ReviewRemoval of heavy metal ions from wastewaters: A review
Introduction
Heavy metals are elements having atomic weights between 63.5 and 200.6, and a specific gravity greater than 5.0 (Srivastava and Majumder, 2008). With the rapid development of industries such as metal plating facilities, mining operations, fertilizer industries, tanneries, batteries, paper industries and pesticides, etc., heavy metals wastewaters are directly or indirectly discharged into the environment increasingly, especially in developing countries. Unlike organic contaminants, heavy metals are not biodegradable and tend to accumulate in living organisms and many heavy metal ions are known to be toxic or carcinogenic. Toxic heavy metals of particular concern in treatment of industrial wastewaters include zinc, copper, nickel, mercury, cadmium, lead and chromium.
Zinc is a trace element that is essential for human health. It is important for the physiological functions of living tissue and regulates many biochemical processes. However, too much zinc can cause eminent health problems, such as stomach cramps, skin irritations, vomiting, nausea and anemia (Oyaro et al., 2007). Copper does essential work in animal metabolism. But the excessive ingestion of copper brings about serious toxicological concerns, such as vomiting, cramps, convulsions, or even death (Paulino et al., 2006).
Nickel exceeding its critical level might bring about serious lung and kidney problems aside from gastrointestinal distress, pulmonary fibrosis and skin dermatitis (Borba et al., 2006). And it is known that nickel is human carcinogen. Mercury is a neurotoxin that can cause damage to the central nervous system. High concentrations of mercury cause impairment of pulmonary and kidney function, chest pain and dyspnoea (Namasivayam and Kadirvelu, 1999). The classic example of mercury poisoning is Minamata Bay. Cadmium has been classified by U.S. Environmental Protection Agency as a probable human carcinogen. Cadmium exposes human health to severe risks. Chronic exposure of cadmium results in kidney dysfunction and high levels of exposure will result in death.
Lead can cause central nervous system damage. Lead can also damage the kidney, liver and reproductive system, basic cellular processes and brain functions. The toxic symptoms are anemia, insomnia, headache, dizziness, irritability, weakness of muscles, hallucination and renal damages (Naseem and Tahir, 2001). Chromium exits in the aquatic environment mainly in two states: Cr(III) and Cr(VI). In general, Cr(VI) is more toxic than Cr(III). Cr(VI) affects human physiology, accumulates in the food chain and causes severe health problems ranging from simple skin irritation to lung carcinoma (Khezami and Capart, 2005).
Faced with more and more stringent regulations, nowadays heavy metals are the environmental priority pollutants and are becoming one of the most serious environmental problems. So these toxic heavy metals should be removed from the wastewater to protect the people and the environment. Many methods that are being used to remove heavy metal ions include chemical precipitation, ion-exchange, adsorption, membrane filtration, electrochemical treatment technologies, etc. The present review article deals with the current techniques for the removal of heavy metal ions from wastewater. Their advantages and limitations in application are also evaluated.
Section snippets
Chemical precipitation
Chemical precipitation is effective and by far the most widely used process in industry (Ku and Jung, 2001) because it is relatively simple and inexpensive to operate. In precipitation processes, chemicals react with heavy metal ions to form insoluble precipitates. The forming precipitates can be separated from the water by sedimentation or filtration. And the treated water is then decanted and appropriately discharged or reused. The conventional chemical precipitation processes include
Remarks of heavy metal treatment methods
Although all the heavy metal wastewater treatment techniques can be employed to remove heavy metals, they have their inherent advantages and limitations.
Heavy metals removal from aqueous solutions has been traditionally carried out by chemical precipitation for its simplicity process and inexpensive capital cost. However, chemical precipitation is usually adapted to treat high concentration wastewater containing heavy metal ions and it is ineffective when metal ion concentration is low. And
Conclusions
Hazardous heavy metal pollution of wastewater is one of the most important environmental problems throughout the world. To meet the increased more and more stringent environmental regulations, a wide range of treatment technologies such as chemical precipitation, coagulation–flocculation, flotation, ion-exchange and membrane filtration, have been developed for heavy metal removal from wastewater. It is evident from the literature survey of 185 articles that ion-exchange, adsorption and membrane
Acknowledgements
The authors thank the financial supports from National Natural Science Foundation of China (No. 51008084) and Natural Science Foundation of Guangdong Province (No. 9451009001002753).
References (184)
- et al.
Removal of some heavy metal cations by synthetic resin purolite C100
J. Hazard. Mater.
(2009) - et al.
A study on acid reclamation and copper recovery using low pressure nanofiltration membrane
Chem. Eng. J.
(2010) - et al.
Removal of cationic heavy metal from aqueous solution by activated carbon impregnated with anionic surfactants
J. Hazard. Mater.
(2009) - et al.
Biosorption of Cu2+ and Zn2+ from aqueous solutions by dried marine green macroalga Chaetomorpha linum
J. Environ. Manage.
(2009) - et al.
Chromium(VI) biosorption by dried Rhizopus arrhizus: effect of salt (NaCl) concentration on equilibrium and kinetic parameters
J. Hazard. Mater.
(2007) - et al.
Saudi Arabian clays for lead removal in wastewater
Appl. Clay Sci.
(2009) - et al.
Precipitation of Zn(II), Cu(II) and Pb(II) at bench-scale using biogenic hydrogen sulfide from the utilization of volatile fatty acids
Chemosphere
(2007) - et al.
Kinetics and equilibrium studies for the removal of nickel and zinc from aqueous solutions by ion exchange resins
J. Hazard. Mater.
(2009) - et al.
