The applications of porous FO membranes and polyelectrolyte draw solution in the high-salinity organic wastewater treatment with a hybrid forward osmosis-membrane distillation system

Hybrid forward osmosis-membrane distillation (FO-MD) system have been considered as a promising technology for wastewater treatment. In the current study, initial and modified porous FO membranes are fabricated, and the intrinsic membrane separation properties are also investigated. Polyacrylic acid sodium (PAAS), sodium polystyrene sulfonate (PSS) and polyethylene glycol (PEG) are used to evaluate the effects of draw solution (DS) in FO experiments. Particularly, alkali treated modified porous FO membrane and PAAS are utilized in the subsequent wastewater treatment owing to the high performance of permeation and rejection. Furthermore, the optimal values of operating parameters (flow velocity, DS concentration and DS temperature), which are selected according to the effects of water flux (J(V)) in the FO and MD process, are evaluated and utilized to investigate the dynamic changes of J(V) in the high-salinity organic wastewater treatment with hybrid FO-MD system. Results show that the hybrid FO-MD system with porous FO membranes and polyelectrolyte DS maintain the operation in a constant flux of 16.61 LMH, and the permeate solution can be effectively recovered with favorable quality. This study provides remarkable implications for the design of porous FO membranes and the application of hybrid FO-MD system in the wastewater treatment.

Automated summary

Hybrid forward osmosis-membrane distillation (FO-MD) system is a promising technology for wastewater treatment. This study investigates the separation properties of initial and modified porous FO membranes and evaluates the effects of draw solution (DS) using PAAS, PSS, and PEG. The alkali treated modified porous FO membrane and PAAS are found to have high permeation and rejection performance for wastewater treatment. The study also explores the dynamic changes of water flux (J(V)) in the high-salinity organic wastewater treatment using the hybrid FO-MD system with optimal operating parameters.