Fate of pharmaceuticals--photodegradation by simulated solar UV-light

The fate of pharmaceuticals in surface waters under solar irradiation was investigated. Photodegradation of pharmaceuticals caused by sun irradiation may be of major significance in the natural elimination process. Based on a data compilation from the literature, the lipid lowering agent metabolite clofibric acid, the iodinated X-ray contrast media iomeprol, which contribute to the adsorbable organic halogen compounds, and the antiepileptic drug carbamazepine were selected. The irradiation experiments were carried out in batch experiments with simulated UV–sunlight. The photodegradation of the pharmaceuticals showed a pseudo-first-order kinetics. The objective of this investigation was to demonstrate that the extent of photoinduced degradation of pharmaceuticals can vary significantly for the different pharmaceuticals and it strongly depends on the water constituents present in solution. The influences of different initial pharmaceutical concentrations, the presence of other pharmaceuticals like carbamazepine or clofibric acid and the presence of natural organic matter on the photochemical degradation rate of pharmaceuticals in aqueous solutions were investigated. Analyses of the pharmaceuticals and their photodegradation products were carried out by high performance liquid chromatography with diode-array and fluorescence detection.     

From first generation biofuels to advanced solar biofuels

Roadmaps towards sustainable bioeconomy, including the production of biofuels, in many EU countries mostly rely on biomass use. However, although biomass is renewable, the efficiency of biomass production is too low to be able to fully replace the fossil fuels. The use of land for fuel production also introduces ethical problems in increasing the food price. Harvesting solar energy by the photosynthetic machinery of plants and autotrophic microorganisms is the basis for all biomass production. This paper describes current challenges and possibilities to sustainably increase the biomass production and highlights future technologies to further enhance biofuel production directly from sunlight. The biggest scientific breakthroughs are expected to rely on a new technology called “synthetic biology”, which makes engineering of biological systems possible. It will enable direct conversion of solar energy to a fuel from inexhaustible raw materials: sun light, water and CO₂. In the future, such solar biofuels are expected to be produced in engineered photosynthetic microorganisms or in completely synthetic living factories.     

Degradation of atrazine using solar driven fenton-like advanced oxidation processes

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was degraded using cobalt-peroximonosulfate (Co/PMS) advanced oxidation process (AOP). Three Co concentrations (0.00, 0.25 and 0.50 mM) and five peroximonosulfate (PMS) concentrations (0, 5, 8, 16 and 32 mM) were tested. Maximum degradation reached was 88% using dark Co/PMS in 126 minutes when 0.25 mM of cobalt and 32 mM of PMS were used. Complete atrazine degradation was achieved when the samples were irradiated by the sun under the same experimental conditions described. Tests for identification of intermediate products allowed identification and quantification of deethylatrazine in both dark and radiated conditions. Kinetic data for both processes was calculated fitting a pseudo-first order reaction rate approach to the experimental data. Having kinetic parameters enabled comparison between both conditions. It was found that the kinetic approach describes data behavior appropriately (R2 > or = 0.95). Pseudo-kinetic constants determined for both Co/PMS processes, show k value of 10(-4) for Co/PMS and a k value of 10(-3) for Co/PMS/ultraviolet (UV). This means, that, with the same Co/PMS concentrations, UV light increases the reaction rate by around one order of magnitude than performing the reaction under dark conditions.     

Degradation of atrazine using solar driven fenton-like advanced oxidation processes

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was degraded using cobalt-peroximonosulfate (Co/PMS) advanced oxidation process (AOP). Three Co concentrations (0.00, 0.25 and 0.50 mM) and five peroximonosulfate (PMS) concentrations (0, 5, 8, 16 and 32 mM) were tested. Maximum degradation reached was 88% using dark Co/PMS in 126 minutes when 0.25 mM of cobalt and 32 mM of PMS were used. Complete atrazine degradation was achieved when the samples were irradiated by the sun under the same experimental conditions described. Tests for identification of intermediate products allowed identification and quantification of deethylatrazine in both dark and radiated conditions. Kinetic data for both processes was calculated fitting a pseudo-first order reaction rate approach to the experimental data. Having kinetic parameters enabled comparison between both conditions. It was found that the kinetic approach describes data behavior appropriately (R² ≥ 0.95). Pseudo-kinetic constants determined for both Co/PMS processes, show k value of 10^?4 for Co/PMS and a k value of 10^?3 for Co/PMS/ultraviolet (UV). This means, that, with the same Co/PMS concentrations, UV light increases the reaction rate by around one order of magnitude than performing the reaction under dark conditions.     

