Cadmium is a heavy metal which is toxic for plants and human at its excess content. However, how can be removed cadmium (Cd) easily from soil?
Cadmium in soils can be remove either through bioremediation or phytoremediation. Bioremediation is the branch of biotechnology that uses biological process to solve environmental problems. It provides an innovative, cost effective and natural means of removing contaminants from contaminated soils and water. It is the use of biological agents, such as bacteria and fungi, to remove or neutralize contaminants, as in polluted soil or water. Bacteria and fungi generally work by breaking down contaminants such as petroleum into less harmful substances. Bioremediation technology exploits various naturally occurring mitigation processes such as: natural attenuation, biostimulation and bioaugmentation. Bioremediation are of two methods: in-situ and ex-situ methods.
Phytoremediation is defined as the use of living plants to remediate contaminated soil or water through removal, degradation or containment of the pollutants. It is a technique that is gaining more and more acceptance in bio-hydrogeology. Although phytoremediation has been employed in field of botany for many years, it is an emerging technique in the field of hydrobiology. Plants and large trees have been used for centuries to drain swamps, absorb heavy metals and organics (Amadi, 2014). Plants, like indian mustard, are used to extract heavy metals from contaminated sites. Phytoremediation techniques includes: phytoextraction, hyperaccumulation, rhizofiltration, rhizodegradation, phytovolatilization and phytostabalization.
Biosurfactants such as rhamnoiolipids,surfactin, saponin and sophorolipids have been employed to remove lead ,Cd, Ni, Cu and Zn from contaminated soil.
Soil washing is an effective approach to remove soil heavy metals, and the washing agent is generally regarded as one of the primary factors in the process, but there is still a lack of efficient and eco-friendly agents for this technique.
read this Removal of Pb, Zn, and Cd from contaminated soil by new washing agent from plant material ,reed Yaru Cao,et al
- Environmental Science and Pollution Research volume 24, pages8525–8533 (2017)
Phytoremediation can be applied to a large scale of toxic metals. In addition, for a given type of contaminant, such as metals, the selectivity of the plant is not strict. Thus, some Thlaspi plants coming from calamine environments (rich in Zn, Pb, Cd) can accumulate more than 3% of Zn, 0.8% of Pb and 0.1% of Cd in the dry matter.@
(1) A 30-mM aescin Solution is the most effective in the removal of Cadmium and Lead at pH 6.8. Cadmium and Lead migrated from the soil to the aescin-containing aqueous phase depending on the pH Value (Kyung-Jin H et Al 1998)
(2) Biosurfactants such as Sophorolipids (SLs) are also to be efficient in the remediation of Cadmium or Lead Contaminated soil (Xiaoyu Qui et Al 2018)
(3) At concentration of 50 g/L, pH 3 and contact duration of 120 min, F esculentum had higher removals of Pb (5.98-6.83 percent), Zn (21.82-27.94 percent) and Cd (39.90-40.74 percent) than those of F.faberi (Ting Li 2020)
Biosurfactants, such as rhamnolipids, surfactin, saponin, and sophorolipids (SLs), have been employed to remove lead (Pb), cadmium (Cd), nickel (Ni), copper (Cu), and zinc (Zn) from contaminated soils [11,12,13,14].
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