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Water fraction of edible medicinal fern Stenochlaena palustris is a potent α-glucosidase inhibitor with concurrent antioxidant activity

Chai TT, Kwek MT, Ong HC, Wong FC

Food Chem, 2015 Nov 1;186:26-31.
PMID: 25976787 DOI: 10.1016/j.foodchem.2014.12.099

This study aimed to isolate a potent antiglucosidase and antioxidant fraction from Stenochlaena palustris. Extraction was performed with hexane, chloroform, ethyl acetate, methanol, and water. Antiglucosidase, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing antioxidant power (FRAP) assays found methanol extract (ME) to be the most active. Water fraction (WF) of ME was a stronger α-glucosidase inhibitor (EC50 2.9 μg/mL) than quercetin, with weak antiamylase activity. WF was a competitive α-glucosidase inhibitor. DPPH scavenging activity of WF (EC50 7.7 μg/mL) was weaker than quercetin. WF (EC50 364 μg/mL) was a stronger hydrogen peroxide scavenger than gallic acid (EC50 838 μg/mL) and was equally strong as quercetin in scavenging superoxide. WF possessed moderate copper chelating activity. WF was enriched in total phenolics (TP) and hydroxycinnamic acids (THC). TP correlated with antioxidant activity (R(2) > 0.76). Only THC correlated with antiglucosidase activity (R(2) = 0.86). Overall, WF demonstrated concurrent, potent antiglucosidase and antioxidant activities.
Valorization of sorghum distillery residue to produce bioethanol for pollution mitigation and circular economy

Chen WH, Lo HJ, Yu KL, Ong HC, Sheen HK

Environ Pollut, 2021 Sep 15;285:117196.
PMID: 33962308 DOI: 10.1016/j.envpol.2021.117196

This research aims to study the wet torrefaction (WT) and saccharification of sorghum distillery residue (SDR) towards hydrochar and bioethanol production. The experiments are designed by Box-Behnken design from response surface methodology where the operating conditions include sulfuric acid concentration (0, 0.01, and 0.02 M), amyloglucosidase concentration (36, 51, and 66 IU), and saccharification time (120, 180, and 240 min). Compared to conventional dry torrefaction, the hydrochar yield is between 13.24 and 14.73%, which is much lower than dry torrefaction biochar (yield >50%). The calorific value of the raw SDR is 17.15 MJ/kg, which is significantly enhanced to 22.36-23.37 MJ/kg after WT. When the sulfuric acid concentration increases from 0 to 0.02 M, the glucose concentration in the product increases from 5.59 g/L to 13.05 g/L. The prediction of analysis of variance suggests that the best combination to maximum glucose production is 0.02 M H2SO4, 66 IU enzyme concentration, and 120 min saccharification time, and the glucose concentration is 30.85 g/L. The maximum bioethanol concentration of 19.21 g/L is obtained, which is higher than those from wheat straw (18.1 g/L) and sweet sorghum residue (16.2 g/L). A large amount of SDR is generated in the kaoliang liquor production process, which may cause environmental problems if it is not appropriately treated. This study fulfills SDR valorization for hydrochar and bioenergy to lower environmental pollution and even achieve a circular economy.
Fulltext Valorisation of medical waste through pyrolysis for a cleaner environment: Progress and challenges

Su G, Ong HC, Ibrahim S, Fattah IMR, Mofijur M, Chong CT

Environ Pollut, 2021 Jun 15;279:116934.
PMID: 33744627 DOI: 10.1016/j.envpol.2021.116934

The COVID-19 pandemic has exerted great shocks and challenges to the environment, society and economy. Simultaneously, an intractable issue appeared: a considerable number of hazardous medical wastes have been generated from the hospitals, clinics, and other health care facilities, constituting a serious threat to public health and environmental sustainability without proper management. Traditional disposal methods like incineration, landfill and autoclaving are unable to reduce environmental burden due to the issues such as toxic gas release, large land occupation, and unsustainability. While the application of clean and safe pyrolysis technology on the medical wastes treatment to produce high-grade bioproducts has the potential to alleviate the situation. Besides, medical wastes are excellent and ideal raw materials, which possess high hydrogen, carbon content and heating value. Consequently, pyrolysis of medical wastes can deal with wastes and generate valuable products like bio-oil and biochar. Consequently, this paper presents a critical and comprehensive review of the pyrolysis of medical wastes. It demonstrates the feasibility of pyrolysis, which mainly includes pyrolysis characteristics, product properties, related problems, the prospects and future challenges of pyrolysis of medical wastes.
Fulltext Use of Composite Outcomes in Neonatal Trials: An Analysis of the Cochrane Reviews

Lai NM, Yap AQY, Ong HC, Wai SX, Yeo JHH, Koo CYE, et al.