Performance improvement and advancement studies of mixed-mode solar thermal dryers: a review

Solar thermal dryers are solar-operated gadgets utilized to dehumidify various products, especially food items and rubber sheets. This article provides detailed design, parametric studies, and an in-depth review of mixed-mode solar dryers (MMSD) with a case study of fish drying near coastal lines. Due to several advantages compared to open sun drying and prominent performance index compared to indirect and direct type solar dryers, mixed-mode solar dryers have large adaptability on the field. Moreover, mixed-mode solar thermal dryers with different augmentations are reviewed, for instance, mixed-mode solar dryers with evacuated tube collectors, phase change materials, ultraviolet rays stabilized housing, and dehumidifiers. The case study of fish drying near the coastal line of Gujarat, India has been carried out to study the present scenario of the drying activities. Hence, the objective of this review is to identify the capable mixed-mode solar dryer with heat recovery systems. Substantial reviews within the article suggest an essential need to implement the hybrid mixed-mode solar dryer cum distiller technology for small-scale enterprises that can simultaneously provide potable water near coastal lines along with drying of fishes from the solar dryer. Furthermore, future research demands such hybrid mixed-mode solar drying systems that strongly fulfill the requirements of local communities near coastal lines involved in fish drying activities.

     

Effects of soiling and cleaning on the reflectance and solar heat gain of a light-colored roofing membrane

A roof with high solar reflectance and high thermal emittance (e.g., a white roof) stays cool in the sun, reducing cooling power demand in a conditioned building and increasing summertime comfort in an unconditioned building. The high initial solar reflectance of a white membrane roof (circa 0.8) can be lowered by deposition of soot, dust, and/or biomass (e.g., fungi or algae) to about 0.6; degraded solar reflectances range from 0.3 to 0.8, depending on exposure. We investigate the effects of soiling and cleaning on the solar spectral reflectances and solar absorptances of 15 initially white or light-gray polyvinyl chloride membrane samples taken from roofs across the United States. Black carbon and organic carbon were the two identifiable strongly absorbing contaminants on the membranes. Wiping was effective at removing black carbon, and less so at removing organic carbon. Rinsing and/or washing removed nearly all of the remaining soil layer, with the exception of (a) thin layers of organic carbon and (b) isolated dark spots of biomass. Bleach was required to clear these last two features. At the most soiled location on each membrane, the ratio of solar reflectance to unsoiled solar reflectance (a measure of cleanliness) ranged from 0.41 to 0.89 for the soiled samples; 0.53 to 0.95 for the wiped samples; 0.74 to 0.98 for the rinsed samples; 0.79 to 1.00 for the washed samples; and 0.94 to 1.02 for the bleached samples. However, the influences of membrane soiling and cleaning on roof heat gain are better gauged by fractional variations in solar absorptance. Solar absorptance ratios (indicating solar heat gain relative to that of an unsoiled membrane) ranged from 1.4 to 3.5 for the soiled samples; 1.1 to 3.1 for the wiped samples; 1.0 to 2.0 for the rinsed samples; 1.0 to 1.9 for the washed samples; and 0.9 to 1.3 for the bleached samples.     

Aqueous photolysis of the iron (III) complexes of NTA, EDTA and DTPA

The rate of photolysis of iron complexes with three common complexing agents, NTA, EDTA and DTPA was analysed. Aqueous solutions of each complex were illuminated in a Xenotest 1200. Using a sun spectrum from 60°N (Stockholm latitude), environmentally related half lifetimes were calculated.

The half lifetimes were 43, 11 and 8 min for the three 1:1 complexes, resp., dissolved in the top layer of a water system and illuminated at the yearly maximum of sun light in the specified area. In the environment several factors operate to reduce this rate. However, photolytic degradation pathways seem to be an important environmental fate of these substances.     

California black oak response to nitrogen amendment at a high O3, nitrogen-saturated site

In a nitrogen (N) saturated forest downwind from Los Angeles, California, the cumulative response to long-term background-N and N-amendment on black oak (Quercus kelloggii) was described in a below-average and average precipitation year. Monthly measurements of leaf and branch growth, gas exchange, and canopy health attributes were conducted. The effects of both pollutant exposure and drought stress were complex due to whole tree and leaf level responses, and shade versus full sun leaf responses. N-amended trees had lower late summer carbon (C) gain and greater foliar chlorosis in the drought year. Leaf water use efficiency was lower in N-amended trees in midsummer of the average precipitation year, and there was evidence of poor stomatal control in full sun. In shade, N-amendment enhanced stomatal control. Small differences in instantaneous C uptake in full sun, lower foliar respiration, and greater C gain in low light contributed to the greater aboveground growth observed.     

