scholarly journals Fast and Effective Catalytic Degradation of an Organic Dye by Eco-friendly Capped ZnS and Mn doped ZnS nanocrystals

2021 ◽  
Author(s):  
Sabri Ouni ◽  
Naim Bel Haj Mohamed ◽  
Noureddine Chaaben ◽  
Adrian Bonilla-Petriciolet ◽  
Mohamed Haouari
Keyword(s):  
Statistical Physics ◽  
Thioglycolic Acid ◽  
Dye Degradation ◽  
Low Cost ◽  
Quantum Confinement Effect ◽  
Dye Adsorption ◽  
Blue Shift ◽  
Order Kinetic ◽  
Zns Nanocrystals ◽  
Mn Doped

Abstract Undoped and Mn-doped ZnS nanocrystals encapsulated with thioglycolic acid were synthetized and characterized with different techniques, and finally tested in the photodegradation of a methyl orange in aqueous solution under UV and sunlight irradiations. FTIR and X-ray diffraction results confirmed the functionalization of these nanocrystals surface by thioglycolic acid and the formation of crystalline structures of ZnS and Mn-doped ZnS with cubic and hexagonal phases. Calculated average size of ZnS nanocrystals was in the range of 2 - 3 nm. It was observed a blue shift of the absorbance threshold and the estimated bandgap energies were higher than that of Bulk ZnS thus confirming the quantum confinement effect of charge carriers. Photoluminescence spectra of ZnS nanocrystals exhibited emission in the range of 410- 490 nm and the appearance of an additional emission band around 580 nm (2.13eV) connected to the 4𝑇1→ 6𝐴1 transition of the Mn2+ions. Photodegradation of methylene orange with undoped and Mn-doped ZnS-TGA nanocrystals was investigated. Dye adsorption prior to photocatalysis using nanocrystals was studied via kinetic experiments and statistical physics models. The maximum dye adsorption capacity on doped ZnS-TGA was ~ 26.98 mg/g. The adsorption kinetic was found to follow the pseudo-second-order kinetic model.According to the statistical physics results, the calculated adsorption energy was 22.47-23.47 kJ/mol and it showed that the dye adsorption was associated to the hydrogen interaction where the removal process was feasible and multi-molecular. The photocatalytic activity of undoped ZnS nanoparticles under UV irradiation showed better efficiency than doped nanocrystals thus indicating that manganese doping generated a dropping of the photocatalytic degradation of the dye. Dye degradation efficiency of 81.37% using ZnS-TGA nanocrystals was achieved after 6 min, which indicated that ZnMnS-TGA nanocrystals may be considered as an alternative low cost and environmental friendly material for facing water pollution caused by organic compounds via photodegradation processes.

Optical, Structural and Spectroscopic Characterization of ZnS Nanocrystals Embedded in KBr Single Crystal Matrix Grown by Czochralski Method

2021 ◽  
Vol 406 ◽  
pp. 274-284
Author(s):  
Soria Zeroual ◽  
Mohammed Sadok Mahboub ◽  
Ghani Rihia ◽  
Mourad Mimouni ◽  
Ghougali Mebrouk ◽  
...  
Keyword(s):  
Single Crystal ◽  
Absorption Edge ◽  
Quantum Confinement Effect ◽  
Blue Shift ◽  
Czochralski Method ◽  
Spectroscopic Characterization ◽  
Czochralski Growth ◽  
X Ray Diffraction ◽  
Crystal Matrix ◽  
Zns Nanocrystals

ZnS nanocrystals were embedded in a KBr single crystal matrix using the Czochralski growth technique. The X-ray diffraction, FT-IR and optical spectroscopy revealed the incorporation of ZnS nanocrystals. A blue shift of the absorption edge of the obtained samples has been observed, indicating the quantum confinement effect. The optical band-gap is estimated to be about 4.67 eV. Two excitonic peaks appeared at 300.4 nm and 271 nm. The average nanocrystal size was derived from the optical spectra. Annealing led to a shift in the absorption edge towards longer wavelengths and an increasing of the emissions intensity. Raman lines of the nanoparticles are broader and frequency-shifted compared to those of the bulk crystals. These results show that KBr is a good matrix-host of ZnS nanocrystals, and that the elaborated samples can be used for important technological applications.

scholarly journals Optical Studies of Organically Functionalized Mn doped ZnS Quantum Dots

