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Factors such as particle type and its loading have been previously studied in tailoring the efficiency of particles-modified polymeric membranes for water treatment. However, the role of particle sizes in membrane modification is often overlooked. Thus, in this work, two commercial iron oxide (Fe 3 O 4 ) particles (i.e., 50–100 nm and

High organic materials in palm oil mill effluent (POME) can result in serious water pollution. To date, biological treatment has been used to reduce the environmental risks of these effluents prior of their discharge into water streams. However, the effluents’ dark brownish colour remains as a significant issue that must be addressed, as it affects the overall quality of water. Although membrane technology has been frequently used to address these difficulties, membrane fouling has become a serious limitation in POME treatment. On the other hand, zwitterions with balanced charge groups have received growing interest in the fabrication of antifouling membranes due to their hydrated nature. The development of a simple and efficient covalent bonding technique to improve the stability of zwitterions on membrane surfaces remains a challenge. By grafting and co-depositing polyethylenimine (PEI)-based zwitterion (Z-PEI) with super hydrophilic polydopamine (PDA) on the surface of a commercial polysulfone (PSf) ultrafiltration membrane at ambient temperature, a new zwitterionic surface with a neutral surface charge was created (PDA/Z-PEI). This study aims to investigate the effect of different loading ratios of PDA/Z-PEI (1:1, 1:2, and 1:3) and evaluate their performance on treating brownish coloured anaerobically treated POME (AT-POME). SEM and FTIR analysis showed the successful incorporation of the PDA/Z-PEI membrane while the zwitterionic feature is indicated by zeta potential analysis. Water flux analysis demonstrated that a lower water flux was achieved for M-ZPEI membranes as compared to the PSf and PSf-MDPA membranes, attributed by the tight skin layer of PDA-ZPEI. In the development of a tight hydration layer on the membrane surface by zwitterions, zwitterionic membranes demonstrated excellent antifouling capabilities, particularly PDA/Z-PEI with a loading ratio of (1:2) with a flux recovery ratio of around 84% and colour rejection of 81.75%. Overall, this research contributes to the development of a unique coating with improved stability and antifouling properties by altering the membrane surface in a simple and reliable manner.

Today, some of the major disadvantages of conventional palm oil mill effluent (POME) treatment are that the process is time consuming, as well as space consuming. Besides, most of the recent photocatalyst still have a limitation that able to demonstrate their good performances only under sources of light. The visible-light-driven energy storage photocatalyst, which is tungsten trioxide (WO3), has been developed to overcome the limitations mentioned. Therefore, the present study aims to investigate the comparative calcination temperature and the degradation of POME using WO3 as a photocatalyst in adsorption and photocatalytic processes under visible light irradiation. An eco-friendly WO3 photocatalyst was synthesized by coprecipitation method. Subsequently, the resulting WO3 was characterized by Fourier-transform infrared spectroscopy (FTIR) to evaluate the significance of calcination temperature towards WO3. Furthermore, the adsorption activity of WO3 towards POME was investigated at different sources of ponds (cooling, anaerobic and aeration) throughout 300 min. This study reports on the efficiency of adsorption activity of WO3-400 °C towards pond aeration pollution, which showed that it was better than that in anaerobic and cooling ponds based on the chosen study criteria of color and suspended solid removal for the investigation of photocatalytic activity. Moreover, WO3 was proven to be able to conserve energy, where it was demonstrated that POME can still degrade consistently in darkness, with the highest color removal of approximately 48% was obtained. An extraordinary photocatalytic treatment with WO3 functioning simultaneously as the light harvesting and energy storage material is deemed as an efficient photocatalyst for POME in terms of decolorization and removal of suspended solid.

