scholarly journals Photolysis of sulfosalicylic acid in aqueous solutions over a wide pH range

2006 ◽  
Vol 181 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Ivan P. Pozdnyakov ◽  
Victor F. Plyusnin ◽  
Vjacheslav P. Grivin ◽  
Dmitry Yu. Vorobyev ◽  
Nikolai M. Bazhin ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Sulfosalicylic Acid ◽  
Wide Ph Range ◽  
Ph Range

Utilization of cross-linked chitosan/bentonite composite in the removal of methyl orange from aqueous solution

2014 ◽  
Vol 71 (2) ◽  
pp. 174-182 ◽  
Author(s):  
Ruihua Huang ◽  
Qian Liu ◽  
Lujie Zhang ◽  
Bingchao Yang
Keyword(s):  
Methyl Orange ◽  
Aqueous Solutions ◽  
Ph Value ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Wide Ph Range ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Ph Range ◽  
A Minor

A kind of biocomposite was prepared by the intercalation of chitosan in bentonite and the cross-linking reaction of chitosan with glutaraldehyde, which was referred to as cross-linked chitosan/bentonite (CCS/BT) composite. Adsorptive removal of methyl orange (MO) from aqueous solutions was investigated by batch method. The adsorption of MO onto CCS/BT composite was affected by the ratio of chitosan to BT and contact time. pH value had only a minor impact on MO adsorption in a wide pH range. Adsorption kinetics was mainly controlled by the pseudo-second-order kinetic model. The adsorption of MO onto CCS/BT composite followed the Langmuir isotherm model, and the maximum adsorption capacity of CCS/BT composite calculated by the Langmuir model was 224.8 mg/g. Experimental results indicated that this adsorbent had a potential for the removal of MO from aqueous solutions.

Amidoxime-functionalized hydrothermal carbon materials for uranium removal from aqueous solution

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 102462-102471 ◽  
Author(s):  
Zhibin Zhang ◽  
Zhimin Dong ◽  
Ying Dai ◽  
Saijin Xiao ◽  
Xiaohong Cao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
High Selectivity ◽  
Carbon Materials ◽  
Uranium Removal ◽  
Wide Ph Range ◽  
Ph Range

Amidoxime-functionalized hydrothermal carbon (AO-HTC) has been synthesized and applied to adsorb U(vi) from aqueous solutions, exhibiting a high selectivity above 60% for a wide pH range from 1.0 to 5.0.

scholarly journals EPR study of the production of oh radicals in aqueous solutions of uranium irradiated by ultraviolet light

2009 ◽  
Vol 74 (6) ◽  
pp. 651-661 ◽  
Author(s):  
Marko Dakovic ◽  
Milos Mojovic ◽  
Goran Bacic
Keyword(s):  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Fluorescence Decay ◽  
Uranyl Acetate ◽  
Oh Radicals ◽  
Solution Ph ◽  
Trapping Method ◽  
Wide Ph Range ◽  
Ph Range ◽  
Epr Spin Trapping

The aim of the study was to establish whether hydroxyl radicals (?OH) were produced in UV-irradiated aqueous solutions of uranyl salts. The production of ?OH was studied in uranyl acetate and nitrate solutions by an EPR spin trap method over a wide pH range, with variation of the uranium concentrations. The production of ?OH in uranyl solutions irradiated with UV was unequivocally demonstrated for the first time using the EPR spin-trapping method. The production of ?OH can be connected to speciation of uranium species in aqueous solutions, showing a complex dependence on the solution pH. When compared with the results of radiative de-excitation of excited uranyl (+22*UO ) by the quenching of its fluorescence, the present results indicate that the generation of hydroxyl radicals plays a major role in the fluorescence decay of + 22 *UO . The role of the presence of carbonates and counter ions pertinent to environmental conditions in biological systems on the production of hydroxyl radicals was also assessed in an attempt to reveal the mechanism of +22*UO de-excitation. Various mechanisms, including ?OH production, are inferred but the main point is that the generation of ?OH in uranium containing solutions must be considered when assessing uranium toxicity.

scholarly journals Radionuclide 106Ru behavior in aqueous solutions by ion exchange, ultrafiltration, and centrifugation methods

2021 ◽  
Vol 57 (3) ◽  
pp. 331-339
Author(s):  
O. B. Korenkova ◽  
A. V. Radkevich ◽  
N. I. Voronik
Keyword(s):  
Ion Exchange ◽  
Aqueous Solutions ◽  
Waste Treatment ◽  
Membrane Separation ◽  
Liquid Radioactive Waste ◽  
Ionic Species ◽  
Species Formation ◽  
Wide Ph Range ◽  
Ph Range ◽  
Ru Species

The paper presents the results of 106Ru radionuclide behavior regularities study in aqueous solutions in a wide pH range by ultrafiltration, ion exchange and centrifugation methods. The regions of 106Ru various species existence in solution have been established: cationic 106Ru species at pH < 3.5; the transition region of non-ionic species formation in the range of pH 3.5–4.2 and the region of non-ionic species predominant formation at pH > 4.2. A characteristic feature of the studied solutions is the formation of non-ionic particles by microconcentrations of 106Ru via pseudocolloids at lower pH values as compared to ruthenium solutions with a concentration of 10-6–10-4 mol/dm3. The established regularities of the behavior of ruthenium radionuclides can be utilized to increase the efficiency of ion exchange and membrane separation methods at nuclear and radiation facilities for technological solutions and liquid radioactive waste treatment.