2021 ◽  
Vol 33 (12) ◽  
pp. 2972-2976
Author(s):  
Anju Bala ◽  
Rajeev Sehrawat ◽  
Renu Bala ◽  
Ashutosh Dixit
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement Effect ◽  
Emission Spectra ◽  
Blue Shift ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Uv Visible ◽  
Mn Doped

Organically functionalized manganese doped zinc sulfide (ZnS/Mn) quantum dots were prepared by simple chemical method with polypyrrole (PPy) used as a capping agent. Prepared quantum dots were characterized with Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction microscope (XRD), UV-visible spectroscopy and photoluminescence spectroscopy. Crystalline size of PPy capped ZnS/Mn quantum dots for various concentrations of PPy were approximate 2 nm as analyzed by XRD and TEM analysis. The absorption spectra revealed the occurrence of a blue shift in the peak of absorption and an increase in the band gap value due to the quantum confinement effect. FTIR spectroscopy confirmed that shifting of broad peak at 2335.8 cm–1 was due to S-H stretching vibrations, which confirmed interaction of hydrogen and sulphur in ZnS/Mn/PPy nanocomposites. Uncapped ZnS/Mn and PPy capped ZnS/Mn quantum dots reveal the effective photoluminescence emission spectra in the range of 300-700 nm. With increase the value of capping agent in ZnS/Mn quantum dots, photoluminescence spectra going to red shifting. The photoluminescence properties of the organically functionalized ZnS nanoparticles are favourable for the application in optoelectronic devices.

scholarly journals Syringa vulgaris leaves powder a novel low-cost adsorbent for methylene blue removal: isotherms, kinetics, thermodynamic and optimization by Taguchi method

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Giannin Mosoarca ◽  
Cosmin Vancea ◽  
Simona Popa ◽  
Marius Gheju ◽  
Sorina Boran
Keyword(s):  
Methylene Blue ◽  
Low Cost ◽  
Dye Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorbent Surface ◽  
Order Kinetic Model ◽  
Endothermic Process ◽  
Pseudo Second Order ◽  
Better Than

Abstract In this study, the potential of a new low-cost adsorbent, Syringa vulgaris leaves powder, for methylene blue adsorption from aqueous solution was investigated. The adsorbent surface was examined using SEM and FTIR techniques. The experiments were conducted, in batch system, to find out the effect of pH, contact time, adsorbent dose, initial dye concentration, temperature and ionic strength on dye adsorption. The process is best described by Langmuir isotherm and the pseudo second order kinetic model. Maximum adsorption capacity, 188.2 (mg g−1), is better than other similar adsorbent materials. Thermodynamic parameters revealed a spontaneous and endothermic process, suggesting a physisorption mechanism. A Taguchi orthogonal array (L27) experimental design was used to determine the optimum conditions for the removal of dye. Various desorbing agents were used to investigate the regeneration possibility of used adsorbent. Results suggest that the adsorbent material is very effective for removal of methylene blue from aqueous solutions.

Kinetic Study and Equilibrium Isotherm Analysis of Cationic Dye Adsorption onto Attapulgite and Rectorite

2012 ◽  
Vol 446-449 ◽  
pp. 2960-2963
Author(s):  
Jing Yan Song ◽  
Jing Yang
Keyword(s):  
Low Cost ◽  
Dye Adsorption ◽  
Second Order ◽  
Order Kinetic ◽  
Cationic Dye ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Langmuir And Freundlich Equations

The adsorption properties of the attapulgite and the rectorite were investigated by removal of a cationic dye, methylene blue (MB) from aqueous solution. The attapulgite and the rectorite were characterized by Fourier transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). The analysis of the isotherm equilibrium data using the Langmuir and Freundlich equations showed that the data fitted better with Langmuir model. Pseudo-first-order and pseudo-second-order models were considered to evaluate the rate parameters. The experimental data were well described by the pseudo-second-order kinetic model. The results indicate that the attapulgite exhibited higher adsorption capacity for MB than rectorite and could be employed as a low-cost alternative in wastewater treatment for the removal of cationic dyes.

scholarly journals Structural and optical properties of NiO and Mn doped NiO nanparticles

2020 ◽  
Vol 1 (1) ◽  
pp. 20-30
Author(s):  
C. Thangamani ◽  
S.Revathi ◽  
P. Matheswaran ◽  
K. Pushpanathan
Keyword(s):  
Quantum Confinement Effect ◽  
Blue Shift ◽  
Precipitation Method ◽  
Average Crystalline Size ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Optical Microstructure ◽  
Mn Doped ◽  
Fcc Structure ◽  
Microstructure And Magnetic Properties

