Novel Solid Base Catalyst Derived from Drinking Water Defluoridation for Biodiesel Synthesis

In this study, a novel heterogeneous catalyst was synthesized from drinking water treatment sludge obtained during defluoridation in biodiesel production by transesterification. More specifically, the sludge was converted into an effective catalyst by calcination at 950 ºC for 3 h. The catalyst was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, Thermogravimetric analysis, Scanning electron microscopy, Hammett titration method, and ion exchange method. The catalyst had a basicity of 12.57 mmol/g and a basic strength of 9.8 < H <17.2. It showed good catalytic activity in biodiesel synthesis. The maximum biodiesel yield obtained was 89% for the following reaction conditions: catalyst loading of 4 wt%, a reaction temperature of 65 ºC, the methanol-to-oil molar ratio of 12:1, and reaction time of 3 h. Thus, it was found that harmful waste can be used as an effective solid base heterogeneous catalyst

Fischer–Tropsch Synthesis for Light Olefins from Syngas: A Review of Catalyst Development

Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer– Tropsch synthesis. The effects of metals, promoters and supports as the most influential parameters on the catalytic performance of catalysts are discussed meticulously. Fe and Co as the main active metals in FT catalysts are investigated in terms of pore size, crystal size, and crystal phase for obtaining desirable light olefin selectivity. Larger pore size of Fe-based catalysts is suggested to increase olefin selectivity via suppressing 1-olefin readsorption and secondary reactions. Iron carbide as the most probable phase of Fe-based catalysts is proposed for light olefin generation via FTS. Smaller crystal size of Co active metal leads to higher olefin selectivity. Hexagonal close-packed (HCP) structure of Co has higher FTS activity than face-centered cubic (FCC) structure. Transition from Co to Co3C is mainly proposed for formation of light olefins over Co-based catalysts. Moreover, various catalysts’ deactivation routes are reviewed. Additionally, techno-economic assessment of FTS plants in terms of different costs including capital expenditure and minimum fuel selling price are presented based on the most recent literature. Finally, the potential for global environmental impacts associated with FTS plants including atmospheric and toxicological impacts is considered via lifecycle assessment (LCA)

Characteristic studies on the biochars produced by hydro-thermal and steam gasification of canola hull and canola meal fuel pellets

Biochars, based on their production process and biomass precursor, can have a broad range of structural, compositional, chemical, and physical properties. These properties are important for identifying the biochar performance and stability in further applications. Non-food biomass has a great potential to produce biochars. Two inherent agricultural biomasses from Canadian prairies including canola hull and canola meal were used for the production of fuel pellets. This study provides information on the specific features of biochars produced by steam and hydro-thermal gasification of these fuel pellets compared with those of well-known pyrolysis biochars. For steam gasification, the steam to biomass ratio (SBR=0.31, 0.47, and 0.62) and gasification temperature (T=650, 750 and 850 oC) were used as the main process parameters. In contrast, for hydro-thermal (supercritical water) gasification, the effects of gasification temperature (T= 350, 450, 550, and 650 oC) were studied on the biochar properties at a constant pressure, feed concentration and reaction time. Different characterization techniques were used to study the physical, chemical, and structural characteristics of biochar products. Characterization results, for steam-gasified biochars confirmed development of aromatic carbon structure and formation of composite char. XRD spectra for biochars produced through steam gasification showed no retention of biochemical features from the parent precursors in the biochars prepared in different levels of operating conditions. FTIR spectra confirmed the rearrangement of biomass structure at the early stages of steam gasification for all used operating conditions. Elemental analysis and Van Krevelen plot showed that for pellets, the H/C and O/C atomic ratios were in the range of biomass material. However, after gasification, the these atomic ratios for biochars were in the range of them for coal material, especially lignite coal. SEM analysis showed that steam-gasified biochars had much more cracked surface as compared with hydro-thermally prepared biochars. This observation was consistent with the results of porous characteristics for biochars which showed low BET surface area (\u3c11 \u3em2/g) for hydro-thermally produced biochars but it was much larger (\u3e 400 m2/g) for steam-gasified biochars. XRD results for hydro-thermally prepared biochars at 350 oC showed the presence of cellulose I and cellulose II in the material structure, but the related peaks were not observed for the biochar prepared at hydro-thermal gasification temperature of 650 oC. For prepared biochars prepared at the highest temperature of hydro-thermal gasification, Raman analysis showed a large change in ID/IG ratio compared with that for biochar prepared at temperature of 350 oC confirming a drastic structural change in biochar structure. Results from other characterization techniques such as XRD, ICP-MS, and thermogravimetric analysis will be also discussed in the presentation. The degradation of biochars was progressive with the rise in hydro-thermal gasification temperature from 350 to 650°C. Hydro-thermally produced biochars showed characteristics of transition char at low temperature (350 oC as gasification temperature) and properties of amorphous char at high temperature (≥550 oC). For steam-gasified biochars, higher BET surface area indicated the development of composite char. It is noteworthy that characterization results showed that the steam-gasified biochars did not have the compact aromatic structure of turbostratic char and their aromatic structure is not developed as biochars produced via pyrolysis. However, properties of steam-gasified biochars showed their great potential for industrial applications such as adsorptive and/or catalytic applications. In addition, both types of biochars due to their mineral contents can be tested for agricultural applications(soil amendment and productivity)

