In this paper, fallen coconut (Cocos nucifera) leaves were used as precursors to prepare activated carbon by thermal carbonization using KOH-activation method. The physical properties of the prepared coconut leaves-activated carbon (KAC) were calculated through the bulk density, ash content, moisture content, and iodine number. The surface characterization of KAC was undertaken using Scanning Electron Microscopy, Fourier Transform Infrared, and point of zero charge (pH_PZC) method. Batch mode experiments were performed to assess the influence of the adsorbent dose (0.02–0.25 g), initial pH (3–11), initial dye concentration (30–400 mg/L), contact time (5–300 min), and temperature (303–323 K) on the adsorption of the methylene blue (MB). The kinetic uptake profiles are well described by the pseudo-second-order model, while the Langmuir model describes the adsorption behavior at equilibrium. The adsorption capacity (q_m) of KAC increased with temperature where q_m varied as follows; 147.1 (303 K), 151.5 (313 K), and 151.5 mg/g (323 K). Thermodynamic parameters such as standard enthalpy (∆H°), standard entropy (∆S°), and standard free energy (∆G°) showed that the adsorption of MB onto KAC was spontaneous and endothermic in nature under examined conditions. The results showed the potential use of activated carbon developed from waste coconut leaves for the removal of cationic dye (MB).

The study describes the production of an upgrading bio oil from pyrolysis of torrefied demineralized palm empty fruit bunch (TDEFB) using a fixed bed reactor system. TDEFB used as a feedstock was produced by demineralization and torrefaction pre-treatment empty fruit bunches (EFB) on raw EFB. The pyrolysis process was examined with multiple responses such as bio oil (response, Y1), bio char (response, Y2) and bio gas (response, Y3). The effect of these pyrolysis process parameters was observed by the production of bio oil, bio char and bio gas yields as the responses. Twenty runs of pyrolysis experiments were suggested by CCD indicated the optimum pyrolysis condition were found to be at reaction temperature of 490 °C, heating rate of 85 °C/min and holding time of 250 s. The maximum bio oil yield was obtained as 51.53 % with 28.5 % of bio char and 11.97 % of bio gas under optimum condition. The p-value 0.9 which indicated that there was a good correlation between the dependable and non-dependable parameters.

Co-gasification of pretreated palm kernel shell (PKS) and pretreated Malaysian low rank coal has been conducted using a fix bed reactor system. Response surface methodology (RSM) based on central composite design (CCD) was used to determine the optimum condition on gas yield in co-gasification products. The effect of the three factors, i.e. gasification temperature, biomass blending ratio and steam flow rate on response variables (gas, tar and char yield) were examined. The p-value <0.05 for all factors indicated that the factors were significant. The predicted optimum conditions for gasification temperature, biomass blending ratio and steam flow rate were at 767 °C, 52 % and 54 ml/min, correspondingly. These optimum conditions produced maximum gas yield, minimum char and tar yield of 67.28 %, 20.83 % and 11.90 %, respectively. Thus, this study showed that the assessed RSM model has effectively determined the optimum process condition, which designates to the optimum gas yield in co-gasification.

This study describes the properties of upgraded palm kernel shell (PKS) and mukah balingian (MB) coal by microwave irradiation pretreatment. The microwave power level and processing time were varied in this research. The pretreated samples were analysed for mass and energy yield, calorific value and proximate and elemental composition. The characteristics of pretreated samples were improved with increasing microwave power level and reaction time. The oxygen content, O/C ratio of upgraded sample were reduced with increasing microwave power level. The carbon content of pretreated PKS was closed to the untreated MB coal properties with comparable calorific value was obtained. The microwave power level of 450 W and processing time of 8 min were appropriate to upgrade the PKS and MB coal for co-gasification. Thus, it can be concluded that the change in physical and chemical properties of upgraded PKS and MB coal revealed the potential of applying these feedstocks in co-gasification for hydrogen production.