Removal of Heavy Metals from the Environment by Biosorption

Abstract

The pollution of the environment with toxic metals is a result of many human activities, such as mining and metallurgy, and the effects of these metals on the ecosystems are of large economic and public‐healthsignificance. This paper presents the features and advantages of the unconventional removal method of heavy metals – biosorption – as a part of bioremediation. Bioremediation consists of a group of applications, which involvethe detoxification of hazardous substances instead of transferring them from one medium to another, by means of microbes and plants. This process is characterized as less disruptive and can be often carried out on site, eliminating the need to transport the toxic materials to treatment sites. The biosorption (sorption of metallic ions from solutions by live or dried biomass) offers an alternative to the remediation of industrial effluents as well as the recovery of metals contained in other media. Biosorbents are prepared from naturally abundant and/or waste biomass. Due to the high uptake capacity and very cost‐effective source of the raw material, biosorption is a progression towards a perspective method. The mechanism by which microorganisms take up metals is relatively unclear, but it has been demonstrated that both living and non‐living biomass may be utilized in biosorptive processes, as they often exhibit a marked tolerance towards metals and other adverse conditions. One of their major advantages is the treatment of large volumes of effluents with low concentrations of pollutants. Models developed were presented to determine both the number of adsorption sites required to bind each metal ion and the rate of adsorption, using a batch reactor mass balance and the Langmuir theory of adsorption to surfaces or continuous dynamic systems. Two main categories of bioreactors used in bioremediation – suspended growth and fixed film bioreactors – are discussed. Reactors with varying configurations to meet the different requirements for biosorption are analyzed considering two major groups of reactors – batch reactors and continuous reactors. Biosorption is treated as an emerging technology effective in removing even very low levels of heavy metal.

Predicting the capability of carboxylated cellulose nanowhiskers for the remediation of copper from water using response surface methodology (RSM) and artificial neural network (ANN) models

“…Since the majority of conventional technologies are impractical for treating heavy metal at low concentrations due to high operating cost (Gavrilescu, 2004), the range for the initial Cu(II) ion solution was chosen to be 10-60 mg/L. Thus, the temperature (6-25°C), initial Cu(II) ion concentration (10-60 mg/L), and sorbent dosage (0.2-10 g/L)…”

Biosorption of Mn (II), Co (II) and Cr (VI) in a horizontal rotating tubular bioreactor: experiments and evaluation of the integral bioprocess model

“…The Cr 6+ ion sorption process in the HRTB was mostly carried out only on the first 50% of bioreactor length where the pH was below 5 due to the fact that the overall microbial cell surface charge becomes more positive, promoting sorption of anionic Cr 6+ ion species (Baes and Mesmer, 1976;Zhou et al, 2007). Furthermore, hydrodynamic conditions in the HRTB also affected all previously mentioned factors (Gavrilescu, 2004). Therefore, on the basis of these results it is clear that biological and hydrodynamic conditions in the HRTB have a significant effect on the suspended biomass concentration and its sorption capacity (Table 2).…”

“…As an alternative, different biological methods could be applied because they do not destroy metals, but concentrate and immobilize them (Gavrilescu, 2004;Vieira et al, 2012;Michalak et al, 2013;Sicupira et al, 2014;Vieira et al, 2014). Biosorption is the removal of metals and their complexes by biological materials such as active or inactive microorganisms, microbial aggregates or biofilms (Singh et al, 2006;Baysal, et al, 2009;Xie, et al, 2013).…”

Heavy Metal Tolerance Potential of Fungus Isolated From Copper Smelting Industry

“…In naturally polluted environments, the heavy metal toxicity of microbes depends largely on the concentration and availability of metals 11 . The most common heavy metal tolerate microbes are fungi and yeast 12,13 . They are a versatile group, as they can adapt and grow under various extreme conditions of pH, temperature and nutrient availability, as well as high metal concentrations 14 .…”