Background
Heavy metal ions +2Pb and +2Cu are hazardous and non-biodegradable pollutants that pose a serious threat to human health and the environment. Although polyacrylonitrile (PAN) fibers are widely used as adsorbent membranes, their adsorption efficiency is limited due to the limited number of active functional groups and low hydrophilicity. Therefore, surface modification and incorporation with nanomaterials are necessary to improve the adsorption efficiency and selectivity.
Objective
The aim of this research is to develop polyacrylonitrile (PAN HF) hollow fiber adsorbents with high selectivity and efficiency for the removal of +2Pb and +2Cu ions from aqueous solutions. To improve the surface performance, 3O2Al-γ nanoparticles and multi-walled carbon nanotubes (MWCNTs) were added to the PAN structure and finally the surface was modified with the amino acid L-cysteine (L-Cys) to create active thiol, amine and carboxyl functional groups for selective adsorption of metal ions.
Research Method
3O2Al-γ nanoparticles were biosynthesized and immobilized on the surface of PAN fibers to increase the specific surface area and the number of active sites. MWCNTs were added to the structure to enhance mechanical strength and increase porosity. In the final step, surface modification with L-Cys was performed to create hydrophilic and active functional groups for binding metal ions on the surface and obtain the adsorbent /MWCNTs/L-Cys HF3O2Al/PAN. Determination of the physical and chemical properties of the adsorbent was carried out using FESEM, EDX, AFM, FTIR, XRD and contact angle tests. BET test was used to determine the specific surface area and flame atomic absorption (FAAS) was used to measure the concentration of metal ions before and after adsorption. The adsorption process was investigated with pseudo-second-order kinetic models and Freundlich, Temkin and Dubinin-Radoshkevich (D–R) isotherms. Also, desorption tests with 0.11 mol L-1 hydrochloric acid solution and