Nanofiltration Method Research Articles

The influence of the nanofiltration method on the retentate composition after simulated chromium tannery wastewater concentration

The influence of the nanofiltration method on the retentate composition after simulated chromium tannery wastewater concentration

A study of a ferric-lactate complex as draw solute in forward osmosis

In forward osmosis (FO), draw solution is a critical problem which restricts the progress and application of FO technology. The study of an optimal draw solution is essential in the application of the FO technology. In this paper, a mild one-pot method was used to synthesize a ferric-lactate (LAFe) complex, which had a good performance of high osmotic pressure, moderate viscosity and high solubility, as a potential draw solute. Then, the properties of the LAFe complex in FO were systematically studied. The water flux was improved to 18.78±1.56Lm−2h−1 (LMH) at 1M LAFe, which was 1.8 times than that of 1M NaCl. And, the reverse salt flux of the 1M LAFe (1.00±0.09gm−2h−1) obviously was diminishing, only 1/4 of the 1M NaCl. Furthermore, in the application test, 1M LAFe exhibited the water flux of 7.54LMH (in the first hour) when the seawater of Huanghai coast was used as the feed solution. The recovery of the LAFe was employed successfully by a nanofiltration method, achieving a high efficiency of 96%.

Removal of radionuclides, macrocomponent metal ions, and organic compounds from solutions by nanofiltration

Removal of Mg2+, Сa2+, Cu2+, Ni2+, Zn2+, Fe3+, and Pr3+ ions, tracer amounts of 137Cs, 85Sr, and 60Co radionuclides, and oxalate and ethylenediaminetetraacetate ions from solutions using a polymeric nanofiltration (NF) membrane produced by RM Nanotekh (Russia) was studied. The selectivity (S) of the NF membrane to multicharged metal cations is considerably higher than to single-charged cations. The NF membrane exhibits the highest selectivity (S = 94–97%) to triple-charged Fe3+ and Pr3+ ions and double-charged Cu2+ ions. The selectivity to double-charged Mg2+ and Zn2+ ions is somewhat lower (90–94% on the average). Among doublecharged cations, the NF membrane exhibits the lowest selectivity (80–88%) to Ni2+ and Cа2+ ions. The NF membrane shows high performance in retention of tracer amounts of Sr (S = 95%) and Co (S > 99%) radionuclides, and also of oxalate (S = 94.5%) and ethylenediaminetetraacetate (S = 97.5%) ions. Examples of using the nanofiltration method for removing 60Co from a model solution simulating NPP bottom residue and for removing transition metal impurities from a LiCl solution are presented.

Separation of 1,3-Propanediol by Nanofiltration Method

Separation of 1,3-Propanediol by Nanofiltration Method

Separation of 1,3-Propanediol by Nanofiltration Method

The application potential of nanofiltration (NF) method on the separation of 1,3-propanediol (1,3-PDO) from synthetically prepared fermentation broth was investigated. The rejection tests at different pressures (10, 20, 30 bar) and pH values (7 and 10) were performed on laboratory scale using Desal DL-5 NF membrane. The rejection of succinic acid, having the molecular weight larger than or closer to the molecular weight cut-offs (MWCOs) of Desal-5 DL NF membrane was 100% independent of operating pressure and pH. The results of this study clearly showed that NF process is a very promising pretreatment step for the removal of volatile organic acids from the fermentation broth.

Removal of Phosphate and Fluoride from Industrial Wastewater – A Short Review

Industries producing fertilizers, aluminium, steel, bricks, glass, and semiconductor discharge several thousand tons of phosphate and fluoride per year into the open atmosphere in the form of wastewater which cause many environmental issues as well as loss of drinking water. The objective of this review is to select the suitable method for the removal of phosphate and fluoride from industrial wastewater which is highly hazardous and acidic in nature. So that treated water can be reused for agricultural and industrial purposes. Industries discharge several thousand tons of phosphate and fluoride per year in the form of wastewater which cause many environmental issues and loss of drinking water. This review is provided with aimed a precise and accurate knowledge for the removal of phosphate and fluoride from industrial wastewater. A lot of technologies are available for the treatment of industrial wastewater treatment including chemical precipitation, crystallization, ion exchange, adsorption, reverse osmosis and nanofiltration methods. The selection of most suitable treatment technology is based on retention time, principle of operation, applications, chemicals and maintenance cost.

