scholarly journals Studies of the rate of gold sorption by the AM-2B anionite from cyanide-alkaline solutions

2022 ◽  
Vol 320 (1) ◽  
pp. 88-94
Author(s):  
D.S. Kaumetova ◽  
◽  
A.K. Koizhanova ◽  
Kh.K. Absalyamov ◽  
D.R. Magomedov ◽  
...  
Keyword(s):  
Sorption Process ◽  
Alkaline Solutions ◽  
Sorption Rate ◽  
Alkali Solutions ◽  
Dimethyl Ammonium ◽  
Temperature Dependences ◽  
Sorption Leaching ◽  
Quantitative Separation ◽  
New Generation ◽  
Physical And Chemical

The paper presents the results of studies on the sorption leaching of gold-containing ore of the Vasilkovskoye deposit. Kinetic dependences of the sorption of gold and associated metals from cyanide-alkali solutions under different physical and chemical factors were obtained. It was found that gold on the AM-2B resin sorbed at a higher rate than, for example, copper and zinc. The solutions were analyzed using modern devices of a new generation: FT-IR spectrometer "Avatar 370". Laboratory studies were performed to determine the gold sorption rate by the AM-2B anionite from cyanide-alkaline solutions. It was found in the process of sorption of gold from multicomponent cyanide-alkali solutions on AM-2B anionite of mixed basicity, with the macroporous structure containing benzyl dimethylamine and dibenzyl dimethyl ammonium functional groups, that an important factor of qualitative and quantitative separation of gold and impurity metals is the concentration of cyanide and hydroxyl ions in solution. The temperature effect on the sorption rate of gold from cyanide-alkali solutions was studied with the temperature dependences F of t, Bt, of t, ln (l - F) of t, and D of t that show that the sorption process of dicyanoaurate ions is controlled by mixed diffusion.

Silver Nanoparticles Supported on Ordered Mesoporous Carbon for Formaldehyde Electrooxidation

2011 ◽  
Vol 110-116 ◽  
pp. 508-513
Author(s):  
Ling Bin Kong ◽  
Ru Tao Wang ◽  
Xiao Wei Wang ◽  
Zhen Sheng Yang ◽  
Yong Chun Luo ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Mesoporous Carbon ◽  
Chemical Reduction ◽  
Chemical Properties ◽  
Ordered Mesoporous Carbon ◽  
Alkaline Solutions ◽  
Cyclic Voltammograms ◽  
Peak Current Density ◽  
Ordered Mesoporous ◽  
Physical And Chemical

Metal nanocatalysts, as the anodic materials, have become increasingly important in fuel cells due to their unique physical and chemical properties. Here we report the ordered mesoporous carbon (CMK-3) supported silver nanocatalysts have been prepared through the wet chemical reduction by using the reduction of formaldehyde. The electrochemical properties of the Ag/CMK-3 nanocatalysts for formaldehyde oxidation are studied by cyclic voltammograms (CV) and chronoamperometric curves (i-t) in alkaline aqueous solutions. The results show that the peak current density (from CV) of the Ag/CMK-3 electrode is 112 mA cm-2, above 2 times higher than that of Ag/XC-72 at the same Ag loading (14.15 μg cm-2). Furthermore, the i-t curves demonstrate that the Ag/CMK-3 nanocatalysts are efficient and stable electrocatalysts for anodic oxidation of formaldehyde in alkaline solutions. Our results indicate that the application potential of Ag/CMK-3 nanocatalysts with the improved electrocatalytic activity has far reaching effects on fuel cells and sensors.

Hollow Nanostructures for Application in Solar Cells

2021 ◽  
pp. 129-147
Keyword(s):  
Solar Cell ◽  
Load Capacity ◽  
High Porosity ◽  
Structural Modifications ◽  
Hollow Structures ◽  
Hollow Nanostructures ◽  
Feedstock Availability ◽  
New Generation ◽  
Physical And Chemical ◽  
Structure Engineering

Hollow nanostructures are nanoscale materials with interior cavities, high volumetric load capacity ratio and high porosity. This new generation structure has gained huge momentum in the field of energy storage and photovoltaics due to such promising physical and chemical features. This chapter highlights contributions of various works where hollow nanostructures of metals and carbonaceous materials had been used in solar cell over the last few years. The harnessing of efficiency with structural modifications in the hollow structures over the years was shown in various works. The effect of structure engineering on the performance of solar cell has been explained in detail where voids in metallic hollow nanostructure enhance light scattering and high charge recombination. Simultaneously, carbonaceous hollow nanostructured materials are considered to be the latest photoelectrode materials and designated to be alternatives for metallic hollow nanostructures counterpart due to their high feedstock availability and fabrication charges.

