Effect of preparation conditions on arsenic rejection performance of polyamide-based thin film composite membranes            

Pham Minh Xuan^{1, 2*}, Le Hai Tran^1*, Huynh Ky Phuong Ha¹, Mai Thanh Phong¹, Van-Huy Nguyen³, Chao-Wei Huang⁴

¹Faculty of Chemical Engineering, University of Technology, Vietnam National University, Ho Chi Minh city, Vietnam

²Department of Chemical Engineering, Dong Thap University, Vietnam

³Key Laboratory of Advanced Materials for Energy and Environmental Applications, Lac Hong University, Vietnam

⁴Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan

Received 10 January 2020; accepted 10 March 2020

 

Abstract:

Herein, a polyamide-based thin film composite (TFC) membrane was fabricated for the removal of arsenic (As) from water. The polyamide thin film was synthesized through IP onto a polysulfone porous substrate. A Box-Behnken design of response surface methodology was used to investigate the effect of preparation conditions, including piperazine (PIP) concentration, trimesoyl chloride (TMC) concentration, and reaction time on the As rejection and permeate flux of the synthesized membrane. The separation performance of the prepared membranes from 15 designed experiments were conducted with an arsenate (Na₂AsHSO₄) solution of 150 ppm at a pressure of 400 psi and temperature of 25^oC. The analysis of variance revealed the regression models to be adequate. From the regression analysis, the flux and As rejection were expressed by quadratic equations as a function of PIP concentration, TMC concentration, and reaction time. It was observed that the PIP concentration, TMC concentration, and reaction time had a significant effect on the flux and As rejection of the polyamide membrane. Moreover, a strong impact from the interaction of PIP and TMC was also observed on rejection of the resulting membrane. Using the desirability function approach to analyse the regression model, the optimal preparation conditions of the polyamide membrane were a PIP concentration of 2.5 wt.%, TMC concentration of 0.11 wt.%, and reaction time of 40 sec. The membrane exhibited a good As rejection of 95%.

Keywords: arsenic, composite, membrane, polyamide, thin film.

Classification numbers: 2.2, 2.3