Yazar "Singh, Pardeep" seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • Küçük Resim Yok
    Öğe
    DFT and experimental studies of the facet-dependent oxygen vacancies modulated WS2/BiOCl-OV S-scheme structure for enhanced photocatalytic removal of ciprofloxacin from wastewater
    (Academic Press Inc Elsevier Science, 2024) Kumar, Abhinandan; Singh, Pardeep; Nguyen, Van-Huy; Van Le, Quyet; Ahamad, Tansir; Thakur, Sourbh; Matsagar, Babasaheb M.
    The present study explores visible light-assisted photodegradation of ciprofloxacin hydrochloride (CIP) antibiotic as a promising solution to water pollution. The focus is on transforming the optical and electronic properties of BiOCl through the generation of oxygen vacancies (OVs) and the exposure of (110) facets, forming a robust Sscheme heterojunction with WS2. The resultant OVs mediated composite with an optimal ratio of WS2 and BiOClOV (4-WS2/BiOCl-OV) demonstrated remarkable efficiency (94.3%) in the visible light-assisted photodegradation of CIP antibiotic within 1.5 h. The CIP degradation using 4-WS2/BiOCl-OV followed pseudo -firstorder kinetics with the rate constant of 0.023 min -1, outperforming bare WS2, BiOCl, and BiOCl-OV by 8, 6, and 4 times, respectively. Density functional theory (DFT) analysis aligned well with experimental results, providing insights into the structural arrangement and bandgap analysis of the photocatalysts. Liquid chromatography-mass spectrometry (LC-MS) analysis utilized for identifying potentially degraded products while scavenging experiments and electron paramagnetic resonance (EPR) spin trapping analysis elucidated the S-scheme charge transfer mechanism. This research contributes to advancing the design of oxygen vacancymediated S-scheme systems in the realm of photocatalysis, with potential implications for addressing water pollution concerns.
  • Küçük Resim Yok
    Öğe
    Dual S-scheme Bi2MoO6/g-C3N4/Ag2MoO4 ternary heterojunction: Interfacial charge transfer, broadband spectrum, enhanced redox ability
    (Elsevier, 2024) Hasija, Vasudha; Khan, Aftab Aslam Parwaz; Sonu; Katin, Konstantin P.; Kaya, Savas; Singh, Pardeep; Raizada, Pankaj
    A ternary heterojunction bearing Bi2MoO6 and g-C3N4 is deposited on Ag2MoO4 for the photocatalytic degradation of sulfamethoxazole (SMX) antibiotic. Though the hydrothermal synthesis is non-directional, the dual Sscheme heterojunction formation is governed by the g-C3N4 serving as an electron bridge between Bi2MoO6 and Ag2MoO4. The potent strong interaction with both Bi2MoO6 and Ag2MoO4 facilitates high oxidation and reduction potential. The optimized Bi2MoO6/g-C3N4/Ag2MoO4 heterojunction with extended visible light absorption exhibits 96 % SMX degradation efficiency within 240 min of irradiations. The dual S-scheme configuration endows in-built electric field with vigorous driving force for charge carrier separation. The charge transfer mechanisms were validated by the photoluminescence results. Bi2MoO6/g-C3N4/Ag2MoO4 MoO 4 heterojunction demonstrates pseudo-first order kinetics with 0.143 kmin(-1) for SMX degradation and ternary photo-catalyst 83 % degraded SMX after successive five cycles. In the formed dual S-scheme Bi2MoO6/g-C3N4/Ag2MoO4 heterojunction, (OH)-O-center dot and center dot O-2(-) radicals were the main reactive species for SMX degradation. This research contributes to the formation of stable multicomponent photocatalytic systems.
