scholarly journals Hexavalent chromium removal by waste mycelium of Aspergillus awamori

2010 ◽  
Vol 75 (4) ◽  
pp. 551-564 ◽  
Author(s):  
Velizar Gochev ◽  
Zdravka Velkova ◽  
Margarita Stoytcheva
Keyword(s):  
Metal Binding ◽  
Low Cost ◽  
Ion Concentration ◽  
Aspergillus Awamori ◽  
Stage Process ◽  
Decreasing Ph ◽  
Chitin And Chitosan ◽  
Initial Adsorption ◽  
Increasing Temperature ◽  
Waste Mycelium

In this study, the Cr(VI) removal potential of waste mycelium from the industrial xylanase-producing strain Aspergillus awamori was evaluated. It was determined by FTIR analysis that amino groups from the major fungal wall constituents, chitin and chitosan, played a key role in the metal binding process. The effect of pH, initial ion concentration, temperature and amount of biomass on the removal was also studied. The removal efficiency increased with decreasing pH and increasing temperature and amount of biomass. The mechanism of Cr(VI) removal by A. awamori can be explained by a two-stage process involving an initial adsorption stage followed by a reducing stage. The removal process was described by a second-order polynomial and the optimal process parameters for attaining Rmax 94.4 % in 48 h were predicted, i.e., pH 1.5 and T 40?C. From both economic and ecological points of view, a promising possibility for the utilization of waste industrial mycelium of A. awamori as a low-cost Cr(VI) removal agent was proposed.

Removal of Pb(II) and Cd(II) From Aqueous Solution by Adsorption Using Agrowaste-Modified Kaolinite Clay

2021 ◽  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Metal Ion ◽  
Low Cost ◽  
Ion Concentration ◽  
Kaolinite Clay ◽  
Adsorbent Surface ◽  
Initial Adsorption ◽  
Adsorption Rates

This study showed that kaolinite clay modified with Moringa oleifera pods is a promising low cost adsorbent for the removal of metals from aqueous solution because the resultant composite has higher adsorption capacities, and hence a better metal ions removal efficiency. The efficiencies of these adsorbents for the removal of Pb (II) and Cd (II) ions from aqueous solutions were studied as a function of pH, time, adsorbate concentration and adsorbent dose. Adsorption results showed that pH did significantly affect removal of heavy metal ions between pH 3 and 6. Increasing contact time and initial metal ion concentration increased the sorption capacity of the adsorbent for the metal ions. Adsorbent dosage indicated mainly surface phenomena involving sharing of electrons between the adsorbent surface and the metal ion species. The adsorption of metal ions from aqueous solutions of both metal ions at different initial metal ion concentrations reduced the initial adsorption rates of the adsorption of Pb (II) and Cd (II) by unmodified and modified kaolinite clay.

scholarly journals Thermo-Responsive Behavior of Mixed Aqueous Solution of Hydrophilic Polymer with Pendant Phosphorylcholine Group and Poly(Acrylic Acid)

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 148
Author(s):  
Hirokazu Fukumoto ◽  
Kazuhiko Ishihara ◽  
Shin-Ichi Yusa
Keyword(s):  
Aqueous Solution ◽  
Acrylic Acid ◽  
Solution Temperature ◽  
Interpolymer Complex ◽  
Mixed Aqueous Solution ◽  
Upper Critical Solution Temperature ◽  
Acidic Conditions ◽  
Decreasing Ph ◽  
Increasing Temperature ◽  
Poly Acrylic Acid

A mixed aqueous solution of hydrophilic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and poly(acrylic acid) (PAAc) becomes cloudy under acidic conditions at room temperature. The pendant carboxylic acid groups in PAAc form hydrogen bonds with the ester and phosphate groups in PMPC. While the polymers aggregate under acidic conditions, neither one associate under basic conditions because of the deprotonation of the pendant carboxy groups in PAAc. We observed that the interpolymer complex formed from PMPC, and PAAc was dissociated in aqueous solutions with increasing temperature, which is an upper critical solution temperature behavior. With increasing temperature, the molecular motion increased to dissociate the interpolymer complex. The phase transition temperature increased with increasing polymer and salt concentrations, and with decreasing pH.

