Wyniki wyszukiwania - Biblioteka Nauki

1

ELECTROLYTIC METHOD FOR OBTAINING POROUS CHITOSAN STRUCTURES WITH HYDROXYAPATIT

100%

Tylman M. , Mucha M.

Progress on Chemistry and Application of Chitin and its Derivatives

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2011

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tom 16

5 - 14

EN

The aim of this study was to develop a preparation method of porous chitosan structures, in the electrolysis of the chitosan solution in acetic acid. Chitosan in aqueous acetic acid is a polyelectrolyte. During the constant flow of electric current through this system, pure chitosan begins to accumulate on an anode, in the form of porous hydrogel layers. The addition of hydroxyapatite (HAp) to the electrolyte enhances the process and allows for obtaining spatially arranged complex structures of chitosan.

2

Cyclic Voltammetry and Electronic Absorption Spectroscopy in Investigations of the Nature of the Electrochemical reduction of Phenyldiazonium and Phenyl-bis-diazonium Cations

100%

Koval'chuk E. , Kozlovs'ka Z. , Jackowska K. , Roshal A. , Wróblewska A. , Reshetnyak O. , Błażejowski J.

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2004

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tom Vol. 78 / nr 1

139-147

EN

The electrochemical reduction of phenyldiazonium and phenyl-bis-diazonium cations on mercury drop and platinum cathodes exhibits a multistep nature, as demonstrate the results of polarographic and cyclic voltammetry measurements. The primarily formed radicals participate in various secondary processes, as a result of which occur species absorbing UV-VIS radiation. Electronic absorption in the visible region can be ascribed to entities forming from the recombination of two azophenyl or azophenyl and phenyl radicals, originating from the one- or two-electron reduction of primarily or secondary formed cations.

3

Nitrification onto a rotating electro-biological contactor

100%

Rodziewicz J. , Filipkowska U.

Polish Journal of Natural Sciences

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2011

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tom 26

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nr 4

EN

The goal of the conducted experiment was to determine the electric current impact on the efficiency of nitrogen compounds oxidation at COD to total Kjeldahl’s nitrogen ratio of 20, 10, 5. The experiments were run in bench scale, in a rotating electro-biological contactor (REBC) under both, conventional conditions (i.e. without electric current) and with electric current passage at the following densities: 0.2 A m⁻², 0.8 A m⁻², and 1.5 A m⁻². The cathode comprised stainless steel discs with immobile biofilm, and the anode a stainless steel electrode, submerged in waste water contained in the flow-tank of the contactor. The process of nitrogen oxidation was the most effective with electric current passage at the density of 1.5 A m⁻² regardless of applied COD/NTK ratio.

PL

Celem doświadczenia było określenie wpływu przepływu prądu elektrycznego na sprawność utleniania związków azotu gdy stosunek ChZT do azotu ogólnego Kjeldahla wynosił 20, 10 i 5. Badania prowadzono w skali laboratoryjnej na elektrobiologicznym złożu tarczowym (REBC) gdy nie przepływał prąd elektryczny, oraz gdy przepływał prąd elektryczny o gęstości: 0,2 A m⁻², 0,8 A m⁻², 1,5 A m⁻². Katodą były tarcze ze stali nierdzewnej z unieruchomioną błoną biologiczną, anodą – elektroda ze stali nierdzewnej, zanurzona w ściekach komory przepływowej złoża. Najefektywniej proces utleniania azotu przebiegał gdy przepływał prąd elektryczny o gęstości 1,5 A m⁻², niezależnie od stosunku ChZT:NTK.

4

Modification of Aluminium-Silicon Near-Eutectic Alloy with Use of Electrolysis of Sodium Salt

100%

Białobrzeski A. , Pezda J. , Jarco A.

