Publications

Removal by absorptive ceramic membranes can simultaneously absorb and separate metal ions from water. Alumina/yttria‐stabilized zirconia (Al 2 O 3 /YSZ) hollow‐fiber membranes, fabricated using phase inversion and sintering process, were deposited with iron oxide by an in‐situ hydrothermal process. The results showed that α ‐Fe 2 O 3 was produced and incorporated across the membranes. A reduction in flux was recorded with the deposition of α ‐Fe 2 O 3. However, it improved the adsorption capacity for heavy metal adsorption. The adsorption‐separation test demonstrated that the optimized membrane is able to completely remove Pb(II) ions after two hours.

No abstract is provided for this article.

This work investigates the use of novel BiOI@ZIF-8 nanocomposite for the removal of acetaminophen (Ace) from synthetic wastewater. The samples were analyzed using FTIR, XRD, XPS, DRS, PL, FESEM-EDS, and ESR techniques. The effects of the loading capacity of ZIF-8 on the photocatalytic oxidation performance of bismuth oxyiodide (BiOI) were studied. The photocatalytic degradation of Ace was maximized by optimizing pH, reaction time and the amount of photocatalyst. On this basis, the removal mechanisms of the target pollutant by the nanocomposite and its photodegradation pathways were elucidated. Under optimized conditions of 1 g/L of composite, pH 6.8, and 4 h of reaction time, it was found that the BiOI@ZIF-8 (w/w = 1:0.01) nanocomposite exhibited the highest Ace removal (94%), as compared to that of other loading ratios at the same Ace concentration of 25 mg/L. Although this result was encouraging, the treated wastewater still did not satisfy the required statutory of 0.2 mg/L. It is suggested that the further biological processes need to be adopted to complement Ace removal in the samples. To sustain its economic viability for wastewater treatment, the spent composite still could be reused for consecutive five cycles with 82% of regeneration efficiency. Overall, this series of work shows that the nanocomposite was a promising photocatalyst for Ace removal from wastewater samples.

Over the past years, Indonesia, the world’s fourth most populous country, has confronted environmental problems due to uncontrolled generation of municipal solid waste (MSW). While the integrated solid waste management (ISWM) represents a critical strategy for Indonesia to control its production, it is also recognized that economic approaches also need to be promoted to address the waste problem concertedly. In this case study, empirical approaches are developed to understand how a volume-based waste fee could be incorporated into MSW collection services and how to apply a zero-waste approach in Indonesia by adapting resource recovery initiatives, adapted from Germany’s mature experiences in integrating the CE paradigm into the latter’s MSWM practices. Currently, Sukunan village (Yogyakarta, Indonesia) promotes waste reduction at sources in the framework of community-based solid waste management (CBSWM) by mobilizing the local community for waste separation (organic and non-organic) and waste recycling. As a result, about 0.2 million Mt of CO2-eq emissions was avoided annually from local landfills. The economic benefits of recycling activities by the village’s community also resulted in 30% reduction of the waste generated. This CBSWM scheme not only saves the government budget on waste collection, transport and disposal, but also extends the lifetime of local landfills as the final disposal sites. By integrating the CE paradigm into its MSWM practices through the implementation of economic instruments and adherence to the rule of law in the same way as Germany does, Indonesia could make positive changes to its environmental policy and regulation of MSW. A sound MSWM in Indonesia could play important roles in promoting the effectiveness of urban development with resource recovery approaches to facilitate its transition towards a CE nationwide in the long-term.

