scholarly journals Electrochemical Removal of Cesium Ions via Capacitive Deionization Using an Ion-Exchange Layer Coated on a Carbon Electrode

2021 ◽  
Vol 11 (21) ◽  
pp. 10042
Author(s):  
Sang-Hun Lee ◽  
Mansoo Choi ◽  
Jei-Kwon Moon ◽  
Songbok Lee ◽  
Jihoon Choi ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Carbon Electrode ◽  
Capacitive Deionization ◽  
Exchange Layer ◽  
Ph Values ◽  
Influent Water ◽  
Electrochemical Removal ◽  
Cs Ions

This study was conducted to evaluate the feasibility of using electrosorption to remove cesium (Cs+) ions from aqueous solutions using the membrane capacitive deionization (MCDI) process. The electrochemical properties were analyzed using cyclic voltammetry (CV) and impedance spectroscopy (EIS). The activated carbon electrode coated by a polymer layer showed higher specific adsorption capacity (SAC) and removal efficiency of Cs+ than the AC electrode. The effects of potential, flow rate, initial Cs+ concentration, and pH values were investigated to optimize the electrosorption performance. The electrosorption capacity increased with an increase in the applied potential and the concentration of Cs+ in the influent water. The pH value is an important parameter on electrosorption performance. The removal of Cs+ ions was affected by the pH of the influent water because H+ ions acted as competing ions during the electrosorption process. Cs+ was preferentially adsorbed to the electrode in the early stages of adsorption but was later replaced by H+. A higher presence of H+ ions could reduce the adsorption capacity of Cs+ ions. The ion-exchange layer coated AC electrode was shown to be favorable for the removal of Cs+, despite the limited electrosorption ability in a highly acidic solution.

Adsorption of Organic Compounds on Refined Latvian Clay

2018 ◽  
Vol 788 ◽  
pp. 83-88
Author(s):  
Oskars Leščinskis ◽  
Ruta Švinka ◽  
Visvaldis Švinka
Keyword(s):  
Methyl Orange ◽  
Zeta Potential ◽  
Adsorption Capacity ◽  
Clay Minerals ◽  
Organic Compounds ◽  
Clay Mineral ◽  
Rhodamine B ◽  
Ph Value ◽  
Ftir Spectra ◽  
Ph Values

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.

scholarly journals Cd(II) Adsorption on Different Modified Rice Straws under FTIR Spectroscopy as Influenced by Initial pH, Cd(II) Concentration, and Ionic Strength

2019 ◽  
Vol 16 (21) ◽  
pp. 4129
Author(s):  
Shuai Wang ◽  
Wanhong Li ◽  
Xinhua Yin ◽  
Nan Wang ◽  
Shuai Yuan ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ionic Strength ◽  
Ion Exchange ◽  
Adsorption Capacity ◽  
Rice Straw ◽  
Ph Value ◽  
Sorption Process ◽  
Oh Groups ◽  
Chemical Structures ◽  
Adsorption Amount

Rice straw is a kind of low-cost biosorbent. Through mechanical crushing, pyrolysis, incineration, and citric acid (CA) modification, it could be converted to rice straw powder (Sp), biochar (Sb), ash (Sa), and modified rice straw (Ms) accordingly. Using rice straw as an adsorbent, the influence of pH value (2, 4, and 9), initial Cd(II) concentration (0, 200, and 800 mg/L), and ionic strength (0, 0.2, to 0.6 mg/L) on the adsorption capacity for Cd(II) were examined with three replicates, and the relevant mechanisms were explored using Fourier transform infrared (FTIR) technology. Results showed that the modifications could improve the adsorption capacity of Cd(II) by changing their chemical structures. The products (Sb and Sa) of the pyrolysis and incineration of rice straw contained fewer hydroxyl and alkyl groups, but more Si–O groups. Citric acid modification removed a portion of silica in rice straw, increased its carboxylic content, and made more –OH groups exposed. Compared with Sp, Sb, Sa, and Ms were more likely to act as π donors in the Cd(II) sorption process and exhibited more carboxyl binding. The bands of C = C, –O–CH3, and the O–H, carboxyl, Si–O–Si or Si–O groups were involved in the Cd(II) sorption process. The adsorption amount of Cd(II) by the four adsorbents increased with the increase in the pH value of the solution and the initial Cd(II) concentration. Affected by pH in a solution, ion exchange, surface complexation, and precipitation were the major adsorption mechanisms. Further, under the influence of the initial Cd(II) concentration, electrostatic attraction played a leading role. With no interference by ionic strength, all the adsorbents had the greatest adsorption amount of Cd(II), and the intensity of O–H vibration was also the weakest; ion exchange was the most important mechanism in this process. Regardless of the influencing factors, Sa, with the greatest specific surface area, had an absolute advantage in the adsorption capacity of Cd(II) over Sp, Sb, and Ms.

scholarly journals Adsorption Behaviors of 17α-Ethinylestradiol in Sediment-Water System in Northern Taihu Lake, China

