05/02489 SO2 and NO selective adsorption properties of coal-based activated carbons

Pristine Macadamia nutshell-based activated carbons were chemically oxidized with different concentrations of H3PO4 and HNO3 to increase their surface adsorption properties and further explore if they could be an attractive alternative low-cost adsorbent for gold recovery from cyanide-leached liquors. The modified activated carbons were labeled MACN20, MACN40 and MACN55 to signify the materials prepared from 20%, 40% and 55% (v/v) HNO3, respectively. Similar nomenclature was followed for H3PO4-modified activated carbons. Brunauer-Emmet-Teller, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, elemental analysis and X-ray diffraction spectroscopy were used to characterize the prepared activated carbons. The physical properties were attained through determining attrition, ash content, volatile matter and moisture content of all the activated carbons. Various parameters that affect selective adsorption such as the effect of initial concentration, time, agitation speed, interfering species and the dose of the adsorbent were investigated. Optimal parameters for gold ion adsorption were as follows: solution pH, 10; contact time, 6 h; agitation speed, 150 r/min; sorbent amount, 4 g and initial concentration, 5.5 mg/L. The observed selectivity order was not the same for all the adsorbents, but the adsorption of gold was found to be mostly influenced in the presence of nickel and least influenced by copper. MACN55 was found to be the most efficient adsorbent with 74% of gold adsorption from a real-world sample and displayed a similar performance to coconut-based activated carbons.

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Changes in the Adsorption Properties of Activated Carbon due to Partial Oxidation of the Surface

Adsorption Science & Technology ◽

10.1177/026361749501200305 ◽

1995 ◽

Vol 12 (3) ◽

pp. 211-219 ◽

Cited By ~ 13

Author(s):

A.M. Youssef ◽

A.A. El-Khouly ◽

A.I. Ahmed ◽

E.I. El-Shafey

Keyword(s):

Water Vapour ◽

Surface Coverage ◽

Activated Carbons ◽

Textural Properties ◽

Isosteric Heat ◽

Adsorption Properties ◽

Adsorption Of Water ◽

Oxygen Groups ◽

Initial Adsorption ◽

Entropy Of Adsorption

The textural properties (surface area and porosity) of activated carbons change upon treatment with oxidizing solutions. The extent of this change is related to the strength of the oxidizing agent. Oxidation also changes the chemistry of the surface by forming carbon–oxygen groups which are the sites upon which the initial adsorption of water vapour takes place. The adsorption of water vapour at 300–320 K is mainly physical and the isosteric heat of adsorption decreases continuously as the surface coverage increases. The entropy of adsorption of water vapour on untreated and oxidized carbons, at different adsorption temperatures, has been calculated.

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A Mini-Review on Anion Exchange and Chelating Polymers for Applications in Hydrometallurgy, Environmental Protection, and Biomedicine

Polymers ◽

10.3390/polym12040784 ◽

2020 ◽

Vol 12 (4) ◽

pp. 784

Author(s):

Piotr Cyganowski ◽

Anna Dzimitrowicz

Keyword(s):

Ion Exchange ◽

Environmental Protection ◽

Sharp Increase ◽

Selective Adsorption ◽

Adsorption Properties ◽

Heat Management ◽

Chelating Resins ◽

Increasing Demand ◽

Trace Concentrations ◽

Chelating Polymers

The rapidly increasing demand for technologies aiming to resolve challenges of separations and environmental protection causes a sharp increase in the demand for ion exchange (IX) and chelating polymers. These unique materials can offer target-selective adsorption properties vital for the removal or recovery of harmful and precious materials, where trace concentrations thereof make other techniques insufficient. Hence, recent achievements in syntheses of IX and chelating resins designed and developed in our research group are discussed within this mini-review. The aim of the present work is to reveal that, due to the diversified and unique physiochemical characteristics of the proposed materials, they are not limited to traditional separation techniques and could be used in multifunctional areas of applications, including catalysis, heat management, and biomedicine.

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A flexible supramolecular host with a crowned chair octameric water cluster and highly selective adsorption properties

CrystEngComm ◽

10.1039/b924511a ◽

2010 ◽

Vol 12 (10) ◽

pp. 2775 ◽

Cited By ~ 21

Author(s):

Arpan Hazra ◽

Prakash Kanoo ◽

Sudip Mohapatra ◽

Golam Mostafa ◽

Tapas Kumar Maji

Keyword(s):

Water Cluster ◽

Selective Adsorption ◽

Adsorption Properties

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SO2 and NO adsorption properties of activated carbons obtained from a pitch containing iron derivatives

Carbon ◽

10.1016/s0008-6223(01)00035-5 ◽

2001 ◽

Vol 39 (14) ◽

pp. 2173-2179 ◽

Cited By ~ 38

Author(s):

Paolo Davini

Keyword(s):

Activated Carbons ◽

Adsorption Properties ◽

No Adsorption

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Selective adsorption properties of the surfaces of attapulgite and sepiolite

Journal of Chromatography A ◽

10.1016/s0021-9673(00)93938-4 ◽

1973 ◽

Vol 77 (1) ◽

pp. 109-118 ◽

Cited By ~ 6

Author(s):

Giovanni Manara ◽

Marco Taramasso

Keyword(s):

Selective Adsorption ◽

Adsorption Properties

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SURFACE ALTERATION OF ACTIVATED CARBON FOR DETOXIFICATION OF COPPER (II) FROM INDUSTRIAL EFFLUENTS

Surface Review and Letters ◽

10.1142/s0218625x13500212 ◽

2013 ◽

Vol 20 (02) ◽

pp. 1350021

Author(s):

SADAF BHUTTO ◽

M. NASIRUDDIN KHAN

Keyword(s):

Activated Carbons ◽

Selective Adsorption ◽

Low Cost ◽

Industrial Effluents ◽

Copper Adsorption ◽

Adsorption Capacities ◽

Surface Alteration ◽

Equilibrium Data ◽

Modified Activated Carbons ◽

Acetic Acids

The low-cost modified activated carbons were prepared from Thar and Lakhra (Pakistan) coals by activation with sulfuric acid and further modified with citric, tartaric and acetic acids for the selective adsorption of Cu(II) from aqueous solution. The original carbon obtained from activated Thar and Lakhra coals at pH 3.0 displayed significant adsorption capacity for lead and insignificant capacity values (0.880 and 0.830 mg⋅g-1) for copper. However, after modification with citric, tartaric and acetic acid the copper adsorption capacities enhanced in the range of 5.56–21.85 and 6.05–44.61 times, respectively. The Langmuir, Freundlich and Temkin adsorption isotherms were used to elucidate the observed sorption phenomena. The isotherm equilibrium data was well fitted by the Langmuir and sufficiently fitted to the Freundlich models. The calculated thermodynamic parameters such as change in Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) inferred that the investigated adsorption was spontaneous and endothermic in nature. Based on the results, it was concluded that the surface alteration with citric and tartaric acid, Thar and Lakhra activated carbons had significant potential for selective removal of copper(II) from industrial wastewater.

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