Removal of heavy metal ions from aqueous solution by modified barks

Abstract

The bioconcentration of fenitrothion in the brain of the european eel (Anguilla anguilla) and its posterior elimination have been studied. Animals were exposed to a sublethal concentration of fenitrothion (0.04 mg/L) for 96 hours in a flow-through test system. After this pesticide exposure, animals were transferred to clean water for 72 hours more. Bioconcentration and elimination processes of fenitrothion were studied in blood and brain. This insecticide showed a strong tendency to bioconcentrate into selected tissues. A steady-state was observed in blood in few hours. Highest accumulation was detected in brain, where any steady-state could be observed. Elimination started rapidly from both tissues when a recovery period was allowed. Elimination kinetics were adjusted to one-compartment model. K2 of 0.015 and 0.044 hr-1 were calculated for fenitrothion in blood and brain. These K2 values were related with a relatively short half-live of fenitrothion in the analyzed tissues; probably due to the low biotransformation rate of this toxicant in the european eel. That fact would protect the animals against many biotransformation products even more toxic than the parent fenitrothion.

Thermodynamic Properties of Chromium (III) Ion Adsorption by Sweet Orange (<i>Citrus sinensis</i>) Peels

“…One of such methods is the use of adsorption. Interest has recently risen in the investigation of some unconventional methods and low cost materials for scavenging heavy metal ions from industrial waste waters [4]. In general, an adsorbent can be assumed as "low cost" if it requires little processing, is abundant in nature, or is a by-product or waste material from the industry [2].…”

Heavy metals removal in aqueous environments using bark as a biosorbent

“…When there is only one metal available, the adsorption is non-competitive, but in treatments of industrial effluents, there are many metals available for the adsorption that may suppress each other (competitive adsorption) (Gloaguen and Morvan 1997). In contrast, Hanzlik et al (2004) reported that copper and silver were adsorbed better when both existed in solution and total metal uptake was higher than in single metal ion solutions.…”

“…Extractives have advantages in heavy metal treatments: Some extractives such as flavonoids (particularly the B ring) can complex with metals in water (Vazquez et al 2002), while tannins and pectins are considered as active ion-exchange compounds with their carboxylic and phenolic groups providing active sites for metal binding (Gloaguen and Morvan 1997). Netzahuatl-Muñoz et al (2012) reported the involvement of phenolic groups of lignin and tannins present in Cupressus lusitanica bark in the Cr(III) adsorption.…”

“…Miranda et al (2012Miranda et al ( , 2013 reported that smaller bark particles have higher mineral contents than bigger particles in pine, eucalypt, birch and spruce barks. Gloaguen and Morvan (1997) Scientific names in parentheses indicate probable species; in the corresponding references, the species was not mentioned…”

Bark, a suitable biosorbent for the removal of uranium from wastewater – From laboratory to industry

“…This ability has been attributed to bark pectin and tannin, and more precisely to their respective carboxylic and phenolic groups which can bind metallic cations (Aoyama et al, 1993;Kumar and Dara, 1980). The ability of barks to remove heavy metal ions from polluted solutions (Al-Asheh et al, 1998;Gaballah et al, 1997;Gloaguen et al, 1997;Seki et al, 1997;Aoyama et al, 1993;Deshkar et al, 1990;Kumar et al, 1980;Randall et al, 1974) and the impact of various operating factors on this phenomenon (Deshkar et al, 1990) are well documented. In one of our precedent papers, these interactions were modeled using a Langmuir isotherm (Martin-Dupont et al, 2002) and adsorbent performances were improved using chemical modification by attachment of anionic functions (Martin-Dupont et al, 2004).…”