Publications

Investigation on the effect of sintering temperature on kaolin hollow fibre membrane for dye filtration

No abstract is provided for this article.

Proton Conductions

No abstract is provided for this article.

Efficient reduction of graphene oxide nanosheets using <font>Na</font>₂<font>C</font>₂<font>O</font>₄ as a reducing agent

The efficient synthesis of reduced graphene oxide (RGO) nanosheets via chemical reduction process of exfoliated graphene oxide (GO) nanosheets was performed by introducing sodium oxalate ( Na 2 C 2 O 4 ) as a reducing agent. To study the effects of the reduction time on the synthesized RGO, the GO was reduced within -1/2, 1 and 2 h for RGO-1, RGO-2 and RGO-3, respectively. The C/O atomic ratio of the synthesized RGO-3 has increased from 2.16 to 6.32 after reduction as determined by X-ray photoelectron spectroscopy (XPS). The morphology analysis of the RGO-3 was determined by high-resolution transmission electron microscopy (HRTEM) almost revealed the formation of single layer. The number of RGO layers decreases as the time of the reduction increases. Based on these analysis results, sodium oxalate plays an important role in the efficient removal of the oxygen containing groups in the GO to produce high quality of RGO.

Author response for "Mass transfer kinetics of Cr(&lt;scp&gt;vi&lt;/scp&gt;) adsorption on a green mussel shell-polyethersulfone membrane"

No abstract is provided for this article.

Textile dye Reactive Black 5 (RB5) removal by visible light photocatalyst and its characterization

Visible light photocatalysis is now a subject of interest for researchers to explore further in the treatment of wastewater as it can save costs and be environmentally friendly. Cadmium sulphide (CdS) is one of the photocatalysts of visible light that has excellent properties and a low band gap. The toxicity and carcinogenicity of textile industry effluent containing predominantly textile dyes disturbs the environment. In this study, the removal of reactive black 5 (RB5), the most used dyes with CdS as visible light photocatalyst, was tested. Using X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometers and photocatalytic tests under visible light, the physical and chemical properties of CdS were characterised. CdS has an irregular shape and this can be demonstrated through SEM. The band gap obtained was 2.12 eV and this was associated with the degradation efficiency of CdS under visible light as it can degrade RB5 after 360 minutes of exposure by up to 80 percent. This study proves that CdS is a strong photocatalyst of visible light that has a small band gap and crystalline particles.

Promoting digital transformation in waste collection service and waste recycling in Moscow (Russia): Applying a circular economy paradigm to mitigate climate change impacts on the environment

Due to industrialization, recently Moscow (Russia) has been inundated with municipal solid waste (MSW), while the capital does not have an organized waste collection and waste recycling system. Digitalization enables smart cities such as Moscow to do more work with less resources. This article identifies and analyzes the existing waste management facilities in Moscow with respect to drawbacks and the ways forward to mitigate the bottlenecks. To improve its waste management, lessons drawn from Berlin's experiences in waste management are discussed to inspire a transformation in the city's waste sector in the framewok of resource recovery. In line with the 2030 UN Agenda, this work proposes a digitalization to accelerate a societal transition through waste recycling industry. Its global relevance is elaborated by presenting a perspective of digitalization in waste management practices. In this work, case-study was selected as the research method to provide a means to investigate a complex waste problem in Moscow and Berlin (Germany). It was evident from a cleaner production paradigm that digital technology can minimize the amount of unrecycled MSW, while conserving raw materials and reducing operational cost and GHG emissions. Digitalization builds cities' resilience by strengthening local waste management practices to respond to the Covid-19 global pandemic. In Moscow, the transition towards the digitalization of waste recycling through informal waste sectors has created 5,000 new jobs that reduces unemployment rate. This maximizes pick up time and enhances efficiency with a lower cost of operating trucks up to 75%. A convolutional neural network–based identification system that classifies identified materials yields almost perfect accuracy. A single robot arm can handle four varying fractions of construction and demolition waste with 99% of purity. Robotic deployment could reduce the volume of unrecycled waste by 20%. This could be replicated worldwide to resist the pressure of resource consumption and deliver socio-economic and environmental benefits.

Investigating the potential of cobalt-doped zinc oxide (Zn1-xCoxOδ) as a buffer layer for CZTS thin-film solar cells

No abstract is provided for this article.

Pore Former Addition in the Preparation of Highly Porous Anode Using Phase-inversion Technique for Solid Oxide Fuel Cell

A detailed study on the anode structure of solid oxide fuel cell (SOFC) is very crucial in developing high performance power generating devices, given how porous electrodes are known to provide a number of active sites for reaction, consequently accelerate fuel conversion. This present study investigates the feasibility of pore former addition to nickel oxideyttria stabilized zirconia (NiO-YSZ) anode, fabricated via phase inversion-based casting and sintering technique. The loading of two types of pore former (i.e. polyetheretherketone [PEEK] and corn starch) was varied from 0 to 10 wt% of total suspension. The effects of pore former loading and its types were examined based on anode morphology using scanning electron microscopy (SEM), crystal phase by X-ray diffraction (XRD), apparent porosity based on standard ASTM C373-88, and bending strength using three-point bending test. Results had shown that higher loading of pore former increased the porosity, yet significantly reduced the bending strength. SEM images of anode displayed that by generating more connected open pores through the addition of 2 wt.% PEEK, it produced an effective porous structure. In fact, the sample recorded to be 67 % mechanically stronger compared to the best loading which is corn starch (4 wt.%). Based on these findings, PEEK can be used as pore former in anode fabrication that creates appropriate porosity, which benefits gas diffusion and also provides good mechanical strength as an anode support.