scholarly journals Using decades of spawning data and hydraulic models to construct a temperature dependent resource selection function for management of an endangered salmonid

2021 ◽  
Author(s):  
Peter N Dudley ◽  
Sara N John ◽  
Miles E Daniels ◽  
Eric M. Danner
Keyword(s):  
Water Temperature ◽  
Environmental Variables ◽  
Resource Selection ◽  
Oncorhynchus Tshawytscha ◽  
Linear Models ◽  
Low Cost ◽  
Hydraulic Modeling ◽  
Selection Function ◽  
Spawning Habitat ◽  
Increasing Temperature

In North America, impassable, man-made barriers block access to salmonid spawning habitat and require costly restoration efforts in the remaining habitats. Evaluating restored spawning habitat quality requires information on salmon water velocity and depth preferences, which may vary in relation to other variables (e.g. water temperature). We demonstrate a generalizable, low cost method to gather and analyze this data by combining aerial redd surveys of winter-run Chinook salmon (Oncorhynchus tshawytscha), 2D hydraulic modeling, and generalized linear models to calculate spawning resource selection functions (RSFs). Our method permits the examination of interactions between environmental variables on habitat selection, which are frequently treated as independent. Our methods resulted in a RSF that shows interactions between both velocity and depth preference with changing temperature. Preferred depth increased and preferred velocity decreased with increasing temperature. Spawning RSFs for environmental variables may change as other environmental conditions (i.e. water temperature) change, thus it is importance to account for potential interactions when using or producing RSFs.

scholarly journals Removal of Zinc ions from industrial wastewater with wool fibers

2010 ◽  
Vol 7 (3) ◽  
pp. 1193-1201
Author(s):  
Baghdad Science Journal
Keyword(s):  
Acid Concentration ◽  
Contact Time ◽  
Industrial Wastewater ◽  
Metal Ion ◽  
Low Cost ◽  
Zinc Ion ◽  
Ion Concentration ◽  
Natural Material ◽  
Zinc Ions ◽  
Wool Fibers

In this research, the efficiency of low-cost unmodified wool fibers were used to remove zinc ion from industrial wastewater. Removal of zinc ion was achieved at 99.52% by using simple wool column. The experiment was carried out under varying conditions of (2h) contact time, metal ion concentration (50mg/l), wool fibers quantity to treated water (70g/l), pH(7) & acid concentration (0.05M). The aim of this method is to use a high sensitive, available & cheep natural material which applied successfully for industrial wastewater& synthetic water, where zinc ion concentration was reduced from (14.6mg/l) to (0.07mg/l) & consequently the hazardous effect of contamination was minimized.

scholarly journals Effects of the Temperature and the pH on the Main Protease of SARS-CoV-2: A Molecular Dynamics Simulation Study

2021 ◽  
Vol 12 (6) ◽  
pp. 7239-7248
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Root Mean Square ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Water Molecules ◽  
Mean Square ◽  
Main Protease ◽  
Decreasing Ph ◽  
Increasing Temperature

The novel coronavirus, recognized as COVID-19, is the cause of an infection outbreak in December 2019. The effect of temperature and pH changes on the main protease of SARS-CoV-2 were investigated using all-atom molecular dynamics simulation. The obtained results from the root mean square deviation (RMSD) and root mean square fluctuations (RMSF) analyses showed that at a constant temperature of 25℃ and pH=5, the conformational change of the main protease is more significant than that of pH=6 and 7. Also, by increasing temperature from 25℃ to 55℃ at constant pH=7, a remarkable change in protein structure was observed. The radial probability of water molecules around the main protease was decreased by increasing temperature and decreasing pH. The weakening of the binding energy between the main protease and water molecules due to the increasing temperature and decreasing pH has reduced the number of hydrogen bonds between the main protease and water molecules. Finding conditions that alter the conformation of the main protease could be fundamental because this change could affect the virus’s functionality and its ability to impose illness.

scholarly journals Adsorption Study of Cu2+ Ions from Aqueous Solutions by Bael Flowers (Aegle marmelos)

