As a typical high concentration saline wastewater

Na+

Mg2+//Cl--H2O solution system was treated via membrane distillation and crystallization to recycle the pure water and high NaCl crystal products with high property

simultaneously. The performance of membrane distillation and the properties NaCl product were explored under the different operation temperature and the various concentration of salts. The results indicate that

the permeate flux obviously increased with the increasing of the operation temperature

due to the increasing of the different vapour pressure with the temperature. Moreover

the permeate flux slightly decreased with the adding content of MgCl2 to the solution

it was mainly due to the decrease of the mass fraction of water and the increase of solution viscosity. The surface crystal particle deposition was also evaluated via lunching the comparison experiments. In addition

the hollow fiber membrane used in the experiments presents favorable reusability with 20 cycles during the membrane distillation. The NaCl crystal products obtained under the operation temperature of 65℃ exhibited the narrow size distribution

the smooth crystal surface

the perfect cube structure and without agglomeration

and the average size was 91.04

91.38 and 122.56 μm

and the coefficient of variation (C.V.) was 28.78

30.63 and 36.77

respectively. Meanwhile

the conductivity recycled water was 5 μS?m-1

and the purity of crystal products were higher than 98.15% after washing with the selective solution (ethanol). Therefore

by regulate the membrane permeate flux and interface function

the membrane distillation crystallization is a feasible technology to process the high concentration saline wastewater (Na+

Mg2+//Cl--H2O) to recycle the pure water and NaCl product with high purity

smooth surface and uniform size under the appropriate operation temperature and the lower Mg2+ concentration. This research can explore the potential approach for the ‘near zero discharge’ treatment of multiple ions high saline wastewater and the reuse of the inorganic salt resource.