Nanofiltration for textile dye–water treatment: Experimental and parameter estimation studies using a spiral wound module and validation of the Spiegler–Kedem-based model

The present work deals with the study of the nanofiltration process for textile dye wastewater treatment. Effects of feed pressure, dye concentration, and feed flow rate on dye rejection and recovery for the spiral wound nanofiltration module were studied. The permeate characteristics were predicted by using the Spiegler–Kedem (SK)-based model. A finite difference numerical technique is used to discretize the transport equations and an optimization technique was used for estimation of unknown parameters (B, σ, ka, and kb) in the SK-based model. The model and the estimated parameter values were validated with experimental results for the spiral wound nanofiltration (NF) membrane module.