13:40
Emerging micropollutants removal by combined persulfate oxidation – membrane distillation process for wastewater reuse
Prof. Faisal Hai | University of Wollongong | Australia
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Prof. Faisal Hai | University of Wollongong | Australia
A broad spectrum of micropollutants, particularly pharmaceuticals and pesticides, are ubiquitously detected in wastewater and wastewater-impacted waterbodies because they are resistant to conventional wastewater treatment systems. This raises significant concern due to their potential harmful impact on aquatic organisms and even human. Membrane distillation (MD) has been assessed as a post-treatment step for effective removal of micropollutants from secondary treated effluent. In this study, persulfate (PS) oxidation process was integrated with the MD process for effective degradation of 12 recalcitrant micropollutants from secondary treated effluent. PS (1mM) dosing resulted in micropollutant degradation that ranged between 25 and 100%. The integrated PS-MD system achieved an overall removal of >99% of the micropollutants. Along with micropollutants, PS degraded other effluent organic matters (up to 70%) present in the secondary treated effluent, which reduced their accumulation in the MD feed. This improved the hydraulic performance of the integrated PS-MD system by minimizing the membrane fouling. This is the first study that shows the performance of persulfate oxidation process in a continuous system for micropollutant removal and membrane fouling control.
14:00
Electrospun nanofiber membranes incorporating PDMS-aerogel superhydrophobic coating with enhanced flux and improved selectively for membrane distillation
Bhaskar Jyoti Deka | City University Hong Kong | Hong Kong
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Bhaskar Jyoti Deka | City University Hong Kong | Hong Kong
Electrospun nanofiber membranes (ENMs) have continued to gain recognition and are of great interest due to their high void volume fraction and hydrophobicity, in particular for its application for Membrane distillation (MD).1 However, still MD technology has limitations in transforming from labscale to service plant application mainly due to low permeate flux and contamination over time at permeate side due to membrane wetting, predominantly during treatment of feed consisting of low surface tension compounds such as surfactant. Herein, we report a high flux and anti-wettability property of hybrid dual layer electrospun nanofibrous membranes (ENMs) by PDMS-aerogel spray-coating on the PVDF-HFP (E-PH) membrane. The fabricated ENM with 30% aerogel (E-M3-A30) exhibited superhydrophobicity with a water contact angle (CA) of 170˚ and high anti-wetting treating in harsh saline water (3.5% of NaCl) consisting 0.5 mM sodium dodecyl sulfate (SDS), and synthetic algal organic matter (AOM) comprised of sodium alginate (SA), humic acid (HA), and bovine serum albumin (BSA) over MD operation. Meanwhile, the same E-M3-A30 membrane presented significant performance in 48 hours DCMD operation mainly due to its superior advantages in terms of liquid entry pressure (LEP) of 129.5 ± 3.4 kPa, average pore size (µm) of 0.47 ± 0.05, porosity of 85.8 ± 0.28 %, vibrant short water droplet bouncing performance (11.6 ms), and higher surface roughness (Ra) value of 5.05 um.
14:20
A real seawater membrane distillation system development by reproducible superhydrophobic TiO2 electrospun membrane with anti-fouling and anti-wetting function
JIAXIN GUO | City University of Hong Kong | Hong Kong
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JIAXIN GUO | City University of Hong Kong | Hong Kong
Here we show an easy way to control the membrane fouling during seawater desalination via application of reproducible superhydrophobic TiO2 electrospun membrane coupled with coagulation/oxidation/dissolved air floatation (DAF) (COD) system. The characteristics of fabricated membrane, effect of pretreatment, membrane performance and fouling mitigation were investigated. TiO2 nanoparticles were well coated on the electrospun poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) (E-PH) membrane using electrospraying. The fabricated membrane (E-TiO2) showed improved seawater desalination performance and strong reproducibility after 30 mins of simple water flushing of fouled E-TiO2 membrane (contract angle: from 131.4°±2.2° to 151.3°±1.2°). Compared with commercial PVDF membrane, this E-TiO2 membrane had increased anti-fouling and anti-wetting properties that could efficiently be recovered by simple physical water flushing. Additionally, the combination of NaOCl with Fe(III) was able to enhance the removal of DOC and mitigation of membrane fouling due to the formation of robust oxidizing agent (ferrate)[1]. This reproducible superhydrophobic E-TiO2 membrane coupled with COD system has proven its potential to be applied in removal of algal organic matter (AOM) and membrane fouling mitigation and has shown its performance as a novel technology for seawater desalination.
Keywords: Desalination; Membrane distillation; Membrane fouling; Pretreatment; Superhydrophobic membrane