Efficiency of multi walled carbon nanotubes for removing Direct Blue 71 from aqueous solutions

Dye wastewater produced from industrial activity is usually toxic, resistant to biodegradation and persistent in the environment. The aim of this study was to evaluate the efficiency of multiwalled carbon nanotubes (MWCNTs) for decolorization of Direct Blue 71 (DB71). In this experimental study, the effect of various variables including contact time, solution pH, adsorbent dose, and initial dye concentration was evaluated in a batch reactor. The adsorption and kinetic models were evaluated to explain the adsorbed dye and dynamic reaction. The results of this study showed that the efficiency of dye removal increased, as the contact time and adsorbent dose increased, but as pH and initial dye concentration increased, removal efficiency decreased. The maximum efficiency of Direct Blue 71 removal was observed at acidic solution (pH=3), contact time of 90 minutes, adsorbent dose of 0.6 g/l and initial dye concentration of 25 mg/l. The adsorption of direct blue 71 best fitted the Langmuir isotherm (R2=0.87) and pseudo first order kinetic equation (R2=0.99). According to the results obtained, multiwalled nanotubes was offered as an effective adsorbent for removing direct blue 71. © Authors

Industrial waste management in Shokuhieh industrial zone of Qom province in 2013

Background and aims: Nowadays, the rapid growth of industries and production of various products has led to an increase in hazardous industrial solid waste. The aim of this study was to examine how to manage industrial solid waste in industrial zone of Shokuhiyeh in Qom province in 2013. Methods: This research was a descriptive, cross-sectional one. The data were gathered by first referring to industrial units and the completion of Iranian Environmental Organization Questionnaire and then analyzing the gathered data. This questionnaire included 24 items covering the quantity, quality, and management of industrial solid waste. In this study, 41 industrial units with personnel of more than 50 were examined. Results: The category of" chemical and metal industries" produced the highest solid waste and specific solid waste. The elements making up the produced solid waste were plastic 38% and glass 27.5%, respectively. Among the storage methods, the temporary solid waste storage in baskets 36% and open-doors method 32% were the most common ones. 41% of industrial units disposed of solid waste monthly, 31.7% weekly, 24.4% daily and 2.4% in an inconsistent manner. 58% of produced solid waste was recycled, 35% was landfilled, 4.6% was burned up, and 2.4% was disposed of in an unknown manner. Conclusion: The results of this study showed that the collection and storage of industrial solid waste in the industrial zone of Shokuhiyeh is not done in a suitable manner. Moreover, no educational program has yet been done about the management of solid waste in most of the industries. Therefore, it seems indispensable to establish a suitable system of solid waste management in order to organize the conditions of industrial solid waste produced in this zone

Efficiency of multi walled carbon nanotubes for removing Direct Blue 71 from aqueous solutions

Dye wastewater produced from industrial activity is usually toxic, resistant to biodegradation and persistent in the environment. The aim of this study was to evaluate the efficiency of multiwalled carbon nanotubes (MWCNTs) for decolorization of Direct Blue 71 (DB71). In this experimental study, the effect of various variables including contact time, solution pH, adsorbent dose, and initial dye concentration was evaluated in a batch reactor. The adsorption and kinetic models were evaluated to explain the adsorbed dye and dynamic reaction. The results of this study showed that the efficiency of dye removal increased, as the contact time and adsorbent dose increased, but as pH and initial dye concentration increased, removal efficiency decreased. The maximum efficiency of Direct Blue 71 removal was observed at acidic solution (pH=3), contact time of 90 minutes, adsorbent dose of 0.6 g/l and initial dye concentration of 25 mg/l. The adsorption of direct blue 71 best fitted the Langmuir isotherm (R2=0.87) and pseudo first order kinetic equation (R2=0.99). According to the results obtained, multiwalled nanotubes was offered as an effective adsorbent for removing direct blue 71. © Authors

Crystallization of calcium carbonate and magnesium hydroxide in the heat exchangers of once-through multistage flash (MSF-OT) desalination process

YesIn this paper, a dynamic model of fouling is presented to predict the crystallization of calcium carbonate and magnesium hydroxide inside the condenser tubes of Once-Through Multistage Flash (MSF-OT) desalination process. The model considers the combination of kinetic and mass diffusion rates taking into account the effect of temperature, velocity and salinity of the seawater. The equations for seawater carbonate system are used to calculate the concentration of the seawater species. The effects of salinity and temperature on the solubility of calcium carbonate and magnesium hydroxide are also considered. The results reveal an increase in the fouling inside the tubes caused by crystallization of CaCO3 and Mg(OH)2 with increase in the stage temperature. The intake seawater temperature and the Top Brine Temperature (TBT) are varied to investigate their impact on the fouling process. The results show that the (TBT) has greater impact than the seawater temperature on increasing the fouling

Survey of Optimal Methods for the Control of Cockroaches in Sewers of Qom City

"n "nBackgrounds and Objectives: Domestic sewers and wastewater treatment plants are suitable places for the growth of some types of Cockroaches. Annually the water and wastewater company of Qom city make considerable attempts to overwhelm the problem. The current study is aimed to determine types of Cockroaches and select the optimal methods for their control."nMaterials andMethods: In this study, 120 manholes are selected in different locations of Qom city, the numbers of Cockroaches are counted and the Cockroaches are classified into different groups. Then, each group are faced to different insecticides Including Simperator, Diazinon , Dursban Ec, Faikam, Sipermetrin, Icon, Deltametrina and Sulfac. One group of manholes was considered as blank sample during one month. Counting and determination of Cockroaches in these manholes conducted before using insecticides and also five months after it."nResults: the study showed that all sewers were 100% polluted by Cockroaches. The number of Cockroaches in manholes range from minimum 4 to maximum 3600 in each manhole. The applied of insecticides including Dursban Ec, Simperator, Sulfac, Dursban, and Deltametrina are used 2 gr in 100 square meter of area of each sewer. The Cockroaches population reduced to approximately zero after application of these insecticides. Spraying sewers by Simperator controlled 100% of Cockroaches."nConclusion: the most effective method for the control of Cockroaches was usage of 2 gr of Dursban (Ec) in squaremeter of area in the beginning of warmseason.If we use 1-1/5months interval between the time of spraying insecticide in selected wells, with using simperator and dursban (Ec) we can overwhelm Cockroaches using Simperator and Dursban Ec. The results of statistical analysis show that reduction of number of coackroaches in one month after using poison is significant (P-value< 0.05). But after 5months it lose meaningful in all of them.Also, reduction of number of coackroachesin blank manholes was not statistically significant