Magnetic Field Effects on Redox Potential of Reduction and Oxidation Agents

Redox potentials of two reducing (sodium dithionite and glucose) and two oxidizing (hydrogen peroxide and sodium hypochlorite) agents were monitored at various concentrations and at different temperatures for 30–75 minutes after the exposure of their water solutions (glucose and hypochlorite solutions once; sodium dithionite and hydrogen peroxide solutions one, two and/or three-times) to the static magnetic field of flux density of 0.9 V s m–2. The aim of the investigation was to suggest improvements, i.e., intensification and stability, of the reduction-oxidation ability of selected agents applicable in textile fibre processing, primarily bleaching and vat dyeing. Results of the experiments show that magnetic treatment (of solutions) raises both the reducing ability of glucose and the oxidation ability of hydrogen peroxide and sodium hypochlorite, promising some technological and economical benefits for the textile industry as well as for other fields of chemistry

The Study of Release of Chlorhexidine from Preparations with Modified Thermosensitive Poly-N-isopropylacrylamide Microspheres

The aim of this study was to investigate and compare the release rates of chlorhexidine (CX) base entrapped in the polymeric beads of modified poly-N-isopropylacrylamides (pNIPAMs) at temperatures below and over the volume phase transition temperature (VPTT) of synthesized polymers: pNIPAM-A with terminal anionic groups resulting from potassium persulfate initiator, pNIPAM-B with cationic amidine terminal groups, and pNIPAM-C comprising anionic terminals, but with increased hydrophobicity maintained by the N-tert-butyl functional groups. The preparations, assessed in vitro below the VPTT, release an initial burst of CX at different time periods between 120 and 240 min, followed by a period of 24 h, when the rate of release remains approximately constant, approaching the zero-order kinetics; the release rates for the polymers beads are as follows: pNIPAM-C>pNIPAM-B>pNIPAM-A. The pattern of release rates at temperature over the VPTT is as follows: pNIPAM-C>pNIPAM-A>pNIPAM-B. In the presence of pNIPAM-C, the duration between the start of the release and the attained minimal inhibitory concentration (MIC) for most of the microbes, in conditions over the VPTT, increased from 60 to 90 min. The release prolongation could be ascribed to some interactions between the practically insoluble CX particle and the hydrophobic functional groups of the polymer

Učinak statičkog magnetskog polja male gustoće na oksidaciju amonijaka s pomoću bakterije Nitrosomonas europaea i aktivnog mulja u komunalnim otpadnim vodama

Ammonium removal is a key step in biological wastewater treatment and novel approaches that improve this process are in great demand. The aim of this study is to test the hypothesis that ammonium removal from wastewater can be stimulated by static magnetic fields. This was achieved by analysis of the eff ects of static magnetic field (SMF) on the growth and activity of Nitrosomonas europaea, a key ammonia-oxidising bacterium, where increased growth and increased ammonia oxidation rate were detected when bacteria were exposed to SMF at 17 mT. Additionally, the eff ect of SMF on mixed cultures of ammonia oxidisers in activated sludge, incubated in sequencing batch bioreactors simulating wastewater treatment process, was assessed. SMFs of 30 and 50 mT, but not of 10 mT, increased ammonium oxidation rate in municipal wastewater by up to 77 % and stimulated ammonia oxidiser growth. The results demonstrate the potential for use of static magnetic fields in increasing ammonium removal rates in biological wastewater treatment plants.Uklanjanje amonijaka je ključni korak u biološkom pročišćavanju otpadnih voda. Potražnja za novim pristupom koji bi poboljšao ovaj proces sve je veća. Svrha je našeg istraživanja bila provjeriti pretpostavku da se uklanjanje amonijaka iz otpadnih voda može stimulirati pomoću statičkog magnetskog polja. Ispitan je učinak statičkog magnetskog polja na rast i aktivnost nitrificirajuće bakterije Nitrosomonas europaea, koja oksidira amonijak u biološkom procesu pročišćavanja otpadnih voda. Otkriveno je da se izlaganjem te bakterije statičkom magnetskom polju jačine 17 mT ubrzao rast bakterija i pospješila oksidacija amonijaka. Osim toga, izmjeren je učinak statičkog magnetskog polja na amonijak-oksidirajuće bakterije koje se nalaze u aktivnom mulju izdvojenom iz postrojenja za pročišćavanje otpadnih voda. Aktivni mulj je inkubiran u sekvencijalnim šaržnim reaktorima, koji simuliraju proces pročišćavanja otpadnih voda. Primjena statičkog magnetskog polja jačine 30 i 50 mT, no ne i 10 mT, pojačala je oksidaciju amonijaka u komunalnim otpadnim vodama do 77 %, te stimulirala rast amonijak-oksidirajućih bakterija. Rezultati istraživanja pokazuju da se pomoću statičkog magnetskog polja može povećati stupanj uklanjanja amonijaka u postrojenjima za biološko pročišćavanje otpadnih voda

Utjecaj magnetskog polja na redoks potencijal redukcijskih i oksidacijskih spojeva

Redox potentials of two reducing (sodium dithionite and glucose) and two oxidizing (hydrogen peroxide and sodium hypochlorite) agents were monitored at various concentrations and at different temperatures for 30-75 minutes after the exposure of their water solutions (glucose and hypochlorite solutions oncesodium dithionite and hydrogen peroxide solutions one, two and/or three-times) to the static magnetic field of flux density of 0.9 V s M-2 . The aim of the investigation was to suggest improvements, i.e., intensification and stability, of the reduction-oxidation ability of selected agents applicable in textile fibre processing, primarily bleaching and vat dyeing. Results of the experiments show that magnetic treatment (of solutions) raises both the reducing ability of glucose and the oxidation ability of hydrogen peroxide and sodium hypochlorite, promising some technological and economical benefits for the textile industry as well as forother fields of chemistry.Redoks potencijali vodenih otopina dvaju redukcijskih (natrijev ditionat i glukoza) i dvaju oksidacijskih (vodikov peroksid i natrijev hipoklorit) spojeva mjereni su pri različitim koncentracijama i različitim temperaturama 30–75 minuta poslije izlaganja otopina statičnom magnetskom polju gustoće toka 0,9 V s m–2. Otopine su polju izlagane ili samo jednom (glukoza i natrijev hipoklorit) ili jednom, dvaput i triput (natrijev ditionat i vodikov peroksid). Cilj je istraživanja predložiti poboljšanje redukcijske, odnosno oksidacijske sposobnosti odabranih spojeva koji se koriste u obradi tekstilnih vlakana, prvenstveno za izbjeljivanje i bojenje. Rezultati eksperimenata pokazuju da se magnetskom obradom otopina povećavaju redukcijska sposobnost glukoze i oksidacijska sposobnost vodikova peroksida i natrijeva hipoklorita, što bi moglo biti tehnološki i ekonomski korisno tekstilnoj industriji, a zanimljivo ostalim granama kemije