Hydrogen-rich syngas production from steam reforming of palm oil mill effluent (POME) over LaNiO3 & LaCoO3 catalysts

The flourishing development of local oil palm industry inflicts concomitant generation of enormous, highly polluted palm oil mill effluent (POME). The prevalent open ponding treatment was land-intensive, sluggish, and incompetent to degrade POME to below discharge threshold yet being accused for greenhouse gases (CO2 and CH4) emission. This study investigated the potentiality of novel catalytic POME steam reforming over LaNiO3 and LaCoO3 to valorise pollutant-laden POME into valuable H2-rich syngas. The POME feedstock was a brownish (A = ~1.93), acidic (pH of 5), and highly polluted (COD = ~70000 mg/L, BOD5 = ~11000 mg/L, and TSS = ~7700 mg/L) wastewater. POME was composed of 99.73 mol% water and 0.27 mol% organics (mainly carboxylic acids, phenol, and alcohols). Through minimisation of total Gibbs free energy, thermodynamic simulation from 573 – 1173 K confirmed syngas production from POME steam reforming and predicted the likelihood of side reactions. Subsequently, LaNiO3 and LaCoO3 were synthesised using modified citrate sol-gel route. Combination of CO2-TPD and NH3-TPD asserted the net-acidity of LaNiO3 and the net-basicity of LaCoO3. Before POME steam reforming, the catalysts were reduced by H2 to form well dispersed active metal (Ni or Co) on La2O3 support. Specifically, the active metal catalysed the reaction while the La2O3 support suppressed the coking deactivation. For both catalytic POME steam reforming, the optimum syngas yield and degradation efficiencies were determined by tuning temperature

Experimental evaluation and empirical modelling of palm oil mill effluent steam reforming

The current work describes a novel application of steam reforming process to treat palm oilmill effluent (POME), whilst co-generating H2-rich syngas from the treatment itself. The effects of reaction temperature, partial pressure of POME and gas-hourly-space-velocity (GHSV) were determined. High crystallinity 20 wt%Ni/80 wt%Al2O3 catalyst with smooth surface was prepared via impregnation method. Baseline runs revealed that the prepared catalyst was highly effective in destructing organic compounds, with a two-fold enhancement observed in the presence of 20 wt% Ni/80 wt%Al2O3 catalyst, despite its low specific surface area (2.09 m2 g−1). In addition, both the temperature and partial pressure of POME abet the COD reduction. Consequently, the highest COD reduction of 99.7% was achieved, with a final COD level of 73 ± 5 ppm from 27,500 ppm, at GHSV of 40,000 mL/h.gcat and partial pressure of POME equivalent to 95 kPa at 1173 K. In terms of gaseous products, H2 was found to be the major component, with selectivity ranged 51.0%–70.9%, followed by CO2(17.7%–34.1%), CO (7.7%–18.4%) and some CH4 (0.6%–3.3%). Furthermore, quadratic models with high R2-values were developed

State-of-the-art of the synthesis and applications of sulfonated carbon-based catalysts for biodiesel production: a review

Sulfonated carbon-based catalysts (SCC) are favorable heterogeneous acids for acid-catalyzed reactions including esterification and transesterification for biodiesel production. They are covalently functionalized with SO3H groups via CPhSO3H or CSO3H linkages with special carbon structures. To date, the types of SCC for biodiesel production ranges from biochar (BC), activated carbon (AC), graphene, graphite oxides, multiwalled carbon nanotubes, order mesoporous carbon, and graphitic carbon nitride. Lignocellulosic and biomass wastes are important carbon precursors for low-cost BC and AC production. This review critically reviews and summarizes the most up-to-date research progress in the evolution of SCC for biodiesel production. Systematic discussions and comparisons on the different carbon materials, preparation methods, and sulfonation preparation parameters which directly affect the physicochemical attributes and catalytic performance are provided. The applications and reusability studies of these materials in biodiesel production are also included. Finally, the challenges to be addressed and future prospects of the research direction on the applications of SCC for biodiesel production are discussed

Long-term evaluation of palm oil mill effluent (POME) steam reforming over lanthanum-based perovskite oxides

