Universal modular device for electrochemical syntesis of the disinficant

For the water disinfections practically four different technologies (chlorine, ozone, hypochlorite, chlorine dioxide) are used nowadays in the world. The oldest and the most exploited one, so called conventional, is the disinfections with gaseous or liquid chlorine. The biggest producers of the equipment for the water treatment in the world mainly possess all mentioned technologies for water disinfections. It is easy to concluded that the technology of water disinfections with the hypochlorite solution produced by the electrolysis of 3% solution of sodium chloride on the site of water chlorination is not only the most convenient from the point of economical aspects, but also from the point of the ecological aspect

Decopperization process of waste solutions from conventional copper electrolysis

This paper is adresses on treatment of sulphuric acid waste solutions obtained during the conventional copper metallurgical activities. Mother liquor is a part of this solutions and it is generated during the regeneration process of copper bleed solution. Copper, nickel and sulphuric acid are the main components and the other registered impurities are: As, Se, Fe, Sb, Zn, Bi, Pb, Cl ions. Aim to copper removing from the mother liquor, the decopperization process on the industrial scale equipment, is investigated. Investigation was done using the rectangular insoluble lead anodes alloyed with 6 wt.% of antimony at current value of 13 000 A, identical to the current in a commercial copper refinery plant. A few parameters as so as: current, cell voltage, electrolyte temperature, electrolyte flow rate, level of electrolyte, were monitored during the test. Comparing the values of copper content in the solution before and after the decopperization of copper, it was found that it decreased of about 80 wt. % of the initial value. Chemical characterization of the sludge obtained on cathode has shown that it is a material with copper content of about 90 wt. %

Characteristics of the citrate-based zinc-polyaniline secondary cell with supercapattery behavior

The electrochemical characteristics of zinc–polyaniline (PANI) secondary cell in the electrolyte containing 0.8 M Na citrate, 0.3 M NH4Cl and 0.3 M ZnCl2 is investigated. Based on the measurements of potentials and voltage of the cell during charge/discharge for the currents in the range of 18 to 45 mA, the specific electrode capacity of 85 to 55 mA h g-1, the specific energy of 60–40 mW h g-1 and the specific power of 150–350 mW g-1, is determined. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON172046: Electrochemical synthesis and characterization of nanostructured functional materials for applications in new technologies

Uniaxial tension of drying sieves

Although the literature contains numerous studies that have been developed to describe the nonlinear behavior of drying sieves' operation, there are no papers in this which report deeper investigation of the drying sieve behavior when exposed to tension and thermo stabilization. The aim of this paper is to provide insight into the elastoplastic behavior of the thermo stabilized and not stabilized sieves subjected to the tensile force. Within this work both theoretical and experimental investigations were performed. The sieves were joined by using a spiral. In separate experiments tests of wire base and weft of the weave mesh were performed, both for thermo stabilized and not thermo stabilized sieves, sieves joining and the sieve thermo stabilization itself. It was established that the thermo stabilization of sieves provides for stability of sieves' dimensions and that open thermo stabilized drying sieve exhibits better mechanical properties and exploitation characteristics then the sieves joining. [Projekat Ministarstva nauke Republike Srbije, br. ON174004: Micromechanics criteria of damage and fracture and br. TR 32036: Development of software for solving the coupled multi-physical problems

Determination of glucose using polyaniline modified electrode

Sensor electrode was formed by immobilization of glucose oxidase (GOx) on polyaniline (PANI), electrochemically synthesized on graphite electrode from aqueous hydrochloride acid electrolyte containing aniline monomer by galvanostatic method. Optimization of the current density used for the synthesis of PANI was performed. Immobilization of GOx was achieved by crosslinking via glutaraldehyde and the efficiency of the immobilization was determined spectrophotometrically. Using chronoamperometric curves of glucose oxidation on polyaniline apparent Michaelis constant was estimated to be 0.273 mM. The storage stability of the enzyme electrode was examined for twenty days, after which it retained 84% of its initial signal

