Hydrodynamic cavitation using orifice plate configurations and arrangements for tertiary treatment of palm oil mill effluent

Hydrodynamic Cavitation (HC) is one of Advanced Oxidation Processes (AOPs), which generates and utilises hydroxyl radicals (HO·) as its oxidising agent. It has been studied for different applications to treat pharmaceuticals waste, seawater and microalgae, where much effort has been conducted to enhance its performance such as using pH, aeration and hydrogen peroxide (H2O2). However, the production of HO· using multiple-plate combination has not yet been studied. The use of pH, aeration and H2O2 has proven to give significant improvement for HO· formation, but these have not being studied previously using multiple-plate combination. The use of HC as a tertiary treatment for POME has not being reported before. Therefore, in this study, the enhancement of the HC has been investigated using double and triple orifice plate configurations and arrangements. The best system was then tested on biologically treated palm oil mill effluent (BT-POME). As the colour of POME is difficult to remove the performance of ponding treatment system was evaluated to understand the causes of colour in POME. The experiments were conducted in a labscale HC system, treating 10 L samples for reaction time ranging from 30 to 180 min. The effect of pH (2-7), aeration (2-10 L/min) and H2O2 dosing (50-200 mg/L) were explored. The performance of the HC system was based on iodine liberation, and removal of colour and chemical oxygen demand (COD). The byproducts of BTPOME degradation was identified. Additionally, the performance of an existing ponding system treating POME was assessed and the relationship between colour and few selected parameters were studied. Within the range of the experimental conditions used in this study, the HC orifice plate configurations and arrangements were found to have significant effects on HO·generation. The iodine liberation for both double and triple plate were higher than that of a single plate. The HO·generation was also affected by the arrangement and the distance between the plates; arrangement plate of P3P2 with 10 cm distance gave the highest iodine liberation (1296 mg/L). The performance of HC was enhanced under the effect of pH, H2O2 and aeration as compared to HC alone. For the conventional ponding treatment system, the anaerobic pond played the most significant role in treating POME with removal up to 97%. Among the pollutants analysed, colour has strong relationship with phenolics, tannin, lignin and carotene, indicating the roles of these compounds in causing colour of POME. The degradation of BT-POME by the HC system was not encouraging as only up to 14.7% of colour was removed, with lower removal of COD. The addition of H2O2 and aeration have significant effect in removing COD, while pH and addition of H2O2 have significant effect on colour removal. The degradation of BT-POME, particularly phenolics and tannin/lignin was found to form catechol and ρ-benzoquinone as by-products. The study showed another approach in improving HC system performance but further work is required before the system can be applied in treating BT-POME effectively

Utilization of optical satellite data for measuring carbon dioxide at Felda Maokil

Currently there are many developments especially in construction’s sectors where a lot of air pollutants have been produced and resulted in the degradation of the environment. The issue has grown in importance in light of recent global warming. This study is based on a short term observation of carbon dioxide (CO2) released due to a road construction at Felda Maokil in Segamat. The method that has currently been used to determine Net Primary Productivity (NPP) at global scale using satellite data known as Moderate Resolution Imaging Radiometer (MODIS). The purpose of this study is to measure the amount carbon dioxide (CO2) that may be absorbed by oil palm tree for an area of about 450 hectares in Oil Palm plantation with low resolution MODIS satellite data. Several objectives have been carried out such as to determine the amount of Net Primary Productivity (NPP) in Felda Maokil, to assess the accuracy of MODIS data by validation process with in-situ data and lastly, to assess the correlation of NPP value from 2001, 2005 and 2009. The data were obtained through two sources which are in-situ as primary source and satellite data as secondary source. Data from four year interval had been chosen to insure more variations during the study period. Therefore the study was verified by the NPP values for year 2001, 2005 and 2009. The resulted acquired presented the mean NPP values for the three years processed were 468.169 g Cm2/y (2001), 560.685 g Cm2/y (2005) and 541.781 g Cm2/y (2009). Meanwhile, Normalized Difference Vegetation Index (NDVI) analysis had gave the resulted as 0.696 (2001), 0.863 (2005) and 0.716 (2009). As a conclusion, the mean NPP values for three years of MODIS images processed have shown similarities and road development had gave some impacts on these results