Archives of Metallurgy and Materials

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2017

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tom Vol. 62, iss. 4

2371--2374

EN

The present work discusses results of preliminary tests concerning the technology of continuous dosage of sodium to a metallic bath from the aspect of modification of EN AC-44200 alloy, through the use of a multiple compound (salt) of sodium. The technology consists in continuous electrolysis of sodium salts occurring directly in a crucible with liquid alloy. As a measure of the degree of alloy modification over the course of testing, the ultimate tensile strength (UTS or Rm) and analysis of microstructure are taken, which confirm the obtained effects of the modification on the investigated alloy. Assurance of stable parameters during the process of continuous modification with sodium, taking into consideration the fact of complex physical-chemical phenomena, requires additional tests aimed at their optimization and determination of a possibility of implementation of such technology in metallurgical processes.

5

Electrowinning of copper and lead from ammonium acetate solutions

100%

Bieszczad T. , Sanak-Rydlewska S.

Physicochemical Problems of Mineral Processing

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2001

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tom Vol. 35

181-193

EN

This paper presents the results of laboratory studies on electrowinning of copper and lead from spent leachate obtained by leaching of copper concentrates with ammonium acetate solutions. The effect of electrolyte composition and the electrolysis current density on the process efficiency was investigated. The electrolyte was also pre-treated with ammonia before it was electrolysed under the same abovementioned conditions.

PL

W artykule przedstawiono wyniki badań laboratoryjnych nad procesem elektrowydzielania miedzi i ołowiu z roztworów modelowych, o składzie podobnym do tego, jakie uzyskuje się w procesie ługowania koncentratów miedziowych roztworami octanu amonowego. Dla roztworów modelowych przebadano wpływ składu roztworu elektrolitu i wielkości prądu elektrolizy na wydajność procesu. Zastosowano również wstępną obróbkę elektrolitu amoniakiem, po której poddano roztwór elektrolizie w takich samych warunkach, jakie stosowano dla roztworów bez dodatku amoniaku. Z przeprowadzonych obliczeń teoretycznych i z wyznaczonych doświadczalnie napięć rozkładowych wynika, że w badanym układzie na katodzie zachodzi reakcja współwydzielania miedzi i ołowiu a przy wysokich prądach także gazowego wodoru. Wydajność prądowa procesu, liczona w stosunku do miedzi, prawie nie zależy od stężenia octanu amonowego i od tego czy roztwór poddawany procesowi elektrolizy zawierał amoniak, czy nie. Wydajność maleje (przy stałym składzie roztworu) ze wzrostem prądu elektrolizy, natomiast rośnie ze wzrostem stężenia miedzi i ołowiu w elektrolicie. Zmiany stężenia jonów ołowiu są tym większe im mniejszy jest prąd elektrolizy. Większe zmiany stężeń ołowiu występują w roztworach amoniakalnych. Napięcia elektrolizy, jak i potencjały katody względem nasyconej elektrody chlorosrebrowej, rosną ze wzrostem prądu elektrolizy, natomiast nie zależą od stężenia octanu amonowego. Przy niskich wartościach prądu otrzymuje się osady bardziej zwarte a przy wyższych, gąbczaste, łatwo odpadające od elektrody. Ponieważ otrzymane osady w procesie elektrolizy stanowią mieszaninę miedzi i ołowiu, w przyszłości będą przedmiotem badań nad ich rozdziałem, w celu odzyskania czystych metali.

6

Elektroliza odpadowego kwasu solnego z zastosowaniem nowych materiałów elektrodowych

100%

Wandachowicz K. , Gnot W. , Dydo P.

Przemysł Chemiczny

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2002

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tom T. 81, nr 1

46-51

7

Application PEM fuel cells in distributed generation

100%

Ceran B. , Bernstein P. A.

Poznan University of Technology Academic Journals. Electrical Engineering

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2014

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tom No. 79

157--163

EN

In this article the laboratory stand for testing the cooperation of three energy sources has been presented. The aspects of the use of PEM cells in distributed generation have been studied. The measurement results of parallel cooperation of the fuel cell with wind turbine and photovoltaic cell have been presented.