Thermal evolution of biochar and its physicochemical properties during hydrothermal gasification

Biochar is a recalcitrant carbonaceous material obtained from pyrolysis and gasification of biomass and other biogenic wastes. Some of the promising biochar applications to be discussed in this presentation includes char gasification and combustion for energy production, soil remediation, carbon sequestration, catalysis, and development of activated carbon and specialty materials with biomedical and industrial uses. Several factors such as pyrolysis/gasification temperature, heating rates and residence time are the limiting factors that determine the biochar properties such as fixed carbon, volatile matter, mineral matter, surface area, porosity and pore size distribution, alkalinity, electrical conductivity, cation-exchange capacity, etc. This paper will comprehensively review the evolution of biochar from several lignocellulosic biomasses influenced by gasification temperature and residence time. Please click on the file below for full content of the abstract

Drug utilization study of co-administration of nonsteroidal anti-inflammatory drugs and gastroprotective agents in an orthopaedics outpatients department of a tertiary care hospital in West Bengal

Background: Non steroidal anti-inflammatory drugs (NSAIDs) are the commonly prescribed analgesic in the orthopaedics department. NSAIDs are prescribed for a long period in both acute condition (like fracture of bones, muscle injury, postoperative procedures etc) or chronic conditions (osteoarthritis etc). However, they have many adverse effects, especially gastrointestinal toxicity when use regularly. For this reason NSAIDs are frequently co-prescribed with gastro protective agents. Common gastroprotective agents are proton pump inhibitors (PPI), H2 blockers, sucralfate, antacids and misoprostol (prostaglandin analogue).Methods: A cross-sectional, unicentric drug utilization study was conducted. Prescriptions were collected from patients attending the orthopaedic outpatients department. The prescription pattern of NSAIDs, gastroprotective agents or co-administration of NSAIDS and gastroprotective agents were analyzed.Results: A total of 977 prescriptions were studied; in which 928 prescriptions contained NSAIDs with gastroprotective agents (97.92%). The most common gastroprotective agents combined with NSAIDs was H2 receptor blockers (60.56%), followed by proton pump inhibitors (PPIs) (21.65%), while antacids are prescribed least (17.78%). Misoprostol or sucralfate were not used at all.Conclusions: NSAIDs are commonly co-prescribed with gastroprotective agents in high percentage

Development of ni-co bimetallic catalyst for hydrogen generation via supercritical water gasification of lignin and waste biomass

In this study, a series of Ni, Co mono and bimetallic catalyst supported by Mg and Al were prepared and evaluated for hydrogen production from various model /waste biomass samples via SCWG process. The SCWG tests were conducted at 650 °C, 26 MPa and water to biomass ratio of five. It was found that for catalyst preparation, coprecipitation technique is better than impregnation, and the best catalyst in terms of hydrogen yield is CopCat-2Ni4Co4. The hydrogen yield from different biomass with this catalyst was found to be in the order of: Canola meal \u3e Timothy grass \u3e Wheat straw ~ Lignin \u3e Cellulose. Canola meal was identified as a promising feedstock for hydrogen production from SCWG. Also, the effect of catalyst loading on hydrogen yield was investigated.It was confirmed that high catalyst loading up to 50 wt% is desirable for hydrogen production. Please click Additional Files below to see the full abstract

Characteristic studies on the waste biomass-based biochars produced by fast pyrolysis

Biochar, as carbonaceous product obtained from pyrolysis of biomass, has many applications in diverse areas due to its versatile physicochemical properties. Non-food biomass has a great potential to produce biochars. In the present study, pinewood sawdust (forest residue), wheat straw and flax straw (agricultural residues), and poultry litter (livestock manure) were used as precursors for pyrolysis. Focus of this study was on the effects of fast pyrolysis temperature (400, 475, and 550 oC) on the characteristics of biochars produced by means of a mobile pyrolysis unit. Different characterization techniques are used to study the physical, chemical, and structural characteristics of biochar products. Please click on the file below for full content of the abstract