An Experimental Investigation of Sorption Process in Fluidized Bed With Cooling Pipe

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Akihiko Horibe ◽  
Syahrul Husain ◽  
Hideo Inaba ◽  
Naoto Haruki ◽  
Ping Tu
Keyword(s):  
Experimental Investigation ◽  
Fluidized Bed ◽  
Air Conditioning ◽  
Sorption Process ◽  
Sorption Rate ◽  
Mass Ratio ◽  
Air Conditioning System ◽  
Cooling Pipe ◽  
Powder Type ◽  
Cooling Pipes

An experimental investigation of a fluidized bed with multiple cooling pipes was conducted to study adsorption characteristics of a new organic sorbent desiccant material (HU300P) for a new air conditioning system. The mass ratio of the present sorbent desiccant powder type is from 1.3 to 2.3 times greater than that of silica gel. The sorption rate of the water vapor in the sorbent bed was measured under various conditions. It was found that the sorption rate is highly dependent on the effect of cooling pipes. The sorption ratio increases and the completion time for the sorption process decreases by using multiple cooling pipes.

Microsensors for physical signals: Principles, device design, and fabrication technologies

1996 ◽  
Vol 74 (S1) ◽  
pp. 115-130 ◽  
Author(s):  
Arokia Nathan
Keyword(s):  
Integrated Circuit ◽  
Computer Aided Design ◽  
Electrical Signal ◽  
Single Chip ◽  
Research Activity ◽  
Rapid Pace ◽  
Silicon Based ◽  
Aided Design ◽  
New Generation ◽  
Physical And Chemical

Microsensors are miniaturized devices, fabricated using silicon-based and related technologies, that convert input physical and chemical signals into an output electrical signal. The key driving force in microsensor research has been the integrated circuit (IC) and micromachining technologies. The latter, in particular, is fueling tremendous activity in micro-electromechanical systems (MEMS). In terms of technology and design tools, MEMS is at a stage where microelectronics was 30 years ago and is expected to evolve at an equally rapid pace. The synergy between the IC, micromachining, and integrated photonics technologies can potentially spawn a new generation of microsystems that will feature a unique marriage of microsensor, signal-conditioning and -processing circuitry, micromechanics, and optomechanics possibly on a single chip. In this paper, the physical transduction principles, materials considerations, process-fabrication technologies, and computer-aided-design (CAD) tools will be reviewed along with pertinent examples drawn from our microsensor research activity at the Microelectronics Laboratory, University of Waterloo.

Development of Geopolymer Mortar from Metakaolin Blended with Agricultural and Industrial Wastes

2018 ◽  
Vol 766 ◽  
pp. 305-310 ◽  
Author(s):  
Chayanee Tippayasam ◽  
Sarochapat Sutikulsombat ◽  
Jamjuree Paramee ◽  
Cristina Leonelli ◽  
Duangrudee Chaysuwan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Chemical Properties ◽  
Cement Industry ◽  
Industrial Wastes ◽  
Engineering Properties ◽  
Alkali Solutions ◽  
Physical And Chemical

Geopolymer is a greener alternative cement produced from the reaction of pozzolans and strong alkali solutions. Generally, the cement industry is one of largest producers of CO2that caused global warming. For geopolymer mortar usage, Portland cement is not utilized at all. In this research, geopolymer mortars were prepared by mixing metakaolin, various wastes (fly ash, bagasse ash and rice husk ash) varied as 80:20, 50:50 and 20:80, 15M NaOH, Na2SiO3and sand. The influence of various parameters such as metakaolin to ashes ratios and pozzolans to alkali ratios on engineering properties of metakaolin blended wastes geopolymer mortar were studied. Compressive strength tests were carried out on 25 x 25 x 25 mm3cube geopolymer mortar specimens at 7, 14, 21, 28 and 91 air curing days. Physical and chemical properties were also investigated at the same times. The test results revealed that the highest compressive strength was 20% metakaolin - 80% fly ash geopolymer mortar. When the curing times increases, the compressive strength of geopolymer mortar also increases. The mixing of metakaolin and bagasse ash/rice husk ash presented lower compressive strength but higher water absorption and porosity. For FTIR results, Si-O, Al-O and Si-O-Na+were found. Moreover, the geopolymer mortar could easily plastered on the wall.

