Characterisation and mechanical modelling of polyacrylonitrile-based nanocomposite membranes reinforced with silica nanoparticles

In this study, neat polyacrylonitrile (PAN) and fumed silica (FS)-doped PAN membranes (0.1, 0.5 and 1 wt% doped PAN/FS) are prepared using the phase inversion method and are characterised extensively. According to the Fourier Transform Infrared (FTIR) spectroscopy analysis, the addition of FS to the neat PAN membrane and the added amount changed the stresses in the membrane structure. The Scanning Electron Microscope (SEM) results show that the addition of FS increased the porosity of the membrane. The water content of all fabricated membranes varied between 50% and 88.8%, their porosity ranged between 62.1% and 90%, and the average pore size ranged between 20.1 and 21.8 nm. While the neat PAN membrane’s pure water flux is 299.8 L/m2 h, it increased by 26% with the addition of 0.5 wt% FS. Furthermore, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques are used to investigate the membranes’ thermal properties. Finally, the mechanical characterisation of manufactured membranes is performed experimentally with tensile testing under dry and wet conditions. To be able to provide further explanation to the explored mechanics of the membranes, numerical methods, namely the finite element method and Mori–Tanaka mean-field homogenisation are performed. The mechanical characterisation results show that FS reinforcement increases the membrane rigidity and wet membranes exhibit more compliant behaviour compared to dry membranes

Halloysite nanotube-enhanced polyacrylonitrile ultrafiltration membranes: fabrication, characterization, and performance evaluation

This research focuses on the production and characterization of pristine polyacrylonitrile (PAN) as well as halloysite nanotube (HNT)-doped PAN ultrafiltration (UF) membranes via the phase inversion technique. Membranes containing 0.1, 0.5, and 1% wt HNT in 16% wt PAN are fabricated, and their chemical compositions are examined using Fourier transform infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) is utilized to characterize the membranes’ surface and cross-sectional morphologies. Atomic force microscopy (AFM) is employed to assess the roughness of the PAN/HNT membrane. Thermal characterization is conducted using thermal gravimetric analysis (TGA) and differential thermal analysis (DTA), while contact angle and water content measurements reveal the hydrophilic/hydrophobic properties. The pure water flux (PWF) performance of the porous UF water filtration membranes is evaluated at 3 bar, with porosity and mean pore size calculations. The iron (Fe), manganese (Mn), and total organic carbon (TOC) removal efficiencies of PAN/HNT membranes from dam water are examined, and the surfaces of fouled membranes are investigated by using SEM post-treatment. Mechanical characterization encompasses tensile testing, the Mori–Tanaka homogenization approach, and finite element analysis. The findings offer valuable insights into the impact of HNT doping on PAN membrane characteristics and performance, which will inform future membrane development initiatives

Leachate removal rate and the effect of leachate on the hydraulic conductivity of natural (undisturbed) clay

Hydraulic conductivity (HC) is perhaps the most important unique parameter determined in the laboratory for predicting mobility of leachates through clay liners. Typically, HC must be < or = 1 x 10(-9) m/s for soil liners and covers used to contain hazardous waste, industrial waste, and municipal solid waste (MSW). Soil samples used in this study were obtained from the Kemerburgaz landfill in Istanbul. The study presents change in clay HC brought about by the chemical reactions between clay and a permeant. Any change induced by such a reaction in the microstructure (microfabric) of the clay was studied by scanning electron microscope. In order to determine the removal capability of the natural clay, COD, SS, VSS, Total P, TKN, Cu, Mn, Fe are also measured in the influent and effluent of the lab-scale reactor

Characterisation and modelling the mechanics of cellulose nanofibril added polyethersulfone ultrafiltration membranes

The performance of the membranes can be improved by adding the appropriate amount of nanomaterials to the polymeric membranes that can be used for water/wastewater treatment. In this study, the effects of polyvinylpyrrolidone (PVP), the impact of different amounts (0.5% and 1% wt.) of cellulose nanofibril (CNF), and the combined effects of PVP-CNF on the properties/performance of the polyethersulfone-based (PES-based) membrane are investigated. All PES-based ultrafiltration (UF) membranes are manufactured employing the phase inversion method and characterised via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and the relevant techniques to determine the properties, including porosity, mean pore size, contact angle, water content, and pure water flux tests. Furthermore, the thermal properties of the prepared membranes are investigated using thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. Experimental and numerical methods are applied for the mechanical characterisation of prepared membranes. For the experimental process, tensile tests under dry and wet conditions are conducted. The finite element (FE) method and Mori-Tanaka mean-field homogenisation are used as numerical methods to provide more detailed knowledge of membrane mechanics