60 Years of the Loeb-Sourirajan Membrane: Principles, New Materials, Modelling, Characterization and Applications bring forth theoretical advances, novel characterization techniques, materials development, advanced treatment processes, and emerging applications of membrane-based technologies. The trigger for writing this book is the 2020, 60th anniversary of the first asymmetric polymeric membrane invented by Dr. Sidney Loeb and Dr. Srinivasa Sourirajan (University of California, Los Angeles, USA) on the breakthrough discovery of the semipermeable membrane for seawater desalination. The book places emphasis on the advances of organic and inorganic membranes in different fields, covering not only the primary application of membranes for water and wastewater treatment but also other applications dealing with energy conversion and storage, organic solvent purification, gas separation, and biomedical processes. 2022 Elsevier Inc. All rights reserved. Scopus

A greener processing route to replace the current environmentally-unfriendly esterification technique to produce biofuels such as pentyl valerate (PeVa) was explored. This study statistically optimized the covalent immobilization of Candida rugosa lipase (CRL) onto biomass-based nanocellulose-silica (NC-SiO2) reinforced polyethersulfone (PES) membrane to synthesize PeVa. Raman spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and atomic force microscopy of NC-SiO2-PES/CRL proved that CRL was successfully conjugated to the membrane. The optimized Taguchi Design-assisted immobilization of CRL onto NC-SiO2-PES membrane (5% glutaraldehyde, 4 h of immobilization, 20 mg/mL CRL concentration, 40 °C and pH 5) gave 90% yield of PeVa in 3 h. The thermal stability of NC-SiO2-PES/CRL was ~ 30% greater over the free CRL, with reusability for up to 14 successive esterification cycles. In a nutshell, the greener NC-SiO2-PES membrane effectively hyperactivated and stabilized the CRL for the esterification production of PeVa. This research provides a promising approach for expanding the use of sustainably sourced NC and SiO2 nanoparticles, as fillers in a PES for improving CRL activity and durability for an extended catalytic process.

In this work, the effect of adding manganese oxide towards polyacrylonitrile-based activated carbon nanofibers (ACNFs) was evaluated. The properties of PAN-based ACNFs/MnO2 were analyzed by using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and Fourier transform infrared (FTIR). The sorption study of the electrospun ACNFs/MnO2 in comparison to neat ACNFs and commercial granular AC towards lead (Pb) was also conducted. SEM micrograph analysis displays more compact nanofibers with dispersion of beads that were observed in the ACNF/MnO2 with the diameter of 437.2 nm while aligned nanofibers with the diameter of 575.5 nm were observed in the neat ACNFs. The FTIR analysis showed the peak of Mn–O, which indicates the presence of MnO2 in the ACNFs/MnO2. In comparison to the neat ACNFs, surface area of the prepared ACNFs/MnO2 is lower. It was found out that the removal of Pb(II) using ACNFs and ACNFs/MnO2 is higher than commercial granular activated carbon with a removal rate of 100% at initial concentration of 3.5 ppm. The promising results of ACNFs/MnO2 contributed by their satisfactory specific surface area and vast presence of surface functional groups.

Recently, the increasing level of water pollution worldwide has not only contributed to environmental issues, but also triggered considerable interest in photocatalysis that act as promising wastewater treatment. Among the explored photocatalysts, tungsten trioxide (WO3) known for its extraordinary characteristics for photocatalytic degradation applications, such as photostability, high crystallinity with high yield and recyclability, inexpensiveness, and photo-corrosion resistance. However, critical issues of high-risk method for inefficient photonic and quantum, and their insignificant structure would lead to recombination of photogenerated carriers, which diminishes photocatalytic efficiency; this is deemed to be a major hurdle to the widespread application of WO3. As a solution, the objective of this review was representing the interpretation several scopes of WO3-based photocatalyst such as the introduction of its basic principles, significant each different precursor, synthesis methods, numerous types of modifications, influential operating parameter and their pro and cons into a photocatalytic system under irradiation. This significant scope could be done to further increase their activity level that attracted much attention in many published studies between year 2010 and 2020. Although energy storage mechanism of photocatalyst is still at an embryonic stage, studies have suggested for the development of photocatalyst with great potential and high rate of degradation. The interesting and unique features of tertiary composites of WO3-based photocatalyst are found to be more effective for photocatalytic degradation due to their more efficient absorption band, band gap, and surface area, as compared to binary and unitary. The enhanced photocatalytic capabilities of WO3-based photocatalyst with their different significant parameters are reviewed towards various pollutant removal, such as synthetic wastewater and real industrial wastewater, among others. Finally, the benefits with ongoing challenges of WO3 are proposed with the aim to improve the design of a highly efficient WO3-based photocatalyst.