  • Küçük Resim Yok
    Öğe
    Oxygen vacancy enriched SrTiO3 and NiO-based S-scheme heterojunction moored on activated carbon from exhausted water filter batteries for ameliorated photodegradation of doxycycline hydrochloride and methyl orange degradation
    (Elsevier, 2024) Soni, Vatika; Sonu; Singh, Pardeep; Thakur, Sourbh; Ahamad, Tansir; Nguyen, Van -Huy; Chaudhary, Vishal
    Background: In this research study, O-SrTiO3/NiO/AC-EWC photocatalytic heterojunction was firstly fabricated hydrothermally followed by a thermal decomposition method for aqueous doxycycline and methyl orange photodegradation. The XRD plots depict the formation of crystalline bare SrTiO3, O-SrTiO3, NiO, and amorphous activated carbon from exhausted water filter cartridges. UV-vis spectroscopy revealed improved light absorption of O-SrTiO3/NiO/AC-EWC than bare semiconductors owing to synergistic effects of present oxygen vacancies and formation of heterojunction. EIS Nyquist plots and PL spectra studies depicted that O-SrTiO3/NiO/AC-EWC heterojunction showed maximum charge isolation and migration to surface of semiconductors. Constructed S-scheme heterojunction between O-SrTiO3 and NiO supported by AC-EWC was significant to separate the photogenerated charges for the generation of active radicals with superior redox potential. Significant findings: Under 30 min of dark, O-SrTiO3/NiO/AC-EWC exhibited the highest DCHCl (39 %) and MO (35 %) adsorption from the reaction mixture. After 60 min of illumination, total DCHCl and MO degradation efficiency order was found to be O-SrTiO3/NiO/AC-EWC>O-SrTiO3/AC-EWC>O-SrTiO3>NiO>SrTiO3. Overall, O-SrTiO3/NiO/AC-EWC heterojunction has the highest degradation rate of 95.7 %, 96.2 % as well as rate constant k, 0.01513 min(-1), and 0.019 min(-1) for DCHCl and MO, respectively. A significant decrease in photoactivity of O-SrTiO3/NiO/AC-EWC on adding scavengers revealed the active role of reactive center dot O-2(-), center dot OH, h(+) for the degradation. Satisfactory reusability of effective O-SrTiO3/NiO/AC-EWC S-scheme heterojunction was demonstrated after 4 runs and found to be 91 % and 92.2 % for DCHCl and MO degradation, respectively in recycling tests. This study will shed new light on the design, and growth of integrated photocatalyst systems, and the removal of antibiotics and dyes.
  • Küçük Resim Yok
    Öğe
    Photocatalysis and adsorption coupling in S-scheme K and P doped g-C3N4/GO/MgFe2O4 photocatalyst for enhanced degradation of Congo red dye
    (Iop Publishing Ltd, 2025) Kumar, Rohit; Khan, Aftab Aslam Parwaz; Sudhaik, Anita; Sonu, Sonu; Kaya, Savas; Singh, Pardeep; Raizada, Pankaj
    Photocatalysis is an environmentally friendly approach for harnessing solar light to degrade pollutants. This study investigates the degradation of Congo red (COR) dye by a visible light-active photocatalyst, with a primary focus on the efficiency and reusability of the photocatalytic material. We synthesized phosphorus- and potassium-doped graphitic carbon nitride photocatalysts attached to graphene oxide and MgFe2O4 (KPCN/GO/MgFe2O4). Doping graphitic carbon nitride enhanced light absorption, while graphene oxide improved the adsorption properties. The addition of magnetic MgFe2O4 enhanced charge separation and reusability. The KPCN/GO/MgFe2O4 composite was analyzed using a range of techniques. The activity of the synthesized materials for Congo red (COR) dye degradation was analyzed under visible light. The photocatalytic activities of bare, binary, and ternary photocatalysts were compared, and KPCN/GO/MgFe2O4 exhibited the highest photoactivity among all. The KPCN/GO/MgFe2O4 photocatalyst (60 mg) showed a 76% removal efficiency for 5 x 10-6 M Congo red within 60 min, which was 2.5 times higher than that of pure graphitic carbon nitride. The OH and O2- were the major reactive species during COR photodegradation. The photocatalyst also displayed good reusability after five cycles, enhancing its overall effectiveness.