Drought Analysis Based on Standardized Precipitation Evapotranspiration Index and Standardized Precipitation Index in Sarawak, Malaysia

Drought analysis via the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) is necessary for effective water resource management in Sarawak, Malaysia. Rainfall is the best indicator of a drought, but the temperature is also significant because it controls evaporation and condensation. This study examined drought periods in the state of Sarawak using the SPI and SPEI based on monthly precipitation and temperature data from thirty-three rainfall stations during a forty-year period (1981–2020). This analysis of drought conditions revealed that both the SPI and SPEI were able to detect drought temporal variations with distinct time scales (3, 6, 9, and 12 months). Taking precipitation and evapotranspiration data into account, the SPEI was able to identify more severe-to-extreme drought in the study area over longer time periods and moderate droughts over shorter time periods than the standard drought index. According to Pearson correlation coefficients, a substantial association existed between the SPI and SPEI during hydrological dryness. Based on the results, the temperature is a decisive factor in drought classification, and the SPI should only be used in the absence of temperature data

Potential of fly ash geopolymer concrete as repairing and retrofitting solutions for marine infrastructure: A review

Corrosion in maritime infrastructure, particularly in reinforced concrete, has emerged as a significant cause for concern due to the presence of chloride ions in seawater. To address this challenge, geopolymer concrete has been proposed as a viable solution for retrofitting and restoring marine structures. This review paper explores the potential application of fly ash geopolymer concrete in marine infrastructure restoration. Fly ash's properties make it ideal for marine infrastructure restoration. Its high levels of amorphous silica and alumina enable geopolymerization, forming a strong binder resistant to chloride corrosion. Its fine, spherical particles enhance concrete workability and density, improving mechanical strength and impermeability. This geopolymer binder offers excellent resistance to corrosion from chloride ions commonly found in seawater, making fly ash geopolymer concrete highly suitable for marine applications. Overall, fly ash's chemical composition and physical traits offer resilience and sustainability in restoring marine infrastructure, ensuring long-term durability against corrosion. This review paper explores the potential application of fly ash geopolymer concrete in marine infrastructure restoration. By examining the primary forms of damage and mechanisms underlying concrete degradation in marine settings, this study highlights the durability and sustainability of geopolymer concrete compared to traditional concrete. Additionally, it discusses current solutions for repairing and retrofitting concrete in marine environments, emphasizing the promising characteristics of geopolymer concrete for integration into such structures. Through this analysis, innovative and environmentally conscious approaches are introduced for addressing corrosion-related challenges in the maritime industry, offering a resilient solution for the construction of enduring marine structures. Finally, recommendations for further research on the application of fly ash geopolymer concrete in marine infrastructure restoration are presented

Friedel–Crafts benzylation of toluene catalyzed by ZnCl2/SiO2 heterogeneous catalyst to para- and ortho-monobenzylated toluene

A series of catalysts was prepared for the liquid-phase Friedel–Crafts benzylation of toluene with benzyl chloride (BC) by impregnating rice husk ash silica with ZnCl2 (3 wt%, 6 wt%, 9 wt%, and 12 wt%) via a wet impregnation method. The XRD analysis indicates that the catalysts were amorphous with ill-defined pore systems. The XPS analysis detected the coexistence of ZnO nanoparticles together with ZnCl2 on the catalyst surface, whereas the 29Si NMR analysis indicates the formation of Si–O–Zn bond. Quantitative conversion of benzyl chloride (100%) was achieved within 3 h at 353 K when a catalyst with 9 wt% ZnCl2 was used due to its narrow pore size and high surface area (635 m2 g−1). Para- and ortho-mono-benzylated toluene was obtained as the products. The reaction is proposed to take place via weak attraction between benzyl chloride and the Zn through its chlorine atom. The catalyst was recycled four times with minimum loss (8%) in activity. The benzylation of benzene, toluene, p-xylene, and anisole followed the classical mechanism of Friedel–Craft-type acid-catalyzed benzylation reaction. The BC conversion increased in the order of toluene = p-xylene > anisole > benzene. The catalyst was also screened to be active in the benzoylation of toluene with benzoyl chloride (BOC). The conversion of BOC was 45% with selectivity toward 2-methylbenzophenone (50%) and 3-methylbenzophenone (50%