Biodegradation for Metal Extraction

Abstract

Heavy metals are nonbiodegradable and accumulate in the environment. Persistent pollutants such as heavy metals can enter the food chain via marine life, affecting predators such as larger fish, birds, and mammals, including humans, who transmit the pollutants to various environments. Much investigation has been carried out to mitigate the heavy metal pollution in the environment. Until now, heavy metal decontamination has relied on ethylenediaminetetraacetic acid (EDTA), a highly effective chelating agent. Although EDTA is particularly effective at mobilizing metals, its limited biodegradability means it can persist in the environment for a long time. As a result, biodegradable chelating agents were introduced to replace nonbiodegradable chelating agents due to their environmental friendliness. The chemical and physical properties of biodegradable aminopolycarboxylates such as iminodisuccinic acid, methylglycinediacetic acid, ethylenediamine-N, N′-disuccinic acid, nitrilotriacetic acid, and tetrasodium glutamate diacetate, as well as organic acids such as citric acid, will be studied and evaluated to see if they can perform similarly to standard chelant EDTA in terms of heavy metal pollution mitigation. Even though the chelating agents used are biodegradable, there is no guarantee that metal extraction effectiveness will be improved over traditional chelating agents, and it also depends on the type of heavy metal to be chelated. In short, many factors that contribute to metal extraction efficiencies, such as pH and chelating agent concentration, should be investigated in this chapter. Most importantly, although biodegradable chelants will decay in the environment, heavy metals will be left behind and will last longer in the ecosystem. In a nutshell, it is worth checking whether heavy metal pollution still exists after using a biodegradable chelant.