جستجوی مقالات مرتبط با کلیدواژه "heavy metal removal" در نشریات گروه "مهندسی شیمی، نفت و پلیمر"

Hypothesis:

 Thin-film nanofiltration membranes based on polyether sulfone were prepared using acrylic acid and carbon nanofibers, and the effect of the coating layer on heavy metal separation and antifouling properties of the membrane was evaluated

Thin film nanofiltration membranes were prepared using dip-coating technique. The properties of the pristine and modified membranes were evaluated by scanning electron microscopy (SEM) images and Fourier transform infrared (FTIR) analysis. Also, by the Taguchi experimental design algorithm, the effect of the coating layer on the physical and chemical properties of the membranes such as pore size membrane hydrophilicity, and their performance in terms of pure water flux, sodium sulfate rejection and flux, and heavy metal removal efficiency were investigated.

The results revealed that the modified membrane with 2.5% acrylic acid 0.5% carbon nanofiber, and 3 h of reaction time exhibited higher hydrophilicity and larger pore size than other membranes. SEM images of the modified membranes revealed that appropriate amounts of surface modification parameters led to the formation of a polyacrylic acid layer with suitable density and desirable dispersion of nanoparticles and no agglomeration in the optimized membrane structure. The results indicated a significant improvement in the permeation flux of heavy metal solutions through the optimized membrane compared to the pristine membrane. Additionally the flux reduction in the optimized membrane was 16.1% less than that of the unmodified sample, demonstrating the suitable resistance of the modified membrane to fouling. The removal percentage of Cu, Cr and Pb was 58.9%, 52.0%, and 62.3% for the neat membrane, whereas it was 82.3%, 80.0%, and 89.5% for the superior modified membrane, respectively. The results indicated that the modified membrane performed better in removing lead than copper and chromium.

In this study, computational fluid dynamics simulation of liquid-liquid extraction of zinc was performed using trifluoroacetylacetone as a solvent in the hollow fiber membrane contactor. Mass and momentum balance equations (Navier-Stokes) were used to express the transport of zinc solutes through the membrane contactor. After applying the conditions, the governing equations were simulated using the finite element method. After validating the results, simulation was performed to study the distribution of zinc concentration in two-dimensional and three-dimensional form, as well as to investigate the effect of different parameters such as distribution coefficient and current intensity on the extraction efficiency. The results showed that by increasing the partition coefficient from 1 to 10, the amount of single-pass extraction increased from 10 to 100 percent. Also, the extraction efficiency in the counter-current flow of pipe and shell is 9% higher than in the co-current flow. Furthermore, this study showed that computational fluid dynamics could be used as an effective tool for the development of membrane-based extraction processes.