scholarly journals Poly (N-vinyl Imidazole)/Nitrogen-Doped Graphene Quantum Dot Hydrogel Adsorbent With Remarkable Capability for Metal Ion Removal From Aqueous Systems

2021 ◽  
Author(s):  
Solmaz Massoudi ◽  
Massoumeh Bagheri ◽  
Maryam Hosseini
Keyword(s):  
Adsorption Capacity ◽  
Contact Time ◽  
Metal Ion ◽  
Graphene Quantum Dots ◽  
Molar Ratio ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Abstract The present work studies the adsorptive removal of cadmium, nickel and chromium ions from an aqueous solution using a highly efficient nanocomposite adsorbent hydrogel. pH-sensitive nanocomposite hydrogels prepared easily by the free radical polymerization of N‑vinyl imidazole (VI) monomer using N, N′- methylene-bis-acrylamide (MBA) and dicationic imidazolium-based (DIL) cross-linkers with molar ratios of monomer/cross-linker in the presence of 0.0, 0.9 and 4.0 wt.% nitrogen doped graphene quantum dots (NGQD). The prepared hydrogel (PVI/NGQD) with higher swelling degree (V-D-G1) with molar ratio of VI/DIL=24 and 4.0 wt.% NGQD was a prominent candidate for adsorption study of three elements (Cd, Ni, and Cr) from the solution. FT-IR, DSC, XRD, SEM, and EDS analysis were used to characterize the structure and the surface morphology of adsorbent before and after the metal ions adsorption. The effects of pH, initial concentration of ions and contact time on the adsorption capacity of the hydrogel were also studied. Adsorption of ions were investigated at pH 1.0, 7.0 and 9.0 and maximum removal efficiencies for Cd(II), Ni(II) and Cr(VI) ions (75%, 94.6% and 70.9%) were achieved at pH=7.0 and optimum ions concentration and contact time of 1000 mg/L, and 40, 40 and 150 min, respectively. The maximum adsorption capacity values of V-D-G1 is found to be 5000, 5000 and 370.370 mg/g for Cd(II), Ni(II) and Cr(VI), respectively. The adsorption data were used to study the adsorption kinetic and isotherm models in which Langmuir model and pseudo-first order model showed the better applicability.

scholarly journals Highly Fluorescent Nitrogen-Doped Graphene Quantum Dots’ Synthesis and Their Applications as Fe(III) Ions Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Fei Lu ◽  
Yi-hua Zhou ◽  
Li-hui Wu ◽  
Jun Qian ◽  
Sheng Cao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Quantum Dots ◽  
Metal Ion ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Blue Fluorescence ◽  
One Pot ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Nitrogen-doped graphene quantum dots (N-GQDs) with strong blue fluorescence and a high quantum yield of 88.9% were synthesized via a facile one-pot hydrothermal treatment with citric acid (CA) and ethylenediamine (EDA) as carbon and nitrogen sources, respectively. The blue fluorescence emission is independent of the excitation wavelengths. These N-GQDs dispersed well in water and ethyl alcohol and showed a highly selective and sensitive detection of hazardous and toxic Fe3+in the range of 1600μmol/L to 6000μmol/L through a fluorescence quenching process with a detection limit of 2.37μmol/L. Based on the excellent sensitivity and selectivity of N-GQDs to heavy metal ions, paper-based sensors can be fabricated by inkjet printing, which are rapid but low cost. So the visual instant on-site identification of heavy metal ion will be realized in the future.

scholarly journals Nitrogen-doped graphene-like carbon material derived via a simple, cost-effective method as an excellent adsorbent for methylene blue adsorption

2020 ◽  
Vol 194 ◽  
pp. 04036
Author(s):  
Bin Ren ◽  
Junfeng Miao ◽  
Shasha Wang ◽  
Yuelong Xu ◽  
Zuozhao Zhai ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Carbon Materials ◽  
Chemical Properties ◽  
Cost Effective ◽  
Polyvinyl Pyrrolidone ◽  
Maximum Adsorption Capacity ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Nitrogen-enriched graphene-like carbon materials were successfully prepared via pyrolysis of a mixture of melamine, ammonia chloride (NH4Cl) and polyvinyl pyrrolidone (PVP) at a mild temperature without inert gas protection. Different techniques were used to analyze the physical and chemical properties of the products. All the prepared materials showed excellent performance in methylene blue (MB) adsorption, In particular, the materials prepared with 3 g polyvinyl pyrrolidone (PVP) (NCG-2) exhibited the best performance, a very high maximum adsorption capacity of 348.2 mg/g, much larger than many reported materials. The high adsorption capacity of the Nitrogen-doped graphene-like carbon materials was possible due to its uniform porous structure, high specific surface area. Moreover, NCG-2 could be recycled and only a only slightly decreased in the removal efficiency were observed after 5 cycles.

