Overview of municipal solid wastes-derived refuse-derived fuels for cement co-processing

The global municipal solid waste (MSW) generation rate is 2.01 billion metric tonnes annually with an average of 0.74 kg waste/person/day. Approximately 92 % of the MSW originates from organics composition (e.g., food waste; plastic; paper; garden waste/woods, and textile), where 33 % of overall MSW is improperly managed in an efficient and environmentally safe manner. One of the promising methods to solve MSW management issues is to convert MSW into refuse-derived fuel (RDF) that can be used for the clinker burning process in cement kiln to replace the usage of fossil-based solid fuel. Thus, the potential of local MSW composition in energy recovery; suitability of RDF production technology; as well as international-industry requirement on RDF in co-processing and environmental concerns are discussed. Due to heterogeneous composition and sizes in nature, high moisture, and substantial amount of chloride content in MSW, it needs to undergo pre-treatment processes to enhance the RDF's physio-chemical properties that comply with RDF ASTM/EN standards, where expected high heating value (HHV) is > 20 MJ/kg, ash (<10 %), Chloride (Cl) (<0.80 – 1.00 %), Sulphate (S) (<1.50 %), Nitrate (N) (<1.00 %). As the development of upgraded MSW to RDF is still new in the commercial phase, there is minimal information and data on the techno-economic analysis, as well as recent industrial-scale of thermos-chemical conversion technologies for RDF preparation. Hence, the present work provides a clear picture on overview of municipal solid waste (MSW) generation, MSW composition, MSW pretreatment, and application as co-processing in cement industry are discussed. Besides, recent thermochemical upgrading process (torrefaction, dry carbonization, and hydrothermal carbonization) of MSW from R&D to commercial scale was further highlighted. In summary, this review serves as basic criterion and strategies to explore the new path of upgrading the waste into RDF for the purpose of sustainable energy recovery that adopting in circular carbon economy framework

Towards sustainable green diesel fuel production: Advancements and opportunities in acid-base catalyzed H2-free deoxygenation process

This review delves into the potential of renewable biomass for green diesel production. Deoxygenation technology offers a promising method for converting biomass-derived oxygenates oil into high-grade hydrocarbon factions. Hence, various deoxygenation pathways of biomass conversion under free‑hydrogen environment were explored. Additionally, the prospects of acid-base bifunctional catalysts to facilitate deoxygenation was discussed, highlighting the correlation between the physicochemical properties of the catalysts and catalytic activity. However, it should be noted that the acid-base characteristics of the catalysts contribute to the breaking of C–O bonds of oxygenated oil via undesirable pathways, which contributed to unfavorable by-product and catalyst deactivation

Progress on Modified Calcium Oxide Derived Waste-Shell Catalysts for Biodiesel Production

The dwindling of global petroleum deposits and worsening environmental issues have triggered researchers to find an alternative energy such as biodiesel. Biodiesel can be produced via transesterification of vegetable oil or animal fat with alcohol in the presence of a catalyst. A heterogeneous catalyst at an economical price has been studied widely for biodiesel production. It was noted that various types of natural waste shell are a potential calcium resource for generation of bio-based CaO, with comparable chemical characteristics, that greatly enhance the transesterification activity. However, CaO catalyzed transesterification is limited in its stability and studies have shown deterioration of catalytic reactivity when the catalyst is reused for several cycles. For this reason, different approaches are reviewed in the present study, which focuses on modification of waste-shell derived CaO based catalyst with the aim of better transesterification reactivity and high reusability of the catalyst for biodiesel production. The catalyst stability and leaching profile of the modified waste shell derived CaO is discussed. In addition, a critical discussion of the structure, composition of the waste shell, mechanism of CaO catalyzed reaction, recent progress in biodiesel reactor systems and challenges in the industrial sector are also included in this review

Environment-friendly deoxygenation of non-edible Ceiba oil to liquid hydrocarbon biofuel: process parameters and optimization study.

Non-edible Ceiba oil has the potential to be a sustainable biofuel resource in tropical countries that can replace a portion of today's fossil fuels. Catalytic deoxygenation of the Ceiba oil (high O/C ratio) was conducted to produce hydrocarbon biofuel (high H/C ratio) over NiO-CaO5/SiO2-Al2O3 catalyst with aims of high diesel selectivity and catalyst reusability. In the present study, response surface methodology (RSM) technique with Box-Behnken experimental designs (BBD) was used to evaluate and optimize liquid hydrocarbon yield by considering the following deoxygenation parameters: catalyst loading (1-9 wt. %), reaction temperature (300-380 °C) and reaction time (30-180 min). According to the RSM results, the maximum yield for liquid hydrocarbon n-(C8-C20) was found to be 77% at 340 °C within 105 min and 5 wt. % catalyst loading. In addition, the deoxygenation model showed that the catalyst loading-reaction time interaction has a major impact on the deoxygenation activity. Based on the product analysis, oxygenated species from Ceiba oil were successfully removed in the form of CO2/CO via decarboxylation/decarbonylation (deCOx) pathways. The NiO-CaO5/SiO2-Al2O3 catalyst rendered stable reusability for five consecutive runs with liquid hydrocarbon yield within the range of 66-75% with n-(C15 + C17) selectivity of 64-72%. Despite this, coke deposition was observed after several times of catalyst usage, which is due to the high deoxygenation temperature (> 300 °C) that resulted in unfavourable polymerization side reaction

