| Membrane filtration |
Excellent performance in scale-up applications, such as excellent heavy metal removal, high efficiency, ease of operation, and low space requirements |
Membrane fouling, capital cost, maintenance and operational cost, less efficient in case of lower metal ion concentration |
Suitable for both high- and low-concentration copper-polluted water; selection of the right polymer/micellar agent is required to improve the rejection efficiency |
Treatment cost of membrane fouling |
| Reverse osmosis |
Effective removal of metals from wastewater |
Membrane scaling problems, low water permeability, high RO operating pressure due to internal concentration polarization, low water flux, and high energy consumption |
Use in drinking water |
| Ion exchange |
Selective removal of heavy metals, high treatment capacity, high metal removal rate |
Fouling and maintenance costs, high capital cost of equipment and instruments, high operational as well as resin regeneration cost |
Treatment of water bodies polluted by a specific metal element, not suitable for large-scale application |
High cost of synthetic resin, pollutant recovery costs |
| Electrochemical reaction |
Reduced chemical consumption, recovery of pure metals, effective removal of desired metals, suitable for initial high concentration contamination remediation |
Low current effect and selectivity, high power consumption |
Electrochemical methods, such as electrodialysis, electrocoagulation, electrodeposition, and capacitive deionization, are capable of removing Cu(II) by different mechanisms and are therefore suitable for a wide range of copper concentrations |
Electricity costs |
| Chemical precipitation |
Low metal concentration in the effluent achieved. This approach can be adapted to handle large quantities of wastewater. Simple to use |
High chemical requirement, pH maintenance at optimum level, handling of colloidal particle sludge disposal problem. A large number of factors, such as temperature, pH, precipitant concentration, etc., have to be monitored when implementing this technique, which is quite difficult |
For the treatment of concentrated copper wastewater, the preferred method is precipitation |
Sludge disposal cost |
| Adsorption |
Highly effective for removing heavy metals within permissible limits; the desorption process can produce a concentrated Cu(II) stream with recovery potential |
Chemical regeneration requirement, fouling and corrosion of treatment plant, disposal of exhausted adsorbents, preparation of the adsorbent involve high costs, such as in the case of activated carbon, loss of adsorption capacity by the adsorbent in each cycle, frequent regeneration, which reduce the simplicity of the adsorption process |
When treating diluted wastewater, adsorption is preferred due to its simplicity and effectiveness |
Cost of desorption and regeneration |