Neonatology, 2021;118(3):259-263.
PMID: 33780936 DOI: 10.1159/000514402

INTRODUCTION: Composite outcomes are used to increase the power of a study by combining event rates. Many composite outcomes in adult clinical trials have components that differ substantially in patient importance, event rate, and effect size, making interpretation challenging. Little is known about the use of composite outcomes in neonatal randomized controlled trials (RCTs).
METHODS: We assessed the use of composite outcomes in neonatal RCTs included in Cochrane Neonatal reviews published till November 2017. Two authors reviewed the components of the composite outcomes to compare their patient importance and computed the ratios of effect sizes and event rates between the components, with an a priori threshold of 1.5, indicating a substantial difference. Descriptive statistics were presented.
RESULTS: We extracted 7,766 outcomes in 2,134 RCTs in 312 systematic reviews. Among them, 55 composite outcomes (0.7%) were identified in 46 RCTs. The vast majority (92.7%) of composite outcomes had 2 components, with death being the most common component (included 51 times [92.7%]). The components in nearly three-quarters of the composite outcomes (n = 40 [72.7%]) had different patient importance, while the effect sizes and event rates differed substantially between the components in 27 (49.1%) and 35 (63.6%) outcomes, respectively, with up to 43-fold difference in the event rates observed.
CONCLUSIONS: The majority of composite outcomes in neonatal RCTs had different patient importance with contrasting effect sizes and event rates between the components. In patient communication, clinicians should highlight individual components, rather than the composites, with explanation on the relationship between the components, to avoid misleading impression on the effect of the intervention. Future trials should report the estimates of all individual components alongside the composite outcomes presented.
Fulltext Towards better perinatal health

Ong HC

Med J Malaysia, 1983 Sep;38(3):176-7.
PMID: 6672555
The ovaries at abdominal hysterectomy-conservation or removal?

Ong HC

Med J Malaysia, 1975 Sep;30(1):48-51.
PMID: 1207532
Synthesis, characteristics and sonocatalytic activities of calcined γ-Fe2O3 and TiO2 nanotubes/γ-Fe2O3 magnetic catalysts in the degradation of Orange G

Pang YL, Lim S, Ong HC, Chong WT

Ultrason Sonochem, 2016 Mar;29:317-27.
PMID: 26585012 DOI: 10.1016/j.ultsonch.2015.10.003

In this work, γ-Fe2O3 and TiO2 NTs/γ-Fe2O3 composites with good magnetism and sonocatalytic activity were prepared by a facile polyol method and utilize the principle of isoelectric point method, respectively. The structural and magnetic features of the prepared calcined γ-Fe2O3 and composite catalysts were investigated by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), surface analysis, UV-Vis diffuse reflectance spectra (UV-Vis DRS), vibrating sample magnetometry (VSM) and zeta potential analysis. The effects of calcination temperature on γ-Fe2O3 phase variation, physical properties and sonocatalytic properties were investigated. The porosity, specific surface area, band gap energy and sonocatalytic activity of γ-Fe2O3 were gradually decreased with calcination temperature increased. TiO2 NTs/γ-Fe2O3 with appropriate composition and specific structural features possess synergetic effects such as efficient separation of charge carriers and hydroxyl radicals produced by heterogeneous fenton and fenton-like reactions. This enhanced the sonocatalytic activity for the degradation of Orange G under ultrasonic irradiation. The sonocatalytic reactions obeyed pseudo first-order kinetics. All these information provide insight into the design and development of high-efficiency catalyst for wastewater treatment.
Synthesis, Molecular Docking, and Biological Evaluation of Benzimidazole Derivatives as Selective Butyrylcholinesterase Inhibitors

Ha ZY, Ong HC, Oo CW, Yeong KY

Curr Alzheimer Res, 2020;17(13):1177-1185.
PMID: 33602088 DOI: 10.2174/1567205018666210218151228

