scholarly journals Ultrasonic Assisted Hydrothermal Synthesis of NiO Nanocatalyst for Low Temperature 3,4-dihydropyrimidin-2-(1H)-Ones and Thiones Condensation Under Solvent-Free Conditions

2020 ◽  
Author(s):  
Leila Kafi-Ahmadi ◽  
shahin khademinia ◽  
Maryam Khashaei
Keyword(s):  
Kinetic Model ◽  
Analysis Data ◽  
Rietveld Analysis ◽  
Spherical Particles ◽  
Order Kinetic ◽  
Solvent Free Conditions ◽  
Ultrasonic Assisted ◽  
Order Kinetic Model ◽  
One Step ◽  
Biginelli Reactions

Abstract Present work reports one step hydrothermal method as a green processto synthesizenickel (II) oxide (NiO) nanoparticles using nickel nitrate, and some natural essences as surfactant including Orange blossom, Yarrow, Hibiscus tea, Green tea, Rosemary and Barberryas at 80 ºC in autoclave for 24 h followed by calcination at 700 ºC for 8 h. Rietveld analysis data revealed that the obtained NiO nanomaterials were crystallized in a pure cubic crystalsystem. Field emission scanning electron microscope (FESEM) images showed that the morphology of the obtained materials was changed from non-homogeneous particles to homogeneous spherical particles when the surfactant type was changed from Orange blossom to Barberryas. Catalytic activity of the nanomaterials was investigated in Biginelli reactions for the synthesis of heterocyclic 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) compounds. The synthesis yields at optimum conditions (60 mg of catalyst, 90 ºC reaction temperature and 90 min reaction time) were 94% and 97% for S1 and S6, respectively. Langmuir–Hinshelwood kinetic model revealed that the reactions followed a pseudo-first order kinetic model.

scholarly journals Composite of Hydroxyapatite-Fe3O4 for the Adsorption of Methylene Blue

2020 ◽  
Vol 20 (2) ◽  
pp. 140
Author(s):  
Nur Hafizah Zainal Abidin ◽  
Nonni Soraya Sambudi ◽  
Norashikin Ahmad Kamal
Keyword(s):  
Heavy Metal ◽  
Methylene Blue ◽  
Magnetic Properties ◽  
Kinetic Model ◽  
Spherical Particles ◽  
Order Kinetic ◽  
Freundlich Isotherms ◽  
Methylene Blue Removal ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The utilization of hydroxyapatite as an adsorbent has been extensively tested to remove the dye and heavy metal. Yet the adsorbent loss to the environment may lead to secondary pollutant issues. Consequently, the hydroxyapatite was incorporated with Fe3O4 amount variation to solve the secondary pollutant problem by utilizing the magnetic properties of Fe3O4 to recollect the adsorbent. In this work, FESEM images showed a mixture of nano-sizes rods and spherical particles corresponded to the presence of hydroxyapatite and Fe3O4 as a composite. The study found that hydroxyapatite- Fe3O4 (100 wt %) could eliminate 12.434 mg methylene blue/g adsorbent after 4 hours. The hydroxyapatite also gained improvement in its surface area from 59.8m2/g to 75.2m2/g when Fe3O4 is added. In addition, the adsorption of methylene blue fits the Freundlich isotherms and pseudo-second-order kinetic model. Furthermore, the methylene blue removal using hydroxyapatite-Fe3O4 composite can be kept at 80% even after 4 times experiments, showing the recyclability of hydroxyapatite-Fe3O4.

scholarly journals Investigation of Seeds and Peels of Citrullus colocynthis as Efficient Natural Adsorbent for Methylene Blue Dye

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1279
Author(s):  
Wafa Mohammed Alghamdi ◽  
Ines El Mannoubi
Keyword(s):  
Methylene Blue ◽  
Kinetic Model ◽  
Langmuir Isotherm ◽  
Order Kinetic ◽  
Citrullus Colocynthis ◽  
Natural Adsorbent ◽  
Spontaneous Process ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Mb Adsorption

