Climatology of atmospheric circulation patterns of Arabian dust in western Iran

Being in vicinity of vast deserts, the west and southwest of Iran are characterized by high levels of dust events, which have adverse consequences on human health, ecosystems, and environment. Using ground based dataset of dust events in western Iran and NCEP/NCAR reanalysis data, the atmospheric circulation patterns of dust events in the Arabian region and west of Iran are identified. The atmospheric circulation patterns which lead to dust events in the Arabian region and western Iran were classified into two main categories: the Shamal dust events that occurs in warm period of year and the frontal dust events as cold period pattern. In frontal dust events, the western trough or blocking pattern at mid-level leads to frontogenesis, instability, and air uplift at lower levels of troposphere in the southwest of Asia. Non-frontal is other pattern of dust event in the cold period and dust generation are due to the regional circulation systems at the lower level of troposphere. In Shamal wind pattern, the Saudi Arabian anticyclone, Turkmenistan anticyclone, and Zagros thermal low play the key roles in formation of this pattern. Summer and transitional patterns are two sub-categories of summer Shamal wind pattern. In summer trough pattern, the mid-tropospheric trough leads to intensify the surface thermal systems in the Middle East and causes instability and rising of wind speed in the region. In synthetic pattern of Shamal wind and summer trough, dust is created by the impact of a trough in mid-levels of troposphere as well as existing the mentioned regional systems which are contributed in formation of summer Shamal wind pattern.     

Eco-Friendly, Vascular Shape and Interpenetrating Poly (Acrylic Acid) Grafted Pectin Hydrogels; Biosorption and Desorption Investigations

The synthesis and characterization of poly (acrylic acid) grafted pectin hydrogel followed by biosorption and desorption characteristics of cadmium, as a model heavy metal, have been studied. The grafted eco-friendly pectin based interpenetrating hydrogel was prepared in the presence of gluteraldehyde crosslinker under N₂ atmosphere and characterized using ¹H-NMR, FTIR, TGA and SEM techniques. Gluteraldehyde was found to form one-arm and two-arm crosslinks in the copolymer. Upon grafting, two-dimensional sheet structures bounded to tubular and vascular cylindrical rods were observed. The biosorption and desorption data, determined experimentally, were fitted to pseudo-second order reaction kinetics. At higher ionic strength values, the maximum metal uptake value (q _max) was lowered and pseudo-second order rate constant (k ₂) was increased. Whereas, at higher pH values the maximum metal uptake value (q _max) was increased and Pseudo-second order rate constant (k ₂) was decreased. 0.1?M HCl solution was a suitable eluent to regenerate the hydrogel surface and recover the adsorbed cadmium metal ions. Pectin based copolymer could be used as an efficient candidature biosorbent for the recovery of cadmium metal ions from aqueous solutions.     

Recovery of heavy metals from waste printed circuit boards: statistical optimization of leaching and residue characterization

Environmental Science and Pollution Research - Despite attempts to enhance the recycling of waste printed circuit boards (WPCBs), the simultaneous recovery of major metals of WPCBs using an...     

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...     

Controlling energy consumption in residential buildings using air infiltration in humid climates

Environment, Development and Sustainability - Given the ever-increasing people’s need for housing, affordable housing and environmental comfort are important, and the use of inactive design...     

The use of artificial neural networks and multiple linear regression to predict rate of medical waste generation

Prediction of the amount of hospital waste production will be helpful in the storage, transportation and disposal of hospital waste management. Based on this fact, two predictor models including artificial neural networks (ANNs) and multiple linear regression (MLR) were applied to predict the rate of medical waste generation totally and in different types of sharp, infectious and general. In this study, a 5-fold cross-validation procedure on a database containing total of 50 hospitals of Fars province (Iran) were used to verify the performance of the models. Three performance measures including MAR, RMSE and R² were used to evaluate performance of models. The MLR as a conventional model obtained poor prediction performance measure values. However, MLR distinguished hospital capacity and bed occupancy as more significant parameters. On the other hand, ANNs as a more powerful model, which has not been introduced in predicting rate of medical waste generation, showed high performance measure values, especially 0.99 value of R² confirming the good fit of the data. Such satisfactory results could be attributed to the non-linear nature of ANNs in problem solving which provides the opportunity for relating independent variables to dependent ones non-linearly. In conclusion, the obtained results showed that our ANN-based model approach is very promising and may play a useful role in developing a better cost-effective strategy for waste management in future.     

Graphene and its derivatives: synthesis,modifications, and applications in wastewater treatment

Graphene was discovered in 2004 and has attracted intensive interests because of its unique mechanical, electric, thermal, optical, and structural properties, which makes graphene a potential candidate for various applications. Graphene is being used as a composite or filler material with metals, metal oxides, and polymers for potential advanced applications in solar cells, lithium-ion batteries, photocatalysis and sensing. These applications depend upon the distinctive properties of graphene, which in turn depend on the adopted synthetic approach. This article reviews the recent developments in synthesis of graphene and related composite materials. The synthesis of graphene through exfoliation, epitaxial growth and direct growth via carbon source, and modification approaches by covalent and noncovalent methodologies are discussed. Graphene-based metal and metal oxide composites for the purification of wastewater using photolytic process are also presented.