Field evaluation of digital optical method to quantify the visual opacity of plumes

Visual Determination of the Opacity of Emissions from Stationary Sources (Method 9) is a reference method established by U.S. Environmental Protection Agency (EPA) to quantify plume opacity. However, Method 9 relies on observations from humans, which introduces subjectivity. In addition, it is expensive to teach and certify personnel to evaluate plume opacity on a semiannual basis. In this study, field tests were completed during a "smoke school" and a 4-month monitoring program of plumes emitted from stationary sources with a Method 9 qualified observer to evaluate the use of digital photography and two computer algorithms as an alternative to Method 9. This Digital Optical Method (DOM) improves objectivity, costs less to implement than Method 9, and provides archival photographic records of the plumes. Results from "smoke school" tests indicate that DOM passed six of eight tests when the sun was located in the 140 degrees sector behind one of the three cameras, with the individual opacity errors of 15% or less and average opacity errors of 7.5% or less. DOM also passed seven of the eight tests when the sun was located in the 216 degrees sector behind another camera. However, DOM passed only one of the eight tests when the sun was located in the 116 degrees sector in front of the third camera. Certification to read plume opacity by a "smoke reader" for 6 months requires that the "smoke reader" pass one of the smoke school tests during smoke school. The average opacity errors and percentage of observations with individual opacity errors above 15% for the results obtained with DOM were lower than those obtained by the smoke school trainees with the sun was located behind the camera, whereas they were higher than the smoke school trainee results with the sun located in front of the camera. In addition, the difference between plume opacity values obtained by DOM and a Method 9 qualified observer, as measured in the field for two industrial sources, were 2.2%. These encouraging results demonstrate that DOM is able to meet Method 9 requirements under a wide variety of field conditions and, therefore, has potential to be used as an alternative to Method 9.     

Characteristics of columnar aerosol optical and microphysical properties retrieved from the sun photometer and its impact on radiative forcing over Skukuza (South Africa) during 1999–2010

Environmental Science and Pollution Research - The detailed analysis of columnar optical and microphysical properties of aerosols obtained from the AErosol RObotic NETwork (AERONET) Cimel sun...     

Review of cooling techniques used to enhance the efficiency of photovoltaic power systems

Environmental Science and Pollution Research - Photovoltaic (PV) panels are one of the most important solar energy sources used to convert the sun’s radiation falling on them into electrical...     

Sun light degradation of 4-chloroaniline in waters and its effect on toxicity. A high performance liquid chromatography - Diode array - Tandem mass spectrometry study

This paper studies the degradation reactions that 4-chloroaniline can naturally undergo in waters for the action of sun light. 10.00 mg L⁻¹ 4-chloroaniline aqueous solution, without any addition of organic solvent, are undergone to photoirradiation under conditions that simulate sun light. The degradation pathway, followed by HPLC-DAD-MS/MS methods, is complex since the pollutant gives rise to many photoproducts: the predominant species are characterized by m/z values of 217 (P5) and 218 (P6) and are compatible with dimeric structures of 4-chloroaniline. Vibrio fischeri tests indicate that the photoproducts of 4-chloroaniline are characterized by a toxicity level significantly greater than the precursor.     

Responses of hybrid poplar clones and red maple seedlings to ambient O(3) under differing light within a mixed hardwood forest

The responses of ramets of hybrid poplar (Populus spp.) (HP) clones NE388 and NE359, and seedlings of red maple (Acer rubrum, L.) to ambient ozone (O(3)) were studied during May-September of 2000 and 2001 under natural forest conditions and differing natural sunlight exposures (sun, partial shade and full shade). Ambient O(3) concentrations at the study site reached hourly peaks of 109 and 98 ppb in 2000 and 2001, respectively. Monthly 12-h average O(3) concentrations ranged from 32.3 to 52.9 ppb. Weekly 12-h average photosynthetically active radiation (PAR) within the sun, partial shade and full shade plots ranged from 200 to 750, 50 to 180, and 25 to 75 micromol m(-2) s(-1), respectively. Ambient O(3) exposure induced visible foliar symptoms on HP NE388 and NE359 in both growing seasons, with more severe injury observed on NE388 than on NE359. Slight foliar symptoms were observed on red maple seedlings during the 2001 growing season. Percentage of total leaf area affected (%LAA) was positively correlated with cumulative O(3) exposures. More severe foliar injury was observed on plants grown within the full shade and partial shade plots than those observed on plants grown within the sun plot. Lower light availability within the partial shade and full shade plots significantly decreased net photosynthetic rate (Pn) and stomatal conductance (g(wv)). The reductions in Pn were greater than reductions in g(wv), which resulted in greater O(3) uptake per unit Pn in plants grown within the partial shade and full shade plots. Greater O(3) uptake per unit Pn was consistently associated with more severe visible foliar injury in all species and/or clones regardless of differences in shade tolerance. These studies suggest that plant physiological responses to O(3) exposure are likely complicated due to multiple factors under natural forest conditions.     