Ni1-xMnxO (x = 0.0 - 0.05) nanoparticles were successfully prepared by precipitation method at room temperature Prepared samples were characterized by structural, optical, microstructure and magnetic properties. X-ray diffraction analysis confirmed that Mn ions substitution of NiO lattice with FCC structure. The average crystalline size found to decrease from 42 to 34 nm. Optical analysis show increase in band from 4 -3.8 eV by strong quantum confinement effect with blue shift in the absorption spectra range of 325 – 290 nm. FTIR spectra confirmed the formation of Ni-Mn-O.

scholarly journals Pure, Size Tunable ZnO Nanocrystals Assembled into Large Area PMMA Layer as Efficient Catalyst

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 162 ◽  
Author(s):  
Issraa Shahine ◽  
Nour Beydoun ◽  
Jean Jacques Gaumet ◽  
El-Eulmi Bendeif ◽  
Hervé Rinnert ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
High Performance ◽  
Low Cost ◽  
Quantum Confinement Effect ◽  
Blue Shift ◽  
Large Area ◽  
Efficient Catalyst ◽  
Aqueous Synthesis ◽  
Pmma Layer ◽  
Zno Nanocrystals

Here, we demonstrate for the first time a strategy to self-assemble ZnO nanoparticles (NP) on a large area by a facile one-step process. First, rough and random ZnO nanocrystals (NC), were produced by free-stabilizing aqueous synthesis. Therefore, a post thermal treatment at various temperatures ranging from 80 to 800 °C was necessary to obtain size-tunable and photoluminescent crystalline NP. The fabricated NP had both efficient UV photoluminescence and photocatalytic activity by photo-degradation of Methylene Blue (MB) dye. The annealed NP showed an absorption blue shift in the UV region with decreasing size. This shift was attributed to high quantum confinement effect since ZnO NP diameter reached values lower than the Bohr radius of ZnO (~2.7 nm). The photocatalytic activity displayed dependency on the particle’s size, number, and crystallinity. Subsequently, the NP were self-assembled inside poly(methyl methacrylate) (PMMA) nanoholes. Subsequently, large area substrate of homogenous properties ZnO NP was obtained. Moreover, the synthesis facility, photoemission and photocatalytic properties of ZnO NP could be a new insight into the realization of high performance and low cost UV laser devices.

scholarly journals Equilibrium and kinetic studies of acid dye adsorption on palm oil empty fruit bunch

2014 ◽  
Vol 9 (3) ◽  
Author(s):  
Norini Tahir ◽  
Zaiton Abdul Majid
Keyword(s):  
Palm Oil ◽  
Low Cost ◽  
Agricultural Waste ◽  
Dye Adsorption ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Empty Fruit Bunch ◽  
Batch Mode ◽  
Pseudo Second Order

Palm oil empty fruit bunch (POEFB), an agricultural waste, used as low-cost adsorbent for removal Acid Orange 51 (AO51) dye from aqueous solutions was studied. Batch mode experiments were carried out at room temperature (28 ± 2) °C to study the effects of contact time and initial dye concentrations (10-200 mg/L). The equilibrium adsorption data of AO51 dye on empty fruit bunch were analyzed by three isotherms, namely the Langmuir isotherm, Freundlich isotherm and Temkin isotherm model. The result indicated that the equilibrium sorption fitted well with the Freundlich isotherm, displaying higher regression coefficient, R2value. The monolayer adsorption capacity of POEFB was found to be 166.67 mg/g. The kinetic data obtained at different concentrations have been analyzed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. It was shown that pseudo-second-order kinetic model could best describe the adsorption kinetics.

scholarly journals Statistical Modeling and Kinetic Studies on the Adsorption of Reactive Red 2 by a Low-Cost Adsorbent: Grape Waste-Based Activated Carbon Using Sulfuric Acid Activator-Assisted Thermal Activation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Seyyed Alireza Mousavi ◽  
Davood Shahbazi ◽  
Arezoo Mahmoudi ◽  
Parviz Mohammadi ◽  
Tooraj Massahi
Keyword(s):  
Activated Carbon ◽  
Statistical Modeling ◽  
Low Cost ◽  
Dye Adsorption ◽  
Kinetic Studies ◽  
Type I ◽  
Order Kinetic ◽  
Grape Waste ◽  
Pseudosecond Order ◽  
Reactive Red 2

