Adsorption, kinetic and thermodynamic study of Al, Mn and Fe adsorption with natural attapulgite
- Ntuli, Freeman, Falayi, Thabo, Mabasa, Cyril
- Authors: Ntuli, Freeman , Falayi, Thabo , Mabasa, Cyril
- Date: 2015
- Subjects: Attapulgite , Aluminum , Manganese , Iron , Adsorption
- Type: Article
- Identifier: uj:5126 , ISBN 978-1-61804-270-5 , http://hdl.handle.net/10210/14089
- Description: Natural attapulgite was utilized as an adsorbent for the removal of Al, Fe and Mn from a mixed metal effluent. Adsorption experiments were carried out by agitation of a fixed amount of attapulgite with a fixed volume of effluent waste stream in a thermostatic shaker for varying times. Attapulgite showed that it was capable of neutralising the acidic waste stream effluent as pH after 3 hour rose from 2 to 7.46. 4% solid loading of attapulgite could remove 85% Mn(II), 90% Al(III) and 100% Fe(III) The experimental data best fit Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models and the adsorption mechanism was physisorption. The adsorption process fitted well the pseudo second order kinetics for all metal ions studied. Thermodynamic data showed that Fe(III) and Mn(II) adsorption was thermodynamically spontaneous whilst Al(III) was not thermodynamically spontaneous. The process is endothermic for all metal ions. An increase in temperature resulted in an increase in spontaneity of the adsorption process. An increase in metal concentration resulted in an increase in amount of metal ion adsorbed per unit weight of attapulgite.
- Full Text:
- Authors: Ntuli, Freeman , Falayi, Thabo , Mabasa, Cyril
- Date: 2015
- Subjects: Attapulgite , Aluminum , Manganese , Iron , Adsorption
- Type: Article
- Identifier: uj:5126 , ISBN 978-1-61804-270-5 , http://hdl.handle.net/10210/14089
- Description: Natural attapulgite was utilized as an adsorbent for the removal of Al, Fe and Mn from a mixed metal effluent. Adsorption experiments were carried out by agitation of a fixed amount of attapulgite with a fixed volume of effluent waste stream in a thermostatic shaker for varying times. Attapulgite showed that it was capable of neutralising the acidic waste stream effluent as pH after 3 hour rose from 2 to 7.46. 4% solid loading of attapulgite could remove 85% Mn(II), 90% Al(III) and 100% Fe(III) The experimental data best fit Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models and the adsorption mechanism was physisorption. The adsorption process fitted well the pseudo second order kinetics for all metal ions studied. Thermodynamic data showed that Fe(III) and Mn(II) adsorption was thermodynamically spontaneous whilst Al(III) was not thermodynamically spontaneous. The process is endothermic for all metal ions. An increase in temperature resulted in an increase in spontaneity of the adsorption process. An increase in metal concentration resulted in an increase in amount of metal ion adsorbed per unit weight of attapulgite.
- Full Text:
Kinetic and thermodynamic parameters of silica leaching from Camden power station fly ash
- Falayi, Thabo, Ntuli, Freeman, Okonta, Felix Ndubisi
- Authors: Falayi, Thabo , Ntuli, Freeman , Okonta, Felix Ndubisi
- Date: 2015
- Subjects: Fly ash , Leaching , Potassium silicate , Silicate leaching
- Type: Article
- Identifier: uj:5142 , ISBN 978-1-61804-270-5 , http://hdl.handle.net/10210/14120
- Description: Fly ash from a South African power station ash dam was used. The fly ash approximated Class F fly ash but had a loss on ignition greater than 6%. The leaching parameters investigated were leaching time, KOH concentration, agitation speed, fly ash particle size, leaching temperature and liquid solid ratio (L/S). It was found that the optimum leaching conditions were leaching time of 6 h, 3M KOH, 500 rpm agitation speed, 25 L/S ratio, leaching temperature of 100˚C. Silica leaching followed a modified Jander equation kinetics with an N value of 1.48 and an activation energy of 5.9 kJ/mol.
- Full Text:
- Authors: Falayi, Thabo , Ntuli, Freeman , Okonta, Felix Ndubisi
- Date: 2015
- Subjects: Fly ash , Leaching , Potassium silicate , Silicate leaching
- Type: Article
- Identifier: uj:5142 , ISBN 978-1-61804-270-5 , http://hdl.handle.net/10210/14120
- Description: Fly ash from a South African power station ash dam was used. The fly ash approximated Class F fly ash but had a loss on ignition greater than 6%. The leaching parameters investigated were leaching time, KOH concentration, agitation speed, fly ash particle size, leaching temperature and liquid solid ratio (L/S). It was found that the optimum leaching conditions were leaching time of 6 h, 3M KOH, 500 rpm agitation speed, 25 L/S ratio, leaching temperature of 100˚C. Silica leaching followed a modified Jander equation kinetics with an N value of 1.48 and an activation energy of 5.9 kJ/mol.
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