Search results for "DEGRADATION"
showing 10 items of 1208 documents
Surface characterization of metal ions loaded TiO2 photocatalysts: structure-activity relationship
2004
Transition metal loaded TiO2 powders were characterised and tested for the photodegradation of some organic acids. Both Lewis and Brønsted surface acid sites were present in the samples containing large amounts of Mo, V and W. The Brønsted sites are associated to the presence of the transition metals as they do not exist in the unloaded support, and in particular to the presence of these metals in high oxidation states. The trend of the pzc values of the various powders matches rather well both with the surface acidity of the samples experimentally determined by NH3 adsorption and with a scale of acidity/basicity for bulk binary oxides. XPS investigation indicates that only the presence of …
Coating Evaporated MAPI Thin Films with Organic Molecules: Improved Stability at High Temperature and Implementation in High-Efficiency Solar Cells
2018
Methylammonium lead iodide (MAPI) has proven to be an exceptional light-absorber for single-junction thin-film solar cells. Nonetheless, degradation induced by environmental agents (air, moisture, heat) limits the stability of this hybrid perovskite. Here, we demonstrate that coating evaporated MAPI thin films with different hydrophobic molecules leads to a significant improvement in their stability. We especially investigated the degradation of MAPI and the subsequent formation of PbI2 at 150 °C by in situ XRD analysis and showed that this transformation is remarkably slowed down in films coated with trioctyl phosphine oxide and tridodecyl methylammonium iodide. This enhances the processab…
Self-cleaning antimicrobial surfaces by bio-enabled growth of SnO2 coatings on glass.
2013
Conventional vapor-deposition techniques for coatings require sophisticated equipment and/or high-temperature resistant substrates. Therefore bio-inspired techniques for the fabrication of inorganic coatings have been developed in recent years. Inspired by the biology behind the formation of the intricate skeletons of diatoms orchestrated by a class of cationic polyamines (silaffins) we have used surface-bound spermine, a naturally occurring polyamine, to promote the fast deposition of homogeneous, thin and transparent biomimetic SnO2 coatings on glass surfaces. The bio-enabled SnO2 film is highly photoactive, i.e. it generates superoxide radicals (O2˙(-)) upon sunlight exposure resulting i…
Assisted phytostabilization of soil from a former military area with mineral amendments.
2019
Abstract Due to the presence of toxic pollutants, soils in former military areas need remedial actions with environmentally friendly methods. Greenhouse experiments were conducted to investigate the aided phytostabilization of multi-heavy metals (HMs), i.e. Cd, Cr, Cu, Ni, Pb, Zn, in post-military soil by Festuca rubra and three mineral amendments (diatomite, dolomite and halloysite). The amendments were applied at 0 and 3.0% to each pot filled with 5 kg of polluted soil. After seven weeks of the phytostabilization, selected soil properties, biomass yield of F. rubra and immobilization of HMs by their accumulation in plant and redistribution among individual fractions in soil were determine…
Use of Biochar as Filler for Biocomposite Blown Films: Structure-Processing-Properties Relationships
2021
In this work, biocomposite blown films based on poly(butylene adipate-co-terephthalate) (PBAT) as biopolymeric matrix and biochar (BC) as filler were successfully fabricated. The materials were subjected to a film-blowing process after being compounded in a twin-screw extruder. The preliminary investigations conducted on melt-mixed PBAT/BC composites allowed PBAT/BC 5% and PBAT/BC 10% to be identified as the most appropriate formulations to be processed via film blowing. The blown films exhibited mechanical performances adequate for possible application as film for packaging, agricultural, and compost bags. The addition of BC led to an improvement of the elastic modulus, still maintaining h…
Comparative study of laboratory-scale thermophilic and mesophilic activated sludge processes.
2005
Laboratory-scale mesophilic (20-35 degrees C) and thermophilic (55 degrees C) activated sludge processes (ASPs) treating diluted molasses wastewater were compared in effluent quality, removal of different COD fractions, sludge yield, floc size, and sludge settleability. The effect of polyaluminium chloride (PAC) with high cationic charge on sludge settleability and effluent quality was also studied. In the ASPs, the hydraulic retention time was 12h in both processes, corresponding to a volumetric loading rate of 3.2+/-1.0 kg COD(filt) m(-3)d(-1). The mesophilic ASP gave 79+/-18% and 90+/-2% and the thermophilic ASP gave 50+/-6% and 67+/-11% total COD (COD(tot)) and GF/A-filtered COD (COD(fi…
Degradation of dimeric lignin model compounds by aerobic bacteria isolated from the hindgut of xylophagous termites.
1997
The capability of the intestinal flora from the gut of xylophagous termites of degrading lignin model compounds was investigated. Different dimeric lignin model compounds-degrading bacteria were obtained from the hindgut flora of Mastotermes darwiniensis FROGGATT, Reticulitermes santonensis FEYTAUD, Nasutitermes nigriceps HALDEMAN and Zootermopsis angusticollis HAGEN. In the presence of oxygen dimeric model compounds were degraded by all isolates. This indicates that the hindgut flora of termites is basically able to produce substrate for their host from aromatic extractives of wood.
Flow injection biamperometric determination of metronidazole with on-line photodegradation
1999
Abstract The determination of metronidazole is performed in a flow injection assembly, provided with a 40 W low pressure mercury lamp and a home-made biamperometric flow-cell furnished with two platinum electrodes polarized at 100 mV. The sample solution after being irradiated is inserted into a pure water stream. It then merges with an in situ mixed solution containing potassium iodide in sulphuric acid. The calibration graph was linear over the range 0.2–8.0 mg l −1 metronidazole; the 3 σ limit of detection was 0.008 mg l −1 ; the relative standard deviation was 0.6% (for 4 mg l −1 n = 13) and the sample throughput 50 h −1 . The influence of foreign compounds is slight and the method is …
Biohydrology research after Landau 2013 conference
2014
Biohydrology gives a new view on hydrological research. The impact of biota on hydrological processes was a disregarded topic in the early years of hydrology research. It has been present since the 1960s, but as a „Cinderella“ research topic. It emerged as a new aspect of the hydrological processes after the 1980s. In the 21st century, it has become a well established research topic, bringing new knowledge to aid understanding on how biota influence the hydrological cycle and the rates of hydrological processes. The importance of biohydrology research is growing, and the number of conferences, publications and research projects is being doubled every decade. The 4th Biohydrology conference,…
Land degradation a matter of attitude? A case study from southern Transylvania (Romania)
2016
A better public perception and knowledge on land degradation increases the individual and collective responsibility in land use and land management. Based on interviews, this paper presents results of evaluation of public perception and attitude towards degrading phenomena in the central part of Romania, an area prone to geomorphologic processes, with different land uses and a high proportion of degraded land. The research reveals natural causes, improper land use, categories of land owned, socio-economic causes and involvement of institutions as key aspects of public perception. Our research could be useful in the identification and design of measures in regional planning to attract popula…