scholarly journals Polyoxometalates in solution: speciation under spotlight

2020 ◽  
Vol 49 (21) ◽  
pp. 7568-7601 ◽  
Author(s):  
Nadiia I. Gumerova ◽  
Annette Rompel
Keyword(s):  
Aqueous Solutions ◽  
Ion Distribution ◽  
Wide Ph Range ◽  
Ph Range ◽  
Solution Speciation

The review covers stability and transformations of classical polyoxometalates in aqueous solutions and provides their ion-distribution diagrams over a wide pH range.

A robust polyoxometalate-templated four-fold interpenetrating metal–organic framework showing efficient organic dye photodegradation in various pH aqueous solutions

2018 ◽  
Vol 47 (15) ◽  
pp. 5245-5251 ◽  
Author(s):  
Min Liu ◽  
Xu-Feng Yang ◽  
Hai-Bin Zhu ◽  
Bao-Sheng Di ◽  
Yue Zhao
Keyword(s):  
Aqueous Solutions ◽  
Organic Dyes ◽  
Metal Organic Framework ◽  
Organic Dye ◽  
Light Irradiation ◽  
Wide Ph Range ◽  
Metal Organic ◽  
Ph Range ◽  
Organic Framework

A polyoxometalate-templated four-fold interpenetrating 3-D MOF of 1 acts as a photocatalyst, which can efficiently degrade the organic dyes under UV-Vis light irradiation in aqueous solutions over a wide pH range.

scholarly journals Mechanism of adsorption of cadmium and lead ions by iron-activated biochar

BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 842-857 ◽  
Author(s):  
Liqiang Cui ◽  
Tianming Chen ◽  
Chuntao Yin ◽  
Jinlong Yan ◽  
James A. Ippolito ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Functional Groups ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Ferrous Ammonium Sulfate ◽  
Activated Biochar ◽  
Wide Ph Range ◽  
Ph Range ◽  
Cadmium And Lead ◽  
Ferrous Ammonium

Heavy metal removal from aqueous matrices may help reduce disease and cancer incidences. In this study, reed biochar (RBC) and RBC modified by ferrous ammonium sulfate addition (1 mol Fe L-1) were compared for potential Cd and Pb removal from varying pH aqueous solutions. Surface functional groups were identified using Fourier transform infrared (FTIR) analysis, and their surface physicochemical structure was observed using scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). Batch experiments showed that the modified-reed biochar (MRBC) had greater Cd and Pb removal capacities over a wide pH range (1 to 8), as well as greater metal sorption capacities compared to RBC. Metal reaction kinetics occurred relatively quickly (i.e., within 60 min), and Langmuir modeling suggested that Cd and Pb removal by MRBC was maximized at 2.97 mg g−1 and 17.5 mg g−1 at 45 °C, respectively. The MRBC effectively sorbed Cd and Pb likely due to associations with functional groups modified by the Fe addition. In the future, MRBC may be used as an efficient and eco-friendly adsorbent for Cd and Pb removal from aqueous solutions and may help reduce water-borne issues associated with metal contamination.

Synthesis and Characterization of Chitosan templated Mesoporous Silica: Efficient use of Mesoporous Silica in the removal of Cu(II) from Aqueous Solutions

2016 ◽  
Vol 4 (2) ◽  
pp. 105-112
Author(s):  
Lalchhing puii ◽  
◽  
Seung-Mok Lee ◽  
Diwakar Tiwari ◽  
◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Aqueous Solutions ◽  
Background Electrolyte ◽  
Second Order ◽  
Order Kinetic ◽  
Sorption Data ◽  
Column Reactor ◽  
Wide Ph Range ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order

A mesoporous silica was synthesized by annealing (3-Aminopropyl) triethoxysilane grafted chitosan at 800˚C. The mesoporous silica was characterized by the XRD (X-ray diffraction) analysis. The BET specific surface area and pore size of silica was found to be 178.42 m2/g and 4.13 nm. The mesoporous silica was then employed for the efficient remediation of aqueous solutions contaminated with Cu(II) under batch and column reactor operations. The mesoporous silica showed extremely high per cent removal of Cu(II) at wide pH range i.e., pH ~2.0 to 7.0. Relatively a fast uptake of Cu(II) was occurred and high percentage removal was obtained at initial concentrations studied from 1.0 to 15.0 mg/L. The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Moreover, the effect of an increase in background electrolyte concentrations from 0.0001 to 0.1 mol/L NaNO3 was assessed for the uptake of Cu(II) by mesoporous silica. The equilibrium sorption was achieved within 240 min of contact and the kinetic data is best fitted to the pseudo-second-order and fractal like pseudo-second-order kinetic models. In addition, the mesoporous silica was used for dynamic studies under column reactor operations. The breakthrough curve was then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cu(II) was estimated.

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