scholarly journals EXPRESS EVALUATION OF SORPTION MECHANISM ON PEAT CONTAINING MATERIALS

2020 ◽  
Vol 17 (34) ◽  
pp. 469-477
Author(s):  
Silva A GEVORGYAN ◽  
Sergey S HAYRAPETYAN ◽  
Martin S HAYRAPETYAN ◽  
Hambardzum G KHACHATRYAN
Keyword(s):  
Heavy Metals ◽  
Ion Exchange ◽  
Cation Exchange ◽  
Cation Exchanger ◽  
Sorption Mechanism ◽  
Ph Change ◽  
Static Mode ◽  
Peat Sample ◽  
Wide Range ◽  
Effective Sorbent

Peat is an effective sorbent of heavy metals, which is due to its high cation-exchange ability. The use of peat sorbents has many advantages. It is an inexpensive, affordable, and effective sorbent for a wide range of environmental pollutants. Also, it can be used either separately or as a combined sorbent and complex constituents; however, it also has several disadvantages, such as insufficient mechanical strength and low chemical stability of peat particles. To overcome these shortcomings, various methods of peat modification have been developed (e.g., peat modified with chitosan, which is used as a sorbent for heavy metals removal like peat). The ion-exchange sorption properties of sorbents on the base of peat and chitosan - modified peat were evaluated by the method of pH meter. An acid-activated peat sample was also investigated. The experiments were carried out in a static mode using natural peat samples taken from the Lake Sevan (near the city of Vardenis of the Gegharkunik region of the Republic of Armenia). Also, a similar study was conducted on KU-2-8 cation exchange resin. The purpose of this article was the express evaluation of the sorption mechanism of peat sorbents. Cation exchanger was transferred to the H+ form by treatment with HCl (1N). Changes in the pH profile as a function of the exposure time indicate their identity with the pattern of the pH change of the cation exchanger. It was found that acid activation of peat (exposure of a peat sample in HCl 1N for 10-16 hours) increases its adsorption capacity. In this case, the maximum decrease in pH is pH = 2.33, which is 1.44 points lower than for peat (pH = 3.77) and 0.95 points more than for KU-2-8 cationite. This indicates that sorbents based on peat can be regenerated. Chitosan-modified peat exhibits deterioration in sorption capacity. In this case, pHmin = 3.9, which shows that sorption on chitosan is not ion-exchange in nature.

Soil solution chemistry of contrasting soils amended with heavy metals

Soil Research ◽  
1999 ◽  
Vol 37 (5) ◽  
pp. 993 ◽  
Author(s):  
H. J. Percival ◽  
T. W. Speir ◽  
A. Parshotam
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Cation Exchange ◽  
Soil Solution ◽  
Solution Chemistry ◽  
Percentage Increase ◽  
Soil Solution Chemistry ◽  
Soil Solutions ◽  
Wide Range

The soil solution chemistry of heavy metal amended soils is of great importance in assessing the bioavailability of heavy metals and their toxicity to the soil biota. Three contrasting soils were amended with Cd(II), Cu(II), Ni(II), Pb(II), Zn(II), and Cr(III) nitrate salts at rates of 10–100 mmol/kg. This concentration range was chosen to encompass a wide range of effects on sensitive soil biochemical properties as part of a larger project. Soil solutions were extracted and analysed for pH, and for concentrations of heavy metals, and major cations and anions. Heavy metal speciation was calculated with the GEOCHEM-PC model. Heavy metal concentrations in the soil solutions increased both in absolute terms and as a percentage of added heavy metal as amendment rates increased. This observation is due to decreasing specific adsorption (caused by decreasing pH induced by the amendments), and to increasing saturation of cation exchange sites. For all 3 soils, the percentage increase commonly follows the order Cr(III) < Pb < Cu < Ni < Cd < Zn. The percentage of each metal held in the soil solution increased from soil to soil as cation exchange capacity, and therefore sorptivity, decreased. Both the concentration and activity of free heavy metal ions were substantially lower than the corresponding total metal concentration. This was ascribed to ion-pairing of metal ions with anions, particularly nitrate introduced in the amending solutions, as well as to increases in ionic strength as a result of amendment. Metal-anion species were mainly inorganic but where Cu and Pb were relatively low in concentration because of strong adsorption by the soils, organic complexation was likely to be significant. Speciation trends were similar for the 3 soils but different in magnitude.