BACKGROUND: Benzimidazole is an interesting pharmacophore which has been extensively studied in medicinal chemistry due to its high affinity towards various enzymes and receptors. Its derivatives have been previously shown to possess a wide range of biological activities including anthelmintic, antihypertensive, antiulcer, as well as anticholinesterase activity.
OBJECTIVE: The objective of this study is to search for more potent benzimidazole-based cholinesterase inhibitors, through the modification of the 1- and 2-positions of the benzimidazole core.
METHODS: Synthesis of compounds were carried out via a 4-step reaction scheme following a previously reported protocol. Structure-activity relationship of the compounds are established through in vitro cholinesterase assays and in silico docking studies. Furthermore, cytotoxicity and blood brain barrier (BBB) permeability of the compounds were also investigated.
RESULTS: Among the synthesised compounds, three of them (5IIa, 5IIb, and 5IIc) exhibited potent selective butyrylcholinesterase inhibition at low micromolar level. The compounds did not show any significant cytotoxicity when tested against a panel of human cell lines. Moreover, the most active compound, 5IIc, was highly permeable across the blood brain barrier.
CONCLUSION: In total 10 benzimidazole derivatives were synthesized and screened for their AChE and BuChE inhibitory activities. Lead compound 5Iic, represents a valuable compound for further development as potential AD therapeutics.
Sustainable approach in phlorotannin recovery from macroalgae

Chia SR, Show PL, Phang SM, Ling TC, Ong HC

J Biosci Bioeng, 2018 Aug;126(2):220-225.
PMID: 29673988 DOI: 10.1016/j.jbiosc.2018.02.015

In this present study, alcohol/salt liquid biphasic system was used to extract phlorotannin from brown macroalgae. Liquid biphasic system is a new green technology that integrated with various processes into one-step, by concentrating, separating and purifying the bioproduct in a unit operation. The solvent used is non-toxic and there is potential for solvent recovery which is beneficial to the environment. Phlorotannin is a bioactive compound that has gained much attention due to its health beneficial effect. Therefore, the isolation of phlorotannin is lucrative as it contains various biological activities that are capable to be utilised into food and pharmaceutical application. By using 2-propanol/ammonium sulphate system, the highest recovery of phlorotannin was 76.1% and 91.67% with purification factor of 2.49 and 1.59 from Padina australis and Sargassum binderi, respectively. A recycling study was performed and the salt phase of system was recycled where maximum salt recovery of 41.04% and 72.39% could be obtained from systems containing P. australis and S. binderi, respectively. Similar recovery of phlorotannin was observed after performing two cycles of the system, this concludes that the system has good recyclability and eco-friendly.
State-of-the-art of the pyrolysis and co-pyrolysis of food waste: Progress and challenges

Su G, Ong HC, Fattah IMR, Ok YS, Jang JH, Wang CT

Sci Total Environ, 2022 Feb 25;809:151170.
PMID: 34699825 DOI: 10.1016/j.scitotenv.2021.151170

The continuous growth of population and the steady improvement of people's living standards have accelerated the generation of massive food waste. Untreated food waste has great potential to harm the environment and human health due to bad odor release, bacterial leaching, and virus transmission. However, the application of traditional disposal techniques like composting, landfilling, animal feeding, and anaerobic digestion are difficult to ease the environmental burdens because of problems such as large land occupation, virus transmission, hazardous gas emissions, and poor efficiency. Pyrolysis is a practical and promising route to reduce the environmental burden by converting food waste into bioenergy. This paper aims to analyze the characteristics of food waste, introduce the production of biofuels from conventional and advanced pyrolysis of food waste, and provide a basis for scientific disposal and sustainable management of food waste. The review shows that co-pyrolysis and catalytic pyrolysis significantly impact the pyrolysis process and product characteristics. The addition of tire waste promotes the synthesis of hydrocarbons and inhibits the formation of oxygenated compounds efficiently. The application of calcium oxide (CaO) exhibits good performance in the increment of bio-oil yield and hydrocarbon content. Based on this literature review, pyrolysis can be considered as the optimal technique for dealing with food waste and producing valuable products.
Source, distribution and emerging threat of micro- and nanoplastics to marine organism and human health: Socio-economic impact and management strategies

Mofijur M, Ahmed SF, Rahman SMA, Arafat Siddiki SY, Islam ABMS, Shahabuddin M, et al.