To replace the obsolete ponding system, palm oil mill effluent (POME) steam reforming (SR) over net-acidic LaNiO3 and net-basic LaCoO3 were proposed as the POME primary treatments, with promising H2-rich syngas production. Herein, the long-term evaluation of POME SR was scrutinized with both catalysts under the optimal conditions (600 °C, 0.09 mL POME/min, 0.3 g catalyst, & 74–105 μm catalyst particle size) to examine the catalyst microstructure changes, transient process stability, and final effluent evaluation. Extensive characterization proved the (i) adsorption of POME vapour on catalysts before SR, (ii) deposition of carbon and minerals on spent SR catalysts, and (iii) dominance of coking deactivation over sintering deactivation at 600 °C. Despite its longer run, spent LaCoO3 (50.54 wt%) had similar carbon deposition with spent LaNiO3 (50.44 wt%), concurring with its excellent coke resistance. Spent LaCoO3 (6.12 wt%; large protruding crystals) suffered a harsher mineral deposition than spent LaNiO3 (3.71 wt%; thin film coating), confirming that lower reactivity increased residence time of reactants. Transient syngas evolution of both SR catalysts was relatively steady up to 4 h but perturbed by coking deactivation thereafter. La2O2CO3 acted as an intermediate species that hastened the coke removal via reverse Boudouard reaction upon its decarbonation. La2O2CO3 decarbonation occurred continuously in LaCoO3 system but intermittently in LaNiO3 system. LaNiO3 system only lasted for 13 h as its compact ash blocked the gas flow. LaCoO3 system lasted longer (17 h) with its porous ash, but it eventually failed because KCl crystallites blocked its active sites. Relatively, LaCoO3 system offered greater net H2 production (72.78%) and POME treatment volume (30.77%) than LaNiO3 system. SR could attain appreciable POME degradation (>97% COD, BOD5, TSS, & colour intensity). Withal, SR-treated POME should be polished to further reduce its incompliant COD and BOD5

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Biomass energy: a review on waste to energy approaches

Although Malaysia is blessed with significant reserves of fossil fuels, the crisis of these non-replenishable energy resources is foreseen with escalating human population. Fortunately, Malaysia is an agroindustry-based country while transforming into a manufacturing-based country. It is believed that the tremendous biomass waste sourced from various industrial sectors could be ameliorated into renewable biomass energy. Therefore, this paper reviews four major approaches that facilitate the conversion of biomass waste into energy, particularly gasification, fast pyrolysis and liquefaction, transesterification, and hydrolysis. It is worthwhile to declare that these pathways generate energy and mitigate environmental issue concurrently

Optimization of Photocatalytic Degradation of Palm Oil Mill Effluent in UV/ZnO system based on Response Surface Methodology

This paper reports on the optimization of palm oil mill effluent (POME) degradation in a UV-activated-ZnO system based on central composite design (CCD) in response surface methodology (RSM). Three potential factors, viz. O2 flowrate (A), ZnO loading (B) and initial concentration of POME (C) were evaluated for the significance analysis using a 23 full factorial design before the optimization process. It is found that all the three main factors were significant, with contributions of 58.27% (A), 15.96% (B) and 13.85% (C), respectively, to the POME degradation. In addition, the interactions between the factors AB, AC and BC also have contributed 4.02%, 3.12% and 1.01% to the POME degradation. Subsequently, all the three factors were subjected to statistical central composite design (CCD) analysis. Quadratic models were developed and rigorously checked. A 3D-response surface was subsequently generated. Two successive validation experiments were carried out and the degradation achieved were 55.25 and 55.33%, contrasted with 52.45% for predicted degradation value

A study into syngas production from catalytic steam reforming of palm oil mill effluent (POME): A new treatment approach

This paper reports on the novel application of catalytic steam reforming process to convert palm oil mill effluent (POME) into syngas over a 20wt% Ni/80wt% Al 2 O 3 catalyst. The catalyst possessed high degree of crystallinity and was impurity-free, judging from the obtained XRD pattern. Furthermore, the BET specific surface area of catalyst was low (2.09 m 2 g− 1), consistent with smooth surface captured by the FESEM images. CO 2-desorption and NH 3-desorption profiles showed a presence of both acid and basic sites on the surface of catalyst. In the absence of catalyst, about 7.0% reduction of chemical oxygen demand (COD) was achieved at 6.0 mL h− 1 flow rate of POME, reforming temperature of 873 K and 20 mL min− 1 of N 2-flow. Significantly, the COD reduction shot up to 93.7% in the presence of catalyst and liquid-hourly-space-velocity (LHSV) of POME of 90 mL h− 1 g cat− 1 at 87