Enhanced solar still productivity using transparent walls with an integral trough and organic porous absorber material

This experimental work has been conducted to compare the performance of the modified stills with that of the conventional still. Three modified stills (S1, S2, and S3) and conventional still (S4) were fabricated, each with 0.5 m² of the basin area. S1 and S3 had transparent double glass walls with air in between acting as insulation, whereas S2 has a single transparent wall. S4 has insulated plywood walls painted black from inside. A mixture of coco peat and charcoal was used in S1, S2, and S3, whereas there was no basin material for S4. Experiments were conducted by changing the water quantity in the solar still ranging from 5 to 10 kg. Maximum distillate output of 5.46 l/m²-d was obtained for S2, whereas it was 3.80 l/m²-d for S4 for an average solar radiation intensity of 675 W/m² (24.3 MJ/m²-d). Use of transparent walls with troughs to collect condensate increased the condenser area by 78.4%. The distillate water cost per liter was estimated as Rs. 0.86 (0.013 US$) and Rs. 1.61 (0.025 US$) for S2 and S4, respectively. Energy payback time for S2 was estimated as 4 months. Theoretical and experimental values showed that there is a significant loss of incoming solar radiation due to wall shadow.     

An interpretive structural modeling (ISM) and decision-making trail and evaluation laboratory (DEMATEL) method approach for the analysis of barriers of waste recycling in India

Increasing amount of wastes is posing great difficulties for all countries across the world. The problem of waste management is more severe in developing countries such as India where the rates of economic growth and urbanization are increasing at a fast pace. The governments in these countries are often constrained by limited technical and financial capabilities, which prevent them from effectively addressing these problems. There is a limited participation from the private players too in terms of setting up of waste recycling units. The present study aims at identifying various barriers that challenge the establishment of these units, specific to India. Further, it attempts to identify the most influential barriers by utilizing multicriterion decision-making tools of interpretive structural modeling (ISM) and decision-making trail and evaluation laboratory (DEMATEL). The findings of the study suggest that the lack of funds, input material, and subsidy are the most influential barriers that are needed to be addressed for the development of waste recycling infrastructure in India.

Implications: This work has been carried out to address the problem of proper waste management in India. To deal with this problem, the method of waste recycling has been felt appropriate by the government of various countries, including India. Therefore, the barriers that play vital role in waste recycling for private players have been identified and their importance has been established with the help of ISM and DEMATEL methods. Doing so will assist the government to take appropriate steps for the betterment of waste recycling infrastructure in India and enhance waste management.     

Development,validation of QuEChERS-based method for simultaneous determination of multiclass pesticide residue in milk,and evaluation of the matrix effect

Extraction and quantification of pesticide residue from the milk matrix at or below the established maximum residue limit (MRL) is a challenging task for both analytical chemists and the regulatory institutions to take corrective actions for the human health and safety. The main aim of the study is to develop a simple rapid and less expensive QuEChERS extraction and cleanup method for simultaneous analysis of 41 multiclass pesticide residue in milk by gas chromatography-electron capture detector (GC-ECD), followed by confirmation of the residues with gas chromatography-mass spectrometer (GC-MS). Effect of sorbent type, temperature, spiking concentration, matrix effect (ME), measurement uncertainty (MU), inter- and intra-assay repeatability, reproducibility of recovery, and trueness of the results were investigated to validate the effectiveness of the method. Limit of determination (LOD) and limit of quantitation (LOQ) for all the analytes ranged within 0.001–0.02 and 0.002–0.05 µg mL^?1, respectively. The % recovery of all the pesticides ranged between 91.38 and 117.56% with relative standard deviation (RSD) below 2.79%. The MU for all the analytes was ≤29% of respective LOQs, and except for few pesticides, the ME was largely negative. The method fulfilled all the SANTE guidelines and thus can be extended for routine analysis of multiclass pesticide residue in milk.     

Recent advances based on the synergetic effect of adsorption for removal of dyes from waste water using photocatalytic process

The problem of textile dye pollution has been addressed by various methods,mainly physical,chemical,biological,and acoustical.These methods mainly separate and/or remove the dye present in water.Recently,advanced oxidation processes(AOP)have been focused for removal of dye from waste water due to their advantages such as ecofriendly,economic and capable to degrade many dyes or organic pollutant present in water.Photocatalysis is one of the advance oxidation processes,mainly carried out under irradiation of light and suitable photocatalytic materials.The photocatalytic activity of the photocatalytic materials mainly depends on the band gap,surface area,and generation of electron–hole pair for degradation dyes present in water.It has been observed that the surface area plays a major role in photocatalytic degradation of dyes,by providing higher surface area,which leads to the higher adsorption of dye molecule on the surface of photocatalyst and enhances the photocatalytic activity.This present review discusses the synergic effect of adsorption of dyes on the photocatalytic efficiency of various nanostructured high surface area photocatalysts.In addition,it also provides the properties of the water polluting dyes,their mechanism and various photocatalytic materials;and their morphology used for the dye degradation under irradiation of light along with the future prospects of highly adsorptive photocatalytic material and their application in photocatalytic removal of dye from waste water.     

Analysis of trace elements and ions in ambient fine particulate matter at three elementary schools in Ohio

The results from a chemical characterization study of fine particulate matter (PM2.5) measured at three elementary schools in Central and Southeast Ohio is presented here. PM2.5 aerosol samples were collected from outdoor monitors and indoor samplers at each monitoring location during the period of February 1, 1999, through August 31, 2000. The locations included a rural elementary school in Athens, OH, and two urban schools within Columbus, OH. The trace metal and ionic concentrations in the collected samples were analyzed using an X-ray fluorescence spectrophotometer and ion chromatography unit, respectively. Sulfate ion was found to be the largest component present in the samples at all three of the sites. Other abundant components included nitrate, chloride, ammonium, and sodium ions, as well as calcium, silicon, and iron. The average PM2.5 concentrations showed similar temporal variations among the three sites within the study region. PM2.5 and its major component, sulfate ion, showed strong seasonal variations with maximum concentrations observed during the summer at all three of the sites. The indoor environment was found to be more contaminated during the spring months (March through May) at New Albany (a suburb of Columbus, OH) and East Athens (rural Ohio area). Potential source contribution function analysis showed that particulate matter levels at the monitoring sites were affected by transport from adjoining urban areas and industrial complexes located along the Ohio River Valley. A preliminary outdoor source apportionment using the principal component analysis (PCA) technique was performed. The results from the PCA suggest that the study region was primarily impacted by industrial, fossil fuel combustion, and geological sources. The 2002 emissions inventory data for PM2.5 compiled by Ohio Environmental Protection Agency also showed impacts of similar source types, and this was used to validate the PCA analysis.