| 1. |
|
|
| 2. |
- Batool, Atika, et al.
(author)
-
Synthesis of Polyoxometalates-Ionic Liquids@Fe3O4@SiO2 composites for the extraction of atrazine and deltamethrin pesticides residues from food samples and their determination by HPLC
- 2024
-
In: Microchemical journal (Print). - : Elsevier. - 0026-265X .- 1095-9149. ; 200
-
Journal article (peer-reviewed)abstract
- The excessive use of pesticides in food production has adverse effects on both the environment and human health. In the present study, atrazine and deltamethrin were employed as pesticides in the cultivation of tomatoes, cucumbers, and brinjal. The HPLC method was utilized for thesimultaneous determination of these two pesticides, employing a cleanup approach based on polyoxometalates (POMs)ionic liquids magnetic nanocompositesCuILPOM-Fe3O4@SiO2 and ZnILPOM-Fe3O4@SiO2. These magnetic nanocomposites were synthesized and subjected to comprehensive characterization using various analytical techniques, including fourier-transform infrared spectroscopy(FT-IR), UV–visible spectroscopy, powder X-ray diffraction(P-XRD),transmission electron microscope(TEM),scanning electron microscopy (SEM) and energy dispersive X-rays spectroscopy (EDX),thermogravimetric analysis (TGA), and rheology. Thedispersive solid-phase extraction (d-SPE) method was effectively employed for the extraction of pesticidesresidues using CuILPOM-Fe3O4@SiO2 and ZnILPOM-Fe3O4@SiO2. Under the optimized conditions, the linear concentration ranges for atrazine and deltamethrin were found to be 0.01–100.0 µg/L and 0.05–100 µg/L, respectively. The coefficient of determination (R2) for both compounds was notably high at 0.997 and 0.994, respectively. The limit of detection (LOD) ranged from 0.01 µg/L to 0.05 µg/L, and the relative standard deviations (RSDs) fell within the range of 5.1 % to 7.2 %. Ultimately, the method's performance in various food samples was assessed, resulting in satisfactory recoveries ranging from 80.9 % to 98.6 %.
|
|
| 3. |
- Majeed, Iftekhar, et al.
(author)
-
Preparation of polyoxometalate ionic liquids (POM-ILs) coated on metal coins for anticorrosion activity
- 2023
-
In: Polyhedron. - : Elsevier Ltd. - 0277-5387 .- 1873-3719. ; 243
-
Journal article (peer-reviewed)abstract
- Corrosion is globally a serious problem for metallic structure and materials in recent decades. When there is interaction between acid and metallic structure, a large amount of corrosion produced. Herein, we have synthesized two energetic polyoxometalates (POMs) based ionic liquids by ion exchange method of smaller cations with larger cations tetraalkyl ammonium (CnH2n+1)4N+ (n = 7). FT-IR, SEM, Electrochemical Impedance Spectroscopy (EIS), Optical Imaging Microscopy(OIM), Rheological analysis, 1HNMR and TGA techniques were used to characterize the corresponding ionic liquids. Metals can easily be protected by using hydrophobic polyoxometalate-ionic liquids (POM-ILs). At room-temperature the metallic coins were coated with W17@POM-IL andV3W15@POM-IL, comprising of Dawson anions and quaternary tetraheptylammonium cations (Q7). The acid resistant V3W15@POM-IL and W17@POM-IL were used for coating of coins samples. The un-coated coins have shown corrosion with holes production when treated with HCl while POM-ionic liquid coated coins expressed excellent resistant against corrosion and obviously, no cracking was observed. TGA results of W17@POM-IL revealed minimum weight loss of 4.3% and V3W15@POM-IL has maximum weight loss (9.2%) at highest temperature (500 °C). We have analyzed from the results that coins without coating of POM-ILs have demonstrated the weight loss of 14.3% while the coins coated with V3W15@POM-IL and W17@POM-ILs expressed less weight lost with 3.7% and 1.7% respectively. Furthermore, electrochemical impedance measurement (EIS) has charge transfer ratio of 7.03 Ω, 5.23 Ω and 3.78 Ω for W17@POM-IL, V3W15@POM-IL and un-coated coins respectively. Rheological analysis with highest elastic modulus (103 Pa) and viscous modulus (103 Pa) of W17@POM-IL has given best coating properties. Hence, the POM-ILs have variety of applications as coherent, adherent, chemical stability. Comparison of V3W15@POM-IL with W17@POM-IL inferring us that later is best for protection of metal coins against corrosion and damage production with highest thermal stability.
|
|
| 4. |
- Mushtaq, Afshan, et al.
(author)
-
Catalytic oxidative desulfurization of thio-compounds by employing χ-Anderson-type polyoxometalates-porphyrin covalent organic framework (COF)
- 2023
-
In: Tetrahedron. - : Elsevier. - 0040-4020 .- 1464-5416. ; 144
-
Journal article (peer-reviewed)abstract
- Severe environmental sulfur contents due to the consumption of fuels in automobiles and industries resulted in serious health hazards and pollution because of it, desulfurization of diesel become inevitable. Targeting the profound desulfurization of diesel, we performed experiments to deeply desulphurized the thio-compounds by catalytic-oxidative desulfurization technique. We synthesized new metalloporphyrin (C52H36N4O8Sn)4MeO-SnPor which after conversion into (C64H64N8O16Sn)4Tris-SnTP leading towards the synthesis of covalent organic framework [(N(C4H9)4]12[HNC(CH2O)3]4[(CO)4C44H24N4Sn] [NiMo6O18]4(SnTP@NiAdCOF). SnTP@NiAd COF showed the outstanding catalytic property for deep desulfurization of thio-compounds above than 96% of thiobenzoic acid (TB) and 99% of 2-aminothiophenol (2-ATP) sulfur contents were oxides after 100 min of reaction using H2O2 as an oxidant at room temperature with constant stirring. During desulfurization percentage desulfurization efficiency was checked for different time intervals by TLC and further confirmed by reverse phase high-performance liquid chromatography (RP-HPLC). Reverse-phase high-performance liquid chromatograms indicated that the peak area and peak height of thio-compounds decrease gradually with the passage of reaction time which confirmed the removal of thio-compounds from the reaction mixture. Sulfur contents removed up to 5 ppmw showed excellent catalytic characteristics of synthesized SnTP@NiAdCOF. The exceptional catalytic efficiency of prepared catalyst SnTP@NiAdCOF was because of the existence of active oxidizing centers of χ-NiAd and metalloporphyrin that are MoO and [(Por)SnII], respectively. The potential mechanism appeared to be the formation of Mo(O2) and [(Por)SnII–OOH] from MoO and [(Por)SnII], respectively that act as active oxidizing centers and efficiently converted the thio-group into oxides and sulfones. Effective removal of sulfur grants the desulfurization of fuels by using SnTP@NiAdCOF catalyst to lessen the energy expenditure and also to enhance the production of environmentally-safe fuels.
|
|
