Adsorption of mercury from single and multicomponent metal systems on activated carbon developed from cherry stones

Abstract

The adsorption of mercury from a single/multisolute aqueous solution by activated carbon (AC) prepared from cherry stones (CS) by chemical activation with H 3 PO 4 , ZnCl 2 or KOH is studied. Three series of AC (i.e., P, H 3 PO 4 ; Z, ZnCl 2 ; K, KOH) were prepared by controlling the impregnation ratio and carbonization temperature. The textural characterization of AC was carried out by gas adsorption, mercury porosimetry and density measurements. The surface chemistry was analyzed by the pH of the point of zero charge (pH zpc ), FT-IR spectroscopy and Boehm's method. Experiments of mercury adsorption were conducted by the batch method, using aqueous solutions of mercury and of mercury, cadmium and zinc without pH adjustment. The ACs possess a wide range of pore volumes and sizes. Their microporosity is usually well developed. The meso-and macropore volumes are higher for the P carbons and K carbons, respectively. BET surface areas as a rule range between 1000 and 2000 m 2 g −1 . The pH zpc is much lower for the P carbons. The content of acidic oxygen surface groups is lower for the K carbons, whereas the content of basic groups is higher for these carbons. The kinetics of the adsorption process of mercury is faster for ACs with high volumes of large size pores. However, the surface groups have M. Olivares-Marín · C. Fernández-González · V. Gómez-Serrano ( ) a marked unfavorable influence on the kinetics. The pseudosecond order rate constant (k 2 × 10 −3 , g/mol h) is higher by the order Z-4-800 (67.69) > K-3-800 (43.45) > P-3. 44-400 (36.98). The incorporation of zinc and cadmium to the mercury solution usually decelerates the adsorption process for the P carbons and Z carbons and accelerates it for the K carbons. The amount adsorbed of mercury is much larger for the K carbons than for the other ACs. For the Z carbons, competition effects of zinc and cadmium on the adsorption of mercury are negligible, which indicates that mercury adsorbs specifically on surface active sites of these adsorbents.

Cherry stones as precursor of activated carbons for supercapacitors

“…The resulting activated carbons have been used successfully for the removal of metal ions from water streams [17,18].…”

Preparation of Micropore-Containing Adsorbents from Kenaf Fibers and Their Use in Mercury Removal from Aqueous Solution

“…Other factors than the porous structure could probably influence the adsorption kinetics such as the presence of constrictions in narrow pores or the surface chemistry created in ACFs. In fact, and according to a previous report, the presence of surface groups in samples may render difficult the access of the adsorptive to the adsorption sites because of steric effects (Olivares-Marín et al 2008). This fact is corroborated by the application of molecular modelization to the hydrated HgCl 2 molecule.…”

“…Surface basicities of carbons due to π electron of graphene layers and pyrone-type structures on the edges (Montes- Morán et al 1998;Li et al 2002) could have increased with the activation temperature and therefore increased the amount of HgCl 2 adsorbed. In fact, in a previous report (Olivares-Marín et al 2008), the authors suggested that HgCl 2 becomes adsorbed on the surface of the carbons by acid-basic interactions in which HgCl 2 behaves as an acid. That statement was supported by the fact that the amount adsorbed by the carbons fitted well with the contents of basic groups which were strongly dependent on the activation temperature.…”

“…Upon equilibration, the solid particles were removed by filtration. The mercury remnant concentration was analyzed by effecting absorbance measurements of the tetrahedral coordination complex [HgCl 4 ] 2− at 231 nm using an UV-V Shimadzu PC-3101 spectrophotometer (Olivares-Marín et al 2008).…”

A comparison on efficiency of virgin and sulfurized agro-based adsorbents for mercury removal from aqueous systems

“…Various treatment techniques have been reported and applied for removal of such heavy metals from industrial wastewaters including precipitation (Kurniawan et al 2006;U.S. EPA 1980;Ayres et al 1984), ion-exchange (Chiarle et al 2000;Yang and Renken 2000), membrane processes (Tang et al 2007;Srisuwan and Thongchai 2002;Bessbousse et al 2010), adsorption (Basha et al 2009;Bayramoglu and ArIca 2008;Bhatnagar and Sillanpää 2010;Di Natale et al 2006;Ekinci et al 2002;Olivares-Marin et al 2008;Shafaei et al 2007) etc. Most of these methods suffer from drawbacks like high capital and operational cost and there are also problems in disposal of the residual metal sludge (Namasivayam and Sangeetha 2006).…”