8

Comparative Studies on the Codeposition of Antimony and Tin from Acidic Chloride and Sulfate-Chloride Solutions

88%

Rudnik E. , Kostępski M.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 2

709--717

EN

Codeposition of antimony and tin from acidic chloride and chloride-sulfate baths was investigated. The calculations of distribution of species showed domination of neutral SnCl2 and anionic SbCl4 - complexes in chloride solution, while in the presence of sulfate ions neutral SnSO4 and cationic SbCl2+ complexes were found. Cyclic voltammetry, anodic stripping analysis and potentiostatic measurements showed that antimony deposited favorably and the reaction run under limiting control. Analysis of chronoamperometric curves suggested instantaneous nucleation of the solid phase in the chloride bath, but progressive model was more probable in the presence of sulfate ions.

9

Recovery of Alum from Surabaya Water Treatment Sludge using Electrolysis with Carbon-Silver Electrodes

88%

Barakwan R. A. , Hardina T. T. , Trihadiningrum Y. , Bagastyo A. Y.

Journal of Ecological Engineering

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2019

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tom Vol. 20, nr 7

126--133

EN

Untreated alum sludge from Surabaya water treatment plant (WTP), which contained high concentration of alum was directly discharged into Surabaya River. It might cause problems because of the accumulation of aluminum in the lower part of the river. Alum could be recovered from the drinking water sludge using the electrolysis method. Aims of this study were to determine the optimum pH and electrical current for electrolysis using carbon-silver electrodes to recover aluminum coagulant from the sludge, and to determine the amount of the recovered alum. The sludge was acidified prior to electrolysis. Acidification was done by adding sulfuric acid at pH 3 and 4. Polarization test was conducted at 100, 200, and 300 mA, in order to determine the optimum electrical current. The electrolysis was performed in one compartment batch recirculation reactor, using silver as cathode and carbon as anode for 10 hours. Values of pH were measured every hour. The precipitated matter in the cathode was weighed, and analysed by means of Inductively Coupled Plasma. The optimum conditions of the electrolysis were achieved at initial pH 3 and electrical current 300 mA. The electrolysis resulted in the highest precipitate of 2.6112 g in the cathode.

10

Sustainable development in the tinplate industry: refining tinplate leachate with cementation

88%

Klimko J. , Urban K. I. , Piroskova J. , Orac D. , Havlik T. , Klein D.

Physicochemical Problems of Mineral Processing

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2020

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tom Vol. 56, iss. 1

219--227

EN

Tin sludge produced during tin electroplating of steel sheet is an interesting secondary source of tin. Dried sludge usually contains more than 50% tin. Hydrometallurgical sludge treatment consists of several steps, including leaching in hydrochloric acid and electrolytic recovery of tin. The electrowinning process is negatively affected by the presence of impurities such as antimony and bismuth, which can cut overall current efficiency to 11% as well as reducing the quality of recovered tin. It is appropriate therefore to remove these impurities from the leachate before the electrowinning steps. This work studies the refining of leachate using cementation. The experiments were carried out at temperatures of 20, 40 and 60 °C at solid to liquid ratios of 1:60, 2:60, 3:60 and 4:60 using tin and iron dust as cementing metals. The leachates were mixed at a constant rate of 400 rpm during all cementation experiments. Effective removal of impurities was achieved in the case of iron powder cementation at s/l ratio 2:60 and temperature 20 °C. This cementation removed 98.49% bismuth and 99.14% antimony from the leachate solution. Electrolysis efficiency was increased from 11 to 71% after leachate refining. Antimony and bismuth were not detected in the final product obtained from refined electrolyte by means of electrolysis.

11

Estimation of the Efficiency of Ammonia Oxidation in Anolyte of Two-Chamber Electrolyzer

88%

Gomelya M. , Shabliy T. , Radovenchyk I. , Overchenko T. , Halysh V.

