Recovery of chromate from spent plating solutions by two-stage nanofiltration processes

Chen, Shiao‐Shing; Hsu, Bao-Chrung; Ko, Chun-Han; Chuang, Pei-Chi

doi:10.1016/j.desal.2007.08.015

Cited by 20 publications

(8 citation statements)

References 15 publications

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“…When the pH was adjusted from 8 to 11, nearly complete removal was achieved, resulting from all the chromium species becoming CrO 4 2− . This behavior is also in a good agreement with the literature [ 26 , 28 , 29 ].…”

Section: Resultssupporting

confidence: 92%

“…Thus, in the acidic range, more retention rate was observed at lower initial chromium concentration compared to higher concentration for NF-HL membrane (30 to 20% at pH 5), but passing to alkaline range, a reverse trend was observed, where higher retention rate occurred at higher concentrations (80.0 to 99.7% at pH 8) which can be explained by the dielectric exclusion effect [ 20 ]. In fact, Cr(VI) can exist in the aqueous solution in different ionic forms (HCrO 4 − , CrO 4 2− , Cr 2 O 7 2− ), which depend on Cr(VI) concentration and solution pH [ 25 , 26 ]. According to these results, one can conclude that, in the pH range 4–5.5, the possible form of Cr(VI) according to the concentrations is HCrO 4 − , and in the pH range of 5.5–11, the various possible forms are HCrO 4 − until pH 6.5 and CrO 4 2− until pH 11.…”

Section: Resultsmentioning

confidence: 99%

“…The results show that the retention rate of Cr(VI) decreased with increasing salt concentrations since the electrostatic effects of the membrane become weaker as KCl, KNO 3 , or K 2 SO 4 concentration increases. This is known as the screening phenomenon, where potassium ions neutralize partially the negative charges of the membrane, which involves the decrease of the retention of charged ions, thus facilitating the passage of the hexavalent chromium ions [ 26 ]. This was later reported by Hafiane et al [ 28 ].…”

Section: Resultsmentioning

confidence: 99%

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Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane

Mnif

Bejaoui

Mouelhi

et al. 2017

International Journal of Analytical Chemistry

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Nanofiltration and reverse osmosis are investigated as a possible alternative to the conventional methods of Cr(VI) removal from model water and industrial effluent. The influences of feed concentration, water recovery, pH, and the coexisting anions were studied. The results have shown that retention rates of hexavalent chromium can reach 99.7% using nanofiltration membrane (NF-HL) and vary from 85 to 99.9% using reverse osmosis membrane (RO-SG) depending upon the composition of the solution and operating conditions. This work was also extended to investigate the separation of Cr(VI) from car shock absorber factory effluent. The use of these membranes is very promising for Cr(VI) water treatment and desalting industry effluent. Spiegler-Kedem model was applied to experimental results in the aim to determine phenomenological parameters, the reflection coefficient of the membrane (σ), and the solute permeability coefficient (Ps). The convective and diffusive parts of the mass transfer were quantified with predominance of the diffusive contribution.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane

Mnif

Bejaoui

Mouelhi

et al. 2017

International Journal of Analytical Chemistry

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“…The percentage removal of chromium at pH 9 was only 77.915 % at 5 min which is very less when compared at pH 5 and 7, which are 90.142 and 95.640 %, respectively. This may be because the divalent chromium species CrO 4 2− which is dominant at high pH would have formed metal complex with sodium present in the effluent and passed through the membrane (Chen et al 2008). Figure 10 indicates the percentage removal of chromium in tannery effluent at pH 5, pH 7, and pH 9 during various time intervals.…”

Section: Effect Of Phmentioning

confidence: 99%

Removal of heavy metal chromium from tannery effluent using ultrafiltration membrane

Vinodhini¹,

Sudha²

2016

Text Cloth Sustain

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The present study was aimed to fabricate a novel ultrafiltration membrane using cellulose acetate, nanochitosan, and polyethylene glycol of ratio 1:2:2 by phase inversion method. Analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and scanning electron microscopy (SEM) have been employed to characterize the prepared membrane. FTIR and XRD results revealed the formation of blended membrane with increased amorphous nature. SEM studies exhibited the rough surface with numerous pores. The prepared membrane was also characterized for its ultrafiltration performance by membrane compaction, pure water flux, water content, and porosity. The results showed that the membrane obtained a pure water flux of 25.32 l/m 2 h. The water content was found to be 24 % and a high porosity of 83 % was obtained which showed the membrane's high hydrophilicity and more porous nature. The main focus of the present study was toxic hexavalent chromium removal from tannery effluent using the prepared hydrophilic membrane, which causes various adverse effects. The effect of pH of the solution (viz., pH 5, 7, and 9), membrane thickness (0.1 and 0.2 mm), and the applied pressure (50 and 100 kPa) were studied which are the key factors in determining the efficiency of the prepared membrane in remediation of tannery effluent. The results showed high percentage removal of chromium at pH 7 using 0.2 mm thickness at 100 kPa. The physicochemical parameters of the tannery effluent were also found to be reduced.

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“…Therefore, chemical nature of the Cr (VI) ion depends on the pH and concentration of the solution. Cr (VI) is found in different oxy‐anion forms such as Cr 2 O 7 − , CrO 4 2− , and HCrO 4 − and H 2 CrO 4 depending on pH and the total concentration of the solution [2, 20]. Because experiments were carried out by varying pH of solutions from pH = 2 to pH = 7 at three different concentrations (5, 100, 250 ppm) dichromate species is out of focus of this study (Table 3).…”

Section: Resultsmentioning

confidence: 99%

High performance chromium (VI) removal from water by polyacrylonitrile‐co‐poly (2‐ethyl hexylacrylate) and polyaniline nanoporous membranes

Bozkır

Sankır

Semiz

et al. 2012

Polymer Engineering & Sci

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This article reports the chromium (VI) removal from water by preparing polyacrylonitrile‐co‐poly (2‐ethyl hexylacrylate) (PAN(92)‐co‐P2EHA(8)) and polyaniline (PANI) nanoporous membranes at various PANI loadings. It was observed that chromium (VI) rejections of nanoporous membranes are highly concentration and pH dependent. Almost complete chromium removal (99.9%) with higher flux values (120–177 L m−2 h−1) was observed for nanoporous membranes. Moreover, nanoporous membranes were also demonstrated as fouling resistant. Total flux loss was low and a part was attributed to reversible flux loss, which cannot cause any permanent hysteresis and easily overcome with simple washing. Scanning electron microscopy (SEM) studies were performed for identifying cross sectional morphology. It was pointed out that pore size should be small enough for filtration and optimized for higher flux but pores should be functionalized for rejection. Chemical structure, swelling ratios, sheet resistivity, and fracture morphologies of nanoporous membranes were reported. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

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Recovery of chromate from spent plating solutions by two-stage nanofiltration processes

Cited by 20 publications

References 15 publications

Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane

Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane

Removal of heavy metal chromium from tannery effluent using ultrafiltration membrane

High performance chromium (VI) removal from water by polyacrylonitrile‐co‐poly (2‐ethyl hexylacrylate) and polyaniline nanoporous membranes

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