ZnO-TiO2 doped polyacrylonitrile nano fiber-Mat for elimination of Cr (VI) from polluted water

Abstract

PAN nanofiber-Mat (n-fib@Mat), PAN/ZnO n-fib@Mat, and PAN/ZnO-TiO 2 n-fib@Mat were prepared via electrospinning method. Their high adsorption capacities against dissolved Cr (VI) ions make them as super adsorbents for water treatment. The structure of n-fib@Mat was investigated using XRD, FTIR, SEM, and TEM techniques. The effects of selected parameters such as contact time, initial concentration, and n-fib@Mat amount were assessed in a fixed bed reactor. It was found that the adsorption capacities of PAN n-fib@Mat, PAN/ZnO n-fib@Mat, and PAN/ZnO-TiO 2 n-fib@Mat were pH-dependent and the optimal pH value was between 2.1 and 2.2. The adsorption was rapid, and the equilibrium was reached within 240 min to remove of Cr (VI) ions for PAN/ZnO-TiO 2 n-fib@Mat and 360 min for PAN n-fib@Mat and PAN-ZnO n-fib@Mat. Langmuir isotherms model is preferred for PAN n-fib@Mat, PAN-ZnO n-fib@Mat, and PAN/ZnO-TiO 2 n-fib@Mat for Cr (VI) adsorption. The equilibrium adsorption capacities are 153.85 mg/g, 234.52 mg/g, and 333.43 mg/g for PAN n-fib@Mat, PAN/ZnO n-fib@Mat, and PAN/ZnO-TiO 2 n-fib@Mat for Cr (VI), respectively. The produced n-fib@Mat showed excellent removal ability for Cr (VI). The adsorption kinetic was obeyed pseudo-second-order reaction rate.

Recent developments in electrospun ZnO nanofibers: A short review

“…Production of ZnO nanorods and nanosheets on nanofibers according to Zhu et al 30 PAN/ZnO/TiO 2 nanofiber mats could most rapidly adsorb the Cr(VI) ions from water. 39 ZnO was also suggested as part of a mixed matrix membrane, consisting from a PVA nanofiber mat on a functionalized cellulose-acetate substrate. The nanofiber mat was modified by embedding ZnO nanoparticles and sodium alginate.…”

Preparation and Characterization of Electrospun Poly(lactic acid)/Poly(ethylene glycol)–b–poly(propylene glycol)–b–poly(ethylene glycol)/Silicon Dioxide Nanofibrous Adsorbents for Selective Copper (II) Ions Removal from Wastewater

“…Several works published adsorption of toxic metal ions was improved by incorporating NPs such as iron oxide, zinc oxide (ZnO), titanium dioxide, silicon dioxide (SiO 2 ), etc., into the electrospun nanofibrous adsorbents [ 22 , 23 , 24 , 25 ]. Makaremi et al [ 26 ] reported the improvement of the chromium ion removal efficiency by incorporating ZnO into polyacrylonitrile (PAN) nanofibrous adsorbents.…”

Electrospun polyacrylonitrile nanofibrous membranes supported with montmorillonite for efficient PM2.5 filtration and adsorption of Cu (II) ions

“…37 The modified polyacrylonitrile nanofibrous membranes owing to their larger surface area, resistance to chemicals, lower flammability, better mechanical properties, and thermal stability have been found to be efficient in PM2.5 filtration [11][12][13]38 as well as adsorption of heavy metal ions. 27,[39][40][41][42][43][44][45] The surface modification of PAN nanofibers results in its altered hydrophilicity and introduction of chelating groups, which in turn are responsible to make them suitable for efficient adsorption. 46,47 Clay minerals are hydrous aluminosilicates, which have been widely used for filtration applications.…”

“…One of the widely used polymers for electrospinning is polyacrylonitrile (PAN) due to its ease to spinnability, commercial availability, stability, and good mechanical properties 37 . The modified polyacrylonitrile nanofibrous membranes owing to their larger surface area, resistance to chemicals, lower flammability, better mechanical properties, and thermal stability have been found to be efficient in PM2.5 filtration 11–13,38 as well as adsorption of heavy metal ions 27,39–45 . The surface modification of PAN nanofibers results in its altered hydrophilicity and introduction of chelating groups, which in turn are responsible to make them suitable for efficient adsorption 46,47 …”