Application of activated carbons for the enrichment of toxic metals and their determination by atomic spectroscopy

Abstract The effectiveness of two Azadirachta indica bark activated carbons (ABAC) for the removal of selected toxic metals from mining wastewater and the attendant challenge of multivariate factors in the process were enhanced through optimization studies. Experimental design was carried out using adsorbent dosage, agitation rate, contact time, grain size, pH and temperature as independent variables. Batch adsorption experiments were conducted using the experimental design result, then the experimental data obtained were optimized using Design-Expert software and the results validated. Optimum values for ABAC-NaOH adsorbent were 1.999 g of adsorbent dosage, 149.73 rpm agitation rate, 119.55 min contact time, 2 mm grain size, pH of 7 and 30 °C temperature; while for ABAC-HCl adsorbent the optimum values were 3.993 g of adsorbent dosage, 150 rpm agitation rate, 120 min contact time, 2 mm grain size, pH of 7.001 and 30 °C temperature. These resulted in 100% removal efficiencies for all the selected toxic metals with standard errors of between 0.02 and 2.72%. So the optimization process is a very useful tool in adsorption studies. It has the merits of being economical, energy and time saving, and is therefore strongly recommended for the biosorption of toxic metals from mining wastewater using Azadirachta indica adsorbent.

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In situ modification of activated carbons developed from a native invasive wood on removal of trace toxic metals from wastewater

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2008.03.075 ◽

2009 ◽

Vol 161 (1) ◽

pp. 217-223 ◽

Cited By ~ 44

Author(s):

J. de Celis ◽

N.E. Amadeo ◽

A.L. Cukierman

Keyword(s):

Toxic Metals ◽

Activated Carbons ◽

In Situ Modification ◽

Native Invasive

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Nickel Coated Carbon Nanomaterial for the Removal of Heavy and Toxic Metals (Cd, Cu) from Water and Wastewater

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.778.79 ◽

2018 ◽

Vol 778 ◽

pp. 79-85 ◽

Cited By ~ 2

Author(s):

Tayyaba Asim ◽

Riaz Ahmad ◽

MUHAMMAD Shahid Ansari

Keyword(s):

Heavy Metals ◽

Toxic Metals ◽

Membrane Filtration ◽

Activated Carbons ◽

Acidic Solutions ◽

Supported Nanoparticles ◽

Removal Of Heavy Metals ◽

Nanocarbon Materials ◽

Water And Wastewater ◽

Coated Carbon

Heavy metals in water have always remained a point of concern for the environmental scientists due to their non biodegradability and toxicity. Adsorption and membrane filtration are the most widely studied and applied processes for the treatment of water. Activated carbons have frequently been used for the removal of heavy metals from water by the process of adsorption. With the development of nanotechnology, nanomaterials are used as the adsorbents in water treatment and have proved effective for the removal of heavy and toxic metals from water. nanocarbon materials, nanometal particles and polymer supported nanoparticles are widely used. A new adsorbent comprising of graphite coated with nanonickel particles was prepared, characterized and used for the removal of heavy and toxic metals from water. nanomaterial was characterized using ICP-AES, FTIR, XRD, and SEM. It was used for the removal of cadmium and copper from water. Kinetics and thermodynamics of adsorption of cadmium and copper on both the materials was investigated and compared. Adsorption isotherm of Langmuir, Freundlich and Dubinin-Radushkevich were also applied to the adsorption data for the adsorption and removal of cadmium and copper. Effect of pH was also studied and it was found that nanomaterial was very effective for the removal of Cd and Cu from acidic solutions. Effect of different acids at different concentration was studied and it was found that nanomaterial remained stable for adsorption while carbon alone deteriorated. Results indicate that developed nanomaterial is a very effective adsorbent for the removal of heavy and toxic metals from water and wastewater.

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Atomic Spectroscopy in the FIM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145157 ◽

1986 ◽

Vol 44 ◽

pp. 758-761

Author(s):

J. J. Hren ◽

S. D. Walck

Keyword(s):

Electron Microscope ◽

Electric Fields ◽

Atom Probe ◽

Atomic Spectroscopy ◽

Single Atom ◽

Statistical Sampling ◽

Commercial Instrument ◽

Available Technology ◽

High Electric Fields ◽

Field Ion Microscope

The field ion microscope (FIM) has had the ability to routinely image the surface atoms of metals since Mueller perfected it in 1956. Since 1967, the TOF Atom Probe has had single atom sensitivity in conjunction with the FIM. “Why then hasn't the FIM enjoyed the success of the electron microscope?” The answer is closely related to the evolution of FIM/Atom Probe techniques and the available technology. This paper will review this evolution from Mueller's early discoveries, to the development of a viable commercial instrument. It will touch upon some important contributions of individuals and groups, but will not attempt to be all inclusive. Variations in instrumentation that define the class of problems for which the FIM/AP is uniquely suited and those for which it is not will be described. The influence of high electric fields inherent to the technique on the specimens studied will also be discussed. The specimen geometry as it relates to preparation, statistical sampling and compatibility with the TEM will be examined.

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