Blend Beads Research Articles

Controlled release of insecticide carbaryl from sodium alginate, sodium alginate/gelatin, and sodium alginate/sodium carboxymethyl cellulose blend beads crosslinked with glutaraldehyde

AbstractInterpenetrating network polymeric beads of sodium alginate (NaAlg) and its blend with gelatin (gels) or sodium carboxymethyl cellulose (NaCMC) have been prepared by crosslinking with a common crosslinking agent, glutaraldehyde (GA), for the release of insecticide carbaryl (Carb). The prepared beads were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Scanning electron microscopy confirmed the spherical nature and surface morphology of the particles. Bead characteristics, such as carbaryl entrapment efficiency, particle size, equilibrium swelling degree, and carbaryl release kinetics, were determined. The effects of the preparation conditions, such as Carb/NaAlg ratio, time of exposure to GA, blend ratio, and temperature of release medium on the carbaryl release, were investigated for 25 days at 25°C. It was observed that the carbaryl release decreased with increase in crosslinking of network, while it increased with increase in Carb/NaAlg ratio and temperature. The release of carbaryl also increased with increase in Gel or NaCMC content in the blend beads. The highest carbaryl release was found to be 100%, for the beads that were prepared with 1 : 1 NaAlg/Gel at 16 days. The diffusion coefficients have been calculated for the transport of insecticide through the polymeric beads, using initial time approximation method. These values were also consistent with the carbaryl release data. The carbaryl release from most of the bead formulations followed the Fickian trend. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1310–1319, 2006

Preparation and sorption activity of chitosan/cellulose blend beads

Chitosan microspheres prepared by spray-drying process have a spherical geometry and a smooth surface morphology. These microspheres are found to have a particle size below 3 μm and dissolve readily in N-Methylmorpholine- N-oxide (NMMO). A novel natural polymer chitosan/cellulose blend beads were prepared via homogeneous dissolution of chitosan and cellulose in NMMO. The SEM micrographs of chitosan/cellulose blend beads show that a rough and folded surface morphology and an interior pore structure of beads were obtained. Deodorizing properties of these beads against trimethylamine (TMA) was investigated. We also examined the metal ion sorption properties against Cu(II), Fe(III) and Ni(II) ions. From the sorption activity studies of chitosan/cellulose blend beads that show the chitosan/cellulose blend beads have potential applications for odor treatment as well as metal ions adsorption.

Bacterial characterization of calcium alginate gel immobilized activated sludges biodegrading 2‐chlorophenol or benzene

Abstract Activated sludges before and after acclimation in the laboratory with phenol and 2‐chlorophenol or a mixture of benzene, toluene, and o‐, m‐, and p‐xylene, were immobilized in calcium alginate gel. Before acclimation, after acclimation, and at the end of 2‐chlorophenol or benzene biodegradation studies, dilutions of blended gel beads were plated and all distinct colony types were isolated. A total of 54 isolates were obtained, 23 of which tentatively could be assigned to Bacillus [1], Pseudomonas [2], or Klebsiella [3]. Shaker flask studies with individual isolates and their mixture indicated that the primary degrader of 2‐chlorophenol among the isolates was a Bacillus, and that of benzene was a Pseudomonas.