Recent progress on fabrication and application of electrospun nanofibrous photocatalytic membranes for wastewater treatment: A review

Presently, photocatalytic degradation has emerged as an attractive and efficient technology for water and wastewater treatment. Many photocatalysts have been introduced and applied to treat organic pollutants in an aqueous system such as dyes, antibiotics, pharmaceuticals, and oily wastes. However, several hurdles, such as difficulty in the suspended photocatalyst segregation from the aqueous system and low reutilization rate, urgently need to be addressed for photocatalytic degradation to be independently implemented in wastewater treatment. The suspended photocatalyst in wastewater needs to be separated to enable the recovery of the spent photocatalyst efficiently. The spent photocatalyst can be regenerated and reused to reduce the operational cost. Therefore, extensive studies have been carried out, targeting photocatalyst immobilization in the nanofibrous membrane to promote the photocatalyst's practical usage in natural wastewater treatment. This review aims to comprehensively discuss the recent progress of the developed nanofibrous photocatalytic membrane, emphasizing advancements in physical and morphological structure towards exhibiting high performance in wastewater treatment. Performance evaluation, challenges, and future directions regarding the utilization of electrospun nanofibrous photocatalytic membranes in wastewater treatment are comprehensively reviewed.

Effect of Kaolin Particle Size Towards Preparation of Kaolin Ceramic Membrane

The purpose of this work is to study the effect of kaolin particle size for the preparation of low cost ceramic membrane suspension and ceramic membrane structure. Kaolin particle size is categorized into two categories; i) ≤ 1µm and ii) ≥ 1 µm. The suspension is prepared via stirring technique under 1000 rpm at 60°C. The particle size of kaolin is characterized using field emission scanning electron microscope (FESEM) and the prepared suspension is characterized in term of its viscosity. Results indicate that the particle size gave significant effect to the viscosity of ceramic membrane suspension. Preliminary data showed that kaolin with particle size ≤ 1µm resulted ceramic membrane with dense structure.

Thin Film Nanocomposite Forward Osmosis Membrane with Exfoliated Layered Double Hydroxide Nanosheets Embedded Support for Fouling-Resistant Microalgae Dewatering

Microalgae dewatering using membrane technology has become feasible. The features of membrane are essential for achieving efficient dewatering performance. Thin-film nanocomposite membrane with layered double hydroxide (LDH) nanosheet incorporated substrate and its performance in microalgae dewatering were examined in this research. The membrane has been developed to address the drawbacks of FO in regards to concentration polarization, reverse draw solute diffusion, and antifouling. The morphology, wettability, permeability, fouling resistance, and long-term performance of the membranes was improved by incorporating exfoliated LDH within the polyethersulfone (PES) support layer of polyamide TFN membranes. Dewatering of Chlorella vulgaris by FO in active layer facing feed solution (AL-FS) and active layer facing draw solution (AL-DS) was evaluated with 2M NaCl as draw solution. The findings revealed the 0.5% LDH embedded within PES support, the water flux improved by 111.43% contrasted with neat membrane. The 0.5% LDH-TFN showed improved antifouling properties during the 4-cycle microalgae dewatering. In addition, the incorporation of LDH supressed internal concentration polarization of TFC membranes thus exhibiting good flux stability throughout the 72h operation. This research evidenced the intriguing prospect of exfoliated Zn-Al LDH as a promising additive to modify TFC membrane for high performance microalgae dewatering.

Applications and Future Outlooks of Hollow Nanomaterials for Wastewater Treatment

: Hollow nanomaterials, which emerged from nanotechnology, earned a lot of interest due to their unique morphology and extensive surface area. This technology has been widely utilized in water treatment branches such as photocatalysis, membrane technology, and the sorption process. There are several types of hollow nanomaterials, all of which have the potential to treat contaminated water, including pollutants, namely heavy metals and organic compounds. Here, we provide a review of the benefits and downsides of hollow nanomaterials advancement as well as new progress in those fields. The challenges of using hollow nanomaterials, as well as their prospects, are also discussed.