Study on the Properties and Application of Optim™ Fine Fibers

2011 ◽  
Vol 287-290 ◽  
pp. 2561-2564
Author(s):  
Jiang Wei Yao ◽  
Wei Dong Yu
Keyword(s):  
Chemical Properties ◽  
Wool Fabric ◽  
Physical And Chemical Properties ◽  
Performance Difference ◽  
Merino Wool ◽  
Fine Fiber ◽  
The Difference ◽  
New Generation ◽  
Physical And Chemical ◽  
And Chemical Properties

Optim™ fine is a new generation of ultrafine wool fibres, which are transformed by stretching and setting from merino wool. The Optim™ fine retains some of the physical and chemical properties of merino wool, but the morphology and other properties changes, such as the diameter, length, lusture, breaking extension and shrinkage. These changes results in the performance difference btween the fabric woven from Optim™ fine and fine wool fiber. To clearly understande the reason of the difference, the morphological and physical properties changes of Optim™ fine was examined in this paper, and the performance difference between wool fabric and Optim™ fine fabric was evaluated by Fabric Assurance by Simple Testing(FAST). It was found that the decreasing in breaking extension and increasing in shrinkage of Optim™ fine resulted in the declining in formability and dimensional stability of Optim™ fine fabric. Suggestions on the ways of constructing Optim™ fine into fabric were also given according to the anlysis of relationship between the properties changes of Optim™ fine fiber and that of its fabric.

scholarly journals Isotherms, Kinetics and Break through Curve for Sorptive Removal of Chromium from Wastewater by Activated Sludge

2019 ◽  
Vol 31 (8) ◽  
pp. 1704-1708
Author(s):  
Sunil Kulkarni
Keyword(s):  
Activated Sludge ◽  
Freundlich Isotherm ◽  
Break Point ◽  
Sorption Process ◽  
Low Flow ◽  
Maximum Adsorption Capacity ◽  
Physical And Chemical ◽  
Chromium Uptake ◽  
Better Than ◽  
Sorptive Removal

In the present investigations, activated sludge is used for removal of chromium in batch and continuous mode. It was observed that the sorption process followed Langmuir isotherm better than Freundlich isotherm (R2 = 0.95). The Freudlich model with R2 value above 0.9 suggests that the sorptive removal may involve physical and chemical adsorption with some multilayer sorption. Chromium uptake followed second order kinetics. The maximum adsorption capacity qe was observed to be 208.33 mg/g. The breakeven time and exhaustion time were determined for continuous operation. The non-availability of adsorbate at low flow rates play important role in delaying the break point time. Sludge age and initial concentration also affect the removal of chromium. The data follows the Thomas model with R2 value more than 0.9.

Sorption and desorption kinetics of Np(V) on magnetite and hematite

2000 ◽  
Vol 88 (8) ◽  
Author(s):  
K. Nakata ◽  
S. Nagasaki ◽  
S. Tanaka ◽  
Y. Sakamoto ◽  
T. Tanaka ◽  
...  
Keyword(s):  
Crystalline Phase ◽  
Acidic Solution ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Chemical Form ◽  
Alkaline Solutions ◽  
Desorption Kinetics ◽  
Chemical Forms ◽  
Kinetics Of ◽  
Desorption Method

