Marine Macroalgae as Biosorbents for Cadmium and Nickel in Water

Abstract

Experimental studies showed that brown marine algae, Sargassum vulgaris and Padina pavonia, can be used to develop an efficient biosorbent for heavy metal removal from aqueous solutions. Sargassum vulgaris exhibited high uptake capacities for cadmium (0.9 to 1.1 mmol Cd/gr) and nickel (0.85 to 1 mmol Ni/gr) that are higher than those of other types of biomass and powdered activated carbon, while P. pavonia showed a broader range of nickel and cadmium uptake capacities (0.7 to 1 mmol Ni/gr and 0.8 to 1.1 mmol Cd/gr). The metal adsorption and desorption processes were rapid, with 70% of the sorption and desorption completed within 10 minutes. The equilibrium data for both algae fit well to Langmuir and Freundlich isotherm models. More than 90% desorption of adsorbed metals from the algae was achieved by hydrochloric acid and ethylenediaminetetraacetic acid (1:1 molar ratio). After eight to nine adsorption and desorption cycles, S. vulgaris showed a 15 to 35% decrease in metal uptake capacities; P. pavonia showed a higher decrease of 50 to 60%. Water Environ. Res., 75, 246 (2003). IntroductionThe contamination of water by toxic heavy metal ions is a worldwide environmental problem. Precipitation, filtration, ion exchange, membrane separation, and other techniques usually achieve removal of heavy metals. However, in many situations these processes do not work efficiently or fail to lower the metal concentration below the regulatory standards. Heavy metal precipitation produces intractable sludge that must then be treated and disposed, often at a high cost. In addition, many metal-bearing waste streams contain substances such as organic matter, alkaline earth metals, and others that may decrease the removal capability of the metal cations (Brauckmann, 1990;Eilbeck and Mattock, 1987).Biosorption of heavy metals from aqueous solutions is a relatively new wastewater treatment technology (Volesky, 1990). Adsorbent materials (biosorbents) that are derived from a suitable biomass can be used for the effective removal and recovery of heavy metal ions from wastewater streams. Biosorption of metals involves several mechanisms that differ qualitatively and quantitatively according to the species used and the origin of the biomass and its processing procedure. Metal sequestration during biosorption follows complex mechanisms, primarily ion exchange, chelation, adsorption by physical forces, and ion entrapment in intra interfibrillar capillaries and spaces of the structural polysaccharide network. The following chemical groups could attract and sequester the metals in biomass: acetamido, amino, amido, sulfhydryl, sulfate, and carboxyl (Ashkenazy et al.

Green synthesis of iron oxide (Fe3O4) nanoparticles using two selected brown seaweeds: Characterization and application for lead bioremediation

“…Metals are mobilized and carried into food web as a result of leaching from waste dumps, polluted soils and water. For this motive, many techniques for environmental remediation of heavy metals are being studied (Ofer et al, 2003;Bayramoğlu et al, 2006;Rai, 2008Rai, , 2010Rawat et al, 2011). Lead being one of the "big three" toxic heavy metals because it is rapidly accumulated by organisms including fish (Ribeiro et al, 2010) and becomes concentrated throughout the food chain to humans (ATS-DR, 2001;Crist et al, 1992).…”

Cd(II) biosorption using Lessonia kelps

“…Table 2 compares the maximum sorption properties for different algae. These biosorbents are among the most efficient algae for Cd(II) recovery and L. trabeculata has a maximum sorption capacity about 30% higher than Durvillaea potatorum [34], Sargassum vulgaris [55], and Fucus spiralis [56] that were reported in the literature as the best alga-based sorbents. These values are consistent with those found for Cu(II) and Cd(II) sorption on alginate gels beads: around 1.2 mmol metal g À1 [57].…”

Algae of economic importance that accumulate cadmium and lead: a review

“…Cadmium stands out among the heavy metals because it is relatively easily removed from waste streams, primarily due to its ability to form stable complexes with several different ligands (Ofer et al, 2003). The presence of cadmium in natural waters is extremely undesirable since it is both toxic and a nonessential element for most living organisms (Leborans & Novillo, 1996;Farias et al, 2002).…”

“…Compared to other types of biomass, brown algae showed the highest metal binding capacity, making them particularly attractive for the bioremediation of toxic heavy metals (Ofer et al, 2003). According to Davis et al (2003), the linear polysaccharides known as alginate, which are present in gel form in the stem of algae, are responsible for the biosorption of heavy metals by these algae.…”

“…For this motive, many techniques for environmental remediation of heavy metals are being studied (Ofer et al, 2003;Bayramoğlu et al, 2006;Rai, 2008Rai, , 2010Rawat et al, 2011). Among these techniques, the application of microorganisms has been widely discussed, mainly in view of their capability to remove pollutants from aquatic environments with good effi ciency and relatively low cost.…”