Electroplating wastewater

In a permeation experiment, an HERO module with a membrane area of 200 m is used to remove a nickel salt from an electroplating wastewater. TTie feed to the module has a flowrate of 5 x IQ— m /s, a nickel-salt composition of 4,(X)0 ppm and an osmotic pressure of 2.5 atm. The average pressure difference across the membrane is 28 atm. The permeate is collected at atmospheric pressure. The results of the experiment indicate that the water recovery is 80% while the solute rejection is 95%. Evaluate the transport parameters Ay and (D2u/KS). 

Treatment for the removal of chromium and nickel from electroplating wastewater involves neutralization, hexavalent chromium reduction, pH adjustment, hydroxide precipitation, and final solid-liquid separation.15 37 48... 

Maximum Permissible Concentrations of Electroplating Wastewater Discharge to Surface Waters... 

Cushnie, G.C., Jr, Electroplating Wastewater Pollution Control Technology, Noyes Publishing, Park Ridge, NJ, 1985. 

The use of Zn-Cr(III) alloy plating has almost replaced the use of Cr(VI) in the electroplating industry due to its excellent corrosion resistance and its lower toxicity. Recently, a solvent extraction procedure for separating and selectively recovering the two metals, zinc and chromium, from electroplating wastewaters has been demonstrated [10]. 

Cushnie, George C., "Electroplating Wastewater Pollution Control Technology", Noyes Publication, Park Ridge, New Jersey, 1985... 

Coughlin, R.W., Deshaies, M.R., and Davis E.M., Chitosan in crab shell wastes purifies electroplating wastewater. Environ. Prog., 9, 35, 1990. 

Treatment of Electroplating Wastewater. Toxic cyanide ions are the major pollutant in electroplating wastewater. They must be removed before discharge of the wastewater. As shown in Eqs. (3) and (4), ozone can oxidize free cyanide ion rapidly to less toxic cyanate ion, which then slowly hydrolyzes to nitrogen and ammonia. The reaction equations are as follows " ... 

Zn(II) as presented in Table 24.2 [6], or Cr(VI), more than 99% of which was removed from industrial electroplating wastewater [20], The modeling of the experimental breakthrough of lead (II) onto activated carbon fibers in a fixed bed, using axial dispersion and diffusion equations solved by the orthogonal collocation method, demonstrated that the intraparticle and external mass transfer is not the rate-controlling step, due to the short diffusion path for the adsorbate in activated carbon fibers [21]. 

As the method is designed for industrial applications, the interference of some metallic compounds must be checked. Indeed, different ions, such as copper (II), iron (III), lead (II) and mercury (II), for example, potentially existing in electroplating wastewater, may interfere with the determination of Cr (VI). Except in the presence of Fe3+, the measurement of Cr (VI) gives an error generally lower than 3% for 0.5 or 1 mg/L of metallic ion, and for greater concentrations (up to 10 mg/L), the error is negligible for Cu2+, and lower than 15% for the other ions [42]. 

One of the mejor areas of interest, of course, is the full-rude application of flotation techniques to the treatment of industrial wastewaters. Some pilot-scale studies have been performed on the removal of metals from actual industrial wastes. These wastes included electroplating wastewaters,1 textile wastewatem,2 wood preservation industry,3 tanneries,11 and, importantly, laundry wastewaters.3 This last category is an interesting approach In that the surfactants could be reclaimed fbr rense. This in turn would give it high applicability for mobile units in held hospitals, military camps, and so on. 

Senthilnathan J, Mohan S, Palanivelu K (2005) Recovery of chromium from electroplating wastewater using DI 2-(ethylhexyl) phosphoric acid. Sep Sci Technol 40 2125-2137. doi 10.1081/SS-200068492... 

Park D, Yun YS, Jo JH, Park JM (2006) Biosorption process for treatment of electroplating wastewater containing Cr(VI) laboratory-scale feasibility test. Ind Eng Chem Res 45 5059-5065. doi 10.1021/ ie060002d... 

S.SM. Hassan, M.S.A. Hamza, A.E.A. Kelany, A novel spectrophotometric method for batch and flow injection determination of cyanide in electroplating wastewater, Talanta 71 (2007) 1088-1095. 

M. Noroozifar, M. Khorasani-MoEagh, A. Taheri, R. Zare-Dorahei, A comparative study of AgX (X = Cl, Br , 1 and N 3 solid-phase reactors for flow-injection determination of cyanide in electroplating wastewater. Anal. Sci. 24 (2008) 669-672. 

Pereira FV, Gurgel LVA, Gil F. Removal of Zn2-i- from aqueous single metal solutions and electroplating wastewater with wood sawdust and sugarcane bagasse modified with EDTA dianhydride (EDTAD). J Hazard Mater 2010 176 856-863. 

Which of the following statements is true regarding chromium in water (a) chromium(III) is suspected of being carcinogenic (b) chromium(III) is less likely to be found in a soluble form than chromium(VI) (c) the toxicity of chromium(III) in electroplating wastewaters is decreased by oxidation to chromium(VI) (d) chromium is not an essential trace element ... 

Wet air oxidation has been applied to the destruction of cyanides in electroplating wastewaters. The oxidation reaction for sodium cyanide is the following ... 

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