The volumes of mixing of aqueous solutions of CdCl2, CuCl2, MnCl2, and ZnCl2 with HCl at varying ionic strength at 25�C

1994 ◽  
Vol 23 (8) ◽  
pp. 901-910
Author(s):  
Samia A. Kosa ◽  
Donald R. Schreiber

1994 ◽  
Vol 59 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ladislav Svoboda ◽  
Petr Vořechovský

The properties of cellulose chelating ion exchangers Ostsorb have been studied in the sorption of cadmium and lead from aqueous solutions. The Cd(II) and Pb(II) ions are trapped by the Ostsorb OXIN and Ostsorb DETA ion exchangers most effectively in neutral and alkaline media but at these conditions formation of stable hydrolytic products of both metals competes with the exchange equilibria. From this point of view, Ostsorb DTTA appears to be a more suitable sorbent since it traps the Pb(II) and Cd(II) ions in acidic media already. Chloride ions interfere with the sorption of the two metals by Ostsorb DTTA whereas the ionic strength adjusted by the addition of sodium perchlorate does not affect the exchange capacity of this ion exchanger.



2017 ◽  
Vol 228 ◽  
pp. 98-107 ◽  
Author(s):  
Adriana Campos-Ramírez ◽  
Maripaz Márquez ◽  
Liliana Quintanar ◽  
Luis F. Rojas-Ochoa


2019 ◽  
Vol 107 (4) ◽  
pp. 299-309
Author(s):  
Shuqi Yu ◽  
Xiangxue Wang ◽  
Shunyan Ning ◽  
Zhongshan Chen ◽  
Xiangke Wang

Abstract The three-dimensional (3D) carbonaceous nanofiber and Ni-Al layered double hydroxide (CNF/LDH) nanocomposite was successfully prepared by a facile one-step hydrothermal methodology. Characterization of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), XRD, and Fourier transformed infrared spectroscopy (FTIR) provided a demonstration that the modified CNF/LDH nanocomposite possessed abundant functional groups, for instance, metal-oxygen surface bonding sites (Ni–O as well as Al–O) and free-metal surface bonding sites (C–O, C–O–C, as well as O–C=O). The elimination of representative radionuclide (i.e. U(VI)) on the CNF/LDH nanocomposite from aqueous solutions was explored as a key function of pH, ionic strength, contact time, reaction temperature as well as radionuclide preliminary concentrations with the use of the batch methodology. As revealed by the findings, the sorption of radionuclides on CNF/LDH nanocomposite adhered to the pseudo-second-order kinetic model as well as Langmuir model. The maximum elimination capacity of U(VI) amounted to be 0.7 mmol/g. The independent of ionic strength shed light on the fact that inner-sphere surface complexation mainly overpowered radionuclide uptake by the CNF/LDH nanocomposite, which was further verified through the combination of FTIR and XPS spectral analyses. The abovementioned analyses shed light on the fact that the CNF/LDH nanocomposite can be regarded as a latent material to preconcentration radionuclides for environmental remediation.





2021 ◽  
Author(s):  
Masoumeh Faryadi Shahgoli ◽  
Adel Reyhanitabar ◽  
Nosratollah Najafi ◽  
Shahin Oustan

Abstract The present research aimed at investigating zinc (Zn) sorption capacity of the biochars derived from apple wood (WB) and rice straw (RB) feedstocks at two 300 and 600°C pyrolysis temperatures (WB300, WB600, RB300 and RB600, respectively) in aqueous solutions. Kinetic and equilibrium sorption experiments were conducted via batch technique. In equilibrium adsorption experiments, the study used the concentration range of 5-200 mg Zn L− 1 and focused on the solution pH effect on Zn adsorption in biochars under the following conditions: unadjusted and adjusted pH (4 and 6) and three ionic strength levels (0.01, 0.03, 0.1 M KNO3). Zinc desorption experiments were conducted under all above mentioned conditions but without pH adjustment at five separate stages. Kinetic data analysis indicated that Zn adsorption in biochars reached the near steady state within 24 hours with the sorption rate order of WB300 < WB600 < RB300 < RB600. The best fitness was superior to both Elovich and exponential rate models. Also, Zn adsorption isotherms in the studied biochars were shown to fit quite well to Langmuir, Freundlich and Dubinin-Radushkevich models. Zn sorption maxima were found to be 4.3, 16.4, 17.9 and 33.3 mg g− 1, on average, for WB300, WB600, RB300, and RB600, respectively. The initial increased pH solution from 4 to 6 caused an increase in Zn adsorption in RB600, RB300 and WB600, however the sorption maxima in WB300 was detected at pH 4. The rise in solution ionic strength from 0.01 M to 0.1 M dropped the Zn adsorption capacity in all the studied biochars. Findings suggested that rice straw derived biochars showed a better performance than woody biochars in Zn sorption and retention from aqueous solutions. In addition, this ability increased with increasing pyrolysis temperature in both types of biochars. Finally, the study revealed that rice straw biochars, produced at high pyrolysis temperatures, can serve as economical and efficient absorbents for Zn removal from aqueous solutions.



2015 ◽  
Vol 18 (1) ◽  
pp. 38-46 ◽  

<div> <p>This study was conducted to investigate the effect of praestol, as a coagulant-aid, to improve coagulation-flocculation process in the removal of disperse red 60 from aqueous solutions. The effect of various parameters including coagulants dose (10-1000 mg l<sup>-1</sup>), praestol dose (0-1000 mg l<sup>-1</sup>), solution pH (3-11), initial dye concentration (100-500 mg l<sup>-1</sup>), flocculation speed (30-60 rpm), flocculation time (15-30 min), settling time (5-60 min) and ionic strength (0-6 mg l<sup>-1</sup>) was evaluated on the dye removal. The dye removal efficiency was substantially increased by using praestol in the concentration of 80 mg l<sup>-1 </sup>and 400 mg l<sup>-1 </sup>for coagulation with alum and polyaluminum chloride (PACl), respectively. The maximum dye removal by alum coupled with praestol (Al-P) and PACl coupled with praestol (PA-P) was found to be 97.8% and 98.7%, respectively that were occurred at pH 7. The results showed that the application of PA-P or Al-P can be effectively used to remove disperse red 60 (DR 60) in aqueous solutions.</p> </div> <p>&nbsp;</p>



2005 ◽  
Vol 34 (4) ◽  
pp. 427-441 ◽  
Author(s):  
H. López-González ◽  
M. Solache-Ríos ◽  
M. Jiménez-Reyes ◽  
J. J. Ramírez-García ◽  
A. Rojas-Hernández


2013 ◽  
Vol 46 (17) ◽  
pp. 7106-7111 ◽  
Author(s):  
Patrizio Raffa ◽  
Piter Brandenburg ◽  
Diego A. Z. Wever ◽  
Antonius A. Broekhuis ◽  
Francesco Picchioni


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