Environ Res, 2021 04;195:110857.
PMID: 33581088 DOI: 10.1016/j.envres.2021.110857

The nature of micro- and nanoplastics and their harmful consequences has drawn significant attention in recent years in the context of environmental protection. Therefore, this paper aims to provide an overview of the existing literature related to this evolving subject, focusing on the documented human health and marine environment impacts of micro- and nanoplastics and including a discussion of the economic challenges and strategies to mitigate this waste problem. The study highlights the micro- and nanoplastics distribution across various trophic levels of the food web, and in different organs in infected animals which is possible due to their reduced size and their lightweight, multi-coloured and abundant features. Consequently, micro- and nanoplastics pose significant risks to marine organisms and human health in the form of cytotoxicity, acute reactions, and undesirable immune responses. They affect several sectors including aquaculture, agriculture, fisheries, transportation, industrial sectors, power generation, tourism, and local authorities causing considerable economic losses. This can be minimised by identifying key sources of environmental plastic contamination and educating the public, thus reducing the transfer of micro- and nanoplastics into the environment. Furthermore, the exploitation of the potential of microorganisms, particularly those from marine origins that can degrade plastics, could offer an enhanced and environmentally sound approach to mitigate micro- and nanoplastics pollution.
Recent developments on algal biochar production and characterization

Yu KL, Lau BF, Show PL, Ong HC, Ling TC, Chen WH, et al.

Bioresour Technol, 2017 Dec;246:2-11.
PMID: 28844690 DOI: 10.1016/j.biortech.2017.08.009

Algal biomass is known as a promising sustainable feedstock for the production of biofuels and other valuable products. However, since last decade, massive amount of interests have turned to converting algal biomass into biochar. Due to their high nutrient content and ion-exchange capacity, algal biochars can be used as soil amendment for agriculture purposes or adsorbents in wastewater treatment for the removal of organic or inorganic pollutants. This review describes the conventional (e.g., slow and microwave-assisted pyrolysis) and newly developed (e.g., hydrothermal carbonization and torrefaction) methods used for the synthesis of algae-based biochars. The characterization of algal biochar and a comparison between algal biochar with biochar produced from other feedstocks are also presented. This review aims to provide updated information on the development of algal biochar in terms of the production methods and the characterization of its physical and chemical properties to justify and to expand their potential applications.
Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater

Ahmed SF, Mofijur M, Nuzhat S, Chowdhury AT, Rafa N, Uddin MA, et al.

J Hazard Mater, 2021 08 15;416:125912.
PMID: 34492846 DOI: 10.1016/j.jhazmat.2021.125912

Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.
Fulltext Rapid Ultrasound-Assisted Starch Extraction from Sago Pith Waste (SPW) for the Fabrication of Sustainable Bioplastic Film

Tan SX, Andriyana A, Lim S, Ong HC, Pang YL, Ngoh GC

Polymers (Basel), 2021 Dec 15;13(24).
PMID: 34960953 DOI: 10.3390/polym13244398

The present study was conducted to optimize the extraction yield of starch from sago (Metroxylon sagu) pith waste (SPW) with the assistance of ultrasound ensued by the transformation of extracted starch into a higher value-added bioplastic film. Sago starch with extraction yield of 71.4% was successfully obtained using the ultrasound-assisted extraction, with the following conditions: particle size <250 µm, solid loading of 10 wt.%, ultrasonic amplitude of 70% and duty cycle of 83% in 5 min. The rapid ultrasound approach was proven to be more effective than the conventional extraction with 60.9% extraction yield in 30 min. Ultrasound-extracted starch was found to exhibit higher starch purity than the control starch as indicated by the presence of lower protein and ash contents. The starch granules were found to have irregular and disrupted surfaces after ultrasonication. The disrupted starch granules reduced the particle size and increased the swelling power of starch which was beneficial in producing a film-forming solution. The ultrasound-extracted sago starch was subsequently used to prepare a bioplastic film via solution casting method. A brownish bioplastic film with tensile strength of 0.9 ± 0.1 MPa, Young's modulus of 22 ± 0.8 MPa, elongation at break of 13.6 ± 2.0% and water vapour permeability (WVP) of 1.11 ± 0.1 × 10-8 g m-1 s-1 Pa-1 was obtained, suggesting its feasibility as bioplastic material. These findings provide a means of utilization for SPW which is in line with the contemporary trend towards greener and sustainable products and processes.
Quality of life (QoL) and International Normalized Ratio (INR) control of patients attending anticoagulation clinics

Hasan SS, Teh KM, Ahmed SI, Chong DW, Ong HC, Naina B

Public Health, 2015 Jul;129(7):954-62.
PMID: 26138018 DOI: 10.1016/j.puhe.2015.05.014

