نتایج جستجو برای: increasing in concentration of heavy metals such as lead
تعداد نتایج: 24668008 فیلتر نتایج به سال:
determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...
abstract: regular consumption of seafood has been widely recommended by the authorities. however, some species especially benthic crustaceans accumulate heavy metals. in addition, the health risks associated to the consumption of such seafood might increase if the consumers use cooking methods that enhance the concentration of heavy metals. in this study, the effects of different cooking method...
in this thesis protic and aprotic ammonium-based ionic liquids were synthesized and their surface tensions were measured in the range of 298-373k. the protics are alkyl ammonium-based ils with the carboxylate (formate, acetate, propionate) anion and aprotics are quaternary ammonium-based ils with bis(trifluoromethylsulfonyl)imide anion. capillary rise method was used for surface tension measure...
The programs of managing waste materials in developing countries are often unsatisfactory and the unreasonable disposal of waste is a major issue in the worldwide. The main aim of the current study is to: Assess the applicability of Rumex crispus L. in removing heavy metals from the contaminated wastewater effluent form Pharmaceutical laboratories by bio-adsorption method. The dried R. crispus ...
Background: Water contamination of heavy metals is one of the major threats to human health and food chain. In this study, concentration of heavy metals of lead, chromium, copper and zinc in sediment was measured in order to assess their ecological effects and their risk. Methods: To determine the concentration of metals, 12 stations were selected along the river and 3 samples from the sedi...
in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...
background : the present paper aims to study the effect of human and urban activities on the quality of groundwater within the city of khoy in terms of heavy metals, chemical salts, and minerals from the geological formations of this region. methods : samples were provided from 32 pumping wells and the concentration of heavy metals ( cd, cu, mn, pb, zn, fe, as, and b), the main ions (hco 3 ,so ...
Background and purpose: Using plants for cleaning up the soil contaminated with pollutants, especially heavy metals increased in the last decade. Decrease in the availability of heavy metals in soil by plants is one of the major challenges of phytoremediation. This study was conducted to determine the role of EDTA, ammonium citrate and ammonium phosphate in the mobility and availability of Pb a...
this research was conducted on polluted soil near the lead and zinc factory in zanjan province through which the effects of two organic and three mineral sources were examined on heavy metals fixation in randomized experiment design. experimental treatments includes bagasse and rice husk in three levels: 1.25, 2.5 and 5%, zeolite in three levels: 5%, 10% and 15%, phosphate rock in three rates: ...
the research questions were as follows: 1. is there any relationship between the students concious awareness of the form and implications of the conjuncations and their improvement in using appropriate conjunctions? 2. does students knowledge of the from and the implications of the conjunctions help them to produce more coherent writings. 3. does a comparison between english conjunctions and th...
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