Nanoengineered materials are becoming a focus and being utilized in a wide range of applications, especially for water and wastewater treatments. The presences of these materials have brought various pronounced advantages and great deal of improvement to the environment and industries. Generally, nanoengineered materials can be categorized as carbon (organic) and noncarbon (inorganic) materials. Among carbon based materials are carbon nanotube and graphene, while noncarbon materials include metal and metals oxides. Various forms of nanomaterial have been developed such as nanowires, nanotubes and nanoparticles to showcase the advancement of the technology for water treatments. The chapter begins by outlining the merits and limitations of nanoengineered materials for wastewater treatment in numerous applications. The problems and challenges when utilizing nanoengineered materials as nanosorbents, nanometals/metals oxides, nanocarbon and in membrane process are described in details. Although there are many advantages, some challenges are still present, especially in membrane preparation involving nanomaterials. Agglomeration, low dispersity, easily oxidizes and leakages into contact water are some of the major limitations of nanoengineered materials. These issues ultimately will contribute to adverse effects imposed on human health and the ecosystem. Therefore, methods to overcome the inherent limitation of nanomaterials are presented here. Some of the potential solutions to the problems that are discussed in this chapter are encapsulation, grafting, crosslinking, coating, and composite membrane.

An alternative environmentally benign support was prepared from nanocrystalline silica (SiO2), and cellulose (NCC) acquired from oil palm fronds leaves (OPFL) for incorporation with polyethersulfone (PES). The resultant PES-SiO2-NCC support was then used for covalent immobilization of Candida rugosa lipase (CRL/PES-SiO2−NCC). FTIR-ATR spectral data of SiO2−NCC indicated that NCC was hydrogen-bonded to SiO2 based on the characteristic wavenumbers at 1735 cm−1 and 1650 cm−1 for NCC, 1732 cm−1 and 1657 cm−1 for SiO2, alongside decreased peak intensity and the overall downshifted wavenumbers, respectively. X-ray diffractograms of NCC and SiO2 showed crystallinity indices of 68% and 70%, respectively, implying their crystalline nature. The CRL/ PES-SiO2−NCC biocatalyst yielded pentyl valerate as high as 78.3% after 2 h using a 0.02 cm membrane size and 5% (w/v) incorporation of SiO2−NCC but in the absence of the pore former, PVP K30. The findings invariably envisage the biocompatibility of NCC and SiO2 derived from OPFL as a hybrid nano-filler to prepare the PES-SiO2−NCC composite for lipase immobilization.

Herein, this study extracted nanocrystalline cellulose (NC) and silica (SiO2) from raw oil palm leaves (OPL), and employed as nanofillers in polyethersulfone (PES) to produce NC-SiO2-PES as support to immobilize Candida rugosa lipase (CRL) (NC-SiO2-PES/CRL). XRD, TGA-DTG and FTIR-ATR data affirmed that NC and SiO2 were isolated from OPL with corresponding crystallinity indices of 68 % and 70 %. A 0.02 cm membrane size with 5% (w/v) of NC-SiO2 without PVP K30 was optimal for membrane fabrication. CRL immobilized on the Glut-AP-NC-SiO2-PES membrane gave a higher conversion of pentyl valerate (PeVa) (91.3 %, p < 0.05) compared to Glut-NC-SiO2-PES (73.9 %) (p < 0.05). Characterization of the NC-SiO2-PES/CRL biocatalyst verified the presence of CRL. Hence, raw OPL is a proven good source of NC and SiO2, as reinforcement nanofillers in PES. The overall findings envisage the promising use of NC-SiO2-PES/CRL to catalyze an expedient and high yield of PeVa, alongside the suitability of NC-SiO2-PES for activating other enzymes.