Natural adsorbents as low-cost materials have been proved efficient for water remediation and have significant capacity for the removal of certain chemicals from wastewater. The present investigation aimed to use Citrullus colocynthis seeds (CCSs) and peels (CCPs) as an efficient natural adsorbent for methylene blue (MB) dye in an aqueous solution. The examined biosorbents were characterized using surface area analyzer (BET), scanning electron microscope (SEM), thermogravimetric analyzer (TGA) and Fourier transform infra-red (FT-IR) spectroscopy. Batch adsorption experiments were conducted to optimize the main factors influencing the biosorption process. The equilibrium data for the adsorption of MB by CCSs were best described by the Langmuir isotherm followed by the Freundlich adsorption isotherms, while the equilibrium data for MB adsorption by CCPs were well fitted by the Langmuir isotherm followed by the Temkin isotherm. Under optimum conditions, the maximum biosorption capacity and removal efficiency were 18.832 mg g−1 and 98.00% for MB-CCSs and 4.480 mg g−1 and 91.43% for MB-CCPs. Kinetic studies revealed that MB adsorption onto CCSs obeys pseudo-first order kinetic model (K1 = 0.0274 min−1), while MB adsorption onto CCPs follows the pseudo-second order kinetic model (K2 = 0.0177 g mg−1 min−1). Thermodynamic studies revealed that the MB biosorption by CCSs was endothermic and a spontaneous process in nature associated with a rise in randomness, but the MB adsorption by CCPs was exothermic and a spontaneous process only at room temperature with a decline in disorder. Based on the obtained results, CCSs and CCPSs can be utilized as efficient, natural biosorbents, and CCSs is promising since it showed the highest removal percentage and adsorption capacity of MB dye.

Dyeing mechanism and photodegradation kinetics of gardenia yellow natural colorant

2020 ◽  
pp. 004051752095848
Author(s):  
Huiyu Jiang ◽  
Xiaodong Hu ◽  
Asfandyar Khan ◽  
Jinbo Yao ◽  
Muhammad Tahir Hussain
Keyword(s):  
Kinetic Model ◽  
Cotton Fabric ◽  
Reaction Rate Constant ◽  
Second Order ◽  
Order Kinetic ◽  
Natural Colorant ◽  
Yellow Solution ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Dyeing Rate

In this study, gardenia yellow solution is used to dye 100% cotton fabric. The dyeing rate curve and adsorption isotherms were recorded to explore the thermodynamic model and to calculate the corresponding parameters. A definite concentration of gardenia yellow solution was placed under the xenon arc lamp for irradiation to test its photodegradability. Absorbance of the solution was measured at different degradation times and the corresponding varying curve of the absorbance was drawn to explore the photodegradation reaction order of the natural colorant and consistent parameters were calculated. The experimental results proved that the dyeing of cotton fabric with gardenia yellow colorant followed the pseudo second order kinetic model whereas adsorption isotherm followed the Langmuir model and the photodegradation process followed the second order kinetic model. Values of different parameters were calculated: reaction rate constant k = 2.26 × 10–3 (mg · L−1)1−m h−1, the correlation coefficient R2 = 0.994, and half decay time t1/2 = 5.82 h.

Biosorption of hexavalent chromium from aqueous solution by polyethyleneimine-modified ultrasonic-assisted acid hydrochar from Sargassum horneri

2020 ◽  
Vol 81 (6) ◽  
pp. 1114-1129 ◽  
Author(s):  
Jun Wang ◽  
Qinglong Xie ◽  
Ao Li ◽  
Xuejun Liu ◽  
Fengwen Yu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Batch Adsorption ◽  
Crosslinking Reaction ◽  
Order Kinetic ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Ultrasonic Assisted ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract In this study, an efficient route to synthesizing polyethyleneimine-modified ultrasonic-assisted acid hydrochar (PEI-USAH) is developed and reported. Ultrasonic irradiation technique was used as surface modification method to shorten the crosslinking reaction for hydrochar and polyethyleneimine (PEI). The PEI-USAH showed an excellent adsorption capacity for Cr(VI) from aqueous solution. The physicochemical properties of this PEI-modified adsorbent were comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis and CNHS analysis. The effects of contact time, initial pH, and biosorbent dose on adsorption capacities were investigated. The batch adsorption experiments showed that PEI-USAH possessed the maximum adsorption capacities of 94.38 mg/g and 330.84 mg/g for initial Cr(VI) concentration of 100 mg/L and 500 mg/L, respectively. Furthermore, this adsorption process could be fitted to Langmuir adsorption and described by the pseudo second order kinetic model. Based on the above findings, PEI-USAH could be used as a potential adsorbent for removal of Cr(VI) from wastewater.

