Carbon adsorbents for the sorption of arsenic

Pokonova, Yu. V.

doi:10.1016/s0008-6223(98)00146-8

Cited by 20 publications

(10 citation statements)

References 2 publications

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“…Carbons were also produced from two batches of shale resin (light, medium and heavy) by heating with hexamethylenetetramine [94]. Granulated carbonized adsorbents were prepared from these polycondensates and also from coal dust and a wood resin binder.…”

Section: Synthetic Activated Carbonsmentioning

confidence: 99%

Arsenic removal from water/wastewater using adsorbents—A critical review

Mohan

Pittman

2007

Journal of Hazardous Materials

3,134

1,445

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Section: Synthetic Activated Carbonsmentioning

confidence: 99%

Arsenic removal from water/wastewater using adsorbents—A critical review

Mohan

Pittman

2007

Journal of Hazardous Materials

3,134

1,445

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“…Some of them include carbon (12), lanthanum oxide (13), manganese green sand (14), iron-coated spent catalyst (15), and lanthanum impregnated silica gel (16). Some of them include carbon (12), lanthanum oxide (13), manganese green sand (14), iron-coated spent catalyst (15), and lanthanum impregnated silica gel (16).…”

Section: Introductionmentioning

confidence: 99%

Removal of As(V) by adsorption onto mixed rare earth oxides

Raichur

Panvekar

2002

Separation Science and Technology

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Arsenic pollution of water is a major problem faced worldwide. Arsenic is a suspected carcinogen in human beings and is harmful to other living beings. In the present study, a novel adsorbent was used to remove arsenate [As(V)] from synthetic solutions. The adsorbent, which is a mixture of rare earth oxides, was found to adsorb As(V) rapidly and effectively. The effect of various parameters such as contact time, initial concentration, pH, and adsorbent dose on adsorption efficiency was investigated. More than 90% of the adsorption occurred within the first 10 min and the kinetic rate constant was found to be about 3.5 mg min 21 . Adsorption efficiency was found to be dependent on the initial As(V) concentration, and the adsorption behavior followed the Langmuir adsorption model. The optimum pH was found to be 6.5. The presence of other ions such as nitrate, phosphate, sulphate, and silicate decreased the adsorption of As(V) by about 20-30%. The adsorbed As(V) could be desorbed easily by washing the adsorbent with pH 12 solution. This study demonstrates the applicability of naturally occurring rare earth oxides as selective adsorbents for As(V) from solutions. 1095

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“…The sorption characteristics of the adsorbents were evaluated by the method of constant concentrations of the salt composition (changing the solution) [9]. The selectivity coefficient with respect to silver was determined as the mass fraction of silver absorbed by the adsorbent to the sum of all metals sorbed in the form of cyanide complexes ( Table 3).…”

mentioning

confidence: 99%

Carbon adsorbents made from petroleum asphaltite semicoke

Pokonova

2007

Chem Technol Fuels Oils

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Petroleum asphaltite semicoke added to the batch makes it possible to synthesize adsorbents with important sorption capacity and selectivity in extraction of silver from multicomponent polymetallic solutions with the existing industrial scheme.A stable trend toward using active carbons as adsorbents for extracting precious metals is being observed in our country and abroad [1]. A specific feature of silver-containing ores is an extremely low silver content and the complexity of the component composition determines the necessity of using relatively voluminous and selective Table 1 Indexes Asphaltite Semicoke* from asphaltite Group composition, wt. % oils 12.6 -resins 8 -asphaltenes 79.4 -Heteroatom content, % S 5.45 5.67 N 0.86 1.3 O (by difference) 2.04 5.03 С:Н (atomic) 1.02 2.18 Note. *60% yield of semicoke.423 adsorbents for extracting silver from them. Readily available and economically suitable feedstock is necessary for obtaining such adsorbents.It was shown in [2-4] that adsorbents made from petroleum asphaltites and products of their chemical transformations have higher adsorption characteristics than domestic and foreign industrial adsorbents. We report the manufacture and investigation of adsorbents made with asphaltite semicoke.A sample of asphaltite (Table 1) underwent semicoking in a ZK-1 industrial delayed coking unit. The process was conducted for 10 h at 500-550°C with a temperature elevation rate of 50-60°/h. At the end of the process, the asphaltite was held for 1 h at the same temperature. The yield of products was, wt. %: 55-60% semicoke, 34-40% gas, and 3-5% condensate. As a result of semicoking, the C:H ratio increased by two times. As indicated in [2-4], the asphaltenes obtained in heat treatment of oils and resins contain fewer heteroatoms, are more aromatized, and have an ordered structure in comparison to native asphaltenes.The adsorbents were molded from a batch obtained by mixing previously ground asphaltite semicoke with 10% total shale phenols -a mixture of alkylresorcinols, 37% wood resin, and the dust fraction (0.1 mm particles ≤ 1%) of lean dug coal for 4-6 min in a two-paddle mixer at 60-70°C.The ash content of the latter was 7.09%, the moisture content was 1.25%, and the volatiles content was 13.2%. The batch obtained was granulated, then carbonized in carbon dioxide medium while heating from 200 to 800°C and activated in steam at 800-900°C.A significant amount of volatiles (4-7%) was liberated during carbonization, and the yield of carbon residue was 70-74%. The mechanical strength and density of the adsorbents did not change up to high degrees of combustion loss (Table 2).Experimental isotherms of adsorption of benzene vapors at 20°C on a vacuum microbalance were made to characterize the pore structure and they were used to calculate the pore parameters of the adsorbents [5]. The isotherms were processed with the Kiselev method to calculate the specific micro-and mesopores volumes [6]. The parameters of the microporous structure were calculated with Dubinin's theory of volume ...

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Carbon adsorbents for the sorption of arsenic

Cited by 20 publications

References 2 publications

Arsenic removal from water/wastewater using adsorbents—A critical review

Arsenic removal from water/wastewater using adsorbents—A critical review

Removal of As(V) by adsorption onto mixed rare earth oxides

Carbon adsorbents made from petroleum asphaltite semicoke

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