Studies on Zero Point of Charge and Permanent Charge Density of Mg−Fe Hydrotalcite-like Compounds

Langmuir ◽  
2001 ◽  
Vol 17 (6) ◽  
pp. 1885-1888 ◽  
Author(s):  
Wan-Guo Hou ◽  
Yan-Lei Su ◽  
De-Jun Sun ◽  
Chun-Guang Zhang
Keyword(s):  
Charge Density ◽  
Zero Point ◽  
Zero Point Of Charge

THE ZERO POINT OF CHARGE OF OXIDES1

1962 ◽  
Vol 66 (6) ◽  
pp. 967-973 ◽  
Author(s):  
G. A. Parks ◽  
P. L. de Bruyn
Keyword(s):  
Zero Point ◽  
Zero Point Of Charge

Lead(II) Adsorption by Raw and Acid-Activated Vermiculite

2012 ◽  
Vol 557-559 ◽  
pp. 1127-1130 ◽  
Author(s):  
Wen Jun Xiang
Keyword(s):  
Specific Surface ◽  
Surface Charge ◽  
Langmuir Isotherm ◽  
Cation Exchange Capacity ◽  
Zero Point ◽  
Exchange Capacity ◽  
Zero Point Of Charge ◽  
Adsorption Capacities ◽  
Adsorption Data ◽  
Hcl Solution

Acid-activated vermiculite (AAV) was prepared by treating raw vermiculite (RV) at 80°C with HCl solution. The surface properties and Pb(II) adsorption characteristics of RV and AAV were studied. The specific surface area (SSA), cation exchange capacity (CEC), pH at zero point of charge (pHZPC), and surface charge at pH 5.8 of AAV were 287.62 m2/g, 24.85 cmol/kg, pH 3.06, and -0.361 mmol/g, respectively. Compared to RV, the SSA, CEC and surface charge of AAV increased, but the value of pHZPC decreased. At pH 5.8, the maximum adsorption capacities (qmax) for Pb(II) of RV and AAV were 10.72 and 18.53 mg/g, respectively. The adsorption data for Pb(II) by RV and AAV could be well fitted using Langmuir isotherm (R2 =0.990 and 0.995, respectively)

Long-term in vitro transformation of 2-line ferrihydrite to goethite/hematite at 4, 10, 15 and 25°C

Clay Minerals ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 433-438 ◽  
Author(s):  
U. Schwertmann ◽  
H. Stanjek ◽  
H.-H. Becher
Keyword(s):  
Zero Point ◽  
Transformation Rate ◽  
Ambient Temperatures ◽  
Ph Values ◽  
In Vitro Transformation ◽  
Zero Point Of Charge ◽  
Ph Range ◽  
Increasing Temperature

Abstract2-line ferrihydrite stored in water at ambient temperatures from 4 to 25°C and at ten different pH values between 2.5 and 12 for up to 10–12 y transformed to both goethite and hematite at all temperatures and pH values except at pH 12 where only goethite was formed. The rate and degree of transformation (20–100%) increased with increasing pH and temperature. The hematite/ (hematite+goethite) ratio varied between 0 and ~0.8, increased with increasing temperature and showed a strong maximum at pH 7–8 which increased from 0.1–0.2 at 4°C to 0.7–0.8 at 25°C. The maximum coincides with the zero point of charge of ferrihydrite where its solubility and, thus, its via-solution transformation rate to goethite are minimal. We assume, therefore, that in this pH-range the (slower) via-solution transformation to hematite can more efficiently compete with that to goethite.

The zero point of charge of silica—alumina oxide suspensions

1984 ◽  
Vol 97 (1) ◽  
pp. 55-61 ◽  
Author(s):  
J.A Schwarz ◽  
C.T Driscoll ◽  
A.K Bhanot
Keyword(s):  
Zero Point ◽  
Zero Point Of Charge ◽  
Alumina Oxide ◽  
Silica Alumina

scholarly journals Peach palm and cassava wastes as biosorbents of tartrazine yellow dye and their application in industrial effluent

2021 ◽  
Vol 17 (5) ◽  
Author(s):  
Luciana Nunes Dos Santos ◽  
Carlos Eduardo Porto ◽  
Milena Keller Bulla ◽  
Vagner Roberto Batistela ◽  
Beatriz Cervejeira Bolanho Barros
Keyword(s):  
Adsorption Process ◽  
Low Cost ◽  
Industrial Effluent ◽  
Zero Point ◽  
Peach Palm ◽  
Chemical Treatments ◽  
Zero Point Of Charge ◽  
Main Component ◽  
By Products ◽  
Interesting Alternative

In this study, the wastes from cassava (CAW) and peach palm (PPW) agro-industries were investigated as potential low-cost biosorbents for removing the tartrazine yellow dye (TAR). The by-products were prepared by washing and drying steps and characterized into physicochemical parameters and microstructure. The effects of contact time, pH, dosage and dye concentration were analyzed for the biosorbents in comparison to commercial activated carbon (AC). The biosorbents were applied to the treatment of an effluent from a juice industry containing TAR. Cellulose was the main component of the biosorbents (31.47–51.20 g 100     g-1), which was correlated to the functional groups identified by ATR-FTIR spectra and the materials had a porous surface. The zero point of charge was 3.75 for PPW and 4.60 for CAW. The pH parameter had a significant effect on the adsorption process, with the maximum values of adsorption being reached at pH 2.0, with removal of 94.7% for PPW, 74.4% for CAW and 97.7% for AC, at the dosage of 7.5 g L-1 at 25.0 ºC. The adsorption of TAR was fast in the early stages, and at 120 min the three adsorbents reached the equilibrium. Isotherms of adsorption showed that Langmuir’s and Freundlich’s models fitted the best to the CAW and PPW experimental data, respectively. The wastes evaluated in this work can be an interesting alternative to TAR adsorption in the industrial effluent without being subjected to chemical treatments.

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