PIXE ANALYSIS OF TRACE HEAVY METALS IN RIVER AND TAP WATER USING AN ION-EXCHANGE CELLULOSE PHOSPHATE FILTER

2002 ◽  
Vol 12 (03n04) ◽  
pp. 217-223 ◽  
Author(s):  
TS. AMARTAIVAN ◽  
K. ISHII ◽  
H. YAMAZAKI ◽  
Y. TAKAHASHI ◽  
S. MATSUYAMA ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Ion Exchange ◽  
Filter Paper ◽  
Water Samples ◽  
Tap Water ◽  
Pixe Analysis ◽  
Cellulose Phosphate ◽  
Wide Range ◽  
Single Sheet ◽  
Concentration Changes

An ion-exchange cellulose phosphate filter was used to prepare in-line PIXE targets for long-term monitoring of heavy metal concentrations in river and tap water. River water samples were taken every 30 minutes during 7 hours, and tap water samples every 5 hours during 150 hours. A PIXE target was prepared passing 300 ml of water sample and 2 ml of 20 ppm Y standard solution through a single sheet of the filter paper. Heavy metals ( Mn , Fe , Cu , Zn , Pb and Hg ) were detected by PIXE analysis with lower detection limits of 0.5-1.0 ppb. Analysis results show that the filter paper can trace concentration changes of heavy metals in a wide range.

scholarly journals Stormwater Runoff Treatment Using Pervious Concrete Modified with Various Nanomaterials: A Comprehensive Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8552
Author(s):  
Vahid Alimohammadi ◽  
Mehdi Maghfouri ◽  
Delaram Nourmohammadi ◽  
Pejman Azarsa ◽  
Rishi Gupta ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Stormwater Runoff ◽  
Infiltration Rate ◽  
Stormwater Treatment ◽  
Adsorption Mechanisms ◽  
Wide Range ◽  
Adsorption Processes

Clean water is a vital need for all living creatures during their lifespan. However, contaminated stormwater is a major issue around the globe. A wide range of contaminants, including heavy metals, organic and inorganic impurities, has been discovered in stormwater. Some commonly utilized methods, such as biological, physical and chemical procedures, have been considered to overcome these issues. However, these current approaches result in moderate to low contaminant removal efficiencies for certain classes of contaminants. Of late, filtration and adsorption processes have become more featured in permeable concretes (PCs) for the treatment of stormwater. As nanoparticles have vast potential and unique characterizations, such as a higher surface area to cure polluted stormwater, employing them to improve permeable concretes’ capabilities in stormwater treatment systems is an effective way to increase filtration and adsorption mechanisms. The present study reviews the removal rate of different stormwater contaminants such as heavy metals, organic and other pollutants using nanoparticle-improved PC. The application of different kinds of nanomaterials in PC as porous media to investigate their influences on the properties of PC, including the permeability rate, compressive strength, adsorption capacity and mix design of such concrete, was also studied. The findings of this review show that different types of nanomaterials improve the removal efficiency, compressive strength and adsorption capacity and decrease the infiltration rate of PC during the stormwater treatment process. With regard to the lack of comprehensive investigation concerning the use of nanomaterials in PC to treat polluted stormwater runoff, this study reviews 242 published articles on the removal rate of different stormwater contaminants by using PC improved with nanoparticles.

scholarly journals Evaluation of Electrodialysis Desalination Performance of Novel Bioinspired and Conventional Ion Exchange Membranes with Sodium Chloride Feed Solutions

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 217
Author(s):  
AHM Golam Hyder ◽  
Brian A. Morales ◽  
Malynda A. Cappelle ◽  
Stephen J. Percival ◽  
Leo J. Small ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Current Density ◽  
Feed Solution ◽  
Laboratory Scale ◽  
Cation Exchange Membrane ◽  
Limiting Current ◽  
Ion Exchange Membranes ◽  
Experimental Apparatus ◽  
Exchange Membrane