Seasonal ozone response of mature beech trees (Fagus sylvatica) at high altitude in the Bavarian forest (Germany) in comparison with young beech grown in the field and in phytotrons

Mature beech trees (Fagus sylvatica) grown at two different altitudes in the Bavarian forest were compared with young beech trees grown at nearby field sites or in phytotrons for their macroscopic and physiological responses to different ozone (O(3)) exposures. Cumulative O(3) exposure expressed as the sum of hourly mean concentrations above the canopy ranged between 100 and 150 microl l(-1) h, with the vertical O(3) profiles at the higher altitude site being enhanced by 30%. O(3) profiles at all sites were reduced by up to 20% with increasing depth within and beneath the canopy. The leaf discoloration that developed in the absence of premature leaf loss was similar in the sun foliage of mature and young trees (including plant grown in the phytotron). Injury became apparent at low O(3) exposures, expressed as accumulated hourly means over a threshold of 40 nl l(-1) (AOT40 <3.5 microl l(-1) h) at the lower site in both the mature trees and the young beech at the field site, but only occurred when AOT40 values reached 7 microl l(-1) h at the upper site, and 6 microl l(-1) h in the phytotrons. However, the association between injury and O(3) exposure was improved when cumulative ozone uptake to sun leaves was the ozone index, used with values of about 3 mmol m(-2) resulting in visible injury in both mature and young beech growing in phytotrons. Under high ozone exposure levels of inositol were lowered, whilst concentrations of lignin-like materials were enhanced in mature beech. Similar responses were observed in young beech grown in phytotrons. As the sun foliage was affected by only a small and variable extent each year, the seasonal O(3) impact at high altitude did not appear to pose an acute risk to mature beech trees.     

Trends in aerosol optical depth for cities in India

Recent analysis of trends in global short-wave radiation measured with pyranometers in major cities in India support a decrease in solar radiation in many of those cities since 1990. Since direct and diffuse radiation measurements include cloud effects, spring and summer dust and the variable summer monsoon rains, we concentrate in this paper on wintertime (November–February) aerosol optical depth measurements. The aerosol optical depth is derived from cloud-free turbidity measurements beginning in the 1960s and more recent sun photometer direct aerosol optical depth measurements. We compare the sun photometer derived trends with the pyranometer-derived trends using a radiative transfer model. These results are then compared to total ozone mapping spectrometer (TOMS) satellite-derived regional aerosol optical depths from 1980 to 2000. The results show that inclusion of the earlier turbidity measurements helps to establish an increasing regional turbidity trend. However, most of the increasing trend is confined to the larger cities in the Ganges River Basin of India (mainly Calcutta and New Delhi) with other cities showing a much less increase. Regional satellite data show that there is an increasing trend in aerosol off the coast of India and over the Ganges River Basin. The increase over the Ganges River Basin is consistent with population trends over the region during 1980–2000.     

Brief overview of dye-sensitized solar cells

Dye-sensitized solar cells (DSC) are based on molecular and nanometer-scale components. Record cell efficiencies of 12%, promising stability data and means of energy-efficient production methods have been accomplished. As selling points for the DSC technology the prospect of low-cost investments and fabrication are key features. DSCs offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. The basic principles of the operation of DSC, the state-of-the-art as well as the potentials for future development are described.     

Exhibitors—1967 APCA Annual Meeting

In recent years there has been considerable use of optical observations to determine the aerosol mass loading of the atmosphere. Nephelometer measurements of the scattering coefficient have been used for the local volume mass loading, and the turbidity of the atmosphere determined by the Volz sun photometer has been related to the vertical mass loading. This paper analyses various approaches to measuring the mass loading, and presents improved relationships between the optical observations and the aerosol mass loading.     

Silver prices and solar energy production

Environmental Science and Pollution Research - The goal of this paper is to identify, for the first time, the role of solar production in driving silver prices. The empirical analysis makes use of...     

Cooling Towers and the Environment

Measurements of natural draft cooling tower plume behavior, as well as meteorological variables, were obtained from aircraft flights near major power plants of the American Electric Power System. Persistence of the visible plume to great distances depends essentially on ambient humidity. Atmospheric stability at plume elevation was also important. Cooling tower-induced fog at ground-level was never observed in any of the tests, and aerodynamic downwash of the visible plume was absent also. The cooling towers did cause modification of natural clouds and they occasionally shadowed some local areas from the sun. Merging of the stack and cooling tower plumes was a common occurrence.