A polysulfone/MIL-125(Ti) mixed matrix membrane for removing toxic dyes and heavy metals from water

Abstract

In this work, a titanium-incorporated metal–organic framework nanoadditive was used to study its efficiency in removing heavy metals and dyes from contaminated water. The use of MIL-125 (Ti) nanoadditive-incorporated polysulfone membranes has been tested for the elimination of heavy metals such as cadmium and lead as well as synthetic dyes, such as reactive black-5 (RB-5) and reactive orange -16 (RO-16). The incorporation of metal–organic frameworks (MOFs) into polysulfone matrices can increase the performance of the membrane for specific applications, such as dye removal and heavy metal rejection. The MIL-125 (Ti) is a well-known MOF with excellent chemical stability, large surface area, and adjustable pore size, making it suitable for membrane fabrication. This study fabricated membranes composed of MIL-125(Ti) and polysulfone (PSF) with MOF doses ranging from 0.5 to 3 wt %. Compared with the pristine PSF membrane, the pore-forming agent PVP was used at a 12% concentration, increasing the pore size and porosity. The hydrophilicity, water flux, and antifouling nature of the fabricated membrane were studied. The dye removal and heavy metal rejection experiments were carried out, and a dye removal efficiency of 90% for RB-5 and 47% for RO-16 was exhibited by the M-1 membrane. Furthermore, the M-2 membrane resulted in heavy metal rejection of 89.33% for Cd²⁺, and M-3 resulted in 68.81% for Pb²⁺ at a feed concentration of 500 ppm. Hence, the membranes showed good stability and efficiency with a high feed concentration of heavy metals. In the present study, metal ion rejection was studied without the use of any complexing agents.