Effect of Silica Sodalite Functionalization and PVA Coating on Performance of Sodalite Infused PSF Membrane during Treatment of Acid Mine Drainage.

Nobuhle C Ntshangase,Olawumi O Sadare,Michael O Daramola

doi:10.3390/membranes11050315

Nobuhle C Ntshangase, Olawumi O Sadare + Show 1 more

Open Access

https://doi.org/10.3390/membranes11050315

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Abstract

In this study, silica sodalite (SSOD) nanoparticles were synthesized by topotactic conversion and functionalized using HNO3/H2SO4 (1:3). The SSOD and functionalized SSOD (fSSOD) nanoparticles were infused into a Polysulfone (Psf) membrane to produce mixed matrix membranes. The membranes were fabricated via the phase inversion method. The membranes and the nanoparticles were characterized using Scanning Electron Microscopy (SEM) to check the morphology of the nanoparticles and the membranes and Fourier Transform Infrared to check the surface chemistry of the nanoparticles and the membranes. Thermal stability of the nanoparticles and the membranes was evaluated using Themogravimetry analysis (TGA) and the degree of hydrophilicity of the membranes was checked via contact angle measurements. The mechanical strength of the membranes and their surface nature (roughness) were checked using a nanotensile instrument and Atomic Force Microscopy (AFM), respectively. The textural property of the nanoparticles were checked by conducting N2 physisorption experiments on the nanoparticles at 77 K. AMD-treatment performance of the fabricated membranes was evaluated in a dead-end filtration cell using a synthetic acid mine drainage (AMD) solution prepared by dissolving a known amount of MgCl2, MnCl2·4H2O, Na2SO4, Al(NO3)3, Fe(NO3)3·9H2O, and Ca2OH2 in deionized water. Results from the N2 physisorption experiments on the nanoparticles at 77 K showed a reduction in surface area and increase in pore diameter of the nanoparticles after functionalization. Performance of the membranes during AMD treatment shows that, at 4 bar, a 10% fSSOD/Psf membrane displayed improved heavy metal rejection >50% for all heavy metals considered, expect the SSOD-loaded membrane that showed a rejection <13% (except for Al3+ 89%). In addition, coating the membranes with a PVA layer improved the antifouling property of the membranes. The effects of multiple PVA coating and behaviour of the membranes during real AMD are not reported in this study, these should be investigated in a future study. Therefore, the newly developed functionalized SSOD infused Psf membranes could find applications in the treatment of AMD or for the removal of heavy metals from wastewater.

Highlights

IntroductionHeavy metals are naturally released to the environment through rock weathering and volcanic eruptions
To enhance the fouling resistance of these membranes, the membranes were coated with a Poly vinyl alcohol (PVA) layer
For the PVAcoated membranes, a flux recovery ratio (FRR) of 81% and 56% was obtained for 10%

Summary

Introduction

Heavy metals are naturally released to the environment through rock weathering and volcanic eruptions At times, they are mostly discharged by human activities like mining, agriculture, and other industries, resulting in the discharge of heavy metals to the environment and underground water [1]. Heavy metals deposition is dangerous because they are non-biodegradable and tend to accumulate on living organisms as they can be taken up by plants and be translocated into edible parts of the plant [2,3] Due to these detrimental impacts on human beings, plants, and animals, numerous studies have explored the removal of heavy metals from water bodies using membranes [4,5], agricultural waste [6,7], and other methods

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