ABSTRACT
New N-halamines (I-Cl and II-Cl) based on cellulose extracted from rice straw have been evaluated in single and multistage filtration systems against bacteria and viruses. Escherichia coli and Staphylococcus aureus were used as examples of Gram-negative and Gram-positive bacteria respectively while PRD1 bacteriophage was used as an example for viruses. II-Cl has achieved 9 log reductions in viable counts against E. coli in 2 h and S. aureus in 1h while it has achieved 7 log reductions against PRD1 in 5 h. The particle size of prepared materials was modified as well as the flow rate through the filtration systems. The antimicrobial activity of modified cellulose was proved to be comparable to some synthetic biocidal polymers from the same type in similar water treatment systems.
Subject(s)
Amines/chemistry , Amines/isolation & purification , Filtration/methods , Halogens/chemistry , Oryza/chemistry , Alginates/chemistry , Amines/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/isolation & purification , Antiviral Agents/pharmacology , Bacteria/drug effects , Calcium Chloride/chemistry , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Viruses/drug effects , Water/chemistryABSTRACT
The antimicrobial activity of a new cross-linked N-halamine polymer against bacteria and viruses was evaluated. The polymer achieved a 9-log(10) reduction of bacteria (both Escherichia coli and Staphylococcus aureus) in 1.5 h and a 5-log(10) reduction of bacteriophage PRD1 in 3 h. At the same time, the ability of the nonhalogenated polymer to trap halide ions was examined. The polymer was incorporated into a multifiltration system to study the ability to produce water free of bacteria, viruses, and halide ions. The antimicrobial activity, useful lifetime, halide ion level, and recycling possibilities of the system were quantified on a laboratory scale. A design for a large-scale multifiltration system based on this polymer is proposed.
Subject(s)
Amines/pharmacology , Bacteria/drug effects , Halogens/chemistry , Polymers/pharmacology , Viruses/drug effects , Water Purification/methods , Water Supply , Amines/chemistry , Bacteriophage PRD1/drug effects , Cross-Linking Reagents , Disinfection/methods , Escherichia coli/drug effects , Filtration/methods , Microbial Sensitivity Tests , Polymers/chemistry , Recycling/methods , Staphylococcus aureus/drug effectsABSTRACT
Organic-inorganic hybrid nanoparticles, derived from silica precursors with different organic functionalities (methyl, ethyl, vinyl, and phenyl) synthesized via a modified Stöber method have been investigated. These particles are intended as modifiers for polymers and polymer matrix composites. Therefore, the characteristics of a polyester matrix have also been determined, and the likely interactions with the particles have been proposed. Particles have been characterized using inverse gas chromatography (IGC), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (FT-IR). The particles show two different sets of characteristics, with methyl, ethyl, and vinyl modified silicas showing one type of behavior and the phenyl modified silica behaving rather differently. The methyl, ethyl, and vinyl groups exhibit the appearance of uniform coverage, as they are comparatively small and tightly packed, which will prevent interaction of matrix resin with retained silanol groups. The phenyl group, which is comparatively large, is not able to pack as closely, which results in a reduction of the presence and availability of silanol groups, compared to an unmodified fumed silica, but not complete inaccessibility as far as the matrix resin is concerned.
Subject(s)
Inorganic Chemicals/chemistry , Nanoparticles/chemistry , Organic Chemicals/chemistry , Polyesters/chemistry , Acids/chemistry , Chromatography, Gas , Hydrogen-Ion Concentration , Spectrum Analysis , Surface Properties , Temperature , X-RaysABSTRACT
Organically modified silica (ormosil) particles were prepared using hydrolytic sol-gel methods and the miniemulsion polymerisation approach. Methyl-, ethyl-, and phenylsilsesquioxane nanoparticles with diameters in the range 50-180 nm were obtained using the modified Stöber method with an aqueous sodium silicate solution used as a seed for further growth of the particles. Methyl- and phenylsilsesquioxane particles were prepared by a sol-gel method in the presence of benzethonium chloride used as a surfactant. The miniemulsion polymerisation approach has been extended to the production of methacrylate-modified silica nanoparticles with vinylpyridine or lauryl methacrylate used as comonomers both in the presence and in the absence of a surfactant. Styryl-modified silica particles with diameters in the range 300-800 nm were obtained by the Stöber method using pre-formed SiO2 nanoparticles as the seeds for silsesquioxane nanoparticle formation. The effect of incorporation of the particles produced using different synthetic methods on hardness and water resistance of acrylic coating systems was studied here.
