of MO increased with the increase in contact time, membrane dosage (adsorbent), temperature, and pH while declined with the increase in initial concentration of MO in an aqueous solution and molarity of NaCl. Adsorption isotherm study showed that adsorption of MO was fitted well to the Freundlich adsorption isotherm because the value of the correlation coefficient (R 2 = 0.974) was close to unity. Adsorption kinetics study showed that adsorption of MO fitted well to the pseudo-second-order kinetic model. Adsorption thermodynamics evaluation represented that adsorption of MO was an endothermic (ΔH° = 18.72 kJ/mol) and spontaneous process. The AEM presented a maximum adsorption capacity of 18 mg/g. Moreover, the regeneration of the prepared membrane confirmed its ability to be utilized for three consecutive cycles. The developed BPPO-based AEM was an outstanding candidate for adsorption of MO from an aqueous solution.

18.
ACS Omega ; 7(45): 41437-41448, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36406537

RESUMO

Fipronil, a phenyl pyrazole insecticide, is extensively used in agriculture to control insect infestation. It has the potential to assimilate into the food chain, leading to serious health concerns. We report molecularly imprinted polymer (MIP)-based dispersive solid-phase microextraction for the targeted determination of fipronil in milk samples. Designing such a sorbent is of paramount importance for measuring the accurate amount of fipronil for monitoring its permissible limit. Response surface methodology based on a central composite design following a face-centered approach was used to optimize experimental conditions. The maximum binding capacity of 47 mg g-1 was achieved at optimal parameters of time (18 min), temperature (42 °C), pH (7), and analyte concentration (120 mg L-1). Under these conditions, a high percentage recovery of 94.6 ± 1.90% (n = 9) and a low limit of detection (LOD) and limit of quantitation (LOQ) (5.64 × 10-6 and 1.71 × 10-5 µg mL-1, respectively) were obtained. The MIP was well characterized through a scanning electron microscope (SEM) as well as Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) methods. Adsorption kinetics of the MIP followed the pseudo-first-order model (R 2 0.99 and χ2 0.96), suggesting the MIP-analyte interaction to be a physiosorptive process, while adsorption isotherms followed the Freundlich model (R 2 0.99). The real sample analysis through high-performance liquid chromatography (HPLC) confirmed the selective determination of fipronil from milk samples.

19.
Membranes (Basel) ; 11(3)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673479

RESUMO

This manuscript describes the synthesis of dimethylethanolamine (DMEA)-grafted anion exchange membrane (AEM) by incorporating dimethylethanolamine as ion-exchange content into the polymer matrix via the solution casting method. The synthesis of the DMEA-grafted AEM was demonstrated by Fourier transform infrared (FTIR) spectroscopy. The prepared DMEA-grafted AEM exhibited higher thermal stability, homogeneous morphology, water uptake (WR) of 115%, and an ion exchange capacity (IEC) of 2.70 meq/g. It was used for the adsorptive removal of methyl orange (MO) from an aqueous solution via batch processing. The effect of several operating factors, including contact time, membrane dosage, initial concentration of aqueous dye solution, and temperature on the percentage discharge of MO and adsorption capacity, was evaluated. Experimental data for adsorption of MO onto the DMEA-grafted AEM was analyzed with two parameter and three parameter nonlinear adsorption isotherm models but fitted best using a nonlinear Freundlich isotherm. Adsorption kinetics were studied by using several models, and attained results showed that experimental data fitted well to pseudo-second-order kinetics. A thermodynamic study showed that adsorption of MO onto the prepared DMEA-grafted AEM was an endothermic process. Moreover, it was a feasible and spontaneous process.

20.
Polymers (Basel) ; 13(16)2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34451208

RESUMO

Plant-mediated synthesis of nanoparticles exhibits great potential to minimize the generation of chemical waste through the utilization of non-toxic precursors. In this research work, we report the synthesis of magnesium oxide (MgO) and cobalt oxide (Co3O4) nanoparticles through a green approach using Manilkara zapota leaves extract, their surface modification by polyaniline (PANI), and antifungal properties against Aspergillus niger. Textural and structural characterization of modified and unmodified metal oxide nanoparticles were evaluated using FT-IR, SEM, and XRD. The optimal conditions for inhibition of Aspergillus niger were achieved by varying nanoparticles' concentration and time exposure. Results demonstrate that PANI/MgO nanoparticles were superior in function relative to PANI/Co3O4 nanoparticles to control the growth rate of Aspergillus niger at optimal conditions (time exposure of 72 h and nanoparticles concentration of 24 mM). A percentage decrease of 73.2% and 65.1% in fungal growth was observed using PANI/MgO and PANI/Co3O4 nanoparticles, respectively, which was higher than the unmodified metal oxide nanoparticles (67.5% and 63.2%).

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