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Publications (64)
Little is known about the catastrophic bushfire from a micro‐pollution point of view, and there is also very limited understanding of the emerging contamination of microplastics and nanoplastics. Upon exposure to fire, plastic items, such as water tanks, may release a substantial quantity of microplastics and nanoplastics, as characterized in this...
Confocal Raman imaging can potentially identify and visualise microplastics and nanoplastics, but the imaging lateral resolution is hampered by the diffraction of the laser, making it difficult to analyse nanoplastics that are smaller than the laser spot and the lateral resolution limit (λ/2NA). Fortunately, once a nanoplastic is scanned to collect...
Total oxidisable precursor (TOP) assay can oxidise some per- and polyfluoroalkyl substances (PFASs) and their precursors, most of which cannot be quantitatively detected so far, and convert them to detectable PFASs, such as perfluoroalkyl acids (PFAAs). However, the conversion is constrained by the complexity of the target samples, including co-exi...
Confocal Raman imaging can directly identify and visualise microplastics and even nanoplastics. However, due to diffraction, the excitation laser spot has a size, which defines the image resolution. Consequently, it is difficult to image nanoplastic that is smaller than the diffraction limit. Within the laser spot, fortunately, the excitation energ...
Most teenagers experience orthodontic treatment, but we do not know the possible adverse effect of the released microplastics and nanoplastics that are recently categorized as emerging contaminants. Herein, we test the rubber band that has been employed to improve the biting of teeth during the orthodontic process to confirm the release of micropla...
Plastic products are used ubiquitously and can potentially release microplastics and nanoplastics into the environment, for example, products such as the silicone sealant used in kitchens. It is important to develop an effective method to monitor these emerging contaminants, as reported herein. By using advanced Raman imaging to characterize microp...
Background
COVID-19 pandemic is not yet over, and it has been generating lots of plastic wastes that become a big concern. To catch the virus, for example, no matter via antigen or PCR test, swab is generally used for sampling. Unfortunately, the swab tip is commonly made of plastics, and thus it can be a potential source of microplastics. This stu...
Microplastics and nanoplastics have secretly entered our daily lives but the extent of the problem is still unclear, as the characterisation is still a challenge, particularly for nanoplastics. Herein we test a blender that we use in our kitchen to make juice and we find that a significant amount of microplastics and nanoplastics (∼0.36-0.78 × 109...
Per- and polyfluoroalkyl substances (PFAS) are chemically and thermally stable due to the presence of carbon-fluorine (C-F) bond in their molecular structures, hence have been previously formulated as firefighting ingredients. During the firefighting process, however, owing to the high temperature, PFAS can be potentially degraded, particularly for...
Per-and polyfluoroalkyl substances (PFAS) remediation is still a challenge. In this study, we propose a hybrid system that combines electrochemical treatment with ultrasound irradiation, aiming for an enhanced degradation of PFAS. Equipped with a titanium suboxide (Ti4O7) anode, the electrochemical cell is able to remove perfluorooctanoic acid (PFO...
The sources of microplastics and nanoplastics can be found almost everywhere, including being released from the activities of our daily lives. Unfortunately, the process for determining the sources of microplastics and nanoplastics is hampered by the limited techniques available for characterisation. Herewith, we advance Raman imaging by combining...
Algae blooms and toxins pose a serious threat to the ecological security and human health in coastal areas. Coupling electro-oxidation with ultrafiltration is an effective means of treating algae-laden water. This study was designed to assess the removal of Microcystis aeruginosa and Microcystins in the offshore environment using a hybrid system co...
Numerous plastic items are known to gradually degrade and release microplastics and nanoplastics under certain conditions, which can be significantly accelerated by fire combustion. Unfortunately there is a limited knowledge about this burning process because the characterisation on microplastics and nanoplastics is still a challenge. In this study...
Raman imaging has advanced recently to be able to directly visualise microplastics and even nanoplastics. However, the generated scanning spectrum matrix, akin to a hyperspectral matrix, is challenging to decode. To this end, herein, logic-based, algebra-based, principal component analysis (PCA)-based, and dual-PCA-based algorithms are compared and...
The characterisation of microplastics is still difficult, and the challenge is even greater for nanoplastics. A possible source of these particles is the scratched surface of a non-stick cooking pot that is mainly coated with Teflon. Herein we employ Raman imaging to scan the surfaces of different non-stick pots and collect spectra as spectrum matr...
