title: Comparative performance of flat sheet and spiral wound modules in the nanofiltration of reactive dye solution.
abstract: OBJECTIVE
  Besides the opportunities for reuse, stringent regulations and growing public awareness demand an enhanced quality of effluent from dye industries. Treatment of an aqueous solution of dye (reactive red 198) was carried out in a nanofiltration unit using both flat sheet and spiral wound modules to obtain a comparative performance evaluation in terms of permeate flux and quality.
  
  
  METHODS
  Hydrophilized polyamide membrane with molecular weight cutoff of 150 was used for the experiments. Effects of trans-membrane pressure (TMP), feed concentration and addition of salt on permeate flux were investigated. Percent reduction of color, chemical oxygen demand (COD), total dissolved solid (TDS), and conductivity were determined to assess performance of the membrane.
  
  
  RESULTS
  The maximum flux decline was 16.1% of its initial value at 490 kPa TMP with 50 ppm feed concentration in spiral wound module, whereas the same in flat sheet under same conditions was 7.2%. The effect of TMP showed a quasi-linear increase in flux with increasing pressure. Increased permeate concentration led to the reduction in observed retention of dye in the membrane. The average reduction in color, COD, and TDS were 96.88%, 97.38%, and 89.24%, respectively. The decline in permeate flux was more in case of spiral wound module compared to flat sheet. However, spiral wound module performed better in terms of color removal, COD reduction, and TDS removal.
  
  
  CONCLUSIONS
  Substantial removal of color was achieved in the nanofiltration experiments with a marked reduction in COD and TDS. The process allowed the production of permeate stream with great reutilization possibilities.
authors.affiliation: Department of Chemical Engineering, G H Patel College of Engineering & Technology, Vallabh Vidyanagar, 388 120, Gujarat, India.
authors.forename: Tejal M
authors.initials: TM
authors.lastname: Patel
authors.forename: Harsh
authors.initials: H
authors.lastname: Chheda
authors.forename: Abhisek
authors.initials: A
authors.lastname: Baheti
authors.forename: Punit
authors.initials: P
authors.lastname: Patel
authors.forename: Kaushik
authors.initials: K
authors.lastname: Nath
mesh_terms: D004396:Coloring Agents / Q000737:chemistry; D004553:Electric Conductivity; D005374:Filtration / Q000295:instrumentation*; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry*; D009282:Naphthalenesulfonates / Q000737:chemistry*; D010084:Oxidation-Reduction; D012965:Sodium Chloride / Q000737:chemistry; D013997:Time Factors; D014227:Triazines / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D004396:Coloring Agents; D008567:Membranes, Artificial; D009282:Naphthalenesulfonates; D014227:Triazines; D014874:Water Pollutants, Chemical; D012965:Sodium Chloride; C514337:reactive red 198