The conventional methods for heavy metal removal included chemical precipitation, chemical oxidation or reduction, ion exchange, filtration, electrochemical treatment, reverse osmosis, membrane technologies, and even evaporation recovery [13, 14].
Conventional methods for heavy metal removal from wastewater include reduction, precipitation, ion exchange, filtration, electrochemical treatment, membrane technology, and evaporation, all of which may be ineffective or extremely expensive when metals are dissolved in large volumes of solution at relatively low concentrations [3, 4].
However, pollution can be attenuated as the water moves through the ground by processes that include sorption, ion exchange, filtration, precipitation and biodegradation.
While the separation may be realized by cation-exchange filtration, complete removal of the dissolved metal complex requires extra time, and avoiding partial loss of polarization is hardly possible.
The water purification system was a Milli-Q gradient A 10 (185 nm ultraviolet, ion exchange, and filtration) equipped with an EDS polisher (activated carbon filtration) (Millipore, Bedford, MA, USA).
Other wastewater-based metal recovery technologies exciting interest include ion exchange, ultra filtration (including reverse osmosis, where wastewater is pushed through a membrane at high pressure), electrolytics and various biological treatments to oxidise metals.
Ion exchange, membrane filtration and coagulation are generally used for treating chromium-laden wastewater (Fabbricino et al. 2013).
Other approaches such as ion exchange resins, filtration and direct chemical reduction are also employed (Kurniawan et al. 2006).
Although several water treatment methods are available like chemical precipitation, ion exchange adsorption, filtration and membrane systems, they are slow and non-destructive.
Physical methods, which include precipitation, ion exchange, membrane filtration, electrochemical destruction, irradiation and adsorption, lead to the formation of sludge and various by-products.
Physical processes include adsorption, chelation ion exchange, membrane filtration, and coagulation.