The efficiency of activated carbon produced from grape waste as a low-cost, nontoxic, and available adsorbent to remove Reactive Red 2 from aqueous solution has been investigated. The prepared activated carbon has been characterized by FTIR, SEM, and BET. The results of characterization indicate the successful conversion of grape waste into mesoporous AC with desirable surface area consist of different functional groups. The results of statistical modeling displayed high R 2 value of 0.97% for dye removal that shows the developed model has acceptable accuracy. The effect of independent variables indicated that the highest adsorption (96.83%) obtained at pH 3, adsorbent dosage of 12.25 g/L, and initial dye concentration of 100 mg/L when the adsorption time was 90 min. The results of isotherms modeling showed that the data fit well with the Langmuir (type II). The kinetic studies using pseudofirst-order and pseudosecond-order models pointed out that the type (I) of pseudosecond-order kinetic model provided the best fit to the adsorption data. Parameters of thermodynamics including Gibbs energy ( Δ G ° ) and k o were calculated. The values of Δ G ° indicated that the dye adsorption of RR2 is spontaneous. The agricultural wastes due to special points such as low-cost, availability, and high ability to produce an adsorbent with high efficiency to remove dye can be proposed for water and wastewater treatment.

scholarly journals Various Adsorbents for Removal of Rhodamine B Dye: A Review

2021 ◽  
Vol 21 (4) ◽  
pp. 1039
Author(s):  
Zainab Mohammad Saigl
Keyword(s):  
Rhodamine B ◽  
Low Cost ◽  
Dye Adsorption ◽  
Industrial Effluents ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Waste Biomass ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Wide Range

Lately, there has been an increase in dye manufacturing, resulting in increased environmental pollution. Recent studies show a wide availability of usage adsorbents, including banana peels, potatoes, algae, etc. Food and Drug Administration prohibited the use of Rhodamine B (RhB) for its toxicity and harmful effects. Therefore, this study presents a wide range of non-conventional low-cost alternative adsorbents to remove RhB dye from wastewater. It has been observed that the mechanism of the dye adsorption is focused on kinetics, isotherm, and thermodynamics models, which depend on the chemical nature of the materials and various physicochemical experimental conditions such as solution pH, initial dye concentration, adsorbent dosage, and temperature of the system. The kinetic data of adsorption of RhB dye usually follow the pseudo-first-order and pseudo-second-order kinetic models. Several studies revealed that Langmuir and Freundlich adsorption isotherm models are frequently used to evaluate the adsorption capacity of the adsorbents. Furthermore, thermodynamic examination showed that RhB adsorption was endothermic and unconstrained in nature. Thus, both photocatalytic degradation and adsorption methods offer good potential to remove RhB dye from industrial effluents. The work is in progress to evaluate the possibility of using other modified waste biomass for industrial pollution control.

scholarly journals Synergistic modification of bentonite by acid activation and hydroxyl iron pillaring for enhanced dye adsorption capacity

2020 ◽  
Vol 81 (7) ◽  
pp. 1518-1529
Author(s):  
Huan Xi ◽  
Qingqing Li ◽  
Yan Yang ◽  
Jianfeng Zhang ◽  
Feng Guo ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Low Cost ◽  
Dye Adsorption ◽  
Interlayer Spacing ◽  
Acid Activation ◽  
Order Kinetic ◽  
Environmental Friendliness ◽  
Dye Pollutants ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Despite the fact of natural abundance, low cost and environmental friendliness, the far-from-sufficient adsorption capacity of natural bentonite (BT) has limited such a promising application to remove dye pollutants. In this paper, we proposed a facile modification strategy to enhance adsorption performance of bentonite utilizing synergistic acid activation and hydroxyl iron pillaring, by which the adsorbent (abbreviated as S-Fe-BT) exhibited the highest adsorption capacity (246.06 mg/g) and a high rapid adsorption rate for a typical organic dye, Rhodamine B (RhB). This could be ascribed to the increased interlayer spacing, the increased specific surface area, and the optimized OH/Fe ratio after the synthetic modification of the pristine BT. The adsorption behavior of RhB onto S-Fe-BT was well described by the pseudo-second-order kinetic model, indicating a chemical-adsorption-controlled process. Furthermore, its adsorption isotherm matched well with the Langmuir model due to a monolayer adsorption process. This paper opens a promising direction to remove the dye pollution using low cost bentonite adsorbents treated by such a convenient modification strategy.

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