Inorganic nanoparticles incorporation in polymer membranes for filtration processes has attracted the attention of researchers in order to improve in some ways their performance. In this work, AgNPs were synthesized "in situ" in cellulose acetate (CA) membrane by chemical reduction of a silver salt. The membranes were prepared by the nonsolvent induced phase inversion method. Asymmetric membranes without (CA-M) and with adsorbed AgNPs (CA-Ag-M) were obtained. Ultrafiltration properties were confirmed for both membranes (16 nm of average pore diameter) and average crystallite size of 21 nm for the adsorbed AgNPs was computed. Contact angle measured with Milli-Q water and dry CA-Ag-M is near zero while for the CA-M is around 80°. The CA-M showed water permeability of 214 Lh-1m-2, while the CA-Ag-M permeability was 1651 Lh-1m-2.

Poly(glycolide-co-lactide) (PLGA) nanospheres containing magnetic materials have been extensively studied because of its biomedical applications. Therefore, it is very important to know thermal properties of these materials in addition to other physical properties. Thermal degradation activation energy (Eα) of PLGA nanospheres with maghemite entrapment (PLGA-Mag), PLGA nanospheres (hollow spheres) (PLGA-H) obtained by an emulsion method and unprocessed PLGA (PLGA-R) were calculated by isoconversional Vyazovkin method based on data of TG analysis in order to evaluate modifications in thermal behavior caused by nanospheres obtainment process or by maghemite entrapment. Both hydrodynamic diameter in the range of 200-250 nm and polydispersity index lower than 0.3 are considered satisfactory. Thermal degradation of PLGA-R begins at higher temperatures than those of PLGA-H and PLGA-Mag, but processed samples presented increase in thermal stability, which was greater before processing by emulsion and in the presence of the magnetic materials. PLGA-Mag presents superparamagnetic behavior at room temperature.

New techniques for treating wastewater, particularly the removal or degradation of organic pollutants and heavy metals, among other pollutants, have been extensively studied. The use of nanostructured iron oxides as adsorbent and photocatalyst for the removal of these contaminants has proved a promising approach, not only because of their high treatment efficiency, but also for their cost-effectiveness, having the flexibility for in situ and ex situ applications. In this review, we briefly introduced the most used kinds of iron oxide nanoparticles, some synthesis techniques for iron oxide nanostructure formation, their potential benefits in environmental clean-up, and their recent advances and applications in wastewater treatment. These advances range from the direct applications of synthesized nanoparticles as adsorbents for removing toxic contaminants or as catalysts to oxidize and break down noxious contaminants (including bacteria and viruses) in wastewater, to integrating nanoparticles into conventional treatment technologies, such as composite photocatalytic filters (membranes, sand and ceramic) that combine separation technology with photocatalytic activity. Finally, the impact of nanoparticles on the environment and human health is briefly discussed.