Sorption kinetics of Np(V) on magnetite and hematite were investigated, and a sequential desorption method was applied to investigate changes in the chemical form of Np sorbed according to the amount of time they were in contact with the Np solution. It was found that the sorption process consists of fast sorption and slow sorption which reaches equilibrium in 1 h. According to the desorption results, it was conjectured (i) that fast sorption is attributable to sorption on/into the surface and non-crystalline phases of iron oxides for magnetite and hematite in both acidic and alkaline solutions, (ii) that sorption on/into the crystalline phase also contributes to fast sorption for hematite in an alkaline solution, and (iii) that slow sorption represents sorption into the crystalline phase of magnetite in both acidic and alkaline solutions and that of hematite in an acidic solution. From the results of sorption and desorption kinetics, it was concluded that the equilibrium between various chemical forms of sorbed Np was achieved in about 1 week, although the amount of sorbed Np reached an equilibrium in only 1 h.

scholarly journals Sorption of Coated and Uncoated Nanocrystalline Zinc Oxide from Aqueous Solutions onto Raw and Acetylated Cellulose Sago Hampas: Equilibrium, Kinetic and Thermodynamic Studies

2021 ◽  
Vol 411 ◽  
pp. 37-54
Author(s):  
Eric Kwabena Droepenu ◽  
Boon Siong Wee ◽  
Suk Fun Chin ◽  
Kuan Ying Kok
Keyword(s):  
Zinc Oxide ◽  
Sorption Process ◽  
Equilibration Time ◽  
Zno Nps ◽  
Thermodynamic Studies ◽  
Water And Wastewater ◽  
Physical And Chemical ◽  
Kinetic And Thermodynamic Studies ◽  
Nanocrystalline Zinc Oxide ◽  
Maximum Removal

In this study, sorption efficiency of coated (C-) and uncoated (U-) zinc oxide nanoparticles (ZnO-NPs) in aqueous solution onto raw sago hampas (RSH) and acetylated sago hampas (ACSH) was studied. Physical and chemical characteristics of both the sorbate and sorbents were analysed using various characterization techniques. The mechanism of the sorption process was evaluated using equilibrium isotherms, kinetic and thermodynamic studies. From the study, maximum percentage removal of both sorbate ions were achieved at an equilibration time of 100 minutes with an optimum sorbate mass of 2.0 g per 50 ml. The study recorded a maximum % removal of 85.1% & 87.6% for C-and U-ZnO-NPs (< 50 nm) onto RSH and 90.0% & 91.1% onto ACSH. Langmuir isotherm fitted well for the sorption process with the highest efficiency of 0.793 mg/g recorded for C-ZnO-NPs onto RSH. Pseudo-second model best described the sorption process. An exothermic and non-spontaneous sorption process was realised in all the sorption studies except that of U-ZnO-NPs (< 50 nm) onto ACSH which became spontaneous as temperature increased. Based on the findings from the multiple approaches employed, both sorbents could be proposed as viable alternatives to act as a green sorbent in the removal of ZnO-NPs from water and wastewater.

scholarly journals Mapping the Conformational Landscape of a Dynamic Enzyme by XFEL and Multitemperature Crystallography

2015 ◽  
Author(s):  
Daniel A Keedy ◽  
Lillian R Kenner ◽  
Matthew Warkentin ◽  
Rahel Woldeyes ◽  
Michael C Thompson ◽  
...  
Keyword(s):  
Protein Function ◽  
Fixed Target ◽  
Time Resolved ◽  
Conformational Ensembles ◽  
Catalytic Function ◽  
Abrupt Changes ◽  
Temperature Dependences ◽  
Conformational Landscape ◽  
Conformational Coupling ◽  
New Generation

Determining the interconverting conformations of dynamic proteins in atomic detail is a major challenge for structural biology. Conformational heterogeneity in the active site of the dynamic enzyme cyclophilin A (CypA) has been previously linked to its catalytic function. Here we compare the conformational ensembles of CypA by fixed-target X-ray free electron laser (XFEL) crystallography and multitemperature synchrotron crystallography. The “diffraction-before-destruction” nature of XFEL experiments provides a radiation-damage-free view of the functionally important alternative conformations of CypA. We monitored the temperature dependences of these alternative conformations with eight synchrotron datasets spanning 100-310 K. Multiconformer models show that many alternative conformations in CypA are populated above, but not below, the glass transition temperature (~200 K) and reveal abrupt changes in protein flexibility that provide all-atom insight into conformational coupling. Together, our XFEL data and multitemperature analyses motivate a new generation of time-resolved experiments to structurally characterize the dynamic underpinnings of protein function.  

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