Elektrohemijska sinteza elektroprovodnih polimera

Electroconducting polymers from the group of synthetic metals are extensively investigated due to numerous properties perspective in practical application. These materials may be synthesized by both chemical and electrochemical procedures. Chemical synthesis is suitable when bulk quantities of the polymer are necessary and up to date it presents dominant commercial method of producing electroconducting polymers. Nevertheless, the electrochemical synthesis has its advantages; it avoids usage of oxidants since conducting polymeric material is obtained at anode upon application of positive potential, leading to increased purity. On the other hand, since the polymer is deposited onto electrode, further electrochemical characterization is facilitated. Owing to actuality of the research in the field, this text aims to describe important aspects of electrochemical synthesis of electroconducting polymers, with special emphasis to polyaniline and polypyrrole.Tradicionalno shvatanje o polimerima kao odličnim izolatorima izmenjeno je sedamdesetih godina prošlog veka kada su naučnici uspeli da sintetizuju poiliacetilen čija je provodljivost bila bliska metalnoj. Ova činjenica ukazala je na novo svojstvo polimernih materijala i lansirala potpuno novo multidisciplinarno naučno polje, popularno nazvano, sintetički metali. Iako je danas pojmom elektroprovodnih polimera obuhvaćena velika grupa jedinjenja koja su klasifikovana prema prirodi prenosioca naelektrisanja, naziv elektroprovodni polimeri se najčešće koristi u literaturi upravo za polimerne materijala iz grupe sintetičkih metala koji poseduju elektronsku provodljivost kao posledicu specifičnosti molekulske strukture. Pored zahteva molekulske structure, koja podrazumeva konjugovani sistem dvostrukih veza, za provodljivost elektroprovodnih polimera neophodno je dopovanje. Termin dopovanje, iako preuzet iz terminologije klasičnih neorganskih poluprovodnika, podrazumeva u mnogome drugačiji proces. Dopovanje elektroprovodnih polimera podrazumeva oksidaciju tokom koje se, u cilju održavanja elektroneutralnosti polimernog lanca, uvodi stehiometrijska količina jona (anjona). Terminom dopovanje obuhvaćena je i protonacija polimernog lanca kiselinom, u slučaju polianilina, a nedavno je potvrđena i u slučaju polipirola. Kako je, na ovaj način, uvedena velika količina jona izmenjenja je polazna struktura elektroprovodnog polimera, tako da svojstva nastalog materijala zavise u velikoj meri od svojstava dopanta. Iako su na početku razvoja ove oblasti, elektroprovodni polimeri bili sintetizovani hemijskim postupcima, sticanjem uvida u mehanizam hemijske sinteze koja podrazumeva oksidativnu radikalnu polimerizaciju, postalo je jasno da se ovi materijali mogu dobiti i elektrohemijskim postupcima. Elektrohemijska sinteza ima prednosti, pošto se polimer dobija oksidacijom na elektrodama (anodama), čime je izbegnuta upotreba oksidacinog sredstva i omogućena veća čistoća proizvoda. Sa druge strane, elektroprovodni polimer je u većini slučajeva dobijen u obliku prevlake na elektrodi, pa je njegova dalja karakterizacija elektrohemijskim tenikama olakšana. Interesovanje za oblst sinteze elektroprovodnih polimera ne jenjava, pa je ovaj tekst posvećen osnovnim principima elektrohemijskih postupaka sinteze sa posebnim osvrtom na najpopularnije elektroprovodne polimere, polianilin i polipirol

