Raja Razuan

Herein, blended rubber seed pericarp (RSP) and sunflower seed pericarp (SFSP) were converted into mesoporous activated carbon adsorbent (RSPSFSP-AC) to remove a toxic cationic dye namely fuchsin basic (FB) dye from aqueous environment. The thermochemical conversion process was carried out by using microwave irradiation assisted ZnCl₂ activation for 15 min with 800 W. The physicochemical properties of RSPSFSP-AC were evaluated using several analytical techniques, including pH_pzc, BET, FTIR, and SEM-EDX analysis. The adsorptive property of RSPSFSP-AC for FB removal was evaluated and optimized by using the Box-Behnken design (BBD) and desirability function. The desirability function optimal conditions for FB removal (92.8%) were found to be 0.09 g/100 mL of RSPSFSP-AC dosage and 9.2 solution pH. The adsorption kinetic isotherm of the FB dye was explained by the pseudo-second order (PSO) model and Langmuir isotherm model respectively. The maximum adsorption capacity (q_max) of RSPSFSP-AC for the FB dye was found to be 147.7 mg/g. The adsorption of the FB dye onto the RSPSFSP-AC surface can be explained by several possible interactions including π-π stacking, electrostatic forces, pore filling, and hydrogen bonding. Thus, the output of this research work shows the potential applicability of RSPSFSP-AC for capturing cationic dye from an aqueous environment.

Activated carbon produced from coconut shell and rubber seed pericarp has a great potential to be used as gas adsorbent. Most researchers, however, focus on producing activated carbon from one single biomass. Another option is to produce activated carbon from blending two different types of biomass with the strategy to reduce dependency on one type of biomass and sustain the production of activated carbon. Further, the adsorption capacity of the activated carbon produced from different blended biomass would be increased in comparison to single biomass. Most activated carbon is produced via physical activation using the conventional pyrolysis heating system, which is very time-consuming. In this study, activated carbon from biomass, namely coconut shell (CS-AC), rubber seed pericarp (RSP-AC), and their blends (CSRSP-AC) were successfully produced by using ZnCl2 as the chemical activating agent. The activation process was performed in a modified commercial microwave oven at the irradiation power of 600 W for 20 min. The single activated carbon and its blend were tested for their adsorption capacity for sulfur dioxide gas (SO2) using evolved gas analyzer (EGA). The single RSP-AC and CS-AC samples produced breakthrough time for SO2 adsorption at 23 min and 14 min, respectively. The longest SO2 breakthrough time for the blended activated carbon (CSRSP-AC) was achieved at 15 min with a ratio of 20:80 (CS:RSP) and was slightly longer than the individual CS-AC. The high amount of microporous RSP in the blend increases SO2 adsorption capacity. The presence of fly ash/Ca(OH)2 catalyst in the blended CSRSP-AC (20:80) further improves SO2 adsorption capacity with the breakthrough time achieving at 36 min at the adsorption temperature of 35oC. The SEM micrograph of blended CSRSP-AC with the addition of fly ash/Ca(OH)2 catalyst after SO2 adsorption showed that the pores were clogged with some of the samples agglomerated and clustered, indicating that both activated carbon and fly ash/Ca(OH)2 catalyst had interacted thoroughly with SO2 after the adsorption process.

Activated carbon from biomass namely coconut shell (CS-AC), rubber seed pericarp(RSP-AC) and their mixed blend (50:50 w/w) coconut shell-rubber seed pericarp activated carbon(CSRSP-AC) were successfully produced by using ZnCl2 as chemical activating agent viamicrowave irradiation heating system. Activation process was performed in commercial microwaveoven at power of 600W for 20 min by using 30%, 40% and 50% of ZnCl2 concentrations. Theactivated carbon was characterized according to BET surface morphology, iodine number andpercentage of MB removal. The results showed that the mixed CSRSP-AC produced the highestsurface area of 584.68 mg2/g with comparison to single CS-AC and RSP-AC at 445.9 mg2/g and462.5 mg2/g respectively. Although CSRSP-AC has the highest surface area and pore volumedevelopment, RSP-AC was found to have the highest iodine number, with the opposite trend beingobserved with MB removal indicating that RSP-AC has the highest adsorptive capacity among thethree activated carbons. The iodine number value and percentages of MB removal increased as theZnCl2 concentration increase from 30% to 50%. These findings revealed that activated carbonproduced from mixed blend of coconut shell and rubber seed pericarp has almost similarcharacteristics to their respective activated carbon derived from single individual biomass.

A low temperature thermo-chemical conversion of biomass to maximise the hydrogen-rich sync gas product to replicate a one-step hydrogen production using oil palm empty fruit bunches (EFB) as an alternative process for renewable hydrogen production is studied. The slow pyrolysis with inexpensive and abundant selected catalysts alkali metal hydroxides such as NaOH is conducted in a pyrolyser unit with a continuous feeding system. The bio-hydrogen is expected to be free of CO and CO2, and the process could be optimized at relatively low temperature of 500-600K, which is significantly lower than the normal temperature ranges for biomass gasification process.