Tannin-based thin-film composite membranes integrated with nitrogen-doped graphene quantum dots for butanol dehydration through pervaporation

2021 ◽  
Vol 623 ◽  
pp. 119077
Author(s):  
Rumwald Leo G. Lecaros ◽  
Reincess E. Valbuena ◽  
Lemmuel L. Tayo ◽  
Wei-Song Hung ◽  
Chien-Chieh Hu ◽  
...  
Keyword(s):  
Thin Film ◽  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Composite Membranes ◽  
Film Composite ◽  
Nitrogen Doped ◽  
Thin Film Composite ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Sulfur and nitrogen-doped graphene quantum dots/PANI nanocomposites for supercapacitors

2021 ◽  
Author(s):  
Hemalatha Kuzhandaivel ◽  
Sornalatha Manickam ◽  
Suresh Kannan Balasingam ◽  
Manik Clinton Franklin ◽  
Hee-Je Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Charge Storage ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Supercapacitor Applications ◽  
Storage Properties

Sulfur and nitrogen-doped graphene quantum dots/polyaniline nanocomposites were synthesized and their electrochemical charge storage properties were tested for supercapacitor applications.

scholarly journals Nanocomposite of CuInS/ZnS and Nitrogen-Doped Graphene Quantum Dots for Cholesterol Sensing

ACS Omega ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 2167-2176
Author(s):  
Rania Adel ◽  
Shaker Ebrahim ◽  
Azza Shokry ◽  
Moataz Soliman ◽  
Marwa Khalil
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

scholarly journals Effects of Doxorubicin Delivery by Nitrogen-Doped Graphene Quantum Dots on Cancer Cell Growth: Experimental Study and Mathematical Modeling

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 140
Author(s):  
Madison Frieler ◽  
Christine Pho ◽  
Bong Han Lee ◽  
Hana Dobrovolny ◽  
Giridhar R. Akkaraju ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cell Growth ◽  
Cancer Cell ◽  
Graphene Quantum Dots ◽  
Maximum Effect ◽  
Cancer Cell Growth ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

With 18 million new cases diagnosed each year worldwide, cancer strongly impacts both science and society. Current models of cancer cell growth and therapeutic efficacy in vitro are time-dependent and often do not consider the Emax value (the maximum reduction in the growth rate), leading to inconsistencies in the obtained IC50 (concentration of the drug at half maximum effect). In this work, we introduce a new dual experimental/modeling approach to model HeLa and MCF-7 cancer cell growth and assess the efficacy of doxorubicin chemotherapeutics, whether alone or delivered by novel nitrogen-doped graphene quantum dots (N-GQDs). These biocompatible/biodegradable nanoparticles were used for the first time in this work for the delivery and fluorescence tracking of doxorubicin, ultimately decreasing its IC50 by over 1.5 and allowing for the use of up to 10 times lower doses of the drug to achieve the same therapeutic effect. Based on the experimental in vitro studies with nanomaterial-delivered chemotherapy, we also developed a method of cancer cell growth modeling that (1) includes an Emax value, which is often not characterized, and (2), most importantly, is measurement time-independent. This will allow for the more consistent assessment of the efficiency of anti-cancer drugs and nanomaterial-delivered formulations, as well as efficacy improvements of nanomaterial delivery.

scholarly journals Modified/Unmodified Nanoparticle Adsorbents of Cellulose Origin With High Adsorptive Potential for Removal of Pb(II) From Aqueous Solution

2017 ◽  
Vol 13 (27) ◽  
pp. 425
Author(s):  
Azeh Yakubu ◽  
Gabriel Ademola Olatunji ◽  
Folahan Amoo Adekola
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Adsorption Process ◽  
Correlation Coefficients ◽  
Solution Temperature ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Kinetics Of Adsorption ◽  
Kinetics Of

This investigation was conducted to evaluate the adsorption capacity of nanoparticles of cellulose origin. Nanoparticles were synthesized by acid hydrolysis of microcrystalline cellulose/cellulose acetate using 64% H3PO4 and characterized using FTIR, XRD, TGA-DTGA, BET and SEM analysis. Adsorption kinetics of Pb (II) ions in aqueous solution was investigated and the effect of initial concentration, pH, time, adsorbent dosage and solution temperature. The results showed that adsorption increased with increasing concentration with removal efficiencies of 60% and 92.99% for Azeh2 and Azeh10 respectively for initial lead concentration of 3 mg/g. The effects of contact time showed that adsorption maximum was attained within 24h of contact time. The maximum adsorption capacity and removal efficiency were achieved at pH6. Small dose of adsorbent had better performance. The kinetics of adsorption was best described by the pseudo-second-Order model while the adsorption mechanism was chemisorption and pore diffusion based on intra-particle diffusion model. The isotherm model was Freundlich. Though, all tested isotherm models relatively showed good correlation coefficients ranging from 0.969-1.000. The adsorption process was exothermic for Azeh-TDI, with a negative value of -12.812 X 103 KJ/mol. This indicates that the adsorption process for Pb by Azeh-TDI was spontaneous. Adsorption by Azeh2 was endothermic in nature.

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