Reprint of: “An analytical model for spiral wound reverse osmosis membrane modules: Part II — Experimental validation”

This paper presents the experimental studies carried out for validation of a new mathematical model [1] developed for predicting the performance of spiral wound RO modules. Experiments were conducted on a laboratory scale spiral wound RO module taking chlorophenol as a model solute. Experiments were carried out by varying feed flow rate, feed concentration and feed pressure and recording the readings of permeate concentration, retentate flow rate, retentate concentration and retentate pressure. A total of 73 experimental readings were recorded. The membrane transport parameters Aw (solvent transport coefficient) and Bs (solute transport coefficient) and the feed channel friction parameter b were estimated by a graphical technique developed in this work. The mass transfer coefficient k, estimated using the experimental data, was found to be strongly influenced by solvent flux and solute concentration apart from the fluid velocity. Taking the effects of solvent flux, solute concentration and fluid velocity, a new mass transfer correlation for Sherwood number is proposed in this work for the estimation of mass transfer coefficient. Comparison of model predictions with experimental observations demonstrated that the model was capable of predicting permeate concentration within 10% error, retentate rate flow within 4% error and rejection coefficient within 5% error.

► Experiments were conducted on a spiral wound RO unit taking chlorophenol as a solute.
► Model parameters were estimated using the experimental data.
► A new correlation for estimation of mass transfer coefficient is proposed.
► Proposed correlation accounts for effect of solvent flux, velocity and concentration.
► Model predictions tested with experimental readings showed good agreement.