Comparative Study between Nanofiltration and Reverse Osmosis Membranes for the Removal of Heavy Metals from Electroplating Wastewater (original) (raw)
Related papers
International Journal of Science and Research (IJSR)
The present work aimed to study the efficiency of nanofiltration (NF) and reverse osmosis (RO) membrane for heavy metal removal from wastewater and study the factors affecting the performance of these two membranes: feed concentrations for heavy metal ions, pressure, and flow rate. The experimental results showed, heavy metals concentration in permeate increase with raise in feed concentrations, decline with increase in flow rate. The raise of pressure, heavy metals concentration decreases for RO membrane, but for NF membrane the concentration decrease and then at high pressure increase. The rejection percentage for chromium in NF and RO is 99.7% and 99.9%, for copper is 98.4% and 99.3%, for zinc is 97.9% and 99.5%, for nickel is 97.2% and 99.5% respectively. For a synthetic electroplating wastewater, the maximum recovery was 70.7% and 48.9% for NF and RO respectively.In general, polyamide nanofiltration and reverse osmosis membranes give a high efficiency for removal of chromium, copper, nickel and zinc. A mathematical model describing the process with the existence of the effect of concentration polarization was studied. The agreement between theoretical and experimental results has an accuracy ranging from 86-99.4% for NF and 93-99.9% for RO.
Performance of Nanofiltration and Reverse Osmosis Membranes in Metal Effluent Treatment
Chinese Journal of Chemical Engineering, 2008
The performance of different nanofiltration (NF) and reverse osmosis (RO) membranes was studied in treating the toxic metal effluent from metallurgical industry. The characteristics and filtration behavior of the processes including the wastewater flux, salt rejection and ion rejection versus operating pressure were evaluated. Then the wastewater flux of RO membrane was compared with theoretical calculation using mass transfer models, and good consistency was observed. It was found that a high rejection rate more than 95% of metal ions and a low Chemical Oxygen Demand (COD) value of 10 mg L 1 in permeate could be achieved using the RO composite membrane, while the NF rejection of the salt could be up to 78.9% and the COD value in the permeate was 35 mg L 1. The results showed that the product water by both NF and RO desalination satisfied the State Reutilization Qualification, but NF would be more suitable for large-scale industrial practice, which offered significantly higher permeate flux at low operating pressure.
ChemistrySelect, 2023
Heavy metals present in wastewater and water scarcity are a global challenge worldwide. The elimination of heavy metals in wastewater is necessary to protect the ecosystem and human health. Heavy metals such as lead, cadmium, and mercury are among many other toxic heavy metals present in wastewater. There are several conventional methods that have been implemented to mitigate heavy metal pollution in wastewater and according to literature, it has been evident that the nanofiltration (NF) separation technique requires minimal pressure to obtain high rejections of multivalent inorganic salts compared to conventional methods. NF separation process is highly competitive in terms of selectivity and cost-benefit. The growing research trend of NF fabrication and modification collates that the technology has been applied in various industrial and municipality wastewater treatment facilities. The review paper aims to illustrate the health impacts of heavy metal exposure, the cons of conventional methods and the utilization of NF membranes in wastewater treatment, the overall factors affecting membrane performance, and future aspects of the separation techniques.
International journal of membrane science and technology, 2021
Water contamination by heavy metal is a great environmental concern. It leads to many health issues ranging from diarrhea, vomiting to life-threatening diseases like cancer, lung/kidney damage. This also affects soil biota/plant growth. Metal-ions have a tendency of bioaccumulation, hence pose a major issue upon entry in the food-cycle. Their removal from water is necessary before use for human/agricultural applications. Different methods reported for metal-ion separation are conventional methods viz. chemical-precipitation, ion-exchange, adsorption, coagulation, flocculation, flotation, electrochemical possess good separation efficiency, but the generation of a secondary pollutant, recovery issues restrict their applicability. Hence, there is a need of reliable techno-economical, environment-friendly, sustainable separation, recovery method. Membrane-based methods viz. reverse-osmosis, nanofiltration, electrodialysis, ultrafiltration has ability to treat water for heavy metal recovery without chemical contamination. Recovered materials can be recycled/utilized further. Among different membrane-based processes, micellar/polymer enhanced ultrafiltration requires chemical addition and affects purity. Electrodialysis, reverse-osmosis, nanofiltration processes require large energy/operational issues. Hence, simple ultrafiltration with membrane modification is preferable as low-energy requirements. This paper discusses details of conventional/advanced methods for heavy metal separation with the fundamental process, parameters, advantages/limitations.
2018
The present work aimed to study the efficiency of nanofiltration (NF) and reverse osmosis (RO) process for treatment of heavy metals wastewater contains zinc. In this research, the salt of heavy metals were zinc chloride (ZnCl2) used as feed solution.Nanofiltration and reverse osmosis membranes are made from polyamide as spiral wound module. The parameters studied were: operating time (0 – 70 min), feed concentrations for zinc ions (10 – 300 mg/l), operating pressure (1 – 4 bar).The theoretical results showed, flux of water through membrane decline from 19 to 10.85 LMH with time. Flux decrease from 25.84 to 10.88 LMH with the increment of feed concentration. The raise of pressure, the flux increase for NF and RO membranes.The maximum recovery was 99% and 57% for NF and RO respectively.In general, polyamide nanofiltration and reverse osmosis membranes give a high efficiency for removal of zinc. The separation efficiency of heavy metals in reverse osmosis membrane higher than nanofilt...
Experimental Study and Mathematical Modelling of Zinc Removal by Reverse Osmosis Membranes
Iraqi journal of chemical and petroleum engineering, 2016
In this study, aromatic polyamide reverse osmosis membranes were used to remove zinc ions from electroplating wastewater. Influence of different operating conditions such as time, zinc concentration and pressure on reverse osmosis process efficiency was studied. The experimental results showed, concentration of zinc in permeate increase with increases of time from 0 to 70 min, and flux of water through membrane decline with time. While, the concentrations of zinc in permeate increase with the increase in feed zinc concentration (10-300 mg/l), flux decrease with the increment of feed concentration. The raise of pressure from 1 to 4 bar, the zinc concentration decreases and the flux increase. The highest recovery percentage was found is 54.56% for reverse osmosis element, and the highest rejection of zinc was found is 99.49%. Experimental results showed that the concentrations of zinc ion in permeate was lower than the permissible limits (i.e. ˂ 10 ppm). A mathematical model describing the process was investigated and solved by using MATLAB PROGRAM. Theoretical results were consistent with the experimental results approximately 90%.
Wastewater treatment by nanofiltration membranes
IOP Conference Series: Earth and Environmental Science, 2018
Lower energy consumption compared to reverse osmosis (RO) and higher rejection compared to ultrafiltration make nanofiltration (NF) membrane get more and more attention for wastewater treatment. NF has become a promising technology not only for treating wastewater but also for reusing water from wastewater. This paper presents various application of NF for wastewater treatments. The factors affecting the performance of NF membranes including operating conditions, feed characteristics and membrane characteristics were discussed. In addition, fouling as a severe problem during NF application is also presented. Further, future prospects and challenges of NF for wastewater treatments are explained.
Pilot scale membrane separation of electroplating waste water by reverse osmosis
Journal of Membrane Science, 1997
Electroplating waste water containing copper was treated by means of reverse osmosis (RO) membrane separation on a pilot scale. The copper concentration in the untreated waste water was 340 ppm. After the treatment, the concentration in the treated water was below 4 ppm which is the Hong Kong government discharge limit. It is shown that, by increasing transmembrane pressure drop, metal concentrations in the treated water can be further reduced. This study suggests that larger scale operations on treating electroplating waste water by RO membrane separation is possible and effective. Effects of operating variables including transmembrane pressure drop and temperature on membrane separation performance were studied and explained based on the solution-diffusion model. The present study is part of the recent investigation of industrial waste water management sponsored by the Hong Kong Government. The purpose of this project is to provide guidelines to the local industries for waste minimization which is closely monitored by the Hong Kong legislature.