In the present study, graphene oxide (GO) was incorporated as a nanoadditive into a polyphenylsulfone (PPSU) to develop a PPSU/GO nanocomposite membrane with enhanced antifouling properties. A series of membranes containing different concentrations (0.2, 0.5 and 1.0 wt.%) of GO were fabricated via the phase inversion method, using N-methyl pyrrolidone (NMP) as the solvent, deionized water as the non-solvent, and polyvinylpyrrolidone (PVP) as a pore forming agent. The prepared nanocomposite membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and were also characterized with respect to contact angle, zeta potential and porosity, mean pore radius, tortuosity and molecular weight cut-off (MWCO). Thermogravimetric analysis (TGA) and tensile testing were used to measure thermal and mechanical properties. The membrane performance was evaluated by volumetric flux and rejection of proteins, and antifouling properties. According to the results, the optimum addition of 0.5 wt% GO resulted in a membrane with an increased flux of 171 ± 3 Lm⁻²h⁻¹ with a MWCO of ~40 kDa. In addition, the GO incorporation efficiently inhibited the interaction between proteins and the membrane surface, thereby improving the fouling resistance ability by approximately 58 ± 3%. Also, the resulting membranes showed a significant improvement in mechanical and thermal properties.

We investigate the removal of heavy metal ions from synthetic contaminated water on a laboratory scale using a carboxylated-graphene oxide (GO)-incorporated polyphenylsulfone (PPSU) nanofiltration membrane (the so called PPSU/carboxylated-GO nanocomposite membrane). The prepared membranes were characterized with respect to the rheology of the doping solutions and based on the morphology, topography, and charge density of the membranes. Spectroscopic analysis of the membranes was also performed. The nanofiltration performance was demonstrated by the removal of five heavy metal ions (arsenic, chromium, cadmium, lead, and zinc). The effects of carboxylated-GO on the membrane molecular weight cut-off, hydraulic permeability, and heavy metal ion removal performance were investigated with respect to different factors, including feed concentration from single ions, transmembrane pressure (TMP) with mixed ions, and permeate flux. The addition of carboxylated-GO produced a membrane with enhanced properties that exhibited superior performance. Increasing the feed concentration and TMP did not affect the removal of anions; however, the removal of cations slightly decreased with the resulting membrane. The maximum removal rates of heavy metal ions were >98% and ∼80% for the anions and cations, respectively, and an enhanced volumetric flux of 27 ± 3 L m⁻² h⁻¹ was observed. This result is based on the Donnan exclusion principle, which is attributable to the surface charge of −70 mV and the order of the hydrated metal radii. The prepared PPSU/carboxylated-GO nanocomposite membrane provided impressive heavy metal ion removal and showed an acceptable volumetric flux under the applied parameters; this work demonstrates very economically advantageous conditions for heavy metal ion removal.

Nano-fibrillated cellulose (NFC) was extracted by a chemical method involving alkali and acid hydrolysis. The characterisation of the citrus sinensis fruit peel bran and nano-fibrillated cellulose was performed by XRD, FTIR, TEM, and FESEM. XRD confirmed the phase of NFC which showed monoclinic crystal with spherical to rod shape morphology with a size of 44–50 nm. The crystallinity index of treated NFC increased from 39% to 75%. FTIR showed the removal of lignin and hemicellulose from waste peels due to the alkaline treatment. Silver nanoparticles were also synthesised by utilizing extract of citrus sinensis skins as a reducing agent. Pharmaceutical effluent samples from an industrial area were tested by Atomic Absorption Spectrometry. Out of the four metals obtained, cadmium and chromium were remediated by silver nanoparticles with nano-fibrillated cellulose via simulated method in 100 mg/L metal-salt concentrations over a time period of 160 min. The highest removal efficiency was found for cadmium, i.e., 83%, by using silver and NFC together as adsorbents. The second highest was for chromium, i.e., 47%, but by using only NFC. The Langmuir and Freundlich isotherms were well fitted for the sorption of Cd (II) and Cr (II) with suitable high R² values during kinetic simulation. Thus, the isolation of NFC and synthesis of silver nanoparticles proved efficient for heavy metal sorption by the reuse of waste skins.

Antifungal activity of ecofriendly and cost effectively prepared Al₂O₃NPs onCandia alibicans.