فهرست مطالب babak bonakdarpour

Dyeing wastewater is one of the most important environmental problems in the textile industry. This wastewater contains harmful pollutants that can damage human health and the environment. Electrocoagulation (EC) is a promising technology for dyeing wastewater treatment. This technology passes an electric current through the wastewater, which generates metal hydroxides that act as coagulants to remove pollutants. This article first introduces the EC system and its operation mechanism, then discusses the components that affect the system's performance in removing dye and chemical oxygen demand. The article also summarizes the studies that have been conducted on the use of this process in the treatment of textile dyeing wastewater. In addition, the economic aspects of the EC process and recommendations for its improvement are provided. Finally, the challenges and prospects of the process are discussed. This article provides an effective overview of the current advances and achievements in the EC process for dyeing wastewater treatment, which provides new insights into improving dyeing wastewater treatment with promising environmental applications.

Textile and dyeing industries have made significant progress in recent years, and a large amount of dyes are consumed by these industries. The poor stabilization of dyes leads to the entry of large amounts of them into wastewater. Between different processes for dyeing wastewater treatment, anaerobic treatment is considered an efficient method. Among the anaerobic processes, upflow anaerobic sludge blanket reactor (UASB) is very popular due to its high efficiency in removing dyes, chemical oxygen demand, and other pollutants in textile wastewater, as well as the ability to combine with other textile wastewater treatment methods to improve the quality of the effluent. This study investigates the performance of UASB reactor in dyeing wastewater treatment, dye removal mechanism, and operational parameters. Then, a review of the studies conducted in this field is conducted. Finally, the challenges and prospects ahead are stated. The results and achievements of UASB systems presented in this study can provide new insights into improving UASB performance in dye wastewater treatment with an environmental perspective.

Dust particles have dangerous impacts on human health, the environment, and the economy. Recently dust storms, originating from Arabian countries, have increased remarkably, affecting western and central parts of Iran.HYSPLIT model and the mean monthly maps of AAI (Absorbing Aerosol Index), surface skin temperature, and top soil layer moisture from OMI (Ozone Measurement Instrument) have been used to study the origins and trajectories of suspended particles of dust storms from wind erosion during the warm period in 2010.According to HYSPLIT Model, during their move from their source areas to the downwind ones, dust particles could arrive at city of Ahvaz in different directions: (a) NW-SE (the dust particles are transported from north western region of Iraq and eastern Syria), (b) W-E (the dust particles are transported from central parts of Iraq to the south western and western parts of Iran). Also, inspecting dust emission potential with the aerosol index data from Ozone Measurement Instrument (OMI) shows a persistent intense dust activity in north western parts of Iraq and eastern Syria, hitting South-West of Iran, especially the city of Ahvaz. As a result, the main origins of dust particles in the city of Ahvaz include north west Iraq as well as east Syria.

Polygalacturonase production under different shear stress environments by Aspergillus sp. was studied. It was found that the rate of enzyme production in the stirred tank fermentor decreased with increasing the stirrer speed in the range 300-750 rpm. On the other hand, in a split cylinder air-lift fermentor, the rate of polygalacturonase production slightly increased with increasing in air rate from 1.5 to 2 v.v.m (volume air/culture volume/minute). The maximum enzyme titres at the end of the cultivation period in the airlift fermentor were 35 unit/ml and at least twice of that obtained in agitated fermentors. Measurement of main hyphal length in agitated and air-lift fermentors suggested break up of the mycelia in the higher shear environment of stirred fermentor especially at the higher agitation rates. The similarity in the trend of the enzyme production and main hyphal length suggested a possible relationship between the morphology and productivity of the Aspergillus sp. used in the present study.

Six corn starch-LDPE film blends containing starch in the range 5-40 % by weight,oleic acid as a Lewis catalyst with concentration of either 5 % or 10 %, maleicanhydride as a coupling agent with concentration of either 2 % or 10 % and benzoylperoxide as free radical initiator with concentration of either 0.1 % or 0.25 % wereprepared. Fungal growth tests (ASTM G21) using Penicillium funiculosum were carriedout on the samples made according to the above formulations. Tensile tests (ASTMD638) and SEM imaging were also carried out on the samples before and after incubationwith Penicillium funiculosum for three weeks. The results of ASTM G21 test and SEMimaging showed that the increase in starch content from 5 % to 40 % in the formulationscontaining all three additive increases the biodegradability of the samples whereasincrease in the concentration of oleic acid from 5 % to 10 % has an opposite effect.Formulations containing only 5 % starch with a fairly high concentrations of additives or40 % starch with no additives supported none or very little growth after three weeks,which indicates the importance of the concentration of starch and the presence of additives on the biodegradability of starch-LDPE film blends. Tensile test results showed that increase in starch content in the range of 20-30 % leads to a decrease in the values of the tensile strength and increase in the values of the elongation-at-break whereas furthe increase up to 40 % has the opposite effect. Tests with blends containing 40 % starch and no additive or 5 % starch with a fairly high concentration of additives resulted in low yield stresses and high elongation-at-break values. Increase the concentration of oleic acid from 5 % to 10 % in the blends resulted in a decrease in both the yield stress and elongation- at-break values.