OBJECTIVES: To investigate association between quality of life (QoL) and International Normalized Ratio (INR) control, with the secondary aim of assessing QoL using generic and anticoagulation-specific, the Short Form Health Survey (SF-12) and the Duke Anticoagulation Satisfaction Scale (DASS).
STUDY DESIGN: This study assessed anticoagulation related QoL at three time intervals in two groups of patients on long-term warfarin therapy.
METHODS: Data of 326 randomly sampled patients (163 patients each in DASS and SF-12 groups) who had been on warfarin therapy for at least one year at anticoagulation clinics were analysed. QoL was assessed at three time intervals: at the start, six months and one year of warfarin therapy. Indications and target INR ranges and subjects INR values were recorded. Time in Therapeutic Range (TTR) was estimated for four subject subgroups, based on target ranges of INR for clustered indications.
RESULTS: Of the total, 43% of the subjects were aged between 50 and 64 years, and 51% were female. DASS assessed subjects older than 35 years perceived significant decrease in overall mean scores of anticoagulation related QoL, whilst all SF-12 assessed subjects perceived an increase in QoL. The mean percentage days in range for all INR target range subgroups did not exceed more than 60% but there was only a weak correlation (Rs = 0.104, P > 0.05) between INR control and overall QoL.
CONCLUSION: Malaysian urban outpatients on warfarin treatment longer than one year report a significant overall decrease in QoL, as measured using a validated condition-specific instrument. These patients appeared to adapt well to lifestyle limitations imposed by long-term anticoagulation.
KEYWORDS: Anticoagulation therapy; International Normalized Ratio; Quality of life

Study site: anticoagulation clinics at a
suburban tertiary Ministry of Health hospital in Peninsular
Malaysia
Pyrolysis of waste oils for the production of biofuels: A critical review

Su G, Ong HC, Mofijur M, Mahlia TMI, Ok YS

J Hazard Mater, 2022 Feb 15;424(Pt B):127396.
PMID: 34673394 DOI: 10.1016/j.jhazmat.2021.127396

The application of waste oils as pyrolysis feedstocks to produce high-grade biofuels is receiving extensive attention, which will diversify energy supplies and address environmental challenges caused by waste oils treatment and fossil fuel combustion. Waste oils are the optimal raw materials to produce biofuels due to their high hydrogen and volatile matter content. However, traditional disposal methods such as gasification, transesterification, hydrotreating, solvent extraction, and membrane technology are difficult to achieve satisfactory effects owing to shortcomings like enormous energy demand, long process time, high operational cost, and hazardous material pollution. The usage of clean and safe pyrolysis technology can break through the current predicament. The bio-oil produced by the conventional pyrolysis of waste oils has a high yield and HHV with great potential to replace fossil fuel, but contains a high acid value of about 120 mg KOH/g. Nevertheless, the application of CaO and NaOH can significantly decrease the acid value of bio-oil to close to zero. Additionally, the addition of coexisting bifunctional catalyst, SBA-15@MgO@Zn in particular, can simultaneously reduce the acid value and positively influence the yield and quality of bio-oil. Moreover, co-pyrolysis with plastic waste can effectively save energy and time, and improve bio-oil yield and quality. Consequently, this paper presents a critical and comprehensive review of the production of biofuels using conventional and advanced pyrolysis of waste oils.
Fulltext Psychological distress, perceived stigma, and coping among caregivers of patients with schizophrenia

Ong HC, Ibrahim N, Wahab S

Psychol Res Behav Manag, 2016;9:211-8.
PMID: 27574475 DOI: 10.2147/PRBM.S112129

Nowadays, family members are gradually taking on the role of full-time caregivers for patients suffering from schizophrenia. The increasing burden and tasks of caretaking can cause them psychological distress such as depression or anxiety. The aim of this study was to measure the correlation between perceived stigma and coping, and psychological distress as well as determine the predictors of psychological distress among the caregivers. Results showed that 31.5% of the caregivers experienced psychological distress. "Community rejection" was found to be positively associated with psychological distress. In case of coping subscales, psychological distress had a positive correlation with substance use, use of emotional support, behavioral disengagement, venting, and self-blame, while it was negatively correlated with "positive reframing". Behavioral disengagement was the best predictor of psychological distress among caregivers of patients with schizophrenia, followed by positive reframing, use of emotional support, self-blame, and venting. Health practitioners can use adaptive coping strategies instead of maladaptive for caregivers to help ease their distress and prevent further deterioration of psychological disorders.
Study site: Psychiatric Clinic, Hospital Canselor Tuanku Muhriz (Pusat Perubatan Universiti Kebangsaan Malaysia, PPUKM)
Scales & Questionnaire: Kessler’s K10
Psychological Distress Scale; Devaluation of Consumer Scale (DCS); Devaluation of Consumer Families Scale (DCFS); Brief COPE
Fulltext Prospect of biobased antiviral face mask to limit the coronavirus outbreak

Chowdhury MA, Shuvho MBA, Shahid MA, Haque AKMM, Kashem MA, Lam SS, et al.

