scholarly journals Adsorptive Removal of Aqeous Disperse Dye by using Flocs

2020 ◽  
Vol 9 (6) ◽  
pp. 767-771
Keyword(s):  
Ferric Chloride ◽  
Ferrous Sulphate ◽  
Aluminium Sulphate ◽  
Colour Removal ◽  
Adsorptive Removal ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Rate Limiting

Ferric chloride, Aluminium sulphate, and Ferrous sulphate flocs were used as an adsorbent in the decolourisation of aqueous dye C.I. Disperse yellow 3. To evaluate the potentiality of adsorbents, non-flow agitated experiments were carried out to find the equilibrium contact time, optimum equilibrium adsorbent dose. Preformed flocs at pH:: 4 rather than pH:: 10 produced excellent colour removal. Adsorption capacity of flocs of Ferric chloride, Aluminium sulphate and Ferrous sulphate was obtained as 500 mg/g, 333mg/g and 23.3mg/g at pH:4. The equilibrium data sorption follows Langmuir Isotherm and kinetic data follows pseudo second order stating that chemisorptions is the rate limiting step.

scholarly journals Chlorates(VII) removal on Dowex™PSR-2 resin

2016 ◽  
Vol 71 (1) ◽  
pp. 105
Author(s):  
Dorota Kołodyńska ◽  
Aleksandra Łyko ◽  
Marzena Gęca ◽  
Zbigniew Hubicki
Keyword(s):  
Solution Concentration ◽  
Intraparticle Diffusion ◽  
Optimum Conditions ◽  
Order Model ◽  
Experimental Conditions ◽  
Freundlich Model ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Pseudo Second Order ◽  
Rate Limiting

<p>Lately there has been observed the increased presence of chlorates(VII) in the natural environment which can affect human health negatively. Therefore the removal of chlorate(VII) ions using the gel type resin functionalized with the tri-n-butyl ammonium (Dowex<sup>™</sup>PSR-2) from waters was studied. The main aim was to evaluate the effects of experimental conditions including contact time, initial solution concentration, pH and temperature on chlorate(VII) ions removal as well as the anion exchanger properties on chlorate(VII) ions sorption. It was found that only the pseudo second order model described the experimental data well and the intraparticle diffusion was not the rate-limiting step. According to the Freundlich model, the q<sub>e</sub> value was to be 69.26 mg/g at optimum conditions (pH 7.0 at 25 <sup>o</sup>C).<strong></strong></p>

scholarly journals Equilibrium, Kinetics and Thermodynamics of the Bleaching of Palm Oil Using Activated Nando Clay

2018 ◽  
pp. 1-13
Author(s):  
Nwabanne, Joseph T. ◽  
Onu, Chijioke E. ◽  
Nwankwoukwu, Okwudili C.
Keyword(s):  
Palm Oil ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Bleaching Efficiency ◽  
Rate Limiting Step ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Different Temperatures ◽  
Pseudo Second Order ◽  
Rate Limiting

The effectiveness of Nando clay in the bleaching of palm oil was studied in this work. The clay was prepared by activating it with hydrochloric acid. The bleaching was carried out at different temperatures, adsorbent dosage and particle sizes. The result suggests that increase in temperature and adsorbent dosage increases the bleaching efficiency while the increase in particle size decreases the bleaching efficiency. Both the pseudo-first-order and the pseudo-second-order kinetic models describe efficiently the experimental data of the bleaching process. Intra-particle diffusion though involved in the adsorptive bleaching mechanism, is not the sole rate-limiting step in the bleaching of palm oil with activated Nando clay. The equilibrium data were described better by Langmuir and Freundlich models. The enthalpy, entropy and activation energy were determined to be 6.127 KJ/mol, 3.982 KJ/mol and 15.281 KJ respectively. The free energy was found to vary between- 3.999 to- 3.760 KJ/mol. The result indicates that bleaching efficiency of up to 96% can be obtained with the activated clay as an adsorbent.

scholarly journals Removal of copper from an electroplating industrial effluent using the native and modified spirogyra

2018 ◽  
Vol 78 (1) ◽  
pp. 147-155 ◽  
Author(s):  
Nimra Ilyas ◽  
Sadia Ilyas ◽  
Sajjad-ur-Rahman ◽  
Sidra Yousaf ◽  
Aqsa Zia ◽  
...  
Keyword(s):  
Industrial Effluent ◽  
Order Kinetic ◽  
Sorption Data ◽  
Freundlich Model ◽  
First Order ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Rate Limiting

Abstract In the present study, biosorption behavior of a green filamentous alga, spirogyra in its native and modified states was investigated for copper removal from an electroplating industrial effluent. For this, the effluent containing 194 mg·L−1 Cu2+ in sulfate medium was contacted with both forms of spirogyra, under the parametric variations of effluent pH, adsorbent dosage, contact time, and sorption temperature. The study revealed spirogyra as a prominent candidate for removing contaminant metal cation; however, at the same condition, biosorption capacity of modified biomass in gel form was higher than the native spirogyra. At the optimized condition with 6 g sorbent dosage treated to 100 mL effluent for 30 min at pH 6.0 and temperature 20 °C, the maximum 82.8% and 96.4% copper could be adsorbed by the native and modified spirogyra, respectively. The batch sorption data using native biomass followed pseudo-first-order kinetic; exhibiting the multilayer sorption mechanism via surface diffusion could be defined by the Freundlich model. In contrast, the sulfuric acid treated modified spirogyra followed pseudo-second-order kinetics and intra particle diffusion as the rate-limiting step.

Study of Adsorption of Cu2+ and Ni2+ from Aqueous Solutions Using β-Cyclodextrin Modified Zeolites

2014 ◽  
Vol 955-959 ◽  
pp. 3509-3513
Author(s):  
Xiao Hong Li ◽  
Xue Kui Hao
Keyword(s):  
Contact Time ◽  
Physical Adsorption ◽  
Kinetic Studies ◽  
Order Model ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Modified Zeolites ◽  
Rate Limiting

Adsorption of Cu2+ and Ni2+ from aqueous solution on CCDMZ was investigated. The adsorption capacity of Cu2+ and Ni2+ on CCDMZ was found to have a much higher enhance than that of NZ and to be obviously influenced by contact time, initial concentration and pH. The kinetic studies showed that the adsorption processes of Cu2+ and Ni2+ on CCDMZ were complex, including chemical adsorption and physical adsorption. The adsorption followed the pseudo-second-order model, which suggested that the rate-limiting step might be mainly chemisorption.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting
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