Functionalized MoS2 nanosheets enabled nanofiltration membrane with enhanced permeance and fouling resistance

Abstract

In this study, a novel thin film nanocomposite (TFN) membrane incorporated with -OH functionalized molybdenum disulfide (OH-MoS 2 ) nanosheets was fabricated through interfacial polymerization between piperazine (PIP) and trimesoyl chloride (TMC) by addition of nanosheets in the aqueous phase. The physicochemical characterizations of the resultant TFN membrane confirmed the embedding of OH-MoS 2 nanosheets and showed excellent compatibility with polypiperazine amide (PPA) matrix, as well as the nanosheets incorporation significantly increased the hydrophilicity, negative charge, surface roughness. In addition, the hydroxyl groups attached to the MoS 2 nanosheets can be covalently bonded into the skin layer through its reaction with TMC, promoting excellent compatibility with the polymer matrix. At an optimum concentration of 0.010 wt% OH-MoS 2 , the TFN membrane exhibited 45.17% increase in pure water flux (84.14 L m −2 h −1 ) when compared to control membrane (57.96 L m −2 h −1 ) and maintained stable salt rejection for Na 2 SO 4 (96.67%). This optimized TFN membrane exhibited high normalized flux of 96.92% when compared to 91.22% for control membrane and high flux recovery ratio of 98.88% was maintained as well as enhanced organic removal at 89.14% in terms of dissolved organic carbon (DOC) and 99.2% as ultraviolet absorbance at 254 nm (UV 254 ) was recorded during 6 h filtration studies with humic acid containing feed water. 0.010 wt% OH-MoS 2 incorporated membranes exhibited enhanced permeance, salt rejection and stability along with excellent fouling resistance and organic removal demonstrating the potential of OH-MoS 2 nanosheets for engineering high performance and fouling resistant TFN NF membranes for water treatment. • TFN NF membrane by embedding OH-MoS 2 nanosheet into PPA layer via IP reaction. • OH-MoS 2 with abundant oxygen, sulphur groups improved hydrophilicity of membrane. • 0.01 wt% OH-MoS 2 membrane showed 45.17% higher flux and 96.67% Na 2 SO 4 rejection. • TFN membrane shows 96.92% normalized flux compared to 91.22% for control membrane. • Excellent organic removal and stability was exhibited by TFN membrane.