Pollution,human health risk assessment and spatial distribution of toxic metals in urban soil of Yazd City,Iran

Environmental Geochemistry and Health - Heavy metal pollution significantly reduces the quality of the environment and threatens human health, especially in industrial cities. This study...     

Ultrasound-assisted ionic liquid-based microextraction combined with least squares support vector machines regression for the simultaneous determination of aluminum,gallium, and indium in water and coal samples

A new simple and rapid ultrasound-assisted ionic liquid-based microextraction method was applied to preconcentrate aluminum(III), gallium(III), and indium(III) ions from water samples as a prior step to their simultaneous spectrophotometric determination using least squares support vector machines regression. In the novel procedure, 1-hexyl-3-methylimidazolium hexafluorophosphate [C₆MIM][PF₆] was dispersed into the aqueous sample solution as fine droplets by ultrasonication, and the analytes were extracted into the ionic liquid phase after complexation with 1,2,5,8-tetrahydroxy anthraquinone (quinalizarine). After centrifuging, the fine droplets of extractant phase were settled to the bottom of the conical-bottom glass centrifuge tube. The detection limits for Al(III), Ga(III), and In(III) were 1.70, 2.02, and 2.06 ng mL⁻¹, respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was below 3.2% for all elements. The method was successfully applied for the determination of Al(III), Ga(III), and In(III) in real samples.     

Preparation of Cellulose Nanocrystals Using an Ionic Liquid

In this paper cellulose nanocrystals were prepared by treating microcrystalline cellulose with 1-butyl-3-methylimidazolium hydrogen sulphate ionic liquid. Cellulose nanocrystals, after separation from ionic liquid, were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscopy (FESEM) Transmission Electron Microscope (TEM) and Thermogravimetric analysis. XRD results showed no changes in type of cellulose after the treatment with ionic liquid, however, high crystallinity index was observed in the ionic liquid treated sample. Cellulose nanocrystals, having length around 50–300 nm and diameter around 14–22 nm were observed in the ionic liquid treated sample under FESEM and TEM, and similar patterns of peaks as that of microcrystalline cellulose were observed for cellulose nanocrystals in the FTIR spectra. The thermal stability of the cellulose nanocrystals was measured low as compare to microcrystalline cellulose.     

Source apportionment and deposition of dustfall-bound trace elements around Tabriz,Iran

Environmental Science and Pollution Research - The monthly and spatial variations of atmospheric dustfall (DF) and their elemental components were determined. The DF sampling was performed using...     

Carbon nanotubes from waste cooking palm oil as adsorbent materials for the adsorption of heavy metal ions

Environmental Science and Pollution Research - In this work, waste cooking palm oil (WCPO)-based carbon nanotubes (CNTs) with encapsulated iron (Fe) nanoparticles have been successfully produced...     

Sago pith waste ash as a potential raw material for ceramic and geopolymer fabrication

Journal of Material Cycles and Waste Management - This study focuses on the potential usage of sago pith waste ash (SPWA) obtained from sago pith waste (SPW) calcined from 500 to...     

Radiant Domestic Combustion Stove System: Experimental and Simulated Study of Energy Use and Thermal Comfort

A steady-state space radiant heat model and a stove combustion model are developed to simulate the heat exchanges between various surfaces in the room and the stove and stack surfaces, assuming stiochiometric combustion inside the stove and the exhaust gases flow out through the stack by natural convection. The space heat model calculates the fuel consumption, the stove, stack temperatures, and the mass flow rate of exhaust gases, and provides an opportunity to study the energy efficiency of the stove, while satisfying the constraints of thermal comfort. Fanger (1982) Fanger, P. O. 1982. Thermal Comfort Analysis and Applications in Engineering, 156–198. New York: McGraw Hill.  [Google Scholar] model and a radiation exchange model between various surfaces of the space, the thermal building energy balance, and stove combustion process is applied to determine the mean radiant temperature (MRT) and the extent of thermal comfort as determined by predicted mean vote (PMV).

The overall model is validated by performing experiments in a room placed inside a controlled outdoor environment. The room is heated using a domestic stove common for rural areas of Lebanon and the MRT, the room air temperature, the walls and window temperatures are measured at two stove positions. The measured MRT, the average room temperature, and the wall surface temperatures agreed within ±7% of values predicted by the numerical model.

A parametric study is performed to optimize the stove and occupant locations in the room where adequate comfort level can be maintained at lower fuel consumption levels. The values of MRT and PMV depend strongly on the position of the radiant stove heater and stack with respect to the cold window and the occupant location. It is shown that it is possible to save up to 15% in stove fuel consumption by changing the stove position in the room with respect to the window and to the person, while maintaining the same level of comfort.     

Application of chemometrics in understanding the spatial distribution of human pharmaceuticals in surface water

The growing interest in the environmental occurrence of veterinary and human pharmaceuticals is essentially due to their possible health implications to humans and ecosystem. This study assesses the occurrence of human pharmaceuticals in a Malaysian tropical aquatic environment taking a chemometric approach using cluster analysis, discriminant analysis and principal component analysis. Water samples were collected from seven sampling stations along the heavily populated Langat River basin on the west coast of peninsular Malaysia and its main tributaries. Water samples were extracted using solid-phase extraction and analyzed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for 18 pharmaceuticals and one metabolite, which cover a range of six therapeutic classes widely consumed in Malaysia. Cluster analysis was applied to group both pharmaceutical pollutants and sampling stations. Cluster analysis successfully clustered sampling stations and pollutants into three major clusters. Discriminant analysis was applied to identify those pollutants which had a significant impact in the definition of clusters. Finally, principal component analysis using a three-component model determined the constitution and data variance explained by each of the three main principal components.     

Reactivity of sulfate radicals with natural organic matters

Advanced oxidation processes based on sulfate radicals (SO ₄ ^·? ) are capable of efficiently degrade organic pollutants from ground, surface and wastewaters. However, this degradation may be limited by aqueous natural organic matter (NOM). Here we measured the absolute rate constants of reaction of SO ₄ ^·? with four types of organic matter: two fulvic acids and two lake organic matter. We used laser flash photolysis technique to monitor the SO ₄ ^·? decay and the formation of the transients from organic matters. Reaction rate constants comprised between 1530 and 3500 s^?1 mgC^?1 L were obtained by numerical analysis of differential equations and the weighted average of the extinction coefficient of the generated organic matters radicals between 400 and 800 M^?1 cm^?1.     

Surfactant-mediated complex formation for determination of traces amounts of zinc, cadmium, and lead with 4-(2-thiazolylazo) resorcinol and chemometric methods

The partial least squares modeling is a powerful multivariate statistical tool applied to the spectrophotometric simultaneous determination of the divalent ions of zinc, cadmium, and lead based on the formation of their complexes with 4-(2-thiazolylazo) resorcinol in surfactant media. The linear concentration range for zinc, cadmium, and lead were 0.10-1.31, 0.148-1.92, and 0.148-3.70 mg L(?-1), respectively. The experimental calibration set was composed of 36 sample solutions using a mixture design for three component mixtures. The absorption spectra were recorded from 380 through 650 nm. The effect of pH on the sensitivity in determination of zinc, cadmium, and lead was studied in order to choose the optimum pH (pH = 8) for determination. The root-mean-square errors of predictions for zinc, cadmium, and lead were 0.0466, 0.0282, and 0.050, respectively. The proposed method was successfully applied for the determination of zinc, cadmium, and lead in water samples.