Search

The increase in carbon dioxide (CO 2 ) concentration in atmosphere brings in major concern nowadays. Accordingly, a study on the volumetric CO 2 adsorption by using the palm kernel shell-based activated carbon synthesized via direct activation at 850 °C for 1 h has been investigated. The adsorbents are characterized using various analytical techniques to analyze the elemental, surface, and textural characteristics. Referring to the physiochemical analysis, it verifies that the proposed activation method effectively converts the palm kernel shell to value-added activated carbon material. The synthesized palm kernel shell-based activated carbon shows comparable CO 2 adsorption capacity and CO 2 /nitrogen selectivity with the commercial grade activated carbon. The regeneration study that has been carried out via pressure swing indicates easy regenerability and good stability after the multiple adsorption-desorption cycles. The experimental CO 2 adsorption isotherm data is examined by using several isotherm models – Langmuir, Freundlich, and Sips, by using non-linear regression method. The findings reveal that the Sips model mathematically represents the CO 2 adsorption, irrespective of adsorption temperature. Besides, heterogeneity characteristics of gas-solid adsorption is further confirmed through the isosteric heat of adsorption (Q st ) value that decreases with increasing surface loading. [ABSTRACT FROM AUTHOR]

The activated carbon is acknowledged as a promising adsorbent to be applied in various applications due to its low cost, well-developed pore structures, and high adsorption capacity. At present, the increasing abundance of oil palm wastes has resulted in various environmental problems. Accordingly, these agro wastes can be employed as potential low-cost precursors for the activated carbon production. This review paper presents a comprehensive overview on the recent advancement in the utilisation of oil palm wastes as the origin of the activated carbon production, specifically from the year 2011 to the present. Throughout this review paper, a strong emphasis is put on the recent activation methodology towards the oil palm residues. This includes the types of thermal heating mode: conventional furnace-heating and microwave-heating. The experimental designs applied in fabricating the activated carbons from the oil palm wastes are discussed. Overall, this review paper assists researchers to move forward in exploring a simple and economically-viable technique to produce oil palm wastes-based activated carbon with outstanding physiochemical properties and excellent adsorption capacity. [ABSTRACT FROM AUTHOR]

Abstract: CO2 (Carbon dioxide) emissions are one of the greenhouse gases that cause global warming. The power generation industry is one of the main emitters of CO2, and the emissions are expected to increase in the coming years as there seems to be no abatement in the consumption of fossil fuels for the production of electricity. Thus, there is a need for CO2 adsorption technologies to mitigate the emissions. However, there are several disadvantages associated with the current adsorption technologies. One of the issues is corrosion and the need for specialized equipment. Therefore, alternative and more sustainable materials are sought after to improve the viability of the adsorption technology. In this study, several types of agricultural wastes were used as activated carbon precursors for CO2 adsorption process in a TGA (thermogravimetric analyser). The adsorption was also modelled through a pseudo-first order and second order model, Elovich's kinetic model, and an intra-particle diffusion model. From the correlation coefficient, it was found that pseudo-second order model was well-fitted with the kinetic data. In addition, activation energy below than 42 kJ/mol confirmed that the physisorption process occurred. [Copyright &y& Elsevier]

• K 2 CO 3 -activated carbon is obtained from mixtures of petroleum coke and palm shell. • Facile activation route through mechano-chemical K 2 CO 3 activation has been applied. • Box-Behnken design is used for optimization of yield and CO 2 adsorption capacity. • Optimized activated carbon shows a well-developed porosity and surface morphology. • Porous carbon from blend precursors has superior yield and CO 2 adsorption capacity. In this study, a binary mixture of petroleum coke and palm kernel shell had been investigated as potential starting materials for activated carbon production. Single-stage potassium carbonate (K 2 CO 3) activation under nitrogen (N 2) atmosphere was adopted in this research study. Effect of several operating parameters that included the impregnation ratio (1−3 wt./wt.), activation temperature (600−800 °C), and dwell time (1−2 hrs) were analyzed by using the Box-Behnken experimental design. Influence of these parameters towards activated carbon yield (Y 1) and carbon dioxide (CO 2) adsorption capacity at an atmospheric condition (Y 2) were investigated. The optimum conditions for the activated carbon production were attained at impregnation ratio of 1.75:1, activation temperature of 680 °C, and dwell time of 1 h, with its corresponding Y 1 and Y 2 is 56.2 wt.% and 2.3991 mmol/g, respectively. Physicochemical properties of the pristine materials and synthesized activated carbon at the optimum conditions were analyzed in terms of their decomposition behavior, surface morphology, elemental composition, and textural characteristics. The study revealed that the blend of petroleum coke and palm kernel shell can be effectively used as the activated carbon precursors, and the experimental findings demonstrated comparable CO 2 adsorption performance with commercial activated carbon as well as that in literatures. [ABSTRACT FROM AUTHOR]