Environ Res, 2021 Jan;192:110294.
PMID: 33022215 DOI: 10.1016/j.envres.2020.110294

The rapid spread of COVID-19 has led to nationwide lockdowns in many countries. The COVID-19 pandemic has played serious havoc on economic activities throughout the world. Researchers are immensely curious about how to give the best protection to people before a vaccine becomes available. The coronavirus spreads principally through saliva droplets. Thus, it would be a great opportunity if the virus spread could be controlled at an early stage. The face mask can limit virus spread from both inside and outside the mask. This is the first study that has endeavoured to explore the design and fabrication of an antiviral face mask using licorice root extract, which has antimicrobial properties due to glycyrrhetinic acid (GA) and glycyrrhizin (GL). An electrospinning process was utilized to fabricate nanofibrous membrane and virus deactivation mechanisms discussed. The nanofiber mask material was characterized by SEM and airflow rate testing. SEM results indicated that the nanofibers from electrospinning are about 15-30 μm in diameter with random porosity and orientation which have the potential to capture and kill the virus. Theoretical estimation signifies that an 85 L/min rate of airflow through the face mask is possible which ensures good breathability over an extensive range of pressure drops and pore sizes. Finally, it can be concluded that licorice root membrane may be used to produce a biobased face mask to control COVID-19 spread.
Predictions of biochar production and torrefaction performance from sugarcane bagasse using interpolation and regression analysis

Chen WH, Hsu HJ, Kumar G, Budzianowski WM, Ong HC

Bioresour Technol, 2017 Dec;246:12-19.
PMID: 28803060 DOI: 10.1016/j.biortech.2017.07.184

This study focuses on the biochar formation and torrefaction performance of sugarcane bagasse, and they are predicted using the bilinear interpolation (BLI), inverse distance weighting (IDW) interpolation, and regression analysis. It is found that the biomass torrefied at 275°C for 60min or at 300°C for 30min or longer is appropriate to produce biochar as alternative fuel to coal with low carbon footprint, but the energy yield from the torrefaction at 300°C is too low. From the biochar yield, enhancement factor of HHV, and energy yield, the results suggest that the three methods are all feasible for predicting the performance, especially for the enhancement factor. The power parameter of unity in the IDW method provides the best predictions and the error is below 5%. The second order in regression analysis gives a more reasonable approach than the first order, and is recommended for the predictions.
Physicochemical property enhancement of biodiesel synthesis from hybrid feedstocks of waste cooking vegetable oil and Beauty leaf oil through optimized alkaline-catalysed transesterification

Milano J, Ong HC, Masjuki HH, Silitonga AS, Kusumo F, Dharma S, et al.

Waste Manag, 2018 Oct;80:435-449.
PMID: 30455026 DOI: 10.1016/j.wasman.2018.09.005

Recycling waste cooking vegetable oils by reclaiming and using these oils as biodiesel feedstocks is one of the promising solutions to address global energy demands. However, producing these biodiesels poses a significant challenge because of their poor physicochemical properties due the high free fatty acid content and impurities present in the feedstock, which will reduce the biodiesel yields. Hence, this study implemented the following strategy in order to address this issue: (1) 70 vol% of waste cooking vegetable oil blended with 30 vol% of Calophyllum inophyllum oil named as WC70CI30 used to alter its properties, (2) a three-stage process (degumming, esterification, and transesterification) was conducted which reduces the free fatty acid content and presence of impurities, and (3) the transesterification process parameters (methanol/oil ratio, reaction temperature, reaction time, and catalyst concentration) were optimized using response surface methodology in order to increase the biodiesel conversion yield. The results show that the WC70CI30 biodiesel has favourable physicochemical properties, good cold flow properties, and high oxidation stability (22.4 h), which fulfil the fuel specifications stated in the ASTM D6751 and EN 14214 standards. It found that the WC70CI30 biodiesel has great potential as a diesel substitute without the need for antioxidants and pour point depressants.

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