Nanomaterials in the environment applications and effects

The catalytic performance of nickel loaded zeolite materials was found to be dependent on their acidic feature that influenced metal speciation and its dispersion. The selectivity to ethane and ethane of the Ni loaded catalysts increased when reducing both the number of acid sites and average nickel particle size in zeolite catalysts.

Chromate is a pollutant often found in groundwater and considered a serious threat for humans and ecosystem. Iron nanoparticles produced by green tea polyphenols (GT-nZVI) is a powerful reductant, appropriate for the reduction of Cr(VI) to Cr(III). GT-nZVI suspension was initially conceived ideal for direct injection in the contaminated aquifers. However, many studies demonstrated that this suspension presents very low mobility in calcareous aquifers, which are typical in Mediterrannean countries. An alternative mode of GT-nZVI application is the incorporation of nanoiron in a permeable reactive barrier. This option was evaluated experimentally, assuming that the permeable barrier is filled with a calcareous soil previously loaded with nZVI. Namely an amount of soil was loaded with 0.40 mmol of nZVI per gram of soil (S-nZVI) and its efficiency for Cr(VI) removal was evaluated by conducting batch and column tests. Batch tests were carried out by mixing S-nZVI with contaminated groundwater (GW) containing 1300 μg/L Cr(VI), at five doses from 5 to 50 grams of S-nZVI per liter of GW. Chromate concentration dropped below detection limit within 1 day at the highest dose. Reduction kinetics was slower with the other doses but after 20 days Cr(VI) dropped below the limit of 50 ppb at all doses except the lowest. Column tests confirmed the effectiveness of S-nZVI.

In this study structured photocatalytic systems were successfully developed by a facile method. Polymeric (Alginate) molds, settled the basis in order to effectively disperse and stabilize nanoparticles of an efficient, copper augmented photocatalyst (Degussa P25), which after removal of the polymer by a pyrolytic or calcination-sintering procedure, were shaped in the form of all-ceramic hollow fibers (HFs) with enhanced photocatalytic and mechanical properties and excellent resistance to attrition. The structural and morphological properties have been studied using LN2 porosimetry, XRD, SEM and Raman spectroscopy. The experimental campaign for elucidating the photocatalytic performance encompassed batch experiments, where the abatement of a prototype organic pollutant (Methyl Orange) was investigated in the dark and under UV irradiation. The obtained performance was benchmarked against that of a prototype photocatalyst implemented in slurry or thin film reactors. The role and the contribution of zero-valent Cu nanoparticles in the photocatalytic mechanism, as well as of carbon residues from the pyrolytic procedure, were also examined.

This study was evaluated for the potential use of nanosilver (nAg) as a disinfectant and antimicrobial growth promoter supplement for the poultry. The experiments were conducted in the Kangsabati river basin region, in West Medinipur district, West Bengal, India for six months. Two poultry farms were adopted for the experiment. The rural economy of this region from Jhargram to Barkola is heavily dependent on contract poultry farming. The water samples were collected from the water source of poultry farm which has been used for poultry drinking purpose. The bacteriological analysis of water sample revealed that the total bacterial count (total coliform and E. coli) were higher than the acceptable standards. The bacterial loads badly affected the growth performance and health of the poultry. For disinfection, a number of chemical compounds (like formaldehyde, calcium hypochloride, sodium hypochloride, and sodium bicarbonate) have been used in typical commercial formulations. However, the effects of all these chemical compounds have not been significant over time. As a part of our research-to-market initiative, we used nanosilver (nAg) formulation as a disinfectant. The nAg formulation was synthesized by hydrothermal technique and characterized by UV-visible, TEM, SEM, and EDX. The obtained results revealed that the mortality rate of poultry was reduced due to nAg formulation compared to the mortality rate of the negative control.

In the present study, the photocatalytic degradation of methylene blue (MB), using TiO2-Ag synthesized by sol-gel method, as a catalyst under UV light, was studied. Tests were carried out in a batch reactor, magnetically stirred, with external irradiation using an UV-B. The effects of some parameters, such as catalyst dosage and initial acetone concentration were investigated. Results showed that the optimal catalyst concentration was 0.03 g/L, at a concentration of MB of 1.25∙10-5 mol/L. The results are very promising using TiO2-Ag as photocatalyst, especially in the presence of acetone as photosensitizer; the degradation degree increases from 60% for raw TiO2, to 92.38% for TiO2-Ag and 0.1% acetone and respectively, 97.25% for 0.2% acetone. The photocatalysis followed a pseudo-first order reaction kinetics, with rate constants ranging from 0.0009 to 0.11 min-1 under the studied conditions.