Application of nanofiltration for reuse of wastewater

The present research is a part of efforts to reuse wastewater by applying nanofiltration (NF) method for the secondary treatment of bio-treated wastewater and to check the quality of product water as irrigation water by using various analytical methods. For this, the performances of three different NF membranes (CK, GE-Osmonics; NF-270 and NF-90, Dow-FilmTech) were investigated using a cross-flow flat-sheet membrane test unit (SEPA CF-II, GE). The bio-treated wastewater obtained from ITOB-OSB Wastewater Treatment Plant, Izmir where membrane bioreactor (MBR) technology is employed as a treatment process has a high salinity and a high conductivity which make the treated water unsuitable for irrigation purposes. After applying NF separation for the three membranes at 10 bar as operating pressure, it was concluded that NF-90 gave the best quality of product water for almost all analysed parameters such as salinity calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulphate, phosphate-phosphorous, nitrate-nitrogen, and conductivity.

Improved radiocarbon dating for contaminated archaeological bone collagen, silk, wool and hair samples via cross‐flow nanofiltrated amino acids

Radiocarbon dating and stable isotope analyses of bone collagen, wool, hair and silk contaminated with extraneous carbon (e.g. humic substances) does not yield reliable results if these materials are pre-treated using conventional methods. A cross-flow nanofiltration method was developed that can be applied to various protein materials like collagen, hair, silk, wool and leather, and should be able to remove low-molecular and high-molecular weight contaminants. To avoid extraneous carbon contamination via the filter a ceramic filter (molecular weight cut-off of 200 Da) was used. The amino acids, released by hot acid hydrolysis of the protein material, were collected in the permeate and contaminants in the retentate (>200 Da). (14)C-dating results for various contaminated archaeological samples were compared for bulk material (pre-treated with the conventional methods) and for cross-flow nanofiltrated amino acids (permeate) originating from the same samples. Contamination and quality control of (14)C dates of bulk and permeate samples were obtained by measuring C:N ratios, fluorescence spectra, and δ(13)C and δ(15)N values of the samples. Cross-flow nanofiltration decreases the C:N ratio which means that contaminants have been removed. Cross-flow nanofiltration clearly improved sample quality and (14)C results. It is a quick and non-labor-intensive technique and can easily be implemented in any (14)C and stable isotope laboratory for routine sample pre-treatment analyses.

Quantification and characterization of dissolved organic nitrogen in wastewater effluents by electrodialysis treatment followed by size-exclusion chromatography with nitrogen detection

Dissolved organic nitrogen (DON) can act as a precursor of nitrogenous disinfection byproducts during oxidative water treatment. Quantification and characterization of DON are still challenging for waters with high concentrations of dissolved inorganic nitrogen (DIN, including ammonia, nitrate and nitrite) relative to total dissolved nitrogen (TDN) due to the cumulative analytical errors of independently measured nitrogen species (i.e., DON = TDN − NO2− − NO3− − NH4+/NH3) and interference of DIN species to TDN quantification. In this study, a novel electrodialysis (ED)-based treatment for selective DIN removal was developed and optimized with respect to type of ion-exchange membrane, sample pH, and ED duration. The optimized ED method was then coupled with size-exclusion chromatography with organic carbon, UV, and nitrogen detection (SEC-OCD-ND) for advanced DON analysis in wastewater effluents. Among the tested ion-exchange membranes, the PC-AR anion- and CMT cation-exchange membranes showed the lowest DOC loss (1–7%) during ED treatment of a wastewater effluent at ambient pH (8.0). A good correlation was found between the decrease of the DIN/TDN ratio and conductivity. Therefore, conductivity has been adopted as a convenient way to determine the optimal duration of the ED treatment. In the pH range of 7.0–8.3, ED treatment of various wastewater effluents with the PC-AR/CMT membranes showed that the relative residual conductivity could be reduced to less than 0.50 (DIN removal >90%; DIN/TDN ratio ≤0.60) with lower DOC losses (6%) than the previous dialysis and nanofiltration methods (DOC loss >10%). In addition, the ED method is shorter (0.5 h) than the previous methods (>1–24 h). The relative residual conductivity was further reduced to ∼0.20 (DIN removal >95%; DIN/TDN ratio ≤0.35) by increasing the ED duration to 0.7 h (DOC loss = 8%) for analysis by SEC-OCD-ND, which provided new information on distribution and ratio of organic carbon and nitrogen in different molecular weight fractions of effluent organic matter.

Application of nanofiltration for reuse of municipal wastewater and quality analysis of product water

In this study, the municipal wastewater treated by biological methods was used for further treatment by nanofiltration method for wastewater reuse. For this purpose, different nanofiltration (NF) membranes, such as CK, NF-90, and NF-270 were employed. The quality analysis of product water was carried out using various analytical techniques. The results revealed that the NF-90 membrane can produce the best water quality compared to other two membranes. The CK membrane showed also a good rejection property after NF-90 membrane but its big inconvenience is that it gave a lower water flux. Despite the good water flux by NF-270, the permeate quality obtained with this membrane was not as good as obtained with the NF-90 and CK membranes.