Because of its low-lying location, urbanization, and inadequate infrastructure, Jakarta (Indonesia) has experienced an increase in annual flooding events, rising from an average of five significant floods per year in the 1990s to over 20 annually (2010-2020). With climate change exacerbating extreme weather events, Jakarta encounters escalating risks of flooding. Although the recurrent flooding is exacerbated by non-point source (NPS) of pollution such as urban runoff and agricultural discharge that contribute to 40% of total pollutants leading to flood-related issues in Jakarta, none has investigated this research gap. To reflect its novelty, this work explores the implications of climate change on the annual flooding in Jakarta by focusing on NPS and analyzes their impacts from social perspectives. This work also underscores the implications of flooding on livelihoods, health, and social cohesion in Jakarta. Focus group discussion with affected residents was used to shed light on the coping strategies employed in response to recurrent floods, ranging from community-based initiatives to reliance on informal networks. The empirical findings show that the implications of flooding extend beyond physical damages. Displacement of communities, loss of livelihoods, disruption of essential services, and increased health risks are among the social impacts experienced by local residents. Vulnerable populations, including low-income communities residing in informal settlements, bear their consequences. Economic losses from flooding amount to USD 500 million annually, impacting over 1 million residents. However, recent interventions have led to a 15% reduction in peak flood levels and a 20% reduction in flood duration in affected areas. Community resilience has also improved, with a 25% increase in flood insurance coverage and a 20% rise in community response initiatives. Overall, this study highlights that climate change exacerbates annual flooding in Jakarta, significantly impacting vulnerable communities through NPS pollution. Addressing the challenges requires integrated approaches combining effective pollution control, resilient infrastructure, and community engagement to mitigate social and long-term environmental impacts. PRACTITIONER POINTS: Climate-induced flooding disproportionately affects vulnerable communities in Jakarta. Non-point source pollution from urban runoff contributes to the severity of flooding in Jakarta. Waterborne diseases, disruption of livelihoods, and reduced access to clean water are major concerns identified in the study. The study highlights the importance of community-based adaptation strategies to mitigate the impact of flooding and pollution.

No abstract is provided for this article.

Excessive nutrient contents in water bodies renders eutrophication and causes undesired structural changes to the environment. One of the most straightforward strategies to address eutrophication issue is through the removal of nutrients such as phosphate ions from the water sources. A combination of membrane filtration and adsorption process is an attractive alternative to remove phosphate from aqueous solution. In this work, polysulfone/iron oxide nanoparticles (PSf/IONPs) adsorptive nanocomposite ultrafiltration (UF) membrane was prepared via phase separation process. Flat sheet membranes were characterized using scanning electron microscopy, energy-dispersive X-ray spectrometry, contact angle, overall pore size, porosity and pure water flux (PWF). Results showed that the incorporation of IONPs greatly enhanced the membrane PWF from 10.0 L/m2/h to 55.2 L/m2/h, contributed by the enhanced surface hydrophilicity (contact angle = 63.9°), porosity (74.1%) and larger overall pore size (79.3 nm). It was revealed that the membrane possessed phosphate adsorption capacity of 73.5 mg/g. Filtration experiment demonstrated that the PSf/IONPs membrane exhibited efficient phosphate removal under a steady flux. The design of this adsorptive UF membrane could fulfil the current necessity to remove phosphate from wastewater.

The efficient synthesis of exfoliated graphene oxide nanosheets (GO) via modified Hummers’ method was successfully carried out. The physicochemical properties of GO were determined by Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometry (UV-vis), x-ray diffraction analysis (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The graphite was fully oxidized by strong oxidizing agent caused the oxygen-containing functional groups such as C-O-C, C=O, and COOH were introduced into the graphite layers as analyzed by Raman and FTIR. XRD pattern of GO showed 2θ of 12.0o with interlayer spacing ~ 7.37A which describe non uniform crystal structure with the addition of oxygen containing functional groups. UV-vis spectrum of GO exhibit maximum absorption peak at ~ 234 nm corresponding to the aromatic C=C bond with π-π* transition. The morphology of GO was observed to have flake-like shape and less transparent layers by TEM. The properties of synthesized GO suggest high potential in producing the high quality of graphene which is can be applied as the electrocatalyst support for direct methanol fuel cell application.