Nanolayered composite with enhanced ultraviolet ray absorption properties from simultaneous intercalation of sunscreen molecules

Sumaiyah Megat Nabil Mohsin,1 Mohd Zobir Hussein,2 Siti Halimah Sarijo,3 Sharida Fakurazi,4,5 Palanisamy Arulselvan,6,7 Yun Hin Taufiq-Yap8 1Advanced Oleochemical Technology Division (AOTD), Malaysian Palm Oil Board (MPOB), Kajang, Selangor, Malaysia; 2Material Synthesis and Characterization Laboratory (MSCL), Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 3Faculty of Applied Science, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia; 4Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 5Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 6Muthayammal Centre for Advanced Research, Muthayammal College of Arts and Science, Rasipuram, Namakkal, Tamil Nadu, India; 7Scigen Research and Innovation, Periyar Technology Business Incubator, Thanjavur, Tamil Nadu, India; 8Catalysis Science and Technology Research Centre, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia Introduction: The potential of layered double hydroxide (LDH) as a host of multiple ultraviolet-ray absorbers was investigated by simultaneous intercalation of benzophenone 4 (B4) and Eusolex&reg; 232 (EUS) in Zn/Al LDH.Methods: The nanocomposites were prepared via coprecipitation method at various molar ratios of B4 and EUS.Results: At equal molar ratios, the obtained nanocomposite showed an intercalation selectivity that is preferential to EUS. However, the selectivity ratio of intercalated anions was shown to be capable of being altered by adjusting the molar ratio of intended guests during synthesis. Dual-guest nanocomposite synthesized with B4:EUS molar ratio 3:1 (ZEB [3:1]) showed an intercalation selectivity ratio of B4:EUS =53:47. Properties of ZEB (3:1) were monitored using powder X-ray diffractometer to show a basal spacing of 21.8 &Aring;. Direct-injection mass spectra, Fourier transform infrared spectra, and ultraviolet&ndash;visible spectra confirmed the dual intercalation of both anions into the interlayer regions of dual-guest nanocomposite. The cytotoxicity study of dual-guest nanocomposite ZEB (3:1) on human dermal fibroblast cells showed no significant toxicity until 25 &micro;g/mL. Conclusion: Overall, the findings demonstrate successful customization of ultraviolet-ray absorbers composition in LDH host. Keywords: biocompatibility, cell viability, dermis, layered double hydroxide, nanocomposit

Parametric characterisation of air gasification of chlorella vulgaris biomass

The gasification of green algae Chlorella vulgaris in air was investigated using both a thermogravimetric analyzer (TGA) and a bench scale horizontal axis quartz tube reactor (HQR). The full range of solid state kinetic models produced best fits with TGA results varied for the 5 subzones of conversion vs. temperature, with the nucleation and nuclei growth ‘A2’ followed by ‘A3’ or contracting volume models producing close matches for T ≤ 367 °C, zero order model between 358 and 468 °C, and contracting surface models for T ≥ 458 °C, each model yielding their set of apparent activation energy (E 0.04 s¯¹) corresponding to rate constants in the range 0.001 to 0.005 s¯¹. The HQR was used to investigate the effects of microalgal biomass loading, temperature and equivalence ratio (ER) on CnHm/CO/H₂ gas yield and composition, carbon conversion efficiency (CCE) and lower heating value (LHV) of syngas under air gasification conditions. Increasing microalgal biomass loading from 1 to 2 g led to a decrease in H2 content (24.2 to 19.5 vol. %) in the gases. An optimal temperature of 950 °C resulted in the highest H₂, CO and CH₄ yields at 2.9, 22.8 and 10.1 wt. % of biomass from a maximum gas yield of 76.1 wt. %, and highest H₂/CO ratio (1.75) and CCE of 56.3 %. The effect of ER was measured in two phases 0.1 to 0.26 and 0.26 to 35, respectively. During the first phase, the positive effect of ER performed a major part compared to second phase, so as the H₂ content, H₂ yield, CCE and LHV were increased

Synergising hydrothermal pre-treatment and biological processes for enhancing biohydrogen production from palm oil mill effluent