Journal of Ecological Engineering

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2019

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tom Vol. 20, nr 5

121--129

EN

In this study, the processes of electrochemical oxidation of ammonia in a two-chamber electrolyzer with anion exchange membrane MA-41 were investigated. An estimation of the efficiency of the process of oxidation of ammonia, depending on the chemical composition of the initial solution of anolyte and catholyte, current density and time of electrolysis was carried out. It was shown that the oxidation of ammonia in the anode chamber passes quickly and is accompanied by a significant decrease in pH due to the formation of nitrogen dioxide and nitrates. At the same time, the current output and the electrical conductivity of the dilute solutions was rather low. The effect of chlorides on the process of electrolysis was investigated. It was shown that the presence of chlorides in the anolyte catalyzes the processes of oxidation of ammonia. An increase in the concentration of chlorides in the anolyte increases output and reduces electricity consumption. The presence of chlorides in the catholyte does not accelerate oxidation. The presence of sulfates, both in the anolyte and in the catholyte, slows down the process of oxidation of ammonia as a result of the oxidation of sulfates to persulfates, which are quite passive to ammonium ions. At the same time, electricity consumption increases.

12

Analysis of Energy Storage System with Distributed Hydrogen Production and Gas Turbine

88%

Kotowicz J. , Bartela Ł. , Dubiel-Jurgaś K.

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nr 4

13

Modeling and Performance Analysis of Hydrogen Powered Hybrid Bike

88%

Gurunathan M. K. , Hynes N. R. J. , Bartoszuk M. , Sujana A. J. , Al-Khashman O.

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tom Vol. 18, no 3

360--368

EN

One of the most straightforward and affordable ways to produce hydrogen is by alkaline water electrolysis. In order to split water molecules into hydrogen and oxygen, an electrolyser is often subjected to current levels of 1.23V. The electrodes in an electrolytic cell are the primary structural component. The cathode electrode type is the one where hydrogen is created via the reduction reaction between the two types of electrodes. LPG is combined with hydrogen at a 4:1 ratio to lower the combustion energy because hydrogen cannot be used directly in a traditional SI engine due to its higher energy production during combustion. With the aid of a vaporizer unit, the hydrogen and LPG are combined in the necessary ratio. Through the bypass line created on the input manifold before the carburettor, where air is also mixed with the hydrogen-LPG fuel with the A/F ratio of 17:1 (stoichiometric ratio) for complete combustion, the fuel mixture is transported to the engine's combustion chamber. Due to the usage of LPG and hydrogen, full combustion may occur as a result of the production of a blue flame during combustion. Better mixing of the fuel and air can be achieved since the fuel mixture is conveyed in va-por state instead of semi-liquid form as in a conventional SI engine. This approach of using mix fuel (LPG+H2) for con-ventional SI engines can lower nitrogen oxide and hydrocarbon values in the exhaust gas more effectively.

14

Application of Ammoniacal Solutions for Leaching and Electrochemical Dissolution of Metals from Alloys Produced from Low-Grade E-Scrap

88%

Rudnik E.

Archives of Metallurgy and Materials

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2017

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tom Vol. 62, iss. 3

1681--1688

EN

Paper reports results of the research on the application of ammoniacal solutions (sulfate, chloride, carbonate) for hydrometallurgical treatment of smelted low-grade e-waste. Two Cu-Zn-Sn-Ag-Pb alloys were analyzed in details and discussed. Leaching of copper from the alloys was slow in sulfate solution, but the dissolution rate decreased in chloride and carbonate baths. Anodic alloys dissolution was uniform in sulfate and carbonate electrolytes, but high degradation of the material was observed in chloride bath. Chemical and phase composition of slimes and cathodic deposits produced during electrolysis were characterized. In all cases, separation of copper from other metals was found, but efficiencies of the processes were low.

15

Azo dye wastewater treatment in a novel process of biofilm coupled with electrolysis

88%

Zou H. , Chu L. , Wang Y.