Contributors

WO3–based photocatalysts: A review on synthesis, performance enhancement and photocatalytic memory for environmental applications

A significant drawback of the traditional photocatalysts such as titanium dioxide (TiO2) is their inability to absorb visible light from the solar spectrum due to their wide band gap energy. They are only photoactive in the ultraviolet (UV) region which is just a little fraction of the solar spectrum and could be harmful with much exposure to it. Due to its abundance in the solar spectrum, visible light needs to be harnessed for environmental applications. However, we lack visible light driven photocatalysts with long-lasting energy storage capacity for “round-the-clock photocatalytic” (RTCP) applications. For this reason, there is a growing need to find new photocatalysts that can mitigate these bottlenecks. It is evident from some carefully selected published articles (1976–2021) that tungsten oxide (WO3) and its composites have attracted popularity in recent years because of its outstanding properties and particularly its smaller band gap energy of 2.8 eV. However, pristine WO3 is limited due to relatively low energy density and smaller specific surface area. These drawbacks can be addressed by developing various WO3 – based materials to improve their performance. This paper reviews and discusses their recent development in surface advancement, morphology control, modification of nanostructured WO3 and its composites, and their RTCP energy storage for photocatalytic activities in visible light and the dark for environmental applications. Specific aspects focused on its nature, structure, properties, synthesis, coatings, deposition, approaches at modifying and enhancing its visible light photoactivity for enhanced performance and energy storage potential.

Strengthening waste recycling industry in Malang (Indonesia): Lessons from waste management in the era of Industry 4.0

Over the past years, Malang (Indonesia) has encountered environmental problems due to municipal solid waste (MSW) overgeneration. Nevertheless, the increasing volume and complexity of MSW management in the city could be tackled using digital solutions. As a key location of ICT development, China is a key partner for Indonesia to improve its MSW management using digital technologies. As a miniature of China's sustainable waste management, Nanning represents a model of smart city that applies resource recovery paradigms using digitalization. Using a case-study approach, this work critically investigates how to strengthen waste recycling industry in Malang using digitalization-based circular economy (CE) according to Nanning's experiences in digitalizing waste recycling. It was found that lessons learnt from Nanning in MSW management were transferable and applicable for Malang to replicate its model, while paving the way forward for a transition towards a CE in waste sector. Traditionally, waste segregation at source was not properly conducted in Malang due to lack of environmental awareness and less public participation, while the waste management in Nanning is time-efficient and cost-effective. Nanning's experiences in digitalizing recyclable materials and/or recycled goods could facilitate Malang to shift towards a digitalization-based CE. Integrating automatic segregation and digitalization at waste banks is efficient in terms of time. With digitalization, over 90% of the solid waste in Malang is segregated properly, while diverting 60% of its non-biodegradable trash from landfills. Overall, the use of digital technologies has enabled waste banks to revolutionize waste industry, while promoting sustainable development at local level. To contribute their share to the UN SDGs, other cities in Indonesia are at their transition towards a digitalization-based CE. There is still a long way for them to attain full circularity and reap the benefits of digital transformation in the waste sector. Hence, it is necessary for stakeholders to promulgate effective policies and strengthen CE implementation on non-biodegradable waste through digital technologies.

A Review on Modification of Zeolite for Photocatalytic Applications

Zeolites are microporous crystalline alumina-silicate materials, widely used as catalysts, ion exchangers and adsorbents due to their chemical structure and surface properties. The unique properties of zeolite such as high adsorption capacity and cation exchange make it interesting to be used as a support material. This review article presents the details of various researches of zeolite used as photocatalyst in photocatalytic application. The modifications of zeolite using several methods are described in details for photocatalytic enhancement. The effect of zeolite nanoparticles in membrane fabrication also provided in this article. Furthermore, the efficiency of zeolite used as adsorbents and photocatalyst in the photocatalytic application also presented.

Silica DDR Membrane

No abstract is provided for this article.

The Effect of PCA-g-MWCNTs loading on the performance of PES/MWCNTs hemodialysis membrane

Membrane fouling is one of the biggest obstacles towards hemodialysis treatment. In this work, multi-walled carbon nanotubes (MWCNTs) are incorporated to enhance the hydrophilicity and antifouling property of polyethersulfone (PES) hemodialysis membrane. Prior to the mixing, surface functionalisation of MWCNTs was carried out to introduce a large hyperbranched poly (citric acid) (PCA) for better dispersion. PCA-grafted (g)- MWCNTs were prepared by grafting citric acid monohydrate onto the wall of purified MWCNTs. PCA-g- MWCNTs (0 - 0.2 wt%) were then dispersed in PES and polyvinylpyrrolidone blends. The membranes were spun at 50 cm air gap, characterised in terms of morphology and hydrophilic properties before tested for pure water flux (PWF) and protein rejection using bovine serum albumin (BSA). The results revealed that, compared to the neat PES membrane, the PES/MWCNTs membranes were more hydrophilic. The highest PWF (110.4 L m-2 h-1) was achieved by the membrane incorporated with 0.1 wt% PCA-g-MWCNTs. Same trend was observed for protein rejection, where up to 0.1 wt% loading of PCA-g-MWCNTs, the PES/MWCNTs membrane rejected 97.3 % of BSA compared to 88.2 % as obtained from the neat membrane. It was found that the PES/MWCNTs membranes possessed a greater PWF recovery ratio, proving that the membranes antifouling property was improved. The addition of PCA-g-MWCNTs in the membranes enhanced the hydrophilicity as well as the antifouling property of the PES membrane for hemodialysis application.