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yonghua Wang ◽  
Liangfeng Hu ◽  
Qiuying Wang ◽  
Guanghua Lu ◽  
Yi Li
Keyword(s):  
Adsorption Capacity ◽  
Taihu Lake ◽  
Ph Value ◽  
Water System ◽  
Freundlich Isotherm ◽  
Hydroxyl Group ◽  
High Concentration ◽  
Competitive Effects ◽  
Adsorption Sites ◽  
Ph Values

Adsorption behavior of 17α-ethinylestradiol (EE2) in northern Taihu Lake sediment was analyzed by using batch equilibrium experiment. Freundlich isotherm could describe the adsorption thermodynamic behavior of EE2 in sediment. Sediment organic matter (SOM) contents had important impacts on the adsorption capacity for EE2. The pH values also influenced the adsorption capacity for EE2. Increase of pH value could decrease the EE2 adsorption, which might be due to the electrostatic repulsion between the anionic form of EE2 and sediments with negative charge under high pH values. Competitive effects of bisphenol A (BPA) on EE2 adsorption were further analyzed. The results showed that low concentration BPA did not have significant influences on EE2 adsorption. However, high concentration BPA could reduce EE2 adsorption, which might be due to the similar molecular diameter of BPA with adsorption sites and one more benzene ring with a hydroxyl group in BPA. These results provide primary information of EE2 adsorption in sediment-water system in Taihu Lake, which is useful for the environmental risk assessment and management of EE2 in studied area.

Isotope Effects of Uranium by Ion Exchange in the System Dowex 50 / α-Hydroxyisobutyrate

1974 ◽  
Vol 29 (3-4) ◽  
pp. 190-194 ◽  
Author(s):  
Jorma Aaltonen ◽  
Klaus G. Heumann ◽  
Pikka Pietilä
Keyword(s):  
Ion Exchange ◽  
Isotope Effect ◽  
Separation Factor ◽  
Ph Value ◽  
Isotope Effects ◽  
Uranyl Ions ◽  
Distribution Factor ◽  
Ph Values ◽  
Ion Exchange Column ◽  
Ph Range

In this investigation the isotope effect of uranium in the system Dowex 50 resin/ α- hydroxyisobutyrate solution was studied by mass spectrometry. A recycle ion exchange column was used for the separation experiments. The dependence of the isotope effect on the pH value and on the concentration of the α-hydroxyisobutyrate solution used as eluent was investigated. In the case of a 0.07 ᴍ and a 0.22 ᴍ α-hydroxyisobutyrate solution the elementary separation factor of uranium was calculated to be 1.00019 and 1.00006, respectively. In both cases an enrichment of 235U in relation to 238U was found in the solution.In addition the distribution factor of the uranyl ions in the investigated system was determined in the pH range between 2 and 6. The distribution factor depends strongly on the pH value. With increasing pH values the distribution factor decreases.The results obtained for the elementary separation factor and the distribution factor are compared with other investigations.

A 3D ordered hierarchically porous non-carbon electrode for highly effective and efficient capacitive deionization

2019 ◽  
Vol 7 (26) ◽  
pp. 15633-15639 ◽  
Author(s):  
Yuchen Wu ◽  
Gaopeng Jiang ◽  
Guihua Liu ◽  
Gregory Lui ◽  
Zachary Paul Cano ◽  
...  
Keyword(s):  
Titanium Nitride ◽  
Adsorption Capacity ◽  
Porous Titanium ◽  
Adsorption Rate ◽  
Carbon Electrode ◽  
Capacitive Deionization ◽  
Hierarchically Porous ◽  
Highly Effective ◽  
Ordered Porous

A nanoengineered 3D hierarchical ordered porous titanium nitride electrode is applied as an effective and efficient non-carbon electrode to deliver outstanding salt adsorption capacity and record-breaking salt adsorption rate in a capacitive deionization cell.

Technology of Modified Orange Peel Adsorption Treatment in Wastewater Containing Zinc

2012 ◽  
Vol 610-613 ◽  
pp. 1540-1545
Author(s):  
Rui Yu Jia ◽  
You Hong Lin ◽  
Wei Zhang
Keyword(s):  
Adsorption Capacity ◽  
Ph Value ◽  
Orange Peel ◽  
Sorption Process ◽  
Optimal Conditions ◽  
Adsorption Time ◽  
Initial Concentration ◽  
Ph Values ◽  
Wide Range ◽  
Adsorption Treatment

Using modified flavedo as the adsorbent , the sorption process of Zn2+Superscript text by modified flavedo in wastewater containing heavymetals was studied. The effects of various factors in Zn2+Superscript text adsorption , such as adsorbtion time , temperature , pH value , initial Zn2+ concentration , and pretreatment,were analyzed. The results showed that the pretreatment of modified raised adsorption capacity , and the adsorption capacity was suitable for wastewater with a wide range of pH values. The rate of removal of Zn2+Superscript text reached 98% when the Zn2+ initial concentration was under 100mg/L. The optimal conditions for Zn2 + adsorptionSuperscript text by Modified orange peel were a wastewater pH value of 5.5 , at 25 °C, an adsorption time of 60 minutes , and a dosage of modacrylic flavedo of 2 g/ L.

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