Archives of Environmental Protection

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2019

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tom Vol. 45, no. 3

38--43

EN

Azo dye wastewater treatment is urgent necessary nowadays. Electrochemical technologies commonly enable more efficient degradation of recalcitrant organic contaminants than biological methods, but those rely greatly on the energy consumption. A novel process of biofilm coupled with electrolysis, i.e., bioelectrochemical system (BES), for methyl orange (MO) dye wastewater treatment was proposed and optimization of main influence factors was performed in this study. The results showed that BES had a positive effect on enhancement of color removal of MO wastewater and 81.9% of color removal efficiency was achieved at the optimum process parameters: applied voltage of 2.0 V, initial MO concentration of 20 mg/L, glucose loads of 0.5 g/L and pH of 8.0 when the hydraulic retention time (HRT) was maintained at 3 d, displaying an excellent color removal performance. Importantly, a wide range of effective pH, ranging from 6 to 9, was found, thus greatly favoring the practical application of BES described here. The absence of a peak at 463 nm showed that the azo bond of MO was almost completely cleaved after degradation in BES. From these results, the proposed method of biodegradation combined with electrochemical technique can be an effective technology for dye wastewater treatment and may hopefully be also applied for treatment of other recalcitrant compounds in water and wastewater

16

The study on pH gradient control in solution for driving bacteria

88%

He B. , Wang Z. , Xu C. , Shen R. , Hu S.

Biocybernetics and Biomedical Engineering

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2013

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tom Vol. 33, no. 2

88--95

EN

Medical applications are the most impactful areas of microrobotics, such as targeting tumoral lesions for therapeutic purposes, minimally invasive surgery (MIS) and highly localized drug delivery. However, miniaturization of the power source with an effective on board controllable propulsion system has prevented the implementation of such mobile robots. Flagellated chemotactic bacteria can be used as an effective integrated propulsion system for microrobots. In this paper, we study the pH gradients control in solution for driving bacteria. The swimming property of flagellar bacteria and mechanism of forming the pH gradient field in solution are discussed. By experiments, we found that the pH gradient field distribution in solution is mainly related to the electrode shape. And the input voltage value can control the stable time of the pH gradient field, while it has no effect on the distribution of the field. The electric potential distribution is analyzed by simulation with COMSOL Multiphysics. The simulation results are consistent with the experiment results, which indicate that the bacteria movement can be controlled by the electrodes' shape and the input voltage.

17

Electrochemical Purification of Oil-Containing Shipping Waters

75%

Vozniuk M. , Shabliy T. , Gomelya M. , Sirenko L. , Sidorov D.

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tom Vol. 24, nr 7

246--253

EN

The article describes the modern problems of formation and purification of marine oil-containing waters. The efficiency of using electrocoagulation to remove oil from water-oil emulsions of different mineralization using aluminum and iron anodes was studied. Treatment of water-oil solutions with an oil content of 100 mg/dm3 by electrocoagulation in a single-chamber electrolyzer provides 98–99% oil removal using these electrodes at an anode current density of 0.57–2.11 A/dm2 for highly mineralized waters and 0.34 A/dm2 for freshwater treatment during the first 15 minutes provides a reduction in oil concentration from 100 mg/dm3 to values at the level of 1.55–2.93 mg/dm3. When the water treatment time is extended to 45 minutes, greater efficiency in highly mineralized waters is provided by the aluminum anode.

18

Utilization of Sodium Chloride Solutions to Obtain Ferrous Chlorides

75%

Gomelya M. , Kryzhanovska Y. , Shabliy T. , Levytska O.