In this work, the feasibility study of a superhydrophobic ball clay based ceramic hollow fibre membrane (HFM) through pre-fluorinating of poly(vinylidene fluoride)–co-hexafluoropropylene (PVDF-HFP) and ZnO nanoparticles composite with 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (C8) followed by post-roughening on fluorinated ball clay based ceramic hollow fibre membrane (PH/C8/ZnO-C8/HFM) via universal spray coating. The coating was applied onto ball clay based ceramic hollow fibre membrane’s surface in order to achieve superhydrophobicity, which had not previously been reported. C8 was grafted on the ceramic hollow fibre membrane’s surface using the conventional immersion method and the prepared membrane (C8/HFM) was served as a control. The hierarchical structure of PH/C8/ZnO-C8/HFM is composed of a cooperative layer of fluorinated PVDF-HFP/ZnO nanocomposite in mechanical interlocking mode. PH/C8/ZnO-C8/HFM has better superhydrophobic properties, with a water contact angle of 154.4° and a hysteresis contact angle of 3.2°, than C8/HFM, which has a water contact angle of 151.7° and a hysteresis contact angle of 9.2°. The PH/C8/ZnO-C8/HFM outperforms the C8/HFM in the wetting resistance because the liquid entry pressure of water LEPw (PH/C8/ZnO-C8/HFM = 1.33 ± 0.4 bar, C8/HFM = 0.37 ± 0.1 bar) and salt rejection in MD for the PH/C8/ZnO-C8/HFM is better than C8/HFM.

The adsorption behavior of Cd(II) and Pb(II) ions in a coexisting environment, alongside with both dyes (Reactive Red198 and Blue29) was systematically investigated by using a continuous fixed-bed column completely packed with Rosa damascena waste biosorbent (RDWB). Artificial neural network (ANN) model was also utilized to predict the performance of RDWB for various inputs. Their column performance was assessed by optimizing parameters such as bed depth, influent flow rate, and biosorbents’ concentration. It was found that an increasing bed depth considerably extended the operational lifespan and decrease in flow rate delays the column adsorption. Its adsorption capacities were 24.9, 24.6, 24.0 and 24.3 mg/g for Pb(II), Cd(II), Red198, and Blue29, respectively. The RDWB also had a higher adsorption capacity, as compared to previously used biosorbents such as chitosan and biochars due to its good thermal stability and high surface area of 421.46 m2/g. The adsorption of target pollutants took place through ion exchange and electrostatic interactions with negatively charged functional groups on the adsorbent’s surface. The experimental data were fitted by various column adsorption models such as the Thomas, Yoon-Nelson, and Adams-Bohart. The findings showed that the Thomas model exhibited a strong correlation with the experimental data. In contrast, the Adams-Bohart model was applicable to the initial phase of the breakthrough curve (C e /C 0  ≤ 0.1). For industrial applications, a scale up model was also presented with the cost analysis of the biosorbent. The comparison of predicted values with experimental percentage (%) removal values of target pollutants by the RDWB indicated the excellent performance of the ANN model for this work.

A composite membrane based on cellulose acetate polymer with microcrystalline cellulose (MCC) based filler from lignocellulosic biomass is one of the right solutions to reduce methylene blue (MB) levels in water. MCC has been successfully isolated from water hyacinth, sengon wood, and kapok fiber with an alkalization method. The three MCCs have shown X-ray and FTIR diffraction patterns with characteristic peaks from cellulose and are stable up to 317 °C. Cellulose acetate (CA)/MCC membranes have been prepared using the phase inversion method and characterized by FTIR, tensile strength, contact angle, SEM, and porosity. The characterization results show that the addition of MCC can increase the tensile strength (3.05 N·mm- 2), hydrophilicity (52°), and porosity (88 %). The CA/MCC membrane performed better than the neat membrane in separating MB. The composite membrane with MCC from kapok fiber showed optimum performance with increased flux and MB rejection up to 84 L·m−2·h−1 and 99 %, respectively.