This study aims to analyse the life-cycle assessment of biohydrogen production from palm oil mill effluent (POME) in a pilot-scale up-flow anaerobic sludge blanket fixed-film reactor. The SimaPro LCA ...software and ReCiPe 2016 impact assessment method were used. Electricity usage was found to be a significant source of environmental impacts, with 50–98% of the total impacts. Furthermore, an improvement analysis was conducted, resulted in a reduction in all impacts, especially global warming impact with 77% reduction from 818 to 189 kg CO2-eq per kg biohydrogen. While shifting the pilot reactor to Sarawak may further lessen the impact to 142 kg CO2-eq due to cleaner grid in that region. Besides, if the environmental burden avoided due to usage of POME is considered, the global warming impact can be further reduced to 54.9 kg CO2-eq. Thus, the pilot reactor has huge potential, especially in utilizing waste to produce bioenergy.
•The LCA of bio-H2 production from POME in the pilot-scale reactor was conducted.•Electricity usage contributed highest impact especially in global warming potential.•Improvement analysis was conducted to reduce impact to 54.9 kg CO2 eq per kg H2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Deep eutectic solvents (DESs) have been widely recognized as ionic liquids (ILs) analogues due to their low production cost and superior favorable properties over conventional ILs. Studying the ...physical properties of these solvents will contribute to design processes involving DESs. In this study, five DESs have been successfully prepared using ethylene glycol (EG) as hydrogen bond donor (HBD) with N,N‑diethylethanolammonium chloride (DAC), benzyltriphenylphosphonium chloride (BTPC), choline chloride (ChCl), methyltriphenylphosphonium bromide (MTPB) and tetra‑n‑butylammonium bromide (TBAB) as salts. The freezing point of each of the five studied DESs was measured using Differential Scanning Calorimetry (DSC) and the DES functional groups were identified using the Fourier transform infrared (FTIR) spectroscopy. Moreover, the viscosity, density, electrical conductivity and surface tension were measured at a temperature range of 293.15–353.15 K and they were highly affected by the variation of the temperature. It is worth mentioning that the studied DESs showed many physical characteristics similar to that of ILs, which boost their possibilities to be employed in interdisciplinary domains.
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•Ethylene glycol based deep eutectic solvents (DESs) were prepared from different salts.•The ratios of salt to HBD were selected based on homogeneity and stability of the DES.•The studied DESs showed physical properties similar to that of ionic liquids.•FTIR analysis depicted the existence of new functional groups in DES structure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Micro-bubbles were mechanistically analyzed/characterized using mathematical modeling.•Their equilibrium radius, oscillation velocity, hot spot conditions were investigated.•Acoustic streaming, ...fluid flow pattern, turbulence were analyzed using 3D CFD.•Total volume fraction of micro-bubbles was also analyzed by 3D CFD.•Fluid flow pattern and acoustic streaming were practically analyzed using PIV.
This paper aims at investigating the influence of ultrasound power amplitude on liquid behaviour in a low-frequency (24kHz) sono-reactor. Three types of analysis were employed: (i) mechanical analysis of micro-bubbles formation and their activities/characteristics using mathematical modelling. (ii) Numerical analysis of acoustic streaming, fluid flow pattern, volume fraction of micro-bubbles and turbulence using 3D CFD simulation. (iii) Practical analysis of fluid flow pattern and acoustic streaming under ultrasound irradiation using Particle Image Velocimetry (PIV). In mathematical modelling, a lone micro bubble generated under power ultrasound irradiation was mechanistically analysed. Its characteristics were illustrated as a function of bubble radius, internal temperature and pressure (hot spot conditions) and oscillation (pulsation) velocity. The results showed that ultrasound power significantly affected the conditions of hotspots and bubbles oscillation velocity. From the CFD results, it was observed that the total volume of the micro-bubbles increased by about 4.95% with each 100W-increase in power amplitude. Furthermore, velocity of acoustic streaming increased from 29 to 119cm/s as power increased, which was in good agreement with the PIV analysis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Nano-magnetite was coated on the surface of PSAC via hydrothermal impregnation.•La (hydr)oxide was strongly bound on magnetized PSAC (MPSAC) surfaces.•La surfaces on MPSAC provide ...the enhanced arsenate adsorption capacities.•MPSAC-La has high recyclability and magnetically separable feature.
