Zeta potential measurements for adsorption capacity calculation: case study for a system of natural coal and surfactants

Author(s):  
Roman Maršálek
2012 ◽  
Vol 622-623 ◽  
pp. 1779-1783
Author(s):  
Richard Appiah-Ntiamoah ◽  
Xuan Thang Mai ◽  
Francis W.Y. Momade ◽  
Hern Kim

In this study, the adsorption capacity of expanded perlite (EP) for benzene at low concentrations in water was investigated after EP was treated with sodium hydroxide (NaOH). IR spectra used to characterize the modified EP showed that there was no bonding between NaOH and the hydroxyl groups on the surface of EP. However, the NaOH provided a basic medium for negatively charged surface oxide ions (-SO-) to form on EP. This fact was corroborated by pH readings of the modification solution. This reduced in pH from 10 to 9 at the end of the reaction which indicated that the hydroxyl OH- groups on the EP underwent deprotonation and hence releases H+ into the solution, and also positive sites on EP adsorbed OH- ions from the base solution. Mahir et al. in their paper Zeta potential of unexpanded and expanded perlite samples in various electrolyte media confirmed that EP has no isoelectric point and exhibits negative zeta potential in the pH range of 2-11. The surface oxides (-SO-) were believed to have given EP it adsorptive potential. Adsorption isotherm values correlated reasonably well with the Langmuir isotherm model and it parameters (qo and K) were obtained using linear regression analysis. A maximum adsorption capacity (qo) value of 19.42 mg/g was achieved.


2018 ◽  
Vol 788 ◽  
pp. 83-88
Author(s):  
Oskars Leščinskis ◽  
Ruta Švinka ◽  
Visvaldis Švinka

Clays are materials consisting of clay minerals and non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Clay minerals can be used for water purification and treatment. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) as well as their adsorption capacity concerning organic compounds such as methyl orange and rhodamine B are summarized. Nanosized clay mineral particles were obtained using sedimentation method. Particle size distribution, zeta potential and FTIR spectra is given. The adsorption tests of above mentioned organic compounds were carried out in water solutions at 3 different pH values. The adsorption values were determined by means of UV-spectrophotometric technique. Zeta potential values for clay minerals Apriki, Liepa and Vadakste are -40.9 mV, -49.6 mV and -43.0 mV, respectively. FTIR spectra show similar tendencies for all 3 clay minerals. The best adsorption capacity concerning methyl orange and rhodamine B were in solutions with a pH value of 2, whereas at neutral and alkaline pH values adsorption in 24 hours was not observed.


2012 ◽  
Vol 441 ◽  
pp. 111-115 ◽  
Author(s):  
Lan Zhou ◽  
Jian Zhong Shao ◽  
Li Qin Chai ◽  
Guo Dong Fu

Sericin was investigated as modifier for surface modification on cotton fibers. The measurement of zeta potential was initially used to indicate the effectiveness of the modification. It was found that the sericin largely developed the positive charge on cotton fibers following a decrease in the pH. Adsorption studies of the annatto dye on the modified cotton fibers showed that sericin enhanced the adsorption capacity of the annatto dye on cotton fibers. The results of the zeta potential and the adsorption revealed that the uptake of annatto dye on modified cotton fibers occurred via electrostatic attractions between the anion of the dye and the cationic segments on the modified cotton fibers.


2015 ◽  
Vol 744-746 ◽  
pp. 1786-1791
Author(s):  
Qian Rui Zhao ◽  
Qi Zhang ◽  
Pei Liu

Carrying capacity calculation at high-speed railway stations is closely related to the trains with different types and arriving rules. Traditional method is not feasible to calculate and evaluate carrying capacity at high-speed railway stations efficiently and accurately. Therefore, a method to calculate carrying capacity at high-speed railway stations was presented by establishing a route selection optimization model and designing corresponding algorithm. In the method, the integration concept of calculating carrying capacity was introduced by establishing the relationship between receiving dispatching route and arrival-departure track. An approach was provided to the solution of route selection scheme and calculating carrying capacity at high-speed railway stations efficiently and accurately by considering the differences of trains with different operation modes and operation time. Case study of Jinan West railway station verifies the feasibility of the method. The presented method can provide a technical support for calculating and evaluating carrying capacity at high-speed railway stations in different scenarios.


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