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This study investigates the synthesize of activated carbon for carbon dioxide adsorption using palm kernel shell (PKS), a by-product of oil palm industry. The adsorbent synthesis involved a simple two-step carbonization method. Firstly, PKS was activated with potassium oxide (KOH), followed by functionalization with magnesium oxide (MgO). Surface analysis revealed that KOH activated PKS has resulted in a high specific surface area of 1086 m2/g compared to untreated PKS (435 m2/g). However, impregnation of MgO resulted in the reduction of surface area due to blockage of pores by MgO. Thermogravimetric analysis (TGA) demonstrated that PKS-based adsorbents exhibited minimal weight loss of less than 30% up to 500 °C, indicating their suitability for high-temperature applications. CO2 adsorption experiments revealed that PKS-AC-MgO has achieved a higher adsorption capacity of 155.35 mg/g compared to PKS-AC (149.63 mg/g) at 25 °C and 5 bars. The adsorption behaviour of PKS-AC-MgO was well fitted by both the Sips and Langmuir isotherms, suggesting a combination of both heterogeneous and homogeneous adsorption and indicating a chemical reaction between MgO and CO2. Thermodynamic analysis indicated a spontaneous and thermodynamically favourable process for CO2 capture by PKS-AC-MgO, with negative change in enthalpy (− 0.21 kJ/mol), positive change in entropy (2.44 kJ/mol), and negative change in Gibbs free energy (− 729.61 J/mol, − 790.79 J/mol, and − 851.98 J/mol) across tested temperature. Economic assessment revealed that the cost of PKS-AC-MgO is 21% lower than the current market price of commercial activated carbon, indicating its potential for industrial application. Environmental assessment shows a significant reduction in greenhouse gas emissions (381.9 tCO2) through the utilization of PKS-AC-MgO, underscoring its environmental benefits. In summary, the use of activated carbon produced from PKS and functionalised with MgO shows great potential for absorbing CO2. This aligns with the ideas of a circular economy and sustainable development. [ABSTRACT FROM AUTHOR]

Biodiesel is widely known as a renewable energy that can be directly used as an alternative diesel fuel. This paper emphasizes on the synthesis and characterization of lithium modified calcium oxide (CaO) derived from eggshell and cow bone waste materials. The synthesized catalysts were tested in term of their performance in biodiesel production from dairy waste scum oil (DWSO). The CaO was derived from eggshell and cow bone by calcination at 800 °C and then a mixture of CaO from eggshell and cowbone was combined with lithium via wet impregnation which resulted to four catalysts labeled as eggshell (ES), cow bone (CB), eggshell and cow bone (ESCB) and Lithium modified eggshell and cowbone (Li-ESCB). All catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Field Emission Scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX) and Thermogravimetric Analysis (TGA) to interpret their morphologic, structural and chemical properties. The Li-ESCB showed better properties than ESCB, especially in BET analysis, where the surface area was 2.59 m2/g. Only in XRD analysis can it show the presence of lithium as it is very low in concentration (1 wt %), whereas EDX analysis cannot be detected. The biodiesel production were performed via microwave assisted transesterification and ES catalyst showed the highest biodiesel production (82%). Even though Li-ESCB appeared as the best properties, the biodiesel was still low due to the inhibition of phosphorus from CB. The utilization of waste materials can contribute to sustainability development, environmentally friendly and cost-effective method. [ABSTRACT FROM AUTHOR]

The abundance of food waste across the globe has called for the mitigation and reduction of these discarded wastes. Herein, the potential of biochar derived from food waste is unquestionable as it provides a sustainable way of utilizing the abundance of available biomass, as well as an effective way of preserving the ecosystem through the reduction of concerning environmental issues. This review focuses on the food waste–based biochar as advanced electrode materials in the energy storage devices. Efforts have been made to present and discuss the current exploration of the food waste utilization, along with the biochar production technologies through thermochemical conversion, including combustion, gasification, and pyrolysis method. Finding its limitation in literatures, discussion on the food waste–based biochar fabrication method as the electrode materials is elaborated, alongside the current food waste–based biochar that has been explored in the energy application thus far. Towards the end, the outlook and perspective on the further development of food waste–based biochar have been outlined. [ABSTRACT FROM AUTHOR]

The energy demand in Malaysia has shown a dramatic increase over the last few years: with natural gas and coal being the primary contributors. Nevertheless, due to declining in fossil fuel reserves coupled with negative environmental impacts, shifting to sustainable renewable energy for meeting the future energy demand is recommended. Since Malaysia is rich with natural resources, utilization of biomass energy (bioenergy/biofuel) as the alternative energy is promising to be further explored. Therefore, this review paper intents to discuss the current scenario of different types of biomass energy in Malaysia along with the up-to-date local biomass energy–related environmental policy (from 2016 onwards). In addition, challenges and barriers for large-scale implementation of the biomass energy in Malaysia are to be discussed. Overall, this review paper is interesting as it can assist in promoting the biomass utilization as energy source, and to ensure the future growth of biomass energy market in the country along with its effective implementation while alleviating poor disposal problem and to create job employment opportunities. Furthermore, a collective effort to expand potential biomass feedstocks, apart from oil palm, should be emphasized to encourage the renewable energy production diversification in the nation. [ABSTRACT FROM AUTHOR]

