Improving the biocidal activity of outdoor coating formulations by using zeolite-supported silver nanoparticles.

Zeolite/nanoparticle composites are synthesized and used as additive for waterborne formulations in replacement of traditional isothiazolinone-based biocides. Silver nanoparticles dispersed onto micrometer-sized crystals of A-type zeolite were prepared by thermal treatment or chemical reduction methods applied to the Ag-exchanged zeolite. The antifungal efficiency against Trichoderma sp.

Chromium removal by zeolite-rich materials obtained from an exhausted FCC catalyst: Influence of chromium incorporation on the sorbent structure.

A spent FCC catalyst was converted into a zeolitic mixture, and the product obtained was afterward used as trapping material for Cr(III) species frequently found in aqueous solutions. Eventual changes in the sorbent structure produced by Cr incorporation were studied by different characterization techniques such as point of zero charge determinations (PZC), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and infrared absorption (FTIR). The XRD and FTIR analyses indicated that chromium incorporation produces an amorphization of the material, and PZC measurements show no surface adsorption of charged chromium species.

Modified silica matrices for controlled release of cephalexin.

SBA-15 type ordered silicas possessing amino groups attached onto their surfaces were prepared by using two different functionalization methodologies. These matrices were used for the cephalexin adsorption from aqueous solution and further kinetic study of its release into physiological solution. The materials were characterized by nitrogen adsorption/ desorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-Ray photoelectron spectrometry (XPS) and thermo analytical methods (TG/DSC).

Chromium removal from water using LTA zeolites: effect of pH.

The effect of pH changes on the ability of the synthetic zeolite NaA to remove Cr(3+) from water by ion exchange was investigated. The exchange rate was improved by working near neutrality. Despite of the occurrence of simultaneous adsorption, precipitation or cation exchange phenomena, spectroscopic analyses of samples taken at different contact times suggested the presence of an unique chromium environment in the solid phase.