Palm shell waste–based activated carbon (PSAC) was magnetized via hydrothermal impregnation of nano–magnetite, and further coated by various amounts of lanthanum (La) followed by calcination. Numerous batch tests were carried out to observe arsenate removal by La–impregnated, magnetized PSAC (MPSAC–La) in aqueous phase. Isotherm data showed that MPSAC–La(0.36) (weight ratio of La to Fe=0.36) gave the highest adsorption capacity (227.6mgg−1), which was approximately 16.5 and 1.6 times higher than PSAC and magnetized PSAC (MPSAC), respectively. As an indication of sorption affinity, MPSAC–La(0.36) had the highest Langmuir constant (KL), which was approximately 230 times greater than that of MPSAC. Based on the pH effect and speciation modeling, arsenate was predominantly removed by precipitation at pH<8, while it complexed on the surface of La(OH)3 at pH>8. Lesser La dissolution resulted, owing to a strong binding effect of nano–magnetite with La. XRD, FTIR, SEM–EDS, and N2 gas isotherms showed that the coating of nano–magnetite introduced substantial clogging in the micropores of PSAC, but increased meso– and macropores. However, lanthanum oxide/hydroxide (LO/LH) glued the spaces of nano–magnetite to eliminate most pore structures, and effectively removed arsenate as LaAsO4 at pH6. Overall, MPSAC–La(0.36) is considered a competitive granular material due to its extremely high sorption capabilities, easy magnetic separation and high regeneration rate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Freely assembled palladium nanoparticles (Pd NPs) on titania (TiO2) nano photocatalysts were successfully synthesized through a photodeposition method using natural sunlight. This synthesized ...heterogeneous photocatalyst (Pd/TiO2) was characterized through field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET surface area, UV-vis diffuse reflectance spectra (UV-DRS), Raman and photoluminescence (PL) analyses. The simple and smart synthesis anchored well the deposition with controlled Pd NPs size ranging between 17 and 29 nm onto the surface of TiO2. Thus, it gives the characteristic for Pd NPs to absorb light in the visible region obtained through localized surface plasmon resonance (LSPRs). Apparently, the photocatalytic activity of the prepared photocatalysts was evaluated by degrading the endocrine disrupting compound (EDC) amoxicillin (AMX) excited under an artificial visible light source. In the preliminary run, almost complete degradation (97.5%) was achieved in 5 h with 0.5 wt % Pd loading and the degradation followed pseudo-first-order kinetics. The reusability trend proved the photostability of the prepared photocatalysts. Hence, the study provides a new insight about the modification of TiO2 with noble metals in order to enhance the absorption in the visible-light region for superior photocatalytic performance.
A batch study for biohydrogen production was conducted using raw palm oil mill effluent (POME) and POME sludge as a feed and inoculum respectively. Response Surface Methodology (RSM) was used to ...design the experiments. Experiments were conducted at different reaction temperatures (30–50 °C), inoculum size to substrate ratios (I:S) and reaction times (8–24 h). An optimum condition of biohydrogen production was achieved with COD removal efficiency of 21.95% with hydrogen yield of 28.47 ml H2 g−1 COD removed. The I:S ratio was 40:60, with reaction temperature of 50 °C at 8 h of reaction time. The study showed that a lower substrate concentration (less than 20 g L−1) for biohydrogen production using pre-settled POME was achievable, with optimum HRT of 8 h under thermophilic condition (50 °C). This study also found that pre-settled POME is feasible to be used as a substrate for biohydrogen production under thermophilic condition.
•POME sludge and raw POME is feasible for biohydrogen production.•Shorter reaction time is significantly increased on the hydrogen yield.•Inoculum size gives a significant effect on the hydrogen yield and COD removal efficiency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•Pure anatase titania was synthesized at room temperature by non-hydrolitic sol–gel method.•Photocatalytic activity was examined for as synthesized and calcined TiO2 under natural ...sunlight.•Both the catalyst showed higher photocatalytic activity by complete degradation of 2,4-DCP.•Degradation kinetics depends on surface recombination and crystallinity of the photocatalysts.
Nanocrystalline anatase TiO2 was prepared through modified non-hydrolitic sol–gel method by reacting TiCl4 with benzyl alcohol at room temperature. The as synthesized anatase TiO2 was calcined at 450°C for 5h. The size and morphology of the as synthesized and calcined TiO2 nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and BET surface area analysis. The band gap energy was measured using Kulbeka-Munk function and the electronic state of the prepared TiO2 was determined by X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the prepared samples was investigated by degrading 50mg/L of 2,4-dichlorophenol (2,4-DCP) under natural sunlight as a source of irradiation. The obtained XRD patterns of both as synthesized and calcined TiO2 matches completely with the tetragonal anatase phase of TiO2. The as synthesized sample showed higher surface area (147.34m2/g) with particles size ranging between 3 and 6nm than the calcined titania (64.92m2/g) of prarticle size ranging between 11 and 15nm. Both the TiO2 samples showed excellent photocatalytic activity for the degradation of 2,4-DCP under natural sunlight irradiation. The complete removal of 2,4-DCP is obtained after 2.5h for calcined TiO2 and 3.5h for as synthesized TiO2 suggests that the prepared photocatalysts have the potential to degrade the organic pollutants. The degradation of 2,4-DCP followed first order kinetics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Adsorption is a prominent and cost-effective water treatment method that has been used to remove a variety of contaminants due to its efficacy, ease of use, and environmental friendliness. ...Biosorbents developed from agricultural wastes have been extensively studied. This review gives insight into the potential of carbonaceous coconut shells as a source of biomass material to prepare adsorbents for wastewater treatment. The feasibility of coconut shells as a precursor material is beneficial for extensive industrial-scale applications due to their natural properties and long-term availability. This review article also illustrates the excellent adsorption performance of adsorbents derived from coconut shells that can be an alternative precursor to commercial carbons with a high market price. This review points out the applications of coconut shell-based adsorbents in removing a wide range of contaminants and actual industrial wastewater. Additionally, literature shows that modified coconut shell-based adsorbents show better adsorption performance in removing hazardous pollutants due to enhancement in adsorbents’ structural characteristics. The discussion on the environmental and economic perspectives on utilizing coconut shell-based adsorbents is also of the highlights of this review. It is prospective for industries to explore converting agricultural wastes into low-cost green adsorbents for wastewater treatment.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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