Research on Influences of "A Test of Different Initial pH from the Reaction" with Properties of Environment Materials on Distribution of Arsenic Speciation Arsenic-Ferric Precipitation

2014 ◽  
Vol 1014 ◽  
pp. 307-310
Author(s):  
Xing Guan Ma ◽  
Meng Qi Wang
Keyword(s):  
Sequential Extraction ◽  
Ferric Chloride ◽  
Arsenic Removal ◽  
Arsenic Speciation ◽  
Extraction Procedure ◽  
Water Soluble ◽  
Specific Adsorption ◽  
Physical Absorption ◽  
Initial Ph ◽  
Soluble State

The distribution of arsenic speciation can be applied to elucidate the mechanism of removal arsenic during treatment the water containing arsenic with molysite. In this study, the effect of initial pH on the distribution of arsenic speciation in arsenic-ferric precipitation was determined by a five-step sequential extraction procedure. And then further explore the mechanism of arsenic removal with molysite. This experimental results showed that the main mechanisms governing the arsenic removal with ferric chloride were specific adsorption and coprecipitation. Besides, as pH increased from 5 to 9, the arsenic-ferric coprecipitation played a more and more important role in mechanism of arsenic removal with molysite. At the same time, the water soluble state As and the non-specific adsorption As were barely detectable, which suggested that physical absorption had almost no effect on arsenic removal.

scholarly journals Sequential extraction and thermal desorption of mercury from contaminated soil and tailings from Mongolia

2012 ◽  
Vol 10 (5) ◽  
pp. 1565-1573 ◽  
Author(s):  
Pavel Coufalík ◽  
Pavel Krásenský ◽  
Marek Dosbaba ◽  
Josef Komárek
Keyword(s):  
Sequential Extraction ◽  
Thermal Desorption ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Speciation Analysis ◽  
Water Soluble ◽  
Mercury Species ◽  
Different Temperatures ◽  
Acidic Conditions ◽  
Desorption Method

AbstractMercury forms in contaminated environmental samples were studied by means of sequential extraction and thermal desorption from the solid phase. The sequential extraction procedure involved the following fractions: water soluble mercury, mercury extracted in acidic conditions, mercury bound to humic substances, elemental Hg and mercury bound to complexes, HgS, and residual mercury. In addition to sequential extraction, the distribution of mercury species as a function of soil particles size was studied. The thermal desorption method is based on the thermal decomposition or desorption of Hg compounds at different temperatures. The following four species were observed: Hg0, HgCl2, HgS and Hg(II) bound to humic acids. The Hg release curves from artificial soils and real samples were obtained and their applicability to the speciation analysis was considered.

scholarly journals Application of a Sequential Extraction Method for Analyzing Cu Distribution in Pre-Treated Mine Tailings after Electrodialytic Remediation

2019 ◽  
Vol 16 (4) ◽  
pp. 584 ◽  
Author(s):  
Andrea Lazo ◽  
Henrik Hansen ◽  
Pamela Lazo ◽  
Claudia Gutiérrez
Keyword(s):  
Sequential Extraction ◽  
Mine Tailings ◽  
Extraction Method ◽  
Constant Electric Field ◽  
Extraction Procedure ◽  
Water Soluble ◽  
Copper Compounds ◽  
Leaching Solution ◽  
Sequential Extraction Method ◽  
Pre Treatment

Mine tailings have been analyzed by a sequential extraction procedure after their pre-treatment with a leaching solution for 24 h and electrodialytic remediation during 15 days with a constant electric field of 2.7 V cm−1. Four leaching solutions were tested: H2SO4 + HNO3 (2:1 vol.) pH = 1.9; H2SO4 + HNO3 (2:1 vol) pH = 4.2; NH4Cl 0.8M, pH = 5.5 and 30% H2O2 adjusted to pH 2 with HNO3 1M + HCl 1M. After the treatment, the tailings were divided in six slices from anode to cathode. The highest removal efficiency of copper was obtained with H2SO4 + HNO3 pH = 1.9, which allows one to remove 67% of the copper in the total cell and 85% of the copper in the slice closest to anode. The same solution with pH = 4.2 allows one to remove 62% of the total copper. The analysis realized by the sequential extraction method indicates the easy removal of water-soluble and exchangeable fractions in all experiments, moreover, residual and sulfide are the less mobile fractions. The general trend was the movement of copper associated to different fractions from anode to cathode and its accumulation closest to the cathode in the case of exchangeable, Fe-Mn oxides and acid soluble fractions, possibly due to some precipitation of copper compounds associated with less acidic conditions.

EVALUATION OF LEACHING AND BIOAVAILABILITY OF HEAVY METALS FROM INDUSTRIAL BIOMASS ASHES

2017 ◽  
Vol 167 (47) ◽  
pp. 18-33
Author(s):  
Justyna Koniuszy-Nycz
Keyword(s):  
Sequential Extraction ◽  
Ph Effect ◽  
Microwave Digestion ◽  
Extraction Procedure ◽  
Total Content ◽  
Water Soluble ◽  
Test Material ◽  
Biomass Combustion ◽  
Solution Ph ◽  
Biomass Ashes