Development of a nanofiltration method for bone collagen 14C AMS dating

Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased 14C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) ∼100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used.In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate.Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. 14C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant but incomplete removal of HSs (between 63% and 85%).

Influence of high molecular amines on removal of nitrates from aqueous solutions by the nanofiltration method

The removal of nitrate ions from aqueous solutions using OPMN-P membranes in the presence of high-molecular amines, such as polyhexamethylene guanidine and aethonium was studied. It was shown that within the range of pH 4–7 the five-fold weight excess of amines makes possible to increase retention of nitrate ions up to 0.83 in case of polyhexamethylene guanidine and up to 0.76 in the case of aethonium. The influence of chlorides on the treatment process was also investigated. The interaction mechanisms in the “membrane-high molecular amine-nitrates” system were discussed.

The impact of low-molecular amines on the extraction of nitrates by the nanofiltration method

The paper has investigated extraction of nitrate ions from aqueous solutions by a OPMN-P membrane in the presence of low-molecular amines of guanidine and urotropine. It showed the impact of the pH and the concentration of nitrate ions on this process. It has been found that the presence in the solution of guanidine results in a decrease of the degree of retention of nitrates by the membrane two- or threefold compared with the solutions not containing this amine, while the presence of urotropine in the neutral and acid regions of the pH in the equimolar ratio to nitrate ions makes it possible to raise the retention degree of the latter by 10%.

Organic solvent nanofiltration for microfluidic purification of poly(amidoamine) dendrimers

A nanofiltration method has been developed in a microfluidic format for the continuous-flow pressure-driven purification of half-generation poly(amidoamine) (PAMAM) dendrimers, a family of macromolecules characterized by highly branching structures radiating from a central core, without additional solvents or buffers. An organic solvent resistant nanofiltration membrane, STARMEM 122, has been fully integrated into a hard polymer microfluidic module by transmission laser welding. The membrane was initially characterized in a bench-top test fixture to determine the solvent permeance and percent rejection of a surrogate molecule, Rhodamine B, at lower than typical operating pressures ( P < 7 bar). The microfluidic module then underwent similar testing at 1.4 bar with the surrogate and with the generation-0.5 PAMAM dendrimer. This approach to nanofiltration will readily interface to upstream microreactors.

CJD PrP sc removal by nanofiltration process: Application to a therapeutic immunoglobulin solution (Lymphoglobuline ®)

The characteristic of transmissible spongiform encephalopathies (TSE) is an accumulation of partially protease resistant (PrP res) abnormal prion protein (PrP sc). This pathological prion protein is very resistant to conventional inactivation methods. The risk of transmission of TSE, such as Creutzfeldt–Jakob disease (CJD), by biopharmaceutical products prepared from human cells must be taken into account. The nanofiltration process has been proved to be effective in removing viruses and scrapie agent. The major advantages of this technique are flexibility and efficacy in removing infectious particles without altering biopharmaceutical characteristics and properties. This study focused on the removal of human PrP sc by means of a nanofiltration method after spiking a Lymphoglobuline ® solution with a CJD brain homogenate. Lymphoglobuline ® equine anti-human thymocyte immunoglobulin is a selective immunosuppressive agent acting mainly on human T lymphocytes. The therapeutic indications are: • immunosuppression for transplantation: prevention and treatment of graft rejection; • treatment of aplastic anemia. In our study, CJD homogenate was spiked at three different dilutions (low, moderate and high) in the Lymphoglobuline ® product. The nanofiltration process was performed on each sample. Using the western blot technique, the PrP res signal detected in nanofiltrates was compared to that obtained with a reference scale (dilution series of CJD brain homogenate in Lymphoglobuline ® detected by western blot and elaborated on 3.3 log). After nanofiltration, the PrP res western blot signal was detected with a significant reduction in the less dilute sample, whereas the signal was undetectable in the two other samples. These are the first data in CJD demonstrating a clearance between 1.6 and 3.3 log with a Lymphoglobuline ® recovery of over 93%. The nanofiltration process confirms its relative efficacy in removing human CJD PrP sc.

Application of the Nanofiltration Method in Systems for Recycling of Washing Water in Photographic Development of Motion-Picture Films

The possibility of using the nanofiltration method for purification of washing water in photographic development of professional motion-picture films is analyzed. Characteristics of domestic membranes, OPMN-K of nanofiltration type and OFAM-KN of low-pressure reverse-osmosis type, obtained in desalting of silver-containing washing water, are presented.