2020 ◽  
Vol 11 (4) ◽  
pp. 11891-11904
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Metal Ion ◽  
Low Cost ◽  
Sem Analysis ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
Aegle Marmelos ◽  
Batch Mode ◽  
Initial Ph

In the present study, batch mode adsorption was carried out to investigate the adsorption capacity of dried bael flowers (Aegle marmelos) for the adsorptive removal of Cu(II) ions from aqueous solutions by varying agitation time, initial metal concentration, the dose of adsorbent, temperature, and initial pH of the Cu(II) ion solution. The percentage removal of 98.7% was observed at 50 ppm initial metal ion concentration, 0.5 g/100.00 cm3 adsorbent dosage, within the contact time of 120 minutes at 30 ºC in the pH range of 4 – 7. The sorption processes of Cu(II) ions was best described by pseudo-second-order kinetics. Langmuir isotherm had a good fit with the experimental data with 0.97 of correlation coefficient (R2), and the maximum adsorption capacity obtained was 23.14 mg g-1 at 30 ºC. The results obtained from sorption thermodynamic studies suggested that the adsorption process is exothermic and spontaneous. SEM analysis showed tubular voids on the adsorbent. FTIR studies indicated the presence of functional groups like hydroxyl, –C-O, –C=O, and amide groups in the adsorbent, which can probably involve in metal ion adsorption. Therefore, dried bael flowers can be considered an effective low-cost adsorbent for treating Cu(II) ions.

Novel electrolyte additive of graphene oxide for prolonging the lifespan of Zinc-ion batteries

2021 ◽  
Author(s):  
Xuyang Wang ◽  
Alina Kirianova ◽  
Xieyu Xu ◽  
Yanguang Liu ◽  
Olesya Kapitanova ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Coulombic Efficiency ◽  
Low Cost ◽  
Concentration Field ◽  
Phase Field Model ◽  
Deposition Process ◽  
Zinc Ion ◽  
Ion Concentration ◽  
Environmental Friendliness ◽  
Nucleation Overpotential

Abstract Aqueous zinc-ion batteries have attracted the attention of the industry due to their low cost, good environmental friendliness, and competitive gravimetric energy density. However, zinc anodes, similar to lithium, sodium and other alkali metal anodes, are also plagued by dendrite problems. Zinc dendrites can penetrate through polymer membranes, and even glass fiber membranes which seriously hinders the development and application of aqueous zinc-ion batteries. To resolve this issue, certain additives are required. Here we have synthesized an electrochemical graphene oxide with novel electrolyte based on tryptophan, which allows to obtain few-layered sheets with a remarkably uniform morphology, good aqueous solution dispersion, easy preparation and environmental friendliness. We used this electrochemical graphene oxide as an additive to the electrolyte for aqueous zinc-ion batteries. The results of phase-field model combined with experimental characterization revealed that the addition of this material effectively promotes the uniform distribution of the electric field and the Zn-ion concentration field, reduces the nucleation overpotential of Zn metal, and provides a more uniform deposition process on the metal surface and improved cyclability of the aqueous Zn-ion battery. The resultant Zn|Zn symmetric battery with the electrochemical graphene oxide additive affords a stable Zn anode, which provided service for more than 500 hours at 0.2 mA cm-2 and even more than 250 hours at 1.0 mA cm-2. The Coulombic efficiency (98.7%) of Zn|Cu half-cells and thus cyclability of aqueous Zn-ion batteries using electrochemical graphene oxide is significantly better compared to the additive-free electrolyte system. Therefore, our approach paves a promising avenue to foster the practical application of aqueous Zn-ion batteries for energy storage.

scholarly journals Photoproduction of nitric oxide in seawater

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Ye Tian ◽  
Gui-Peng Yang ◽  
Chun-Ying Liu ◽  
Pei-Feng Li ◽  
Hong-Tao Chen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
North Pacific Ocean ◽  
Artificial Seawater ◽  
Natural Seawater ◽  
Factors Affecting ◽  
Decreasing Ph ◽  
Seawater Samples ◽  
Major Factors ◽  
Increasing Temperature ◽  
Increasing Trends