The purpose of the study was to evaluate the total content, leachability and bioavailability of Fe, Zn, Cu, Cr, Cd, Pb, Ni, Co in industrial ashes obtained from biomass combustion. It was found that metals occur in the test material as: macronutrient - iron (0,67 %), micronutrients - zinc (335,0 mg/kg), nickel (145,0 mg/kg), lead (110,0 mg/kg), copper (100,0 mg/kg), cobalt (25,0 mg/kg), chrome (15 mg/kg) and trace amount of cadmium (10,0 mg/kg). It was claimed that leachability of metals from ash depends on pH of solution and ranges from 1 mg/kg for (Cu, Cd, Ni, Fe) to 4 – 5 mg/kg for (Cr, Co) respectively. It was also found that lead was not extracted from ash, using water as extractant regardless of solution pH. In all experiments no regularities in the pH effect of metal leachability in the investigated systems were observed. Tessier sequential extraction procedure was used to evaluate the mobility and bioavailability of metals, which was carried out conventionally and with aid of microwave digestion. In all experiments the following metal fractions were characterized: water-soluble, exchangeable, acid-soluble, oxide, pseudosulfide and residual fractions respectively. It has been found that the use of microwave mineralization during sequential extraction increases the efficiency of the release of most of the tested metals.

scholarly journals Improvement of the sequential extraction procedure based on supercritical CO2 and subcritical H2O solvents for the estimation of the environmentally mobile potentially toxic element fractions of sediments and soils

2018 ◽  
Vol 67 (1) ◽  
pp. 35-48
Author(s):  
Anita Takács ◽  
Katalin Kovács ◽  
Gábor Halász ◽  
Zoltán Győri ◽  
Ilona Fekete ◽  
...  
Keyword(s):  
Sequential Extraction ◽  
Extraction Procedure ◽  
Potentially Toxic Elements ◽  
Toxic Element ◽  
Water Soluble ◽  
Sequential Extraction Procedure ◽  
Mass Ratio ◽  
Fractionation Procedure ◽  
Soils And Sediments ◽  
Element Contents

The estimation of environmental risk caused by pollution with potentially toxic elements (PTE) is usually carried out using the (3+1) step sequential extraction procedure suggested in 1993 by the Community Bureau of Reference (BCR). In the 1st step the water-soluble, exchangeable and carbonate-bound element content is extracted with acetic acid. In 2002 a fractionation procedure based on the application of supercritical CO2, subcritical H2O and of a mixture of subcritical H2O/CO2 was proposed, which allowed the water-soluble and carbonatebound element contents to be extracted separately from sediment or soil samples weighed into the preparative column of a supercritical fluid extractor and diluted with quartz sand in a mass ratio of 1:20. The aim of the present study was to develop a new reduced-size column construction with which this dilution rate could be decreased to 1:2. A kinetic study was performed to determine the extraction time necessary for samples with different carbonate contents and the extracted element contents were compared to the results of the BCR sequential procedure on the same samples. It was established that fractionation using the reduced-size column may be a rapid way to obtain more reliable information on the easily mobilizable (watersoluble and carbonate-bound) PTE content of soils and sediments than was previously available to supplement BCR fractionation.

scholarly journals Sequential extraction procedure to obtain the composition of terrigenous detritus in marine sediments

MethodsX ◽  
2020 ◽  
Vol 7 ◽  
pp. 100888
Author(s):  
Margit H. Simon ◽  
Daniel P. Babin ◽  
Steven L. Goldstein ◽  
Merry Yue Cai ◽  
Tanzhuo Liu ◽  
...  
Keyword(s):  
Sequential Extraction ◽  
Marine Sediments ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure

Challenges of arsenic removal from municipal wastewater by coagulation with ferric chloride and alum

2020 ◽  
Vol 725 ◽  
pp. 138351 ◽  
Author(s):  
Jie Ge ◽  
Biswarup Guha ◽  
Lee Lippincott ◽  
Stanley Cach ◽  
Jinshan Wei ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Municipal Wastewater ◽  
Arsenic Removal

scholarly journals The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Arsenic Removal ◽  
Ph Value ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Deionized Water ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.

Environmental Availability of Potentially Toxic Elements in an Agricultural Mediterranean Site

2019 ◽  
Vol 25 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Dimitrios Alexakis ◽  
Dimitra Gamvroula ◽  
Eleni Theofili
Keyword(s):  
Sequential Extraction ◽  
Toxic Elements ◽  
Soil Depth ◽  
Extraction Procedure ◽  
Potential Ecological Risk ◽  
Potentially Toxic Elements ◽  
Geochemical Partitioning ◽  
Exchangeable Fraction ◽  
High Bioavailability

ABSTRACT Total contents of 36 potentially toxic elements are summarized for agricultural topsoil (n = 12; soil depth = 0–20 cm), subsoil (n = 12; soil depth = 20–40 cm), and representative rock samples collected from a Mediterranean site (Megara Plain, Greece). The five-stage sequential extraction procedure for the geochemical partitioning of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), and nickel (Ni), proposed by Tessier, was applied to topsoil and subsoil collected from the study area. Soil Cd was highly associated with exchangeable fraction, illustrating high bioavailability of this element. The order of mobility of the elements was as follows: Cd > Cu > Co > Zn > Ni > Cr > Mn. Results from sequential extraction experiments illustrated that the bioavailability of Cu, Co, and Zn is moderate, while Ni, Cr, and Mn presented low bioavailability, indicating that these elements could pose a limited threat to the quality of crops. Cadmium is the chief contamination controlling factor posing moderate potential ecological risk. The contamination sources of the examined elements are discussed.

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