Metabolic independent processes can mediate the biological uptake of heavy metal cations. Biosorption offers an economically feasible technology for efficient removal and recovery of metal(s) from aqueous solution. The process of biosorption has many attractive features including the selective removal of metals over a broad range of pH and temperature, its rapid kinetics of adsorption and desorption and low capital and operation cost. Biosorbent can easily be produced using inexpensive growth media or obtained as a by-product from industry. It is desirable to develop biosorbents with a wide range of metal affinities that can remove a variety of metal cations. These will be particularly useful for industrial effluents, which carry more than one type of metals. Alternatively a mixture of non-living biomass consisting of more than one type of microorganisms can be employed as biosorbents. Such “Combo” biosorbents have to be tested for commercial applications. The use of immobilized biomass rather than native biomass has been recommended for large-scale application but various immobilization techniques have yet to be thoroughly investigated for ease, efficacy and cost effectivity.
Biosorption processes are applicable to effluents containing low concentrations of heavy metals for an extended period. This aspect makes it even more attractive for treatment of dilute effluent that originates either from an industrial plant or from the primary wastewater treatment facility. Thus biomass-based technologies need not necessarily replace the conventional treatment routes but may complement them. At present, information on different biosorbent materials is inadequate to accurately define the parameters for process scale up and design perfection including reliability and economic feasibility. To provide an economically viable treatment, the appropriate choice of biomass and proper operational conditions has to be identified. To predict the difference between the uptake capacities of the biomass, the experimental results should be tested against an adsorption model. The development of a packed bed or fluidized-bed biosorption model would be helpful for evaluating industrial-scale biosorption column performance, based on laboratory scale experiments and to understand the basic mechanism involved in order to develop better and effective biosorbent.
Critical analysis reveals that not all metal-polluted wastewater-generating industries have the interest or the capability to treat effluents and most of the industries opt only for basic treatment techniques simply to comply with regulations. To attract more usage of biosorption, strategies have to be formulated to centralize the facilities for accepting the used biosorbent where processing of the biosorbent can be done to either regenerate the biomass or convert the recovered metal into usable form. This will further require an interdisciplinary approach with integration of metallurgical skills along with sorption and wastewater treatment to apply biosorption technology for combating heavy metal pollution in aqueous system.
Metabolic independent processes can mediate the biological uptake of heavy metal cations. Biosorption offers an economically feasible technology for efficient removal and recovery of metal(s) from aqueous solution. The process of biosorption has many attractive features including the selective removal of metals over a broad range of pH and temperature, its rapid kinetics of adsorption and desorption and low capital and operation cost. Biosorbent can easily be produced using inexpensive growth media or obtained as a by-product from industry. It is desirable to develop biosorbents with a wide range of metal affinities that can remove a variety of metal cations. These will be particularly useful for industrial effluents, which carry more than one type of metals. Alternatively a mixture of non-living biomass consisting of more than one type of microorganisms can be employed as biosorbents. Such “Combo” biosorbents have to be tested for commercial applications. The use of immobilized biomass rather than native biomass has been recommended for large-scale application but various immobilization techniques have yet to be thoroughly investigated for ease, efficacy and cost effectivity.
Biosorption processes are applicable to effluents containing low concentrations of heavy metals for an extended period. This aspect makes it even more attractive for treatment of dilute effluent that originates either from an industrial plant or from the primary wastewater treatment facility. Thus biomass-based technologies need not necessarily replace the conventional treatment routes but may complement them. At present, information on different biosorbent materials is inadequate to accurately define the parameters for process scale up and design perfection including reliability and economic feasibility. To provide an economically viable treatment, the appropriate choice of biomass and proper operational conditions has to be identified. To predict the difference between the uptake capacities of the biomass, the experimental results should be tested against an adsorption model. The development of a packed bed or fluidized-bed biosorption model would be helpful for evaluating industrial-scale biosorption column performance, based on laboratory scale experiments and to understand the basic mechanism involved in order to develop better and effective biosorbent.
Critical analysis reveals that not all metal-polluted wastewater-generating industries have the interest or the capability to treat effluents and most of the industries opt only for basic treatment techniques simply to comply with regulations. To attract more usage of biosorption, strategies have to be formulated to centralize the facilities for accepting the used biosorbent where processing of the biosorbent can be done to either regenerate the biomass or convert the recovered metal into usable form. This will further require an interdisciplinary approach with integration of metallurgical skills along with sorption and wastewater treatment to apply biosorption technology for combating heavy metal pollution in aqueous system.
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