Iron Chelation by Polyamidoamine Dendrimers: A Second-Order Kinetic Model for Metal–Amine Complexation

2011 ◽  
Vol 115 (46) ◽  
pp. 13534-13540 ◽  
Author(s):  
Michael R. Mankbadi ◽  
Mohamed A. Barakat ◽  
Mohamed H. Ramadan ◽  
H. Lee Woodcock ◽  
John N. Kuhn
Keyword(s):  
Kinetic Model ◽  
Iron Chelation ◽  
Second Order ◽  
Order Kinetic ◽  
Polyamidoamine Dendrimers ◽  
Order Kinetic Model ◽  
Metal Amine

scholarly journals Kinetic Modeling of a Heterogeneous Fenton Oxidative Treatment of Petroleum Refining Wastewater

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Diya'uddeen Basheer Hasan ◽  
Abdul Aziz Abdul Raman ◽  
Wan Mohd Ashri Wan Daud
Keyword(s):  
Kinetic Model ◽  
Direct Conversion ◽  
Order Kinetic ◽  
Initial Oxidation ◽  
Oxidation Step ◽  
Kinetic Rate Constants ◽  
Order Kinetic Model ◽  
Generalized Kinetic Model ◽  
Petroleum Refinery Effluent ◽  
Kinetics Of

The mineralisation kinetics of petroleum refinery effluent (PRE) by Fenton oxidation were evaluated. Within the ambit of the experimental data generated, first-order kinetic model (FKM), generalised lumped kinetic model (GLKM), and generalized kinetic model (GKM) were tested. The obtained apparent kinetic rate constants for the initial oxidation step (k2′), their final oxidation step (k1′), and the direct conversion to endproducts step (k3′) were 10.12, 3.78, and 0.24 min−1for GKM; 0.98, 0.98, and nil min−1for GLKM; and nil, nil, and >0.005 min−1for FKM. The findings showed that GKM is superior in estimating the mineralization kinetics.

Kinetic Studies on Sorption of Textile Dyes Using Lamina and Petiole Parts of Eichhornia crassipes

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
S Renganathan ◽  
R Venkatakrishnan ◽  
P Gautam ◽  
Lima Rose Miranda ◽  
M Velan
Keyword(s):  
Diffusion Coefficient ◽  
Kinetic Model ◽  
Eichhornia Crassipes ◽  
Kinetic Studies ◽  
Reactive Dye ◽  
The Other ◽  
Order Kinetic ◽  
Uptake Capacity ◽  
Fast Red ◽  
Order Kinetic Model

Sorption capacity of two different parts of Eichhornia crassipes such as Lamina and Petiole on a Basic dye (Basic Aurophine-O), Acidic dye (Acid Fast Red-A) and Reactive dye (Brill Red-5B) was studied in a batch system. The maximum equilibrium uptake capacity of petiole was 25.5 mg/g for Basic Aurophine-O, 23.1 mg/g for Acid Fast Red-A and 0.18 mg/g for Brill Red-5B. The equilibrium uptake capacity of petiole was found to be more in Basic Aurophine-O dye when compared to all other dyes studied. The maximum equilibrium uptake capacity of lamina was 27.0 mg/g for Basic Aurophine-O, 25.2 mg/g for Acid Fast Red-A and 4.2 mg/g for Brill Red-5B. The equilibrium uptake capacity of lamina was found to be more in Basic Aurophine-O when compared to Brill Red-5B and Acid Fast Red-A dyes studied in the present investigation. From the result, it was observed that the uptake capacity of dyes using E. crassipes part Lamina was found to be more when compared to the other E. crassipes part of Petiole used in the present study. Sorption results were found to be fitted very well with the Pseudo-second order kinetic model when compared to Pseudo-first order kinetic model. The intra particle diffusion coefficient (Ki) and diffusion coefficient (Di) obtained for the removal of dyes studied using Lamina was found to be more when compared to the other part of Petiole. The polynomial equations are developed and can be used as a ready reckoner equation to find out the percentage color removal of dyes studied in the present investigation at different period of time intervals.

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