Abstract. Nitric oxide (NO) is a short-lived intermediate of the oceanic nitrogen cycle. However, our knowledge about its production and consumption pathways in oceanic environments is rudimentary. In order to decipher the major factors affecting NO photochemical production, we irradiated several artificial seawater samples as well as 31 natural surface seawater samples in laboratory experiments. The seawater samples were collected during a cruise to the western tropical North Pacific Ocean (WTNP, a N–S section from 36 to 2∘ N along 146 to 143∘ E with 6 and 12 stations, respectively, and a W–E section from 137 to 161∘ E along the Equator with 13 stations) from November 2015 to January 2016. NO photoproduction rates from dissolved nitrite in artificial seawater showed increasing trends with decreasing pH, increasing temperature, and increasing salinity. In contrast, NO photoproduction rates (average: 0.5±0.2×10-12 mol L−1 s−1) in the natural seawater samples from the WTNP did not show any correlations with pH, water temperature, salinity, or dissolved inorganic nitrite concentrations. The flux induced by NO photoproduction in the WTNP (average: 13×10-12 mol m−2 s−1) was significantly larger than the NO air–sea flux density (average: 1.8×10-12 mol m−2 s−1), indicating a further NO loss process in the surface layer.

scholarly journals A Colorimetric Method for Studying the Dissociation of Oxyhæmocyanin suitable for Class Work

1925 ◽  
Vol 13 (4) ◽  
pp. 970-980 ◽  
Author(s):  
C. F. A. Pantin ◽  
Lancelot T. Hogben
Keyword(s):  
Marked Effect ◽  
Colorimetric Method ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Dissociation Curve ◽  
Hydrogen Ion Concentration ◽  
Laboratory Class ◽  
Wide Range ◽  
Increasing Temperature ◽  
Limits Of Error

1. A simple colorimetric method for plotting the dissociation curve of haemocyanin is indicated. The limits of error are within 5 per cent. The simplicity of the method commends it for laboratory class work.2. The effect of hydrogen ion concentration on the dissociation of the hsemocyanins of the crustacean Palinurus and the pulmonate Helix have been compared. In the snail change of hydrogen ion concentration over a wide range was not found to affect the dissociation of the hsemocyanin: in 'the crustacean there is a marked effect similar to that seen in the dissociation of hæmoglobin.3. The similarity of crustacean hsemocyanin to haemoglobin is also seen in that increasing temperature depresses the dissociation curve. The effects of certain salts upon haemocyanin. have also been recorded.

scholarly journals Oxadiazole Based Polyether as Sensitive Films for Ratiometric Optical Temperature Detection

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
H. C. Neitzert ◽  
S. Cuccurullo ◽  
S. Concilio ◽  
P. Iannelli
Keyword(s):  
Low Cost ◽  
Peak Amplitude ◽  
Exciting Light ◽  
Excitation Wavelength ◽  
Polynomial Fit ◽  
Temperature Detection ◽  
Reflection Peak ◽  
New Type ◽  
Versus Peak ◽  
Increasing Temperature

A new type of polymer, based on the oxadiazole group, has been tested as indicator material for a ratiometric photoluminescence and optical reflection based temperature sensor in the temperature range between 30°C and 60°C. Thin films of the new polymer have been deposited by spin-coating on a glass substrate, excited by means of a low-cost near UV-LED. The optical spectrum, as detected by a fiber-based PC-card optical spectrometer, consisted of the reflection peak at the excitation wavelength and two distinct photoluminescence peaks at 430 nm and 480 nm, both in the blue spectral region. The peak amplitudes of all three spectral peaks depend linearly on the exciting light intensity. Changing the sample temperature, all peak amplitude values decrease monotonously with increasing temperature. By using a ratiometric approach, it has been found that the ratio between the two photoluminescence peaks was almost constant with temperature, while the ratio between the main photoluminescence peak at 430 nm and the reflection peak around 380 nm scaled nicely with the ambient temperature. Therefore, it has been proposed to use the latter criterion and a simple polynomial fit to the temperature versus peak amplitude relation.

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