Biochar decorated with metal-organic framework nanoparticles as robust modifier to manipulate nanofiltration mixed matrix membranes characteristics and performance

UiO-66-NH2 metal-organic framework nanoparticles and carbonaceous biochar prepared from the pyrolysis of Cladophora glomerata alga are introduced as novel modifiers and employed to manipulate polyethersulfone (PES) mixed matrix membranes. The membranes were fabricated through immersion precipitation method and fully assessed through X-ray diffraction pattern, field emission scanning electron microscopy, contact angle, atomic force microscopy, and zeta potential analysis. The membrane performances were also examined by water flux, fouling resistance, and solute rejection. The results indicated that the modified membranes manipulated by 0.2-0.8 wt% of modifier had smoother surfaces than the pristine PES membrane. Moreover, by loading the modifiers in the membrane bulk, the zeta potential was changed from negative to positive values. All the modified membranes revealed superior filtration performance compared to that of the pristine PES membrane. In the modified membrane of the best performance, water flux was increased to up to 85% and contact angle was decreased to 43 degrees. Due to the uniform distribution of modifiers on the membrane surface, and thereby, formation of a barrier layer, up to 98.5% of Reactive Blue 50 dye was rejected by the modified membranes. Salt rejections were also improved in the membranes tailored by the introduced modifiers. Furthermore, through the fouling experiments conducted by humic acid and bovine serum albumin, just 12.9 and 34% reductions in water fluxes were recorded for the modified membrane of the best performance. The experimental results indicated that the higher flux recovery ratios could also be expected for all the membranes modified by the novel hydrophilic modifiers.