The high quantity of nutrient-rich palm oil mill effluent (POME) waste in the industry will have a severe negative environmental impact and a high cost of treatment. However, POME waste could be converted into bioenergy via environmentally sustainable processes. Several studies have explored using hydrothermal carbonisation for solid biomass products in biofuel production, but the potential of the liquid phase produced during these processes has received less attention. Therefore, this study aims to assess the potential of biohydrogen production from treated POME as a substrate by hydrothermal process. This study is presented in two phases: the first phase involves substrate pre-treatment using a hydrothermal process to improve biomass properties at different temperatures, and the second phase explores the potential for biohydrogen production from treated POME through dark fermentation. Substrate pre-treatment was conducted at 180, 210, and 240 °C using 100 % raw POME. Next, the treated POME was incubated for biohydrogen production at 50 °C for 24 h. A microbial analysis was conducted to determine the most dominant species present in the sample. Our findings show that at 180 °C, the total chemical oxygen demand (COD) removal efficiency was 80 %, and acetic acid concentration was 28 %. Compared to raw POME, treated POME generated a maximum hydrogen yield and rate (HPR) of 52.19 mL H2 g−1 CODrem and 0.59 mL H2 mL POME−1 day−1 with a 2.32-fold and 1.59-fold increase, respectively. Meanwhile, Clostridium was a dominant bacterial species identified in the treated POME. These findings demonstrated the feasibility of implementing a hydrothermal process to treat POME and improve its biohydrogen production efficiency. The treated POME from the hydrothermal process is more homogenous and readily consumable by microorganisms used in dark fermentation. Hydrothermal pre-treatment could potentially increase the rate and efficiency of microbial digestion, leading to enhanced hydrogen production. The high COD removal efficiency during the process significantly reduces the environmental impact of POME discharge, and converting POME into a valuable resource through the hydrothermal and dark fermentation process aligns with sustainable waste management practices

Anticancer effect of dentatin and dentatin-hydroxypropyl-&beta;-cyclodextrin complex on human colon cancer (HT-29) cell line

Ashwaq Shakir AL-Abboodi,1,2 Abdullah Rasedee,3 Ahmad Bustamam Abdul,1,4 Yun Hin Taufiq-Yap,5 Wafaa Abd Alwahed Alkaby,6 Mostafa Saddam Ghaji,7 Peter M Waziri,1,8 Mothanna Sadiq Al-Qubaisi1 1MAKNA-UPM, Cancer Research Laboratory, Institute of Bioscience, University Putra Malaysia, Serdang, Malaysia; 2Basic Science Branch, Faculty of Dentistry, University of Al-Qadisiyah, Al Diwaniyah, Iraq; 3Department of Veterinary Laboratory Diagnosis, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia; 4Department of Biomedical Science, Faculty of Medicine and Health Science, University Putra Malaysia, Serdang, Malaysia; 5Department of Chemistry, Faculty of Science, University Putra Malaysia, Serdang, Malaysia; 6Department of Biomedical, Faculty of Biotechnology, University of AL-Qadisiyah, Al Diwaniyah, Iraq; 7Department of Anatomy and Histology, Faculty of Veterinary Medicine, University of Basrah, Basrah, Iraq; 8Department of Biochemistry, Kaduna State University, Main Campus,&nbsp; Kaduna, Nigeria Introduction: Dentatin (DEN) (5-methoxy-2, 2-dimethyl-10-(1, 1-dimethyl-2propenyl) dipyran-2-one), a natural compound present in the roots of Clausena excavata Burm f, possesses pro-apoptotic and antiproliferative effects in various cancer cells. Because of its hydrophobicity, it is believed that its complexation with hydroxy-&beta;-cyclodextrin (HP&beta;CD) will make it a potent inhibitor of cancer cell growth. In the current work, the molecular mechanisms of apoptosis induced by DEN and DEN-HP&beta;CD complex were demonstrated in human colon HT-29 cancer cells.Materials and methods: After the human colon HT-29 cancer cells were treated with DEN and DEN-HP&beta;CD complex, their effects on the expression of apoptotic-regulated gene markers in mitochondria-mediated apoptotic and death receptor pathways were detected by Western blot analysis and reverse transcription polymerase chain reaction. These markers included caspases-9, 3, and 8, cytochrome c, poly (ADP-ribose) polymerase, p53, p21, cyclin A as well as the Bcl-2 family of proteins.Results: At 3, 6, 12, and 24 &micro;g/mL exposure, DEN and DEN-HP&beta;CD complex significantly affected apoptosis in HT-29 cells through the down-regulation of Bcl-2 and cyclin A in turn, and up-regulation of Bax, p53, p21, cytochrome c at both protein and mRNA levels. DEN and DEN-HP&beta;CD complex also decreased cleaved poly (ADP-ribose) polymerase and induced caspases-3, -8, and -9.Conclusion: Results of this study indicate that the apoptotic pathway caused by DEN and DEN-HP&beta;CD complex are mediated by the regulation of caspases and Bcl-2 families in human colon HT-29 cancer cells. The results also suggest that DEN-HP&beta;CD complex may have chemotherapeutic benefits for colon cancer patients. Keywords: natural products, HP&beta;CD, apoptosis, pro-apoptotic proteins, anti-apoptotic protein