scholarly journals Removal of strontium from simulated low-level radioactive wastewater by nanofiltration

2018 ◽  
Vol 78 (8) ◽  
pp. 1733-1740 ◽  
Author(s):  
Lifang Chen ◽  
Xiaokai Bian ◽  
Xiaofeng Lu
Keyword(s):  
Disodium Salt ◽  
Complexing Agent ◽  
Tetraacetic Acid ◽  
Solution Ph ◽  
Membrane Cleaning ◽  
Strontium Concentration ◽  
Strontium Removal ◽  
Radioactive Wastewater ◽  
Long Time ◽  
Recovery Percentage

Abstract The performance of different nanofiltration (NF) membranes for the treatment of strontium-containing radioactive wastewater was investigated. The effects of the initial strontium concentration, solution pH and complexation phenomena on strontium removal were described. For all the three membranes, the strontium rejection increased with decreasing initial strontium concentration. Meanwhile, the strontium rejection was minimum at the membrane isoelectric point (pH 5) primarily due to decreased co-ion electrostatic repulsion. In the presence of a complexing agent (polyacrylic acid or ethylenediamine tetraacetic acid disodium salt), the strontium rejection was generally higher than those obtained without a complexing agent for NF 270 and XN 45. Membrane cleaning experiments were also conducted to recover the performance of the membranes, which exhibited degradation during long-time filtration. The performance of the membranes after cleaning was close to that of the virgin membranes, especially for XN 45, whose recovery percentage was nearly 100%.

Controlled Release of Active Substance from Biodegradable Copolymer Matrix

2006 ◽  
Vol 510-511 ◽  
pp. 798-801
Author(s):  
Hyung Suk So ◽  
Hyun Chul Shin ◽  
Beom Suk Kim ◽  
Yeong Seok Yoo
Keyword(s):  
Methylene Blue ◽  
Active Substance ◽  
Phosphate Buffer Solution ◽  
Ultra Violet ◽  
Hydroxyl Groups ◽  
Buffer Solution ◽  
Solution Ph ◽  
Effective Discharge ◽  
Constant Rate ◽  
Long Time

The purpose of this study is to develop a new system to control effective discharge of active substances such as agricultural chemicals. To synthesize a naturally dissolvable polymer; ε-caprolactone and diglycolide were copolymerized with ethylene glycol as an initiator to produce macrodiol. As macrodiol has hydroxyl groups in both ends, they are modified with methacryloyl chloride for photochemical networking. After standard macromonomer produced by this procedure was physically mixed with methylene blue, it was networked with ultra-violet rays to be filmed. This film is naturally dissolvable and hydrolytic. As a result of hydrolytic test with a crosslinked structure of 10 % methylene blue, it decreased by 9 % for seven weeks in 37 °C phosphate buffer solution (pH = 7). Thus, we verified that active substance can be discharged from a crosslinked structure for a long time at a constant rate under room temperature.

Agricultural utilization of lignosulfonates

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gerhild K. Wurzer ◽  
Hubert Hettegger ◽  
Robert H. Bischof ◽  
Karin Fackler ◽  
Antje Potthast ◽  
...  
Keyword(s):  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Feed Additive ◽  
Complexing Agent ◽  
Fuel Pellets ◽  
Inorganic Substances ◽  
Binding Agents ◽  
Long Time ◽  
Renewable Material ◽  
By Products

Abstract Lignosulfonates (LSs) are by-products of the pulp and paper industry from pulping of lignocellulosic biomass according to the sulfite process. This renewable material already plays a role in low-value applications, such as binding agents for fuel, pellets, as a feed additive, or as a dispersant. Another possible field of application of this technical lignin type is agriculture. It is known that this eco-friendly and cheap material can improve soil quality, fertilizer efficacy and replace or decrease the use of potentially (eco)toxic organic or inorganic substances. The use of LS in agriculture and five main strategies for the implementation of LS in soil are discussed in this review: LS as a complexing agent with micronutrients, co-pelleting of LS with (macro)nutrients, capsule formation with LS for coating of fertilizers or pesticides, LS as a biostimulant, and ammonoxidation of LS. All five ways can be beneficial in fertilizer-related applications, either to slow down the release of nutrients or pesticides, to substitute harmful chemicals, or to inhibit nitrification and modify fertilizer behaviour. Nevertheless, application and long-time studies are often missing, and more research is required for generating products that are economically competitive to commercial bulk products.

Study of Reactive Precipitation in Vortex Impinging Streams Reactor

2012 ◽  
Vol 455-456 ◽  
pp. 617-623
Author(s):  
You Feng Li ◽  
Hong Qi Ye ◽  
Xian Da He ◽  
Hui Liu
Keyword(s):  
Specific Surface ◽  
Infrared Spectra ◽  
Barium Sulfate ◽  
Functional Group ◽  
Stirred Tank ◽  
Complexing Agent ◽  
Tetraacetic Acid ◽  
Orthorhombic Structure ◽  
Tank Reactor ◽  
Ellipsoidal Particles

The vortex impinging streams technology (VIS) has good micromixing in the precipitation processes. The experiments were loaded with two reactants, BaCl2and Na2SO4, using ethylene diamine tetraacetic acid (EDTA) as complexing agent, to prepare BaSO4 in the vortex impinging streams reactor at Re=2500, comparing with those in the stirred tank reactor (STR). The products were characterized by XRD, TEM, BET and FTIR. The results indicate barium sulfate superfine particles are crystallized in the orthorhombic structure with lattice parameters a=7.156 Å, b=8.881 Å, and c=5.454 Å. The size of the ellipsoidal particles from VIS is about 386 nm, with narrower distribution and finer dispersity than that from STR. The specific surface area of the particles from VIS is 29.25 m2/g, comparing to 11.95 m2/g from STR. The infrared spectra decades the surface of the prepared BaSO4absorbs the functional group of EDTA.