Potato peels as solid waste for the removal of heavy metal copper(II) from waste water/industrial effluent
Colloid Surf.
(2008) - et al.
Statistical modeling and optimization of the cadmium biosorption process in an aqueous solution using Aspergillus niger
Colloid Surf.
(2009)
Sorption of Cu2+, Cd2+, and Pb2+ using modified zeolite from coal fly ash
Chem. Eng. J.
Batch and column studies of biosorption of heavy metals by Caulerpa lentillifera
Bioresour. Technol.
Use of clinoptilolite for the removal of nickel ions from water: kinetics and thermodynamics
J. Hazard. Mater.
Removal of chromium ions from aqueous solutions by polymer-enhanced ultrafiltration
J. Hazard. Mater.
Influence of chemical conditioning on the ion exchange capacity and on kinetic of zinc uptake by clinoptilolite
Water Res.
Low-cost adsorbents for heavy metals uptake from contaminated water: a review
J. Hazard. Mater.
The investigation of lead removal by biosorption: an application at storage battery industry wastewaters
Enzym. Micro. Technol.
Effect of electrolyte composition on zinc hydroxide precipitation by lime
Water Res.
Polymer-enhanced ultrafiltration process for heavy metals removal from industrial wastewater
Desalination
Removal of heavy mercury(II), cadmium(II) and zinc(II) metal ions by live and heat inactivated Lentinus edodes pellets
Chem. Eng. J.
Treatment characteristics of textile wastewater and removal of heavy metals using the electroflotation technique
Desalination
Comparison of isotherms for the ion exchange of Pb(II) from aqueous solution onto homoionic clinoptilolite
J. Colloid Interface Sci.
Potentiality of lignin from the Kraft pulping process for removal of trace nickel from wastewater: effect of demineralization
Bioresour. Technol.
Removal of copper ions by the filamentous fungus, Rhizopus oryzae from aqueous solution
Bioresour. Technol.
Adsorption of a few heavy metals on natural and modified kaolinite and montmorillonite: a review
Adv. Colloid Interface Sci.
Low-level mercury removal from groundwater using a synthetic chelating ligand
Water Res.
Removal of Cu2+ and Zn2+ from model wastewaters by spontaneous reduction–coagulation process in flow conditions
J. Hazard. Mater.
Removal of nickel(II) ions from aqueous solution by biosorption in a fixed bed column: experimental and theoretical breakthrough curves
Biochem. Eng. J.
Heavy metals removal by flocculation/precipitation using N-(2-carboxyethyl)chitosans
Colloid Surf.
Modified column flotation of adsorbing iron hydroxide colloidal precipitates
Int. J. Miner. Process
The removal of zinc from liquid streams by electroflotation
Miner. Eng.
Removal of copper from industrial effluent using a spiral wound module — film theory and hydrodynamic approach
Desalination
Reverse osmosis removal of arsenic residues from bioleaching of refractory gold concentrates
Miner. Eng.
Study on the macromolecular coagulant PEX which traps heavy metals
Chem. Eng. Sci.
Integrated copper-containing wastewater treatment using xanthate process
J. Hazard. Mater.
The electrochemical phenomena and kinetics of EDTA–copper wastewater reclamation by electrodeposition and ultrasound
Sep. Purif. Technol.
Removal of Cu2+ and turbidity from wastewater by mercaptoacetyl chitosan
J. Hazard. Mater.
Heavy metals removal by chemical coagulation and precipitation
Wat. Sci. Technol.
Electrochemical technologies in wastewater treatment
Sep. Purif. Technol.
Removal of Pb2+, Ag+, Cs+ and Sr2+ from aqueous solution by brewery’s waste biomass
J. Hazard. Mater.
Adsorption behavior of multiwall carbon nanotube/iron oxide magnetic composites for Ni(II) and Sr(II)
J. Hazard. Mater.
Precipitation of heavy metals from wastewater using simulated flue gas: sequent additions of fly ash, lime and carbon dioxide
Water Res.
The use of electrodialysis for metal separation and water recovery from CuSO4–H2SO4–Fe solutions
Sep. Purif. Technol.
Biosorption of copper(II) ions from aqua solutions using dried yeast biomass
Colloid Surf.
Recovery of copper from process waters by nanofiltration and reverse osmosis
Desalination
Sorption and desorption of lead (II) from wastewater by green algae Cladophora fascicularis
J. Hazard. Mater.
Integration of a membrane bioreactor coupled with reverse osmosis for advanced treatment of municipal wastewater
Desalination
Waste materials for activated carbon preparation and its use in aqueous-phase treatment: a review
J. Environ. Manage.
Simultaneous removal of Cu, Mn and Zn from drinking water with the use of clinoptilolite and its Fe-modified form
Water Res.
Use of an iron-overexchanged clinoptilolite for the removal of Cu2+ ions from heavily contaminated drinking water samples
J. Hazard. Mater.
Cited by (7157)
Enhanced Cd<sup>2+</sup> removal from aqueous solution using olivine and magnesite combination: New insights into the mechanochemical synergistic effect
2025, Journal of Environmental Sciences (China)Study on the kinetics and mechanisms of Cr(VI) removal by nZVI modified with four modifiers
2024, Separation and Purification TechnologyAdsorption of Ag(Ⅰ) on chelate resins containing N and S: Comparison and computational study with anionic resin
2024, Separation and Purification TechnologySimultaneously-efficient electro-sorption of Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) by Cu<sup>2+</sup> modified superactive carbons
2024, Separation and Purification Technology