Mercury Adsorption by Different Modifications of Furfural Adsorbent

Abstract

Adsorption of mercury from aqueous solutions using three types of furfural-based carbon adsorbents was studied. After activation with water vapor and air, carbon adsorbents with basic and acidic characters, respectively, were obtained. The results from the study showed that all modifications of the adsorbents (with both basic and acidic characters, as well as an adsorbent from mixture of furfural and apricot stones tar) are efficient sorbent materials for mercury removal from aquatic solutions. Mercury adsorption follows a Langmuir isotherm. Adsorbents with good adsorption capacities (174 mg/g for the basic adsorbent, 154 mg/g for the adsorbent from a mixture of furfural and tar, and 132 mg/g for the adsorbent with acidic character) were obtained. The pH was determined to be the most crucial parameter. The mercury removal increases with an increase in pH from 2 to 5. It was found that the adsorption capacities of the produced carbons are significantly higher than those of commercial activated carbons. A desorption study was performed with hot water. The percentage of the recovery was 6% for the basic furfural adsorbent, 1% for the furfural adsorbent with acidic character, and 4% for the adsorbent from the mixture of furfural and tar.

Adsorption of Aqueous Mercury(II) on Propylthiol-Functionalized Mesoporous Silica Obtained by Cocondensation

“…The reduction in the adsorption capacity is probably due to the fact that a higher concentration of protons in the solution stabilizes the thiol groups in the functionalized adsorbent, hindering the replacement of hydrogen by mercury species. Nevertheless, for SBA15SH- x materials, the pH appears not to play a crucial role in the mercury removal capacity as frequently occurs for other adsorbent materials such as activated carbon, clays, or silica gel. − ,, …”

“…Among them, the adsorption on activated carbon appears to be one of the most common techniques because of its simplicity of operation. In the last years, there has been an increasing interest to develop new adsorbents including resins, clays, and carbon materials obtained from nonconventional sources (biomass, agricultural products, and the like). − A quite promising alternative for selective adsorption is the use of specific chelating organic groups that can be anchored to the surface of a solid support. Because mercury species show a high affinity toward sulfur, several thio-organic groups have been used for improving the adsorption efficiencies of different materials such as activated charcoal, − clays, , or silica. , Frequently, however, not all of the functional groups that are incorporated into the material are accessible to the mercury species because such materials present small and irregular pore sizes …”

Removal of inorganic mercury from aqueous solutions by biomass of the marine macroalga Cystoseira baccata

“…It can be then concluded that the biomass of the marine alga Cystoseira baccata can efficiently remove high concentrations of mercury in solution over a broad range of pH, highlighting its potential for effluent treatment processes. The high sorption capacity of this seaweed is comparable to or even larger than other natural and synthetic materials, such as fungal biomass [Saglam et al (1999)] (61 mg•g -1 ), the green alga Ulva lactuca [Zeroual et al (2003)] (149 mg•g -1 ), the aquaphyte Potamogeton natans [Lacher and Smith (2002)] (180 mg•g -1 ), active carbons from different sources [Budinova et al (2003); Yardin et al (2003)] (132-174 mg•g -1 ), the synthetic resin Duolite GT-73 [Chiarle et al (2000)] (362 mg•g -1 ) or chitosan [Jeon and Höll (2003); Masri et al (1974);McKay et al (1989)] (460, 1123 and 815 mg•g -1 , respectively).…”

“…Adsorption as a wasterwater treatment process has been found to be an economically feasible alternative for metal removal. Activated carbon is one of the most well-known adsorbents [Bello et al (1999); Budinova et al (2003); Gómez-Serrano et al (1998)] but the high costs of the process has limited its use. A search for a low-cost and easily available adsorbent has led to the investigation of materials of biological origin as potential metal biosorbents.…”

Removal of inorganic mercury from aquatic environments by multi-walled carbon nanotubes

“…The surface results from the existence of tiny pores at it which the chemical property, area, size and distribution of these pores influence the level of an adsorbent’s specific surface. Different materials, such as fruit shell [ 13 ], chitosan [ 14 ], marine macroalga [ 15 ], bagasse pith [ 16 ], furfural [ 17 ], and rubber [ 18 ] have been applied as adsorbents to remove mercury from aqueous environments.…”