Phytoextraction of heavy metals from contaminated soil,water and atmosphere using ornamental plants: mechanisms and efficiency improvement strategies

Environmental Science and Pollution Research - Accumulation of heavy metals (HMs) in soil, water and air is one of the major environmental concerns worldwide, which mainly occurs due to...     

Investigating feasible sites for multi-purpose small dams in Swat District of Khyber Pakhtunkhwa Province,Pakistan: socioeconomic and environmental considerations

Environment, Development and Sustainability - The low water storage capacity caused water crisis in Pakistan; therefore, the country needs both small- and large-scale reservoirs to store surplus...     

A charge model for household waste management services: a case study of Tehran municipality

In practice, it is difficult to implement Pay-As-You-Throw charge systems based on accurate estimates of waste generation. In many cities, this is made impossible, due to lack of technical and administrative infrastructure and cultural considerations, especially in developing countries. This paper presents an alternative two-component charge model that is the combination of cost-accounting technique of Waste Management Services (WMSs) and econometric functions of waste generation. Practical and computation steps considered by the model are presented as a proposal to reform the current system of waste charge in Tehran municipality. The presented model is simple to implement and resolves some of the disadvantages of the traditional methods of waste charge systems, including insufficient revenue to cover the cost of waste management and unfairness related to social inequality.     

Cell Wall Morphology, Chemical and Thermal Analysis of Cultivated Pineapple Leaf Fibres for Industrial Applications

A study on chemical, morphology, and thermal analysis of cultivated pineapple leaf fibres (PALF) were carried out. The chemical compositions were determined by using Technical Association Pulp and Paper Industries standards. Fourier Transform-Infrared Spectroscopy analysis of PALF detect sharp band at 1,733?cm^?1, due to the absorption of carbonyl stretching of ester and carboxyl groups which is most abundant in pineapple leaf hemicelluloses. Cell wall ultra structure of PALF was studied by using Transmission electron microscopy. Transmission electron micrograph confirmed that cell wall structure of PALF consists of middle lamella, primary wall and secondary wall including S₁, S₂ and S₃ layers. X-Ray Diffraction indicated that PALF have crystalline nature. Thermal analysis of PALF shows that T_10% and T_50% weight loss occurred at temperature of 212 and 306?°C respectively. Differential Scanning Calorimetry of PALF showed the broad endothermic peak at a temperature of 80?°C. The relationships between these properties were discussed and relate it with industrial application of pineapple leaf fibers.     

Wastewater degradation by iron/copper nanoparticles and the microorganism growth rate

Nowadays, trends in wastewater treatment by zero-valent iron (ZVI) were turned to use bimetallic NZVI particles by planting another metal onto the ZVI surface to increase its reactivity. Nano size zero-valent iron/copper (NZVI/Cu⁰) bimetallic particles were synthesized in order to examine its toxicity effects on the wastewater microbial life, kinetics of phosphorus, ammonia stripping and the reduction of chemical oxygen demand (COD). Various concentrations of NZVI/Cu⁰ and operation conditions both aerobic and anaerobic were investigated and compared with pure NZVI experiment. The results showed that addition 10 mg/L of NZVI/Cu⁰ significantly increased the numbers of bacteria colonies under anaerobic condition, conversely it inhibited bacteria activity with the presence of oxygen. Furthermore, the impact of nanoparticles on ammonia stripping and phosphorus removal was also linked to the emitted iron ions electrons. It was found that dosing high concentration of bimetallic NZVI/Cu⁰ has a negative effect on ammonia stripping regardless of the aeration condition. In comparison to control, dosing only 10 mg/L NZVI/Cu⁰, the phosphorus removal increased sharply both under aerobic and anaerobic conditions, these outcomes were obtained as a result of complete dissolution of bimetallic nanoparticles which formed copper-iron oxides components that are attributed to increasing the phosphorus adsorption rate.     

Thermal and FT-IR Characterization of Gigantochloa levis and Gigantochloa scortechinii Bamboo, a Naturally Occurring Polymeric Composite

This research presents, thermal (TGA, Kinetics, DSC) analysis and FT-IR characterization of two bamboo species viz. Gigantochloa levis and Gigantochloa scortechinii at different position and locations (Internode and node). The internodes and nodes of Gigantochloa levis and Gigantochloa scortechinii exhibited similar thermal stability, observed up to 200 °C. The decomposition of cellulose and hemicelluloses component of the bamboo species occurred between 220 and 390 °C, while the degradation of lignin was observed above 400 °C. The kinetic studies revealed that Gigantochloa levis is more sensitive to degradation as compared to Gigantochloa scortechinii. The FT-IR studies were carried to assign the functional groups available at different positions and locations.     

Removal of polycyclic aromatic hydrocarbons from aged-contaminated soil using cyclodextrins: experimental study

The removal of polycyclic aromatic hydrocarbons (PAHs) from soil using water as flushing agent is relatively ineffective due to their low aqueous solubility. However, addition of cyclodextrin (CD) in washing solutions has been shown to increase the removal efficiency several times. Herein are investigated the effectiveness of cyclodextrin to remove PAH occurring in industrially aged-contaminated soil. Beta-cyclodextrin (BCD), hydroxypropyl-beta-cyclodextrin (HPCD) and methyl-beta-cyclodextrin (MCD) solutions were used for soil flushing in column test to evaluate some influent parameters that can significantly increase the removal efficiency. The process parameters chosen were CD concentration, ratio of washing solution volume to soil weight, and temperature of washing solution. These parameters were found to have a significant and almost linear effect on PAH removal from the contaminated soil, except the temperature where no significant enhancement in PAH extraction was observed for temperature range from 5 to 35 degrees C. The PAHs extraction enhancement factor compared to water was about 200.     

Atmospheric methylchloride (CH3Cl)

A global time series of atmospheric methylchloride (CH₃Cl) concentrations is reported showing the variability with latitude and season. Springtime concentrations of CH₃Cl at 45°N latitude are 7.5%±3.5% higher than during other seasons. Lowest concentrations were generally observed during fall. CH₃Cl was found to be more abundant by about 6% (±5% NH, ±3% SH) in the tropical regions of both hemispheres. No significant difference in the burdens of CH₃Cl was observed between the two hemispheres. Based on these data the ratio of the average hydroxyl radical (HO) concentration over the southern hemisphere to that over the northern hemisphere was estimated to be 1.3 or less.     

Latitudinal distributions of trace gases in and above the boundary layer

Statistical analyses of global atmospheric concentrations provide evidence that C₂Cl₄, CHCl₃ and CH₃CCl₃ (methylchloroform) are more abundant in the tropical boundary layer than above it (α ? 0.09) by 27% (±27%), 21% (?21%, +12%) and 6.4% (±6%) respectively. The air samples on which these results are based were collected by cryogenic techniques during the June 1978 project GAMETAG flights and analyzed soon afterwards by gas chromatography (EC/GC and GC/FID), thus providing latitudinal concentrations of CO, CH₄, CCl₃F, CCl₂F₂, CH₃CCl₃ and light C₂-hydrocarbons, both in and above the boundary layer. In August 1980, after further development of analytical techniques, the stored air samples were re-analyzed to establish the latitudinal distributions of CH₃I, CHCl₃, C₂Cl₄, C₂F₃Cl₃ (F-113) and CHClF₂ (F-22) in and above the boundary layer. Stability studies, spanning a year, show that the concentrations of these gases do not change in the flasks.