Surface modification of PAN hollow fiber membrane by chemical reaction

Abstract

In this study, a new method was applied to achieve an efficient surface modification of Polyacrylonitrile (PAN) hollow fiber membrane. The surface modification dealt by immersion of PAN hollow fibers in hydroxylamine solution under various conditions (different solution concentrations and reaction time). The nitrile groups on the surface of the membrane were changed to form the amidoxime (-C(NH 2 )=N-OH) groups. The surface modified membranes were assessed by pure water permeation test and the rejection of high molecular weight materials like Polyvinylalcohol (PVA) from water. Permeation test results showed that with increasing hydroxylamine concentration, the amount of water permeation reduces slowly, while the PVA-30 kDa rejection has been somewhat increased after surface modification. FTIR/ATR analysis confirms the presence of amidoxime groups on the membrane surface. Also, the water contact angel was decreased from 64 to 34 after reaction. The ability of silver ions absorption was also assessed for modified membrane. Finally, the antifouling property of the modified hollow fibers was assessed by milk solution ultrafiltration. The obtained results showed that the modified hollow fibers present better antifouling properties.

Thin‐film composite membranes incorporated with large‐area graphene oxide sheets and adjustable surface charges

“…After the amidoximation reaction, the flux decreased by 35.77 L/m 2 .h.bar (Table ). This decrement could be explained in this way that the membrane was heated during the reaction, and it caused to contract and make the pore size smaller . By forming the selective thin layer on the amidoximated ultrafiltration membrane, the pure water flux decreased to 8.48 L/m 2 .h.bar.…”

Removal of methylene blue by amidoxime polyacrylonitrile-grafted cotton fabrics: Kinetic, equilibrium, and simulation studies

“…The cyano groups of the grafted PAN branches on the cotton fabrics were then converted into hydroxime ones by a reaction with hydroxylamine (HA) [23,24] under the following conditions: HA concentration (4 %), reaction time (3 h), and reaction temperature (50 o C). The aminated and grafted cotton fabrics were then alkali treated with 1 % NaOH for 2 h with a material:solution ratio of 1:40.…”

“…The Freundlich model has the form: (24) which may be linearized by taking the logarithm as follows: (25) where C e is the liquid-phase concentration at equilibrium (mg/l) C t : liquid-phase concentration at time t (mg/l) C 0 : initial liquid-phase concentration (mg/l) q e : amount of adsorption at equilibrium (mg/g) K F and n: Freundlich model constants K L and q m : Langmuir model constants Accordingly, the constants can be obtained from the intercepts and slopes of the equations.…”

Preparation of amidoxime‐modified polyacrylonitrile nanofibrous adsorbents for the extraction of copper(II) and lead(II) ions and dye from aqueous media

“…Now, most of the preparation work for amidoxime‐based chelate nanofibers is done through chelating modification with hydroxylamine hydrochloride after the synthesis of polyacrylonitrile (PAN) nanofiber mats by an electrospinning method . Although this method can produce amidoxime‐modified polyacrylonitrile nanofibrous films (AOPAN NFs), several disadvantages exist.…”

“…[15][16][17][18][19][20][21][22][23] Now, most of the preparation work for amidoxime-based chelate nanofibers is done through chelating modification with hydroxylamine hydrochloride after the synthesis of polyacrylonitrile (PAN) nanofiber mats by an electrospinning method. 24,25 Although this method can produce amidoxime-modified polyacrylonitrile nanofibrous films (AOPAN NFs), several disadvantages exist. First, in the progress of chelating modification, the neat fibers will distort and wind after they are soaked in a hydroxylamine aqueous solution.…”