Electrodialysis (ED) desalination performance of different conventional and laboratory-scale ion exchange membranes (IEMs) has been evaluated by many researchers, but most of these studies used their own sets of experimental parameters such as feed solution compositions and concentrations, superficial velocities of the process streams (diluate, concentrate, and electrode rinse), applied electrical voltages, and types of IEMs. Thus, direct comparison of ED desalination performance of different IEMs is virtually impossible. While the use of different conventional IEMs in ED has been reported, the use of bioinspired ion exchange membrane has not been reported yet. The goal of this study was to evaluate the ED desalination performance differences between novel laboratory‑scale bioinspired IEM and conventional IEMs by determining (i) limiting current density, (ii) current density, (iii) current efficiency, (iv) salinity reduction in diluate stream, (v) normalized specific energy consumption, and (vi) water flux by osmosis as a function of (a) initial concentration of NaCl feed solution (diluate and concentrate streams), (b) superficial velocity of feed solution, and (c) applied stack voltage per cell-pair of membranes. A laboratory‑scale single stage batch-recycle electrodialysis experimental apparatus was assembled with five cell‑pairs of IEMs with an active cross-sectional area of 7.84 cm2. In this study, seven combinations of IEMs (commercial and laboratory-made) were compared: (i) Neosepta AMX/CMX, (ii) PCA PCSA/PCSK, (iii) Fujifilm Type 1 AEM/CEM, (iv) SUEZ AR204SZRA/CR67HMR, (v) Ralex AMH-PES/CMH-PES, (vi) Neosepta AMX/Bare Polycarbonate membrane (Polycarb), and (vii) Neosepta AMX/Sandia novel bioinspired cation exchange membrane (SandiaCEM). ED desalination performance with the Sandia novel bioinspired cation exchange membrane (SandiaCEM) was found to be competitive with commercial Neosepta CMX cation exchange membrane.

scholarly journals Towards a Glass New World: The Role of Ion-Exchange in Modern Technology

2021 ◽  
Vol 11 (10) ◽  
pp. 4610
Author(s):  
Simone Berneschi ◽  
Giancarlo C. Righini ◽  
Stefano Pelli
Keyword(s):  
Ion Exchange ◽  
Communication Networks ◽  
High Speed ◽  
High Performance ◽  
Low Cost ◽  
Modern Technology ◽  
Historical Background ◽  
Wide Range ◽  
Happy Marriage

Glasses, in their different forms and compositions, have special properties that are not found in other materials. The combination of transparency and hardness at room temperature, combined with a suitable mechanical strength and excellent chemical durability, makes this material indispensable for many applications in different technological fields (as, for instance, the optical fibres which constitute the physical carrier for high-speed communication networks as well as the transducer for a wide range of high-performance sensors). For its part, ion-exchange from molten salts is a well-established, low-cost technology capable of modifying the chemical-physical properties of glass. The synergy between ion-exchange and glass has always been a happy marriage, from its ancient historical background for the realisation of wonderful artefacts, to the discovery of novel and fascinating solutions for modern technology (e.g., integrated optics). Getting inspiration from some hot topics related to the application context of this technique, the goal of this critical review is to show how ion-exchange in glass, far from being an obsolete process, can still have an important impact in everyday life, both at a merely commercial level as well as at that of frontier research.

scholarly journals Fabrication of a lead ion selective membrane based on a polycarbazole Sn(iv) arsenotungstate nanocomposite and its ion exchange membrane (IEM) kinetic studies

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4210-4220
Author(s):  
Mohd. Zeeshan ◽  
Rais Ahmad ◽  
Asif Ali Khan ◽  
Aftab Aslam Parwaz Khan ◽  
Guillermo C. Bazan ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Polyvinyl Chloride ◽  
Cation Exchanger ◽  
Kinetic Studies ◽  
Ion Exchange Membrane ◽  
Lead Ion ◽  
Solution Technique ◽  
Casting Solution ◽  
Selective Membrane ◽  
Exchange Membrane

A polycarbazole-Sn(iv) arsenotungstate (Pcz-SnAT) nanocomposite cation exchanger membrane (CEM) was prepared via the casting solution technique utilizing polycarbazole-Sn(iv) arsenotungstate and PVC (polyvinyl chloride) as a binder.

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