Screening of Microorganisms for Biodegradation of Simazine Pollution (Obsolete Pesticide Azotop 50 WP)

The capability of environmental microorganisms to biodegrade simazine—an active substance of 2-chloro-s-triazine herbicides (pesticide waste since 2007)—was assessed. An enormous metabolic potential of microorganisms impels to explore the possibilities of using them as an alternative way for thermal and chemical methods of utilization. First, the biotope rich in microorganisms resistant to simazine was examined. Only the higher dose of simazine (100 mg/l) had an actual influence on quantity of bacteria and environmental fungi incubated on substrate with simazine. Most simazine-resistant bacteria populated activated sludge and biohumus (vermicompost); the biggest strain of resistant fungi was found in floral soil and risosphere soil of maize. Compost and biohumus were the sources of microorganisms which biodegraded simazine, though either of them was the dominant considering the quantity of simazine-resistant microorganisms. In both cases of periodic culture (microorganisms from biohumus and compost), nearly 100% of simazine (50 mg/l) was degraded (within 8 days). After the repeated enrichment culture with simazine, the rate of its degradation highly accelerated, and just after 24 h, the significant decrease of simazine (20% in compost and 80% in biohumus) was noted. Although a dozen attempts of isolating various strains responsible for biodegradation of simazine from compost and biohumus were performed, only the strain identified as Arthrobacter urefaciens (NC) was obtained, and it biodegraded simazine with almost 100% efficiency (within 4 days)

Removal of Ni²⁺ from Aqueous Solutions by Adsorption Onto Magnetic Multiwalled Carbon Nanotube Nanocomposite

The removal of Ni2+ from aqueous solution by magnetic multiwalled carbon nanotube nanocomposite (MMWCNTs-C) was investigated. MMWCNTs-C was characterized by X-ray Diffraction method (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), surface area (BET), and Fourier Transform-Infrared Spectroscopy (FTIR). The effects of initial concentration, contact time, solution pH, and temperature on the Ni2+ adsorption onto MMWCNTs-C were studied. The Langmuir and Freundlich isotherm models were applied to fit the adsorption data. The results showed that the adsorption isotherm data were fitted well to the Langmuir isotherm model with the maximum monolayer adsorption capacity of 2.11 mg g–1. The adsorption kinetics was best described by the pseudo-second-order model. The thermodynamic parameters, such as ΔHo, ΔGo and ΔSo, were also determined and evaluated. The adsorption of Ni2+ is generally spontaneous and thermodynamically favorable. The values of ΔHo and ΔGo indicate that the adsorption of Ni2+ onto MMWCNTs-C was a physisorption process

Poliakrylanowe kleje samoprzylepne modyfikowane nanocząstkami srebra

Acrylic pressure-sensitive adhesives (PSA) are generally considered as non electrical conductive materials. The electrical conductivity is also incorporated into acrylic polymer after adding of electrical conductive additives like silver nanoparticles. After addition of electrical conductive silver nanofiller, the main and typical properties of pressure-sensitive adhesives such as tack, adhesion and cohesion are deteriorated. This study is the first trial which reveals that the acrylic self-adhesive basis must be synthesised with ameliorated initial performances like high tack and excellent adhesion. Currently, the electrical conductive solvent-borne acrylic PSA containing silver nanoparticles are not commercially available on the market. They are promising materials which can be applied for the manufacturing of diverse technical or medical high performance self-adhesive products, such as broadest line of special electrically conductive sensitive tapes.Poliakrylanowe kleje samoprzylepne są generalnie uważane za materiały nie przewodzące prądu elektrycznego. Przewodnictwo elektryczne można osiągnąć poprzez dodatek do kleju samoprzylepnego przewodzących prąd elektryczny nanocząstek srebra. Po dodaniu napełniacza nieorganicznego przewodzącego prąd elektryczny typowe właściwości klejów samoprzylepnych, takie jak tack (lepność) oraz adhezja ulegają pogorszeniu. Niniejsza praca przedstawia konieczność stosowania jako matrycy polimerowej modyfikowanych klejów samoprzylepnych o dużej lepności oraz dużej adhezji przed dodatkiem przewodzącego prąd elektryczny napełniacza. Obecnie w sprzedaży nie spotyka się komercyjnych klejów samoprzylepnych przewodzących prąd elektryczny. Otrzymane w wyniku badań poliakrylanowe kleje samoprzylepne przewodzące prąd elektryczny mogą być stosowane do wytwarzania wysokowartościowych materiałów samoprzylepnych, zarówno natury technicznej jak i do zastosowań medycznych