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2020

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tom Vol. 21, nr 8

177--184

EN

In this work, the processes of electrochemical processing of sodium chloride solutions with the production of iron (III) chloride and alkali in a three-chamber electrolyzer with MA-41 anion-exchange membrane and MK-40 cation-exchange membrane were investigated. The conditions for the removal of sodium chloride from water in a three-chamber electrolyzer using an iron anode were determined depending on the anode current density and the reaction of the medium in the anode region. The parameters of the process of concentrating iron chloride in the anode region were established at relatively low concentrations of sodium chloride solution. It was shown that during the electrolysis of a sodium chloride solution with a concentration of 370 mg-eq/dm3 at a current of 0.2 A in a three-chamber electrolyzer with an iron anode, an iron chloride solution is formed in the anolyte at pH < 4.9. The rate of concentration of NaOH to catholyte and FeCl3 to anolyte increased along with the current density. It was found that in order to increase the concentration of iron (III) chloride in the anolyte at relatively low concentrations of sodium chloride solution, it is advisable to gradually renew the demineralized solutions in the working chamber.

19

Wpływ parametrów elektroosadzania na zmiany nanostruktury warstw Al[2]O[3]/WS[2] o przeznaczeniu tribologicznym

75%

Korzekwa J. , Skoneczny W. , Wojnar L.

Czasopismo Techniczne. Mechanika

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2011

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tom R. 108, z. 5-M

11-19

PL

W niniejszym artykule zaproponowano graficzny model mechanizmu tworzenia warstw Al[2]O[3]/WS[2], opierając się na trzech etapach procesu: przenoszenie cząstek stałych z zawiesiny z głębi kąpieli do powierzchni anody, adsorpcja cząstek na powierzchni anody, zarastanie cząstek adsorbowanymi anionami elektrolitu. Wyznaczono wartości promieni nanowłókien oraz rozkład pól powierzchni nanoporów w zależności od warunków elektrolizy. Wykazano, że temperatura kąpieli elektrolitu nie wpływa istotnie na średnie wartości promieni nanowłókien tlenku aluminium, podczas gdy zastosowane gęstości prądu procesu wytwarzania powłok Al[2]O[3]/WS[2] wykazały istotny wpływ na rozmiary nanowłókien. W stałej temperaturze wraz ze wzrostem wartości gęstości prądu zanotowano również wzrost udziału nanoporów o większych polach powierzchni.

EN

The effect of electrodeposition parameters on the changes in the nanostructure of Al[2]O[3]/WS[2] layers was studied using the computer image analysis. The graphic model consisting of three steps in creation the Al[2]O[3]/WS[2] layers was proposed. The radius of nanofibers and size distribution class range of nanopores were determined. It was demonstrated that the temperature of the process does not affect the size of nanofibers. In contrast, the current density affect both size of nanofibers and friction of larger nanopores.

20

Oczyszczanie ekstrakcyjnego kwasu fosforowego z zastosowaniem elektrolizy z kontrolą potencjału

75%

Zielińska E. , Białomazur M. , Tarnowska A. , Zienkiewicz M. , Jasińska I. , Łukomska A. , Lach J. , Wróbel K. , Grzmil B.

Przemysł Chemiczny

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2021

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tom T. 100, nr 4

333--338

PL

Przeprowadzono badania dotyczące oczyszczania ekstrakcyjnego kwasu fosforowego(V) z zanieczyszczeń kationami metali wielowartościowych, zwłaszcza jonami kadmu, metodą elektrolizy z kontrolą potencjału. W pierwszym etapie prac zrealizowano badania w skali laboratoryjnej, a następnie zoptymalizowano proces w elektrolizerze stacjonarnym w skali wielkolaboratoryjnej. Na podstawie uzyskanych wyników stwierdzono, że proponowaną metodą możliwe jest usunięcie jonów kadmu z ekstrakcyjnego kwasu fosforowego do zawartości poniżej 5 mg/kg.

EN

Two samples of com. extractive H3PO4 (P2O5 contents 23.9% by mass and 41.1% by mass) were studied for electrolytic removal of heavy metals (esp. Cd) ions in lab. and large lab. electrolyzers. The Cd content was decreased from 9.8 mg/kg down to below 5 mg/kg.