  • Küçük Resim Yok
    Öğe
    Recent advances in manipulating strategies of NH2-functionalized metallic organic frameworks-based heterojunction photocatalysts for the sustainable mitigation of various pollutants
    (Academic Press Inc Elsevier Science, 2024) Kaur, Balvinder; Soni, Vatika; Kumar, Rohit; Singh, Pardeep; Selvasembian, Rangabhashiyam; Singh, Archana; Thakur, Sourbh
    NH2-functionalized metal-organic frameworks (NH2-functionalized MOFs) can abate organic pollutants, predominantly favored by their chemical, mechanical, and thermal stabilities. The present review stated the chemistry of identifying NH2-functionalization and its role in enhancing the properties of bare MOFs. The integration of the amine group bestows several advantages: 1.) enabling band structure modification, 2.) establishing strong metal-NH2 bonds, 3.) preserving MOF structures from reactive oxygen species, and 4.) shielding MOF structures against pH alterations. Consequently, the NH2-functionalized MOFs are promising materials for the photodegradation of organic contaminants. The following section illustrates the two approaches (pre-synthetic and post-synthetic) for NH2-functionalized MOFs. Nevertheless, specific intrinsic limitations, entailing a high recombination rate of charge carriers and inadequate optical adsorption, restrain the applicability of NH2-functionalized MOFs. Accordingly, the succeeding segment presents strategies to elevate the photocatalytic activities of NH2-functionalized MOFs via heterojunction fabrication. The importance of the NH2- functionalized MOFs-based heterojunction has been evaluated in terms of the effect on the enhancement of charge separation, optical adsorption, and redox ability of charge carriers. Subsequently, the potential application for organic pollutant degradation via NH2-functionalized MOFs-based heterojunctions has been scrutinized, wherein the organic pollutants. Eventually, the review concluded with challenges and potential opportunities in engaging and burgeoning domains of the NH2-functionalized MOFs-based heterojunctions.
  • Küçük Resim Yok
    Öğe
    Transforming waste polyethylene terephthalate (PET) into high-performance activated carbon-supported composites for pollutant degradation: A synergy of experiments and DFT insights
    (Pergamon-Elsevier Science Ltd, 2025) Poonia, Komal; Sonu; Singh, Pardeep; Ahamad, Tansir; Nguyen, Van-Huy; Katin, Konstantin P.; Kaya, Savas
    To date, the global demand for clean water and environmentally detrimental human activities are among the most significant challenges humans face. Therefore, an urgent need is to innovate and implement more effective, sustainable solutions to protect the environment and preserve our vital water resources. In particular, this study successfully developed a new and suitable nanocomposite catalyst from waste polyethylene terephthalate (PET) plastics-derived activated carbon (P-AC) and applied it for the enhanced photo-degradation of tetracycline (TCHCl). Based on the characterizations and density functional theory (DFT) calculations, we suggest that the synergistic effect of adsorption and photocatalysis by synthesizing oxygen vacancy-rich Bi4O5Br2 (BOB) and Co3(PO4)2 (COP) immobilized on P-AC play a critical role in enhancing effectively further the degradation efficiency. Interestingly, the proposed S-scheme charge transfer mechanism demonstrated an impressive TC-HCl degradation efficiency of 90.7 % within 90 min under light irradiation. It notes that the degradation mechanism involved the pre-adsorption of TC-HCl onto the surface of functional group-rich activated carbon, which assisted in hastening the attack of O2 center dot- and h+. Nine primary intermediates were identified, framing three degradation pathways for TC-HCl as per liquid chromatography - mass spectrometry (LC-MS). Lastly, results of consecutive quadruplicate degradation experiments advocated the stability and reusability of the nanocomposite, highlighting the potential of upcycling plastic waste into valuable photocatalytic materials support, offering an effective and environmentally friendly solution for removing priority pollutants from water.
  • Küçük Resim Yok
    Öğe
    Unveiling new horizons of progress on manipulating the structure and characterization of phosphate-modified polymer for selective uranium adsorption
    (Elsevier Science Sa, 2024) Kaur, Balvinder; Rana, Parul; Singh, Pardeep; Singh, Archana; Chaudhary, Vishal; Kaya, Savas; Van Le, Quyet
    The hazardous effect of Uranium (U(VI)) on the environment principally stems from its metallic and radioactive properties. Considering the toxicity and radioactivity of U(VI)), there is an imperative necessity to remove U(VI)) from wastewater through various adsorbents. This comprehensive review delves into the quest for employing phosphate-modified polymers for U(VI) uptake by adsorption. The review emphasizes the critical role of U(VI) specific binding to phosphate-modified polymers in increasing the affinity of polymers toward U(VI). The merging of phosphate-based polymers and interactions such as coordination bonding and complexation generated a precise speculation of the chemisorption exhaustion mechanism. The advertisements for interactions with the adsorbent are determined by parameters like pH, coexisting ions, ionic strength, temperature, and contact time, which gives information about the adsorption process. This review summarises the recent breakthroughs towards the classifications, synthesis, and adsorption mechanism of phosphate-modified polymers. In turn, the capacity of phosphate-modified polymers to adsorb contributes to the fact that the polymers are regeneratable after desorption. Overall, this clarifies the potential of phosphate modification to improve the adsorption capacity of polymer adsorbents.