Rais Hanizam Madon

The increase in the production of municipal solid waste (MSW) and oil palm biomass in Malaysia needs to be managed using more advanced thermochemical solutions to overcome the shortcomings of existing conventional gasification technologies such as high tar production, low conversion efficiency, and unstable syngas quality. This study was conducted to evaluate the performance of a thermal arc plasma co-gasification process using a combination of oil palm empty bunches (EFB) and plastic waste, specifically low-density polyethylene (LDPE) and polyethylene terephthalate (PET) as feedstock. The experiments were conducted in triplicates to ensure data reliability, using a 9 kW plasma integrated downdraft reactor operating at atmospheric pressure with a reaction time of 10–12 minutes at 90/10, 80/20, and 70/30 blend ratios. Gas chromatography analysis revealed that increasing the plastic fraction significantly enhanced hydrogen production (H2), with the EFB-LDPE blend reaching a maximum concentration of 8.83% at the 70/30 ratio, indicating an improvement in syngas quality. The optimum energy yield was obtained at the 80/20 blend ratio, producing a peak high calorific value (HHV) of 3.72 MJ/kg for the LDPE blend and 2.91 MJ/kg for the PET blend, demonstrating favourable energy recovery potential. Scanning Electron Microscopy (SEM) analysis using ImageJ software showed that the incorporation of LDPE increased the porous area to 18.05% with an average pore size of 55.29 µm², suggesting enhanced gas-solid interaction and improved char reactivity during the gasification process. In addition, Fourier Transform Infrared Spectroscopy (FTIR) analysis provided evidence at the molecular level regarding the ability of plasma to decompose complex polymer structures. For the EFB-PET char product, the appearance of peaks at 1014.93 cm⁻¹ and 1378.04 cm⁻¹ indicated the formation of ester bonds and partial decomposition of the polymer chain. For the EFB-LDPE sample, the detection of C=N stretching vibrations at 2332.52 cm⁻¹ and C-O-C ester vibrations at 1012.98 cm⁻¹ confirmed the existence of a structural recombination process and strong interactions between the biomass fraction and the polymer. Overall, these findings prove that plasma co-gasification can not only optimize syngas quality, but also assist in the complete transformation of waste into more stable char residue with the presence of distinctive functional groups.

Photocatalytic is an advanced technology for water remediation which potentially to be applied for river pollution treatment. The key to the highest photocatalytic efficiency is the type of photocatalyst used and the process variables including light sources, light intensity, and time operations. However, the study on the interaction of process variables on photocatalytic efficiency for polluted river water treatment has not been well studied. Thus, the present study focused on the performance of pilot-scale photocatalytic reactor incorporated with ZnO-Kaolin under various light intensities such as 100, 125, and 225 Watts with varied time operation at 20, 40, 60 and 80 minutes for reduction of ammoniacal nitrogen (AN) and chemical oxygen demand (COD). Followed by the elucidation of kinetic study through pseudo-first and pseudo-second-order models. It was found that 225 Watts of UV-light contributed to the highest reduction of AN (59.34%) and COD (90.91%) for 60 minutes of treatment. Furthermore, the kinetic study revealed that the photocatalytic process follows pseudo-first-order model with a rate constant of 0.0184 min-1. Hence, the highest photocatalytic efficiency of ZnO-Kaolin is mainly attributed to the intensive light intensity, leading to the higher generation of reactive species for rapid photocatalytic degradation, consequently improving the performance of pilot-scale photocatalytic reactor.

Over time, population increase, migration, urbanization, and industrialization have influenced freshwater demand throughout time. Scaling-up the water treatment Over time, population increase, migration, urbanization, and industrialization have influenced freshwater demand throughout time. Scaling-up the water treatment

The component of an impeller in stirred tank plays an important role in the mixing process for a wide range of industries. The present study conducted the analysis of impeller design specifically on the number of blades to investigate the flow performance in the stirred tank. The analysis was also performed to identify the location of the particle flow dead zone at the bottom of the tank. The grid development and fluid flow study were accomplished using the CFD simulation method via the Ansys Fluent software package. The impeller design with the arrangement of 3,4 and 5 blades number was involved in this study. The rotational speed of the blade was set constant at 90 rpm. The flow characteristic at the vertical position of a tank at 0.01, 0.1, 0.2 and 0.3 m has been investigated. The general governing equation and solution approach used in this simulation were also presented in this paper. The results showed that 5 blades impeller produced a broader region of high-velocity magnitude distribution compared to the 3 and 4 blades. Hence, 5 blades impeller also relatively produced a higher distribution of velocity magnitude compared to the 3 and 4 blades impeller, typically in the upper region of the tank. However, the effect of a number of blades seemed not significant in the region close to the rotating impeller.