نتایج جستجو برای: bioreduction of hexavalent chromium
تعداد نتایج: 21165796 فیلتر نتایج به سال:
Absorptive characteristics of polyaniline synthesized in mixture of water and acetonitrile in 50/50 volume ratio was studied. Synthesized polyaniline in powder shape is used as an adsorbent to remove toxic hexavalent chromium from aqueous solutions. Experiments were conducted in batch mode with different variables such as agitation time, solution pH and initial concentration of hexavalent chrom...
in parts of desert regions in our country, groundwater is the only source of fresh water and due to geological formation, the concentration of hexavalent chromium in groundwater will reach beyond the allowed limits. furthermore, previous studies showed that hexavalent chromium is a cancerous substance for humans and toxic for other organisms. in this study the removal of hexavalent chromium fro...
Focus of this paper is the description of common used methods for hexavalent chromium measurement. This work is focused especially on commonly available spectrophotometric method based on the reaction with 1,5-diphenylcarbazide, because not every laboratory is equipped with modern devices for this pollutant measurement,. Special attention was focused on the variability possibilities of the basi...
The effects of two widespread environmental pollutants, perchlorate and hexavalent chromium, were assessed on the efficacy of Bacillus thuringiensis subsp. israelensis (Bti) and Bacillus sphaericus (Bsph) against fourth instars of Culex quinquefasciatus Say (Diptera: Culicidae) in 24-h laboratory bioassays. Although 250 mg/liter perchlorate, a level somewhat higher than would be considered ecol...
absorptive characteristics of polyaniline synthesized with two different oxidants including potassium iodate and ammonium persulfate was studied. synthesized polyanilines in powder shape is used as an adsorbent to remove toxic hexavalent chromium from aqueous solutions. experiments were conducted in batch mode with different variables such as agitation time, solution ph and initial concentratio...
in this study, the adsorption of hexavalent chromium and zinc ions from the solution is investigated by raw red mud and mechanical-chemical activated red mud along with the possibility of selective reclamation of these ions from the solution. the mechanical-chemical activation of red mud was done by employing high-energy milling and subsequent acid treatment with hno3. raw red mud (rrm) and mec...
Corrosion is the degradation or deterioration of metal components due to a reaction with the environment. Chromate conversion coating is applied to passivate metallic surface to slow down (and prevent to some extent) corrosion process. Chromate conversion process uses chromium compounds including hexavalent chromium, which is toxic, carcinogenic and hazardous to human health and environment. He...
Purpose: This study aimed to analyze the effects of removal of hexavalent Chromium using carbonated almond green hulls. In the present study, derived carbon fromalmond green hulls of zonal district of Iran were used to remove hexavalent Chromium from Synthetic wastewater. Materials and Methods: The effects of pH (2-10), Adsorbent dose (2-24 g/L), Cr (VI) concentration (10-100 mg/L), Contact...
A literature review of experimental and human exposure studies of skin permeation and cutaneous hypersensitivity reactions evoked by chromium was carried out to provide a basis for making a risk assessment of chromium as a soil contaminant. In vitro and in vivo studies demonstrated that 1 to 4% of the applied dose of hexavalent and trivalent chromium to guinea pig skin penetrated skin within 5 ...
Hexavalent chromium is one of the main heavy metal pollutants. As the environmental legislation becomes increasingly strict, seeking new technology to treat wastewater containing hexavalent chromium is becoming more and more important. In this research, a novel modified ultrafiltration membrane that could be applied to adsorb and purify water containing hexavalent chromium, was prepared by poly...
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