Raman imaging can effectively characterise microplastics and nanoplastics, which is validated here to capture the items released from the plastic gloves when subjected to a mimicked fire. During the COVID-19 pandemic, large quantities of personal protective equipment (PPE) units have been used, such as the disposable gloves. If discarded and poorly...
Plastic contamination is a growing global concern, but the characterisation approaches for microplastics are limited so far, and even more lacking for nanoplastics. As another public concern, bushfire has the potential to exacerbate the negative ecological effects of plastic waste. We thus study the release of microplastics and nanoplastics from to...
Due to COVID-19, large amounts of personal protective equipment (PPE) have been used, and many PPE units are made of plastics, such as face masks. The masks can be burned naturally in a bushfire or artificially at the incineration plants, and release microplastics and nanoplastics from the mask plastic fibres. A fire can cause the plastic, such as...
Microplastics can potentially be released in our daily activities, such as via our showers, as our clothes are made of plastic fibres, and/or cotton fibres. The challenge is how to characterise these microplastics in shower debris. Herewith we employ Raman imaging to directly visualise the microplastics collected from shower wastewater. Raman can m...
As contaminants of emerging concern, microplastics and nanoplastics are ubiquitous in not only aquatic and terrestrial environments but also household settings. While the characterisation of microplastics is still a challenge, the analysis of nanoplastics is even more difficult. In this study, we aim to examine several novel algorithmic methods int...
Microplastics can be found almost everywhere, including in our kitchens. The challenge is how to characterise them, particularly for the small ones (<1 μm), referred to as nanoplastics, when they are mixed with larger particles and other components. Herewith we advance Raman imaging to characterise microplastics and nanoplastics released from a dis...
The characterisation of microplastics is still a challenge. To avoid the “false” characterisation and to increase the signal-noise ratio, we employ Raman imaging to scan the sample surface and generate a Raman spectrum matrix. We then simultaneously map several characteristic peaks to generate several images in parallel, akin to image at multi-chan...
The characterisation of nanoplastics is much more difficult than that of microplastics. Herewith we employ Raman imaging to capture and visualise nanoplastics and microplastics, due to the increased signal-noise ratio from Raman spectrum matrix when compared with that from a single spectrum. The images mapping multiple characteristic peaks can be m...
Industrial dyeing produces highly polluting wastewater and threatens the environment. Effective treatment of dyeing wastewater is a crucial step to prevent toxic chemicals from entering receiving waters. This study aimed to assess a modified attapulgite (ATP)-based adsorbent for dyeing wastewater purification by introducing chitosan (CTS) and titan...
Total oxidisable precursor assay (TOP assay) can degrade and convert “unknown” per- and polyfluoroalkyl substances (PFAS) to detectable PFAS. However, the detailed degradation pathway is still not known, particularly when the TOP assay is applied to analyse complex samples such as aqueous film-forming foam (AFFF). To gain insights into the pathway...
The characterisation of microplastics is still a challenge, and the challenge is even greater for nanoplastics, of which we only have a limited knowledge so far. Herewith we employ Raman imaging to directly visualise microplastics and nanoplastics which are released from the trimmer lines during lawn mowing. The signal-noise ratio of Raman imaging...
Drinking water treatment under rural conditions often require compactness and portability. To address this, the present study developed a pilot-scale helical tubular biological contact oxidation (BCO) reactor filled with annular porous biofilm carriers (fillers). To determine the drinking water treatment efficiency and microbial characteristics, th...
As an emerging contaminant, microplastic is receiving increasing attention. However, the contamination source is not fully known, and new sources are still being identified. Herewith, we report that microplastics can be found in our gardens, either due to the wrongdoing of leaving plastic bubble wraps to be mixed with mulches or due to the use of p...
The characterisation of microplastics is still a challenge, particularly when the sample is a mixture with a complex background, such as an ink mark on paper. To address this challenge, we developed and compared two approaches, (i) Raman imaging, combined with logic-based and principal component analysis (PCA)-based algorithms, and (ii) matrix-assi...
In this study, a BDD electrolytic oxidation-ceramic membrane ultrafiltration (EO-CM) system for the removals of antibiotics, organic matters and ammonia in wastewater was evaluated. Sulfamethazine (SMZ) was degraded following a pseudo first-order kinetics. The removal rate of SMZ improved with the increase of electro-oxidation time (0–60 min) and c...
To visualise microplastics and nanoplastics via Raman imaging, we need to scan the sample surface over a pixel array to collect Raman spectra as a matrix. The challenge is how to decode this spectrum matrix to map accurate and meaningful Raman images. This study compares two decoding approaches. The first approach is used when the sample contains s...