scholarly journals RELAXATION IN EXTRACTED MUSCLE FIBERS

1954 ◽  
Vol 38 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Emil Bozler
Keyword(s):  
Critical Level ◽  
Critical Concentration ◽  
Muscle Fibers ◽  
Complexing Agent ◽  
Tetraacetic Acid ◽  
Relaxation Factor ◽  
Low Concentrations ◽  
High Concentrations ◽  
Relaxing Effect ◽  
Subsequent Addition

1. Ethylenediamine tetraacetic acid (EDTA) in low concentrations imitates all the known effects of the relaxation factor ("Marsh factor"). In extracted muscle fibers which have contracted in a solution containing adenosinetriphosphate (ATP), the addition of EBTA causes relaxation, the subsequent addition of CaCl2, contraction. 2. In fibers which have been briefly immersed in 5 MM EDTA, ATP causes rapid relaxation if Mg is also present. These fibers have essentially the same properties as briefly extracted fibers. Brief immersion into a solution containing CaCl2 restores at once the original condition. It is concluded that EDTA produces its action by firmly combining with bound Ca, thereby inactivating it. 3. In relaxed muscle fibers not only Ca, but also lowering the concentration of Mg below a critical level, causes contraction. In such fibers Mg in the lowest effective concentrations increases contraction, but the effect reverses above a certain concentration. 4. At 0° Mg in the presence of ATP has a relaxing effect without the relaxation factor. 5. The results indicate that Mg has two distinct effects in the presence of ATP. It causes contraction at low concentrations, but above a critical concentration its relaxing action prevails. The last of these effects is blocked by bound Ca. If the latter is inactivated by EDTA, Mg in sufficiently high concentrations causes relaxation. The action of the relaxation factor can similarly be explained by assuming that it acts as a complexing agent which inactivates bound Ca. 6. Previous evidence that the relaxed state depends on the formation of an enzymatically inactive ATP-protein complex was confirmed. It was found that PP in low concentrations strongly increases the relaxing effect of ATP in briefly extracted fibers.

Determination of quaternary ammonium salts and polyhexamethylene biguanide hydrochloride in the coexistence in disinfectants and their biocidal activity

2021 ◽  
pp. 5-10
Author(s):  
Yuliya Vladimirovna Matveichuk ◽  
◽  
Dmitrii Vladislavovich Stanishevsky ◽  
Yurii Viktorovich Shabeka ◽  
◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Ethylenediaminetetraacetic Acid ◽  
Sodium Dodecyl ◽  
Quaternary Ammonium Salts ◽  
Disodium Salt ◽  
Ammonium Salts ◽  
Bromophenol Blue ◽  
Complexing Agent ◽  
Accuracy Index

Titrimetric methods for determining the concentration of quaternary ammonium salts and polyhexame­thylenebiguanide hydrochloride in the presence of a disinfectant are described. In addition, as auxiliary components, the agent contains a nonionic surfactant and an alkyl polyglucoside and a disodium salt of ethylenediaminetetraacetic acid as a complexing agent. The main differences between the methods proposed by us for the determination of quaternary ammonium salts and polyhexamethylenebiguanide hydrochloride is the use of not sodium dodecyl sulfate as a titrant, but a solution of the disinfectant itself, which greatly facilitated the visual fixation of the equivalence point. In addition, the volume of the indicator (methylene blue and bromophenol blue) was selected in such a way that the exposure between the portions of the added titrant was not prolonged, because this would increase the overall duration of the analysis. When titrating with polyhexamethylenebiguanide hydrochloride, the vo­lume of the indicator is selected in such a way as to minimize the interfering effect of HR, which are also part of disinfectants. The reproducibility of the developed methods has been confirmed in accredited laboratories of the relevant state institutions of the Republic of Belarus. Metrological characteristics of the developed methods: accuracy index±3.7 %, reproducibility index 4.0 %, n = 17, P = 0.95 – to determine the QAS; accuracy index±4.2 %, reproducibility index 5.5 %, n = 17, P = 0.95 – for the determination of PHMBG.

Effect of pH Value on Preparation of La2CuO4 Microcrystallites Synthesized by Sol-Gel Process

2012 ◽  
Vol 512-515 ◽  
pp. 231-234 ◽  
Author(s):  
Yi Feng Li ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu
Keyword(s):  
Optical Band Gap ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Complexing Agent ◽  
Solution Ph ◽  
Crystallization Property ◽  
Water As Solvent ◽  
Sol Gel Process ◽  
Single Sphere

La2CuO4 crystallites were prepared via a sol-gel process using lanthanum nitrate and cupric nitrate as raw materials, distilled water as solvent, citric acid as complexing agent and ammonia to control the pH value. The as-prepared La2CuO4 crystallites were characterized by XRD, FESEM, TEM and UV-Vis spectra. Results show that the crystallization property of La2CuO4 crystallites increases firstly and then decreases with increasing of the solution pH value from 1.0 to 2.5, but all of the samples exhibit single sphere-like morphology. It is found that when the solution pH value is controlled at 2.0, the grains display uniform distribution and the size ranges from 100nm to120nm after sintering at 600°C for 2 hours. The optical band gap of the as-prepared La2CuO4 crystallites is calculated to be 1.38eV.

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