ÇEVRE TEKNOLOJİLERİ/ENVIRONMENT1\L TECHNOLOGIES MAKAL�!!!�! 1 Table 1. fnfluence of the concentration in sodium chloride on volume of hydrochloric acid. [NaCI] V Hcı added lnitial pH of Final pH of (g.1" 1 ) (ml.L" 1 ) solution solution o 9.2 1 1 .14 5.36 40 9.2 1 0.33 5.15 50 9.2 10.31 5.17 60 9.2 10.34 5.33 80 9.2 10.32 5.42 disappearance of all compounds likely to harm at the nanofiltration and/or the re-dyeing. The salt concentration varies in a similar way in the retentate as in the permeate: it continuously decreases during the diafiltration step (recover of sodium chloride in the permeate) and increases during the concentration (sodium chloride stili slightly present in the solution and ionic species coming from dyes). Our results were compared to those obtained by an external certified laboratory and are found very close. The rejection of Nacı according to the NaCI concentration in the retentate, decreases when NaCI concentration increases. For economic reasons, it is profitable to recover only 85-90% of salt. We also studied the effects of the transmembrane pressure, the flow velocity, the feed temperature and pH. The best conditions are found as follows : PTM = 1 O bar, Q = 300 L.h -1 , T = 50°C and pH = 5.5. Transmembrane pressure, temperature increase have positive effects on the permeate flux. it is possible to recover more than 95% of sodium chloride and rejection of hydrolysed reactive dyes is higher than 98.5%. lf necessary, it is possible to concentrate nanofiltration permeate and thus to recover pure water and a concentrated brine to a new dyeing. Dyeings with the brines recovered at the exit of our process were performed with several type of reactive dyes. There were no differences between these dyeings and dyeings carried out the same way with the lab water, same depth of shade, same fastenesses, same dyeing kinetics. An example of the overall efficiency of our process is given on the Figure 4. A pre-treated (filtration and neutralisation) effluent sample can be seen on the left hand side : the initial mass was 300kg and the electrolyte concentration was around 102g.1t·1. CONCLUSION AND PERSPECTIVES This innovative process allows to recycle pure water and mineral salt in the dyeing process.Each parameter of each step was optimised in order to define the utmost economy. The re-dyeing with recycled water and electrolyte solution gives no difference with the usual procedure. We present the first investigation [3] resulting finally in a high concentration Figııre 4. An examp/e of ıhe overa/1 effıciency of oıır process (and low volume) of hydrolysed reactive dyes as ultimate effluent and the possible re-use of pure water and electrolyte solution. The validation of this process was demonstrated by re-dyeing tests without any difference (tonality, intensity, kinetic, ete.. ) using recycled species. We are now setting aut an industrial plant which will be placed on the outlet side of a dyeing machine. Presently, we are studying the treatment of the ultimate effluents very concentrated in dyes and this will be the subject of forthcoming presentations. R� erences 1. K.A. GroJJ Texti/e wastes. Res. J. of the water Pollııtion control Federaıion, 63 (1991) 459-462. 2. 8. Marroı and N. Roche. Wasıewater treatınent and reııse in texti/e indııstries, a review. Res. Adv. in Wat. Res. , 3 (2002) 41-53. 3. C. Allegre, P Moıılin, F Charbit, M Maisseu, M Golde,: Traitemenı des bains de teintı.ırerie en vııe de la reuıilisation de l'eau et dıı NaCI dans le procede. Pateni n ° FR 0211363. 41 Table 2. Variation of salts concentration as a function of sodium carbonate concentration with, without bubbles and after 24 hours [Na2CO3] 1nitial pH of Without bubble With bubble After 24H without degassing (g.L-1 ) solution [CO2] 1 [HCO 3] pH [CO2] [HCO3] pH [CO2] [HCO3] pH /moı.L· 1 ı. 10· 5 lmol. L·1 ı. 10· 3 /mol. L"1\.10"5 /mol.L"1 l. 10·3 (mol. L"1\.10"5 lmol.L"1). 10·3 1 10.3 5.3 726 0.6 8.1 1 .03 0.5 6.1 1 10 0.6 - � 1 7 10.3 5.5 1000 1 .2 8.2 1 .52 1 6 346 1.5 8 10.5 5.4 987 1.1 8.1 1 .75 1.1 6 113 0.5 12 10.6 5.4 1920 2.3 8.2 1 .53 1.1 6.6 106 2.1 15 10.5 5.4 1680 1 2.2 8. 1 .69 1 0.7 6.1 335 2.1 20 10.7 5.3 2770 1 2.4 8.1 2.3 1.2 5.9 365 1 .2 ENERJi DÜNYASI EKiM 2006 69
RkJQdWJsaXNoZXIy MTcyMTY=