Rural water treatment is generally more challenging than urban water treatment. This study proposed a novel rural water treatment system effectively harnessing solar energy and gravitational hydropower. Influent was initially fed to a solar-driven electrocoagulation unit, in which UV254 level was reduced (by almost 60%) and large flocs (averaging u...
Microplastics are among the ubiquitous contaminants in our environment. As emerging contaminants, microplastics are still facing with lots of challenges on the characterisation, including their capture, identification and visualisation, particularly from a complex background. For example, when we print documents using a laser printer, we are printi...
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Achieving adequate manganese removal during water treatment is a challenging process. This study aimed to assess the effectiveness of gravity driven ceramic membrane (GDCM) filtration in the elimination of manganese from surface water. The impact of membrane pre-modification with birnessite and molecular weight cut-off on long-term water treatment...
Concurrent presence of algae and manganese (Mn) in water poses a significant challenge for water treatment. This study compared the treatment efficiency of Mn-containing and algae-laden water using either permanganate pre-oxidation (KMnO4) or persulfate/iron(II) (PMS/Fe2+) enhanced coagulation as pretreatment for ceramic membrane ultrafiltration. T...
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Water laden with dissolved manganese ions presents a challenge to water treatment processes and drinking water quality. To address manganese removal, a gravity driven ceramic membrane filtration system was developed; the membrane was pre-modified by depositing freshly formed birnessite type manganese oxide (MnOx) attached on powdered activated carb...
In this study, a boron-doped diamond (BDD) electro-oxidation technology coupled with nanofiltration membrane (EO-NF) technology was investigated for its effectiveness in removing antibiotics (i.e., sulfamethazine:SMZ) and mitigating biofouling during secondary wastewater treatment. The result showed that EO obtained an effective SMZ removal, owing...
Membrane photobioreactors (MPBR) have the opportunity to remove various forms of nitrogen, such as ammonium and nitrate, found in high quantities in secondary effluent. This study provides a holistic comparison of the performance of two membrane photobioreactors treating secondary effluents containing ammonium (NH4⁺-N) or nitrate (NO3⁻-N) as the so...
Microalgae-based systems have been increasingly considered to remediate wastewater, while producing valued biomass. While microalgal monocultures are difficult to maintain in wastewater, mixed cultures have the potential to offer improved system stability and robustness. This research aims to provide a detailed comparison of microalgal monoculture...
Photobioreactors are increasingly being considered for wastewater and biotechnology industries, due to their capability to simultaneously treat wastewater and produce biomass that can be converted into food, fuels and high-value chemicals. However, the resilience of these algal systems during hazardous events such as shock loads of harmful chemical...
Understanding the behaviour of organic materials in bioreactors is an important part of system assessment. This paper focuses on the combined use of liquid chromatography – organic carbon detection and fluorescence excitation–emission matrix spectroscopy for characterising the fate of dissolved organic compounds in membrane photobioreactors operate...
Rainwater harvesting (RWH) coupled with gravity-driven membrane (GDM) filtration was used to simultaneously treat rainwater and recover energy. A pilot GDM could obtain a relatively stable level of permeate flux (~4.0 L/(m2·h)) under a set water head (ΔH=0.4 m) over 140 days of operation. An increased water head (ΔH=0.6 m) did not achieve a sharp i...
Membrane photobioreactor (MPBR) technology is an emerging algae-based wastewater treatment system. Given the limitations due to the general use of conventional analytical approaches in previous research, this study aims to provide a more comprehensive assessment of MPBR performance through advanced characterisation techniques. New performance param...
This review focuses on the potential advantages and challenges of submerged membrane photobioreactors (MPBRs) for microalgae cultivation and wastewater treatment. MPBR technology combines a conventional photobioreactor (PBR) with a membrane process to grow microalgae, enabling complete retention of algal biomass. Microalgae populations in MPBRs are...
A hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system and a conventional membrane bioreactor (CMBR) were compared in terms of micropollutant removal efficiency and membrane fouling propensity. The results show that the hybrid MBBR-MBR system could effectively remove most of the selected micropollutants. By contrast, the CMBR sys...
This study investigated the removal of micropollutants using polyurethane sponge as attached-growth carrier. Batch experiments demonstrated that micropollutants could adsorb to non-acclimatized sponge cubes to varying extents. Acclimatized sponge showed significantly enhanced removal of some less hydrophobic compounds (log D < 2.5), such as ibuprof...