Sinteza kristalnih vanadijum-oksidnih keramićkih glazura

The crystalline phase is the dominant phase in the ceramic body with a small amount of glassy phase. The preparation of ceramic glazes with characteristics similar to glass-ceramics can be performed by controlling the raw glaze composition and nucleating agent. The choice of appropriate nucleating agents that dominate bulk crystallization can be essential. Among multiple nucleating agents such as zirconia, titania, metallic molybdenum, and wolfram particles investigation of the influence of vanadium compound was not well studied on aluminum-silicate glass-ceramics. Metal such as vanadium forms oxides in an oxidation atmosphere at lower temperatures compared to metallic molybdenum and wolfram helping elucidate the effect of oxide on the crystallization behavior. Controlling the microstructure of glass-ceramic by processing parameters further control mechanical and optical properties. The addition of vanadium–pentoxide promotes the formation of entangled flower-like crystals on the porcelain ceramic body in combination with different commercial high-temperature glazes. Red and dark red colorations due to the presence of V5+ were obtained for aluminosilicate glass with a V2O5 content in the 5-10 mass % range. A pronounced spread of crystals beyond the glazed surface is observed on densely sintered stoneware and porcelain, which enables the formation of a decorative effect using simple application techniques.Kristalna faza predstavlja dominantnu fazu porcelana i kamenine sa malim udelom staklaste faze. Priprema keramičkih glazura sa karakteristikama sličnim staklo-keramici može se vršiti kontrolisanjem sastava sirove glazure i sredstva za nukleaciju. Izbor odgovarajućih agenasa ima značajan uticaj na odvijanje procesa nukleacije. Za razliku od najčešće korišćenih nukleatora, kao što je cirkonijum, titanijum, metalni molibden i čestice volframa, ispitivanje uticaja jedinjenja vanadijuma nije dovoljno istraženo u formiranju aluminijum-silikatne staklo-keramike. Metal kao što je vanadijum formira okside u oksidacionoj atmosferi na nižim temperaturama u poređenju sa metalnim molibdenom i volframom, što omogućava proučavanje uticaja oksida na proces kristalizacije. Kontrolisanjem mikrostrukture staklo-keramike kontrolom procesnih parametara moguće je dobiti staklo-keramiku željenih mehaničkih i optičkih svojstava. Dodatak vanadijum-pentoksida promoviše formiranje umrežanih igličastih kristala nalik cvetu na porcelanskoj masi u kombinaciji sa različitim komercijalnim visokotemperaturnim glazurama. Crvena i tamnocrvena boja, uzrokovana prisustvom V5+ dobijena je u alumo-silikatnoj fazi pri koncentraciji V2O5 u opsegu od 5-10 masenih %. Na gusto sinterovanoj kamenini i porcelanu primećen je izraženi rast kristala izvan glazirane površine, što omogućava stvaranje dekorativnog efekta korišćenjem jednostavnih tehnika nanošenja

The use of anodic linear sweep voltammetery analysis (ALSV) for characterization the copper anodes used for sulphur acidic waste solution treatment

This paper addresses on investigation the possibility of electrolytic treatment the sulphur acidic waste solution, obtained in the conventional electrolytic copper refining process. The copper anodes with non-standard nickel, lead, tin and antimony content were specially prepared for the refining process. Nickel content of all anodes was approximately 7.5 mass %, and the content of lead, tin and antimony was varied. Results, obtained using the standard electrochemical techniques, have indicated that the anodes could be used under the same conditions as well as in the conventional copper refining process

Electrochemical Water Treatment Devices

Paper published in 43rd International October Conference on Mining and Metallurgy - IOC 2011, October 12-15, 2011, Kladovo, Serbia: Proceedings, Bor : Technical Faculty, 2011

Analyzing the corrosion characteristics of anodes used for the sulphur acidic waste water treatment

This paper addresses on investigation the possibility of electrolytic treatment the sulphur acidic waste solution, obtained in the conventional electrolytic copper refining process. The copper anodes with non-standard nickel, lead, tin and antimony content were specially prepared for the refining process. Nickel content of all anodes was approximately 7.5 mass %, and the content of lead, tin and antimony was varied. It was observed, that anodes with O2 content lower than 200 ppm, were not passivated. Results, obtained using the standard electrochemical techniques, have indicated that the anodes with non-standard chemical composition could be used under the same conditions as well as in the conventional copper refining process