Bamboo is the fastest-growing plant and is abundant in Malaysia. It is employed as a starting material for activated carbon production and evaluated for its potential in CO2 capture. A single-stage phosphoric acid (H3PO4) activation is adopted by varying the concentrations of H3PO4 between 50 and 70 wt.% at a constant temperature and holding time of 500°C and 120 min, respectively. The bamboo-based activated carbons are characterized in terms of product yield, surface area, and porosity, as well as surface chemistry properties. Referring to the experimental findings, the prepared activated carbons have BET surface area of >1000 m2 g-1, which implies the effectiveness of the single-stage H3PO4 activation. Furthermore, the prepared activated carbon via 50 wt.% H3PO4 activation shows the highest BET surface area and carbon dioxide (CO2) adsorption capacity of 1.45 mmol g-1 at 25°C/1 bar and 9.0 mmol g-1 at 25°C/30 bar. With respect to both the characterization analysis and CO2 adsorption performance, it is concluded that bamboo waste conversion to activated carbon through H3PO4 activation method is indeed promising. [ABSTRACT FROM AUTHOR]

The volumetric adsorption kinetics of carbon dioxide (CO2) onto the synthesized palm kernel shell activated carbon via single-stage CO2 activation and commercial Norit® activated carbon were carried out at an initial pressure of approximately 1 bar at three different temperatures of 25, 50, and 100 °C. The experimental kinetics data were modelled by using the Lagergren's pseudo-first-order model and pseudo-second-order model. Comparing these two, the non-linear pseudo-second-order kinetics model presented a better fit towards CO2 adsorption for both adsorbents, owing to its closer coefficient of determination (R2) to unity, irrespective of the adsorption temperature. In addition, kinetics analysis showed that the corresponding kinetics coefficient (rate of adsorption) of both activated carbons increased with respect to adsorption temperature, and thereby, it indicated higher mobility of CO2 adsorbates at an elevated temperature. Nevertheless, CO2 adsorption capacity of both activated carbons reduced at elevated temperatures, which signified exothermic and physical adsorption (physisorption) behaviour. Besides, process exothermicity of both carbonaceous adsorbents can be corroborated through activation energy (Ea) value, which was deduced from the Arrhenius plot. Ea values that were in range of 32–38 kJ/mol validated exothermic adsorption at low pressure and temperature range of 25–100 °C. To gain an insight into the CO2 adsorption process, experimental data were fitted to intra-particle diffusion model and Boyd's diffusion model, and findings revealed an involvement of both film diffusion and intra-particle diffusion during CO2 adsorption process onto the synthesized activated carbon and commercial activated carbon. [ABSTRACT FROM AUTHOR]

Accelerating greenhouse gas emission particularly carbon dioxide (CO2) in the atmosphere has become a major concern. Adsorption process has been proposed as a promising technology for CO2 adsorption from flue gas, and the carbonaceous adsorbent is a potential candidate for CO2 adsorption at atmospheric pressure and ambient temperature. Biochar derived from palm kernel shell waste was applied as a potential precursor for activated carbon production. This research study employed the response surface methodology coupled with Box-Behnken design to optimize the parameters involved in producing exceptional activated carbon with high yield (Y1) and CO2 adsorptive characteristics (Y2). Specifically, parameters studied include the activation temperature (750–950 °C), holding time (60–120 min), and CO2 flow rate (150–450 mL/min). The activated carbon at the optimum conditions was characterized using various analytical instruments, including elemental analyzer, nitrogen (N2) physisorption analyzer, and field emission scanning electron microscopy. Overall, utilization of biochar as the activated carbon precursor is practical compared with the traditional non-renewable materials, due to its cost efficiencies and it being more environment-friendly ensuring process sustainability. Besides, this research study that incorporates physical activation with CO2 as the activating agent is attractive, because it directly promotes CO2 utilization and capture, in addition to the absence of any chemicals that may result in the secondary pollution problems. [ABSTRACT FROM AUTHOR]

The feasibility of biomass-based activated carbons has received a huge attention due to their excellent characteristics such as inexpensiveness, good adsorption behaviour and potential to reduce a strong dependency towards non-renewable precursors. Therefore, in this research work, eco-friendly activated carbon from palm kernel shell that has been produced from one-stage physical activation by using the Box-Behnken design of Response Surface Methodology is highlighted. The effect of three input parameters—temperature, dwell time and gas flow rate—towards product yield and carbon dioxide (CO2) uptake at room temperature and atmospheric pressure are studied. Model accuracy has been evaluated through the ANOVA analysis and lack-of-fit test. Accordingly, the optimum condition in synthesising the activated carbon with adequate CO2 adsorption capacity of 2.13 mmol/g and product yield of 25.15 wt% is found at a temperature of 850 °C, holding time of 60 min and CO2 flow rate of 450 cm3/min. The synthesised activated carbon has been characterised by diverse analytical instruments including thermogravimetric analyser, scanning electron microscope, as well as N2 adsorption-desorption isotherm. The characterisation analysis indicates that the synthesised activated carbon has higher textural characteristics and porosity, together with better thermal stability and carbon content as compared to pristine palm kernel shell. Activated carbon production via one-step activation approach is economical since its carbon yield is within the industrial target, whereas CO2 uptake is comparable to the synthesised activated carbon from conventional dual-stage activation, commercial activated carbon and other published data from literature. [ABSTRACT FROM AUTHOR]