Membrane Methods for Treating Liquid Radioactive Wastes from the Shelter To Remove Transuranic Elements

The possibility is studied of membrane treatment of liquid radioactive wastes from the inside premises of the Shelter to remove transuranic elements using ultra- and nanofiltration methods. The highest degree of decontamination (about 100%) was obtained for Pu and Am, and the lowest one, for Cs; for U and Sr, the values were intermediate. The effect of characteristics of a nanofiltration membrane on the LRW treatment efficiency is studied.

Surface water treatment by the nanofiltration method

Studies concerning the removal of natural organic matter (NOM) from surface and tap water by nanofiltration are presented. The separation and transport characteristics of nanofiltration membranes were determined. The degree of NOM coefficient and water hardness removal from surface water and a reduction of water hardness were studied. The content of organic matter, both in the feed and the permeate, was estimated by the determination of total organic carbon (TOC), colour, turbidity, chemical oxygen demand (CODMn) and the absorbance in ultraviolet at a wavelength of 254 nm. The investigations demonstrated the complete removal of humic acids determined as the UV254 absorbance, and a high removal of colour (93.3%), TOC (93.5%) and turbidity (85.5%).

Recovery of brightness in paper mill water

This paper investigates the utilisation of nanofiltration (NF), agitation (by pump or sonication), freezing and acetone extraction methods to purify paper machine o-water. The results were judged by regained pulp brightness and reduction of various components. In the NF experiments the brightness was almost totally regained. Also the reduction of most measured components like lignin and carbon were retained well by the membrane (PES). The metal ions (Si, Al, Mg, Na, K, Mn, Ca, Fe and Cu) were reduced in the permeate (retained by the membrane) to the level found in the clear filtrate. This indicated that the metal ions (Si, Al, Mg, Na, K, Mn, Ca, Fe and Cu) were not brightness-reducing components. The flux was rather low for a commercial application because the membrane was a low-flux membrane. The reduction of sugar, colour and lignin residuals was quite high (>80%), and it was considered that these were possibly brightness-reducing components. It was found that by treating the fines with acetone and then returning them to the original water, the colour was reduced to a high enough degree that approximately 50% of the brightness reduction was recovered. It was considered that coloured contaminants that were absorbed on the fines were removed or destroyed. The brightness recovery was >50% for both the TMP and PK4 o-water. The brightness recovery was greater using NF, but in that case so many substances were reduced in the permeate that it was difficult to determine which were the brightness-reducing substances. However, in the case of acetone washing, the only component that was reduced was the colour. For both o-water PK4 and TMP the colour was reduced by 50% and the brightness recovery was 50%, suggesting a direct correlation. Agitation of the water samples by the means of a pump and sonication showed no change in the water, which included no changes in the brightness. The same was also found for water samples that were frozen. These experiments also showed that temperature changes did not affect water composition.

Nanofiltration of highly colored raw water for drinking water production

Water purification with membrane technology was investigated as one of the alternatives for the future drinking water production (6,000 m 3/d) in Nynäshamn community. The selected raw water source was surface water from Lake Muskan rather than brackish water from the Baltic Sea. The lake water, without need for desalination, has a high color number (up to 100 mg/l Pt) due to humic substances as well as taste and odor problems from time to time. This R&D project has been performed in two phases: Phase 1: Laboratory trials for membrane selection (NF/UF/MF) with and without activated carbon treatment compared with a conventional raw water treatment including flocculation, sedimentation, filtration and activated carbon treatment. Phase 2: Pilot plant operation with the selected nanofiltration (NF) method for design of a full scale plant. Phase 1 will be presented separately. The aim of the pilot plant operation has been to evaluate different design parameters, type of prefiltration, two tested NF-membranes, membrane cleaning procedure as well as to estimate the costs of a full-scale plant. The result of the pilot plant operation is satisfactory, implying removal of color and organic matter to undetectable levels and maintaining a higher membrane flux than expected throughout the trial period during 6 months. The membrane cleaning with a detergent (Ultrasil 10) has been repeated every second day. The disposal of the NF reject into the sewage net is not possible due to the increase of the hydraulic load. Purification of the NF-reject with ultrafiltration (UF) to a color level about the same as for the raw water from the lake has been suggested in combination with disposal of the UF reject by irrigation of a nearby golf course. The membrane alternative is according to the cost calculation competitive with other alternatives. The water price will be a little higher (about 0.17 USD/m 3 higher) than conventional treatment including activated carbon, but the drinking water quality will be improved and more consistent. The membrane application above is unique in Sweden but at the same time in accordance with the present trend in several other countries to utilize